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suzuki gz 125...lack of power?????

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stoke-gaz
Renault 5 Driver



Joined: 19 Sep 2012
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PostPosted: 01:17 - 19 Oct 2012    Post subject: suzuki gz 125...lack of power????? Reply with quote

Guys,

After passing my CBT 3 weeks ago, i've been allowed the use of my g/f's dads gz125, named rider on the insurance, now, i use it for the commute to work on certain days and at weekends or when g/f's dad doesn't need it, i've noticed a distinct lack of power/speed, especially on the short section of the A50 on my way to work and after going for a ride with a mate, who also has the same bike, last week, for instance, going from the A34 onto the A51, an uphill section of road, I was struggling to get up said hill in 3rd, 20mph! Struggling to get past 40mph in 5th on the A50, even dropping a gear doesn't help. I know it's only a 125 but surely it should be coping better than that?

I took the carb off last weekend to see if there was a build up of gunk, nothing, clean as a whistle, air filter looks brand new! Spoke to my dad erlier in the week, he's been a biker for years, he reckons the clutch could be slipping? Not checked plug as yet, could this be causing the problem, or is it likely to be something else?

Any advice is very much appreciated.

If it helps its a 54 plate bike with approx 13k on the clock.


Thanks in advance.
____________________
Gaz.
Ex: GZ125HS, Current: Yamaha xv535 virago, Suzuki GSF600.
CBT: passed 30/09/2012 Theory: passed 02/02/2013 MOD 1: 27/03/2013 MOD 2: 18/04/2013.......CAT A LICENCE IS MINE!!!!
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TheSmiler
World Chat Champion



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PostPosted: 01:55 - 19 Oct 2012    Post subject: Reply with quote

I'm a complete novice, you will get better answers later but there are a couple of things you could do to improve it mainly a general service, you could do with the manual if you don't know what you are doing though. Anyway;

Tyre Pressure make sure that its at the right pressure otherwise you could be riding on roughly flat tyres not good for speed. Don't use a supermarket to check tyre pressure as these are normally off.

Valve Adjustment; you can check the clearances make sure that they are at the right amount. Always good to check this.

Spark Plug; Take the plug you have and replace it with a new one, also when you take it out check the colour also whilst you are at it compare it to these. Yours is a CR8E just by googling so check you have the right plug in. http://www.dansmc.com/spark_plugs/spark_plugs_catalog.html

Carb; you have mentioned checking this have you made sure the jets are fully clean (see through the hole) if not I would do this just to check that the main or idle jet isn't slightly blocked.

Air Filter; Check see how clean it is if it has gone chuck it and get a new one if not clean it and put it back in.

Oil; To keep the bike healthy empty the oil and put new in should take about a litre. Make sure it goes in the middle of the marks on the dipstick.

Other things you could check is the chain and sprocket just to make sure they are not worn. Like I said not much of a mechanical expert but some of these should at least make it a bit healthier.
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Teflon-Mike
tl;dr



Joined: 01 Jun 2010
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PostPosted: 03:59 - 19 Oct 2012    Post subject: Reply with quote

GZ isn't fast by any stretch of the imagination.
50 reasonable
55 if you thrash it.
60, down hill with a tail wind on a good day.

Good basic service, a new plug tappet check Cam-chain tensioner adjust, oil change, air-filter clean and a new, surprisingly cartridge, oil filter on them.... will get you about as much as you can hope for.

clutch may be slipping, but if oils old or the wrong grade or its badly adjusted wont help. Still basic servicing stuff though.

Clean the front brake, and grease teh float pins, if that doesn't move freely then you can get pad drag that will slow you down, likewise clean crud out of back drum, grease cam & pivots & adjust so its on a good running clerance and not draggig as you ride.

Tyres, big tyres on them, low pressure adds a lot of extra drag.

HOW YOU RIDE IT

Back brake? adjust pedal to make sure you aren't toe resting on it and holding it on while you ride.

Thrash the engine, rev the nits off it before changing up a gear.

These things have very flat torque curves, very easy to change gear early, and be in third or forth or even fifth before 40mph, and motor will 'lug' at those speeds in that gear becouse it does actually have enough low down power to pull such tall gearing at those speeds, but it wont have enough to offer any acceleration...

If you want it to go 60, you have to rev the thing to max rpm in each gear before you change up, so you don't drop the revs back to point you dont have power for more acceleration.

3rd gear, is best gear for most work, and will probably get you up to about 50, 4th might chuck slowly up from 40 but it will be glacial, and 5th? its an over drive just to knock revs back and hold whatever road speed you have gained in the lower cogs.

Are you a car driver by any chance? Do you normally drive a diesel? If so, then I will lay odds on that its slow mainly becouse you just aren't thrashing it, and are short shifting up to higher gears at too low a revs and making the motor labour too much and never getting at where the [small] power is made up the rev range.
____________________
My Webby'Tef's-tQ, loads of stuff about my bikes, my Land-Rovers, and the stuff I do with them!
Current Bikes:'Honda VF1000F' ;'CB750F2N' ;'CB125TD ( 6 3 of em!)'; 'Montesa Cota 248'. Learner FAQ's:= 'U want to Ride a Motorbike! Where Do U start?'
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Spudly
World Chat Champion



Joined: 04 Apr 2012
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PostPosted: 07:57 - 19 Oct 2012    Post subject: Reply with quote

Hi,

I've got a GZ125 which I call a Passive Aggressor, because Marauder just doesn't fit.

Some sites quote 65mph as its top speed, others quote 55mph. Personally, I've scared myself to the point of spaghettified poo going down ever steeper hills looking for a top speed which in my case has remained firmly at 56mph.

I think the kindest way of putting it would be to say the mighty Passive Aggressor takes its cruiser background seriously. Treat it as motivation to progress on to your full licence.
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insomniac
Nova Slayer



Joined: 19 Sep 2012
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PostPosted: 14:01 - 19 Oct 2012    Post subject: My Marauder Reply with quote

Hi
I too have just past my CBT and went shopping for a bike. I managed to get a very tidy low mileage Suzuki Marauder. It looks lovely.
I thought that, after reading some sites, I would be able to get roughly 60mph out of it.
I took it out for the first time last night and managed to get 50mph.
It's not that I'm a speed freak but I just want to keep up with the traffic and not have some idiot in a car right up my tail pipe.
I think with a service I should be able to get a few more mph out of it when on the main roads. But I bought this to cruise about and take in the sights whilst getting used to operating a bike (still getting the gears wrong).
Anyway, in answer to the first question, this is a 125 so not very fast to start with, it is also based on a cruiser so is heavier and slower than a run of the mill 125. But if you keep it serviced right, as mentioned before, it should get you to around 55mph.
I dont know how to check if a clutch is slipping but again the service should highlight this.
Best of luck
____________________
Most people seem to put in when they've past what so here goes.
CBT: 16/09/12; Theory: 20/02/13 MOD1:20/05/13 MOD2:29/05/13
Suzuki Marauder GZ125; Suzuki Intruder VL800
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stoke-gaz
Renault 5 Driver



Joined: 19 Sep 2012
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PostPosted: 17:24 - 20 Oct 2012    Post subject: Reply with quote

Cheers for the replies guys,

right, from the top, carb is definitely clean, as far as i can see anyway, tyres are correct pressures, checked this morning when cold, oil is reasonably new, possibly could do with a change though, air filter, as said is clean, not checked the plug as yet, will do that when the engines cooled down, chain is now adjusted properly.

Been over to Wrexham today, about 40 miles, got there fine this morning, if a little slow, 35 ish most of the way, come to set off back to stoke and nothing, dead battery, managed to bump it but cut out a couple of miles down the road, started again and struggled in 3rd on a flat ish stretch of road, somethings definitely not right somewhere....

Thoughts please gents?
____________________
Gaz.
Ex: GZ125HS, Current: Yamaha xv535 virago, Suzuki GSF600.
CBT: passed 30/09/2012 Theory: passed 02/02/2013 MOD 1: 27/03/2013 MOD 2: 18/04/2013.......CAT A LICENCE IS MINE!!!!
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Spudly
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PostPosted: 18:36 - 20 Oct 2012    Post subject: Reply with quote

Sounds to me like more than one problem.

The charging problem could be one of three things. Well, probably more than three, but these three are the ones I would check first, in order.

1) New battery seems indicated;
2) Regulator/Rectifier could be dead or dying.
3) Alternater may need seeing to.

The power delivery problem is venturing into the mystical for me, but this is what I would check, again, in order.

Spark plug - don't just check the distance between electrodes, check to see if there are any hairline cracks in the porcelain and maybe give the electrodes a bit of a clean.

The carb is full of tubular things which reduce the jet of fuel from a liquid to a spray. If there is anything partially blocking any if these tubes, that will ultimately reduce the amount of fuel getting to the chamber. (the simplistic names for 'tubular things' is for my benefit nit yours, I have no idea what they are called)

Lastly and it might sound silly, but have a look at your sprockets and see if they have the right number of cogs - someone may have tried fiddling with them and done something odd.

Oh one more thing - it might be worth checking timing and so on, if the explosion is happening at the wrong time I imagine that would interfere with power delivery.

I find my GZ is incredibly sensitive to headwinds, but I find even me, at 20+ stone can get to 56mph given a slight incline and enough of a run up.
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ricklincs45
Nitrous Nuisance



Joined: 11 Oct 2012
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PostPosted: 19:23 - 20 Oct 2012    Post subject: Reply with quote

Gaz, if your bike is in reasonable mechanical condition, she should be able to hit at least 55mph on the flat.

Unfortunately, nothing with 12bhp is going to be quick. Anyway, as others have already said, first thing to do is ensure the bike is properly serviced.

Is the engine mechanically noisy? If so, start with that as a basis for investigation. If not, we need to look elsewhere. Does the engine burn oil/pump blue smoke from the exhaust/is it difficult to start?

If your bike is down on power, the first things I'd check would be;

1. Is the throttle fully opening? Sounds daft, I know, but it's worth making sure!

2. Does the bike have factory standard gearing? The only way to check this is to count the teeth on the gearbox and rear wheel sprockets - if someone has changed them at some point, it may be that your bike is over-geared, meaning the engine can't work as it's meant to. You can find out what standard gearing should be by ringing your local Suzuki dealer and asking nicely.

3. Is the bike down on compression? If it's done a lot of miles, it might be. The only way to remedy this is a new piston/rings and a re-bore (followed by a running-in period of around 500 miles)

If this was my own bike I'd check the gearing and compression first.

Post again if you still have problems.

Hope that helps,

Rick @ www.80bikes.com
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stoke-gaz
Renault 5 Driver



Joined: 19 Sep 2012
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PostPosted: 11:54 - 21 Oct 2012    Post subject: Reply with quote

ricklincs45 wrote:
Gaz, if your bike is in reasonable mechanical condition, she should be able to hit at least 55mph on the flat.

Unfortunately, nothing with 12bhp is going to be quick. Anyway, as others have already said, first thing to do is ensure the bike is properly serviced.

Is the engine mechanically noisy? If so, start with that as a basis for investigation. If not, we need to look elsewhere. Does the engine burn oil/pump blue smoke from the exhaust/is it difficult to start?

If your bike is down on power, the first things I'd check would be;

1. Is the throttle fully opening? Sounds daft, I know, but it's worth making sure!

2. Does the bike have factory standard gearing? The only way to check this is to count the teeth on the gearbox and rear wheel sprockets - if someone has changed them at some point, it may be that your bike is over-geared, meaning the engine can't work as it's meant to. You can find out what standard gearing should be by ringing your local Suzuki dealer and asking nicely.

3. Is the bike down on compression? If it's done a lot of miles, it might be. The only way to remedy this is a new piston/rings and a re-bore (followed by a running-in period of around 500 miles)

If this was my own bike I'd check the gearing and compression first.

Post again if you still have problems.

Hope that helps,

Rick @ www.80bikes.com


Hi Rick,

engine seems mechanically sound, runs nice and smooth, no obvious "noises", tapping etc. Doesn't seem to be buring oil, ehaust gasses seem normal, no blue smoke, starts first time on the button, apart from yesterday, which i've now figured to be my own doing, found out the hard way the bike has a parking light!!!!! Parked at my dads yesterday, put the steering lock on and must've turned the key one click too far without realising, and put the parking light on!!!! That seems to explain the flat battery!

As for the compression, although i'm not sure how to check this properly, I have, with the ignition off, put it into first and tried to move the bike forwards, can feel the resistance of the piston, so presume the compression is good as far as I can tell.

Throttle is opening up ok and fully, so can't see a problem there.

Still need to check the sprockets, will do this today and report back with my findings.

Cheers for the help so far gents, for this (hopefully) soon to be solved mystery.
____________________
Gaz.
Ex: GZ125HS, Current: Yamaha xv535 virago, Suzuki GSF600.
CBT: passed 30/09/2012 Theory: passed 02/02/2013 MOD 1: 27/03/2013 MOD 2: 18/04/2013.......CAT A LICENCE IS MINE!!!!
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ricklincs45
Nitrous Nuisance



Joined: 11 Oct 2012
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PostPosted: 13:07 - 21 Oct 2012    Post subject: Reply with quote

Gaz, glad to hear you're electrics are ok; think we've all been caught out like that at one point.

Ok, so the bike appears to be running fine, with no odd noises. If the gearing checks out as ok, there is one other thing to try. I don't know if this applies to your bike, but some bikes have an additional pump (often called an accelerator pump) on the carburettor; this is meant to provide more fuel under large/full throttle openings.

Usually you can tell if your bike has an accelerator pump because they often have two cables going to the carb - one to the main slide, the other to the pump. If yours does have the pump, it would be worth checking that the cable is adjusted properly - it could be that it isn't pumping enough fuel through.

Regarding the bike's compression, really the only accurate way to check this is with a proper compression gauge (looks a bit like a tyre pump gauge). Tbh, your local dealer would probably do this for you for less than the cost of buying a gauge and doing it yourself. It simply screws into the spark plug hole. However, if the bike is running fine and doesn't burn much/any oil, it may not be a compression issue. Still worth checking if you're still struggling though.

In one of your earlier posts you mentioned having a mate with the same bike; have you tried riding his and comparing how quick it is compared to yours? I'd certainly try this if he's happy to let you ride it - you may find there's nothing wrong with your bike, it just is what it is!

Post back if you're still struggling.

Rick @ www.80bikes.com
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Teflon-Mike
tl;dr



Joined: 01 Jun 2010
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PostPosted: 05:15 - 22 Oct 2012    Post subject: Reply with quote

Stupid questions first:-

1/ have you discounted your riding style?
Have you tried thrashing the kajeebers from the thing in every gear, reving it out as far as it will go, and wont accelerate any more before changing up, to be sure you are getting max power from it in each ratio so it will pull the next?

2/ cleaning the carburettor means taking it off, removing the float bowl from the bottom and cleaning the insides.... when you say it 'looks' clean PLEASE dont tell me that thats from a cursary glance at the outside castings!

This is what inky was trying to describe by 'tubie things'... inside teh carn are 'tubie things' called emulsion tubes, that are a tube with lots of little holes drilled in the side, air is ported to a chamber around the holes to 'froth' fuel as its drawn up the tube into the airstream to help it 'emulsify' with the air. In the bottom is a little brass plug with a tiny, usually less than 1mm diameter hole in it called a 'jet' that controls the amount of fuel that gets sucked into the emulsion tube to control mixture strength.

These are small, delicate and CRITICAL to engine operation; and these tiny holes are very easily blocked with silt or chilaque, residues left when the engine stops running & the fuel starts to evaporate.

3/ Spark-Plug / Ignition
You have not mentioned taking the spark plug out. This is the very fucking FIRST thing you do to assess an engine's 'health'.

This is a real dummy's guide for removing / refitting spark plugs - but worth a read, easy to strip a thread on a motorbike engine and is a common newbie mistake, over tightening them. How2: Replace Spark Plugs

Once you have the plug out, use this:- Sparkers Tell-Tales

The colour of the spark plug electrode, the shape & wear of teh electrodes the size of the gap can tell you more about how your engine is runing and point you towards any problem areas. Its THE first thing you do, it just is. End of. Pushing the thing along in first gear and making comments about whether it makes noises? You are STABBING IN THE DARK! Guessing, and by the sounds of it you haven't got teh first clue what you are listening for or looking for to even tell if it ought to should like it does any way!

Help us help you here; not trying to 'baby' you or put you down, but we saif get the workshop manual and do a service - you haven't done that, and seems you are looking for us to give you a magic cure-all game cheat to make all well... bikes dont work like that I'm afraid. You have to do old fashioned mechanics or pay one!

So: Spark-Plug out, compare to comparioson pics.

Carb 'off' clean it inside and before you ask, NO you cant just spray something down the inlet or into the air box or add something to the fuel! ..... well you could, but chances of it doing anything useful are fuck all.... you need to get spanners out and do mechanics.

And get a manual for your bike.

GZ from memory has a throttle position sensor on the carburettor, basically a radio volume knob carbon track potentiometer, that tells the ignition control unit what load the engine is under and changes the spark timing. Some models have it, some don't. BUT, when the track is dirty or worn, or the contacts corroded, then ignition controller can get a duff signal and retard the ignition, which will reduce power; THAT is a long shot at this stage, and a peculiarity of SOME versions of the model, and COULD be a cause, BUT we are no where NEAR that yet.

Its back to the book, and BASIC SERVICE procedures, following them to the letter, to get a base standard, RATHER than trying to be lazy or cheap and avoiding doing anything because it looks scary or expensive.

We cant help you if you wont help yourself, mate, and if you dont know what we are talking about ask; like compression test...

Pushing the bike in gear, NO thats NOT a compression test and its certainly not an accurate assessement of engine health. Neither is saying there is no blue smoke.

Compression can be low from:-

a/ worn piston rings or bore; that might be accompanies by blue smoke, it may not, you can get a significant drop in compression long before you get significant blow by and obviouse oil burn.

b/ worn valves / valve seats, incorrect valve clerances. These will NOT be accompanied by blue smoke, nor necesserily a clattery noise, especially if the valve clerances are too tight and holding valves off the valve seat so they don't seal.

Propper compression test requires the spark-plug removed.... then a pressure gauge, but like a tyre pressure gauge, with an adapter that pushes or screws into the spark plug hole on the end, and the engine spun up to pressurise the cylinder at cranking revs, throttle fully open so that something gets sucked into the cylinder to get compressed.

We cant help you from vague descriptions of stuff you are doing with half an idea about how engines work, and assurances that it 'looks' , 'sounds' or 'seems' OK.....

Work-Shop Manual, follow instructions for a full engine service; as said, you have a cam-chain tesnioner, screw and lock-nut tappets, and a park plug.

You need to get in use spanners and do some REAL mechanics to eliminate variables and be able to tell us that these things ARE 'OK', not make uneducated guesses on them.....

Problems likely to go away through doing full and propper service, but of NOT we have a base point to work from and some better DATA we can use to inform further investigations.

But we cant diagnose by telepathy nor fix by voodoo, I'm afraid.
____________________
My Webby'Tef's-tQ, loads of stuff about my bikes, my Land-Rovers, and the stuff I do with them!
Current Bikes:'Honda VF1000F' ;'CB750F2N' ;'CB125TD ( 6 3 of em!)'; 'Montesa Cota 248'. Learner FAQ's:= 'U want to Ride a Motorbike! Where Do U start?'
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stoke-gaz
Renault 5 Driver



Joined: 19 Sep 2012
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PostPosted: 00:41 - 23 Oct 2012    Post subject: Reply with quote

Teflon-Mike wrote:
Stupid questions first:-

1/ have you discounted your riding style?
Have you tried thrashing the kajeebers from the thing in every gear, reving it out as far as it will go, and wont accelerate any more before changing up, to be sure you are getting max power from it in each ratio so it will pull the next?

2/ cleaning the carburettor means taking it off, removing the float bowl from the bottom and cleaning the insides.... when you say it 'looks' clean PLEASE dont tell me that thats from a cursary glance at the outside castings!

This is what inky was trying to describe by 'tubie things'... inside teh carn are 'tubie things' called emulsion tubes, that are a tube with lots of little holes drilled in the side, air is ported to a chamber around the holes to 'froth' fuel as its drawn up the tube into the airstream to help it 'emulsify' with the air. In the bottom is a little brass plug with a tiny, usually less than 1mm diameter hole in it called a 'jet' that controls the amount of fuel that gets sucked into the emulsion tube to control mixture strength.

These are small, delicate and CRITICAL to engine operation; and these tiny holes are very easily blocked with silt or chilaque, residues left when the engine stops running & the fuel starts to evaporate.

3/ Spark-Plug / Ignition
You have not mentioned taking the spark plug out. This is the very fucking FIRST thing you do to assess an engine's 'health'.

This is a real dummy's guide for removing / refitting spark plugs - but worth a read, easy to strip a thread on a motorbike engine and is a common newbie mistake, over tightening them. How2: Replace Spark Plugs

Once you have the plug out, use this:- Sparkers Tell-Tales

The colour of the spark plug electrode, the shape & wear of teh electrodes the size of the gap can tell you more about how your engine is runing and point you towards any problem areas. Its THE first thing you do, it just is. End of. Pushing the thing along in first gear and making comments about whether it makes noises? You are STABBING IN THE DARK! Guessing, and by the sounds of it you haven't got teh first clue what you are listening for or looking for to even tell if it ought to should like it does any way!

Help us help you here; not trying to 'baby' you or put you down, but we saif get the workshop manual and do a service - you haven't done that, and seems you are looking for us to give you a magic cure-all game cheat to make all well... bikes dont work like that I'm afraid. You have to do old fashioned mechanics or pay one!

So: Spark-Plug out, compare to comparioson pics.

Carb 'off' clean it inside and before you ask, NO you cant just spray something down the inlet or into the air box or add something to the fuel! ..... well you could, but chances of it doing anything useful are fuck all.... you need to get spanners out and do mechanics.

And get a manual for your bike.

GZ from memory has a throttle position sensor on the carburettor, basically a radio volume knob carbon track potentiometer, that tells the ignition control unit what load the engine is under and changes the spark timing. Some models have it, some don't. BUT, when the track is dirty or worn, or the contacts corroded, then ignition controller can get a duff signal and retard the ignition, which will reduce power; THAT is a long shot at this stage, and a peculiarity of SOME versions of the model, and COULD be a cause, BUT we are no where NEAR that yet.

Its back to the book, and BASIC SERVICE procedures, following them to the letter, to get a base standard, RATHER than trying to be lazy or cheap and avoiding doing anything because it looks scary or expensive.

We cant help you if you wont help yourself, mate, and if you dont know what we are talking about ask; like compression test...

Pushing the bike in gear, NO thats NOT a compression test and its certainly not an accurate assessement of engine health. Neither is saying there is no blue smoke.

Compression can be low from:-

a/ worn piston rings or bore; that might be accompanies by blue smoke, it may not, you can get a significant drop in compression long before you get significant blow by and obviouse oil burn.

b/ worn valves / valve seats, incorrect valve clerances. These will NOT be accompanied by blue smoke, nor necesserily a clattery noise, especially if the valve clerances are too tight and holding valves off the valve seat so they don't seal.

Propper compression test requires the spark-plug removed.... then a pressure gauge, but like a tyre pressure gauge, with an adapter that pushes or screws into the spark plug hole on the end, and the engine spun up to pressurise the cylinder at cranking revs, throttle fully open so that something gets sucked into the cylinder to get compressed.

We cant help you from vague descriptions of stuff you are doing with half an idea about how engines work, and assurances that it 'looks' , 'sounds' or 'seems' OK.....

Work-Shop Manual, follow instructions for a full engine service; as said, you have a cam-chain tesnioner, screw and lock-nut tappets, and a park plug.

You need to get in use spanners and do some REAL mechanics to eliminate variables and be able to tell us that these things ARE 'OK', not make uneducated guesses on them.....

Problems likely to go away through doing full and propper service, but of NOT we have a base point to work from and some better DATA we can use to inform further investigations.

But we cant diagnose by telepathy nor fix by voodoo, I'm afraid.


Stupid answers first then....

1)Yeah tried that one, screams its nuts off in first, up to 2nd and screams, up to third, and so on. Still not hitting above about 45, it's that bad I got over taken by an artic on a single carrigeway road on saturday!

2)If you read my first post you would see i've had the carb off! Although i've not got down to the float and 'tube thingys' (sorry just love that description) as yet, gonna have a spannering session at the weekend.

3)Not had the plug out as yet as I can't find my plug sockets/spanners, this will be done at the weekend when i've bought some replacments AFTER PAYDAY ARRIVES! I would do it before but firstly have to go to work and secondly i'm skint!

I would have gone and bought a service manual/haynes manual if I had money, another thing to be purchased after payday!

When i have said service manual, i will do work that needs to be done and get back to you with reports, if any.

The only thing i'm not going to touch is the valves, wouldn't have a clue where to start! tips or help welcomed for this one.

Plug, oil and filters, cleaning the carb i will do at the weekend when i have some free time and some cash!

I'm not in any way trying to "be lazy or cheap", i'm trying to find a starting point to work from come the weekend when i have funds for a new plug, oil and filters!

EDIT: Cheers for the plug links, the second one will definitely come in handy.
____________________
Gaz.
Ex: GZ125HS, Current: Yamaha xv535 virago, Suzuki GSF600.
CBT: passed 30/09/2012 Theory: passed 02/02/2013 MOD 1: 27/03/2013 MOD 2: 18/04/2013.......CAT A LICENCE IS MINE!!!!
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Teflon-Mike
tl;dr



Joined: 01 Jun 2010
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PostPosted: 01:32 - 23 Oct 2012    Post subject: Reply with quote

Fair enough, but service is needed to base line it; we are fumbling in the dark till that's done.

Instructions for valve clerences are in the manual, you just need feeler guages.

HOW2: Adjust Tappets & CCT (Honda 'Benley' CB/CD/CM twins)

That's on the Super-Dream, principles much the same on the marauder motor.

If I recall the cam-chain tesnioner is on the left hand side of teh cylinder, and is slightly different, but detail instructions are in the book.

Only thing to check carefully is the actual valve clerance numbers, for YOUR year of engine; check the engine number, I seem to recall on EZ's bike we discovered that his bike had an earlier engine to the frame, and on the year of engine he had, one of other valve had a different clerance to the other.

DOES need doing though, and isn't hard. And eliminates variables.

Once the carb is clean, tappets & CCT done, spark-plug checked, and the carb tweeked for idle & mixture, at idle and on load....

Ought to have full compliment of ponies once again and problem ought to go away, but if not, at least we know where NOT to look, and it will be something like that throttle possition sensor, or something daft.

Remember, service dont mean just teh engine though; drum brake needs cleaning out & greasing, adjustment setting, front brake needs wipping off cleaning & float pins greasing; brake fluid flush may ot be a bad idea either; tyres tyre pressure, chain & sprockets, tension & lube, et etc etc. Give it thorough going over, make sure theres no extra drag from rubbing brakes or rusty chain etc.
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Last edited by Teflon-Mike on 15:30 - 23 Oct 2012; edited 1 time in total
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TheSmiler
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PostPosted: 01:57 - 23 Oct 2012    Post subject: Reply with quote

HOW2: Adjust Tappets & CCT (Honda 'Benley' CB/CD/CM twins)

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Teflon-Mike
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PostPosted: 15:32 - 23 Oct 2012    Post subject: Reply with quote

TheSmiler wrote:


Oh dear, she's NOT happy with you!
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stoke-gaz
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PostPosted: 01:46 - 31 Oct 2012    Post subject: Reply with quote

Hi guys,

Right, I got as far as removing and inspecting the plug and found it to be black! Now looking at the plug links this leads me to believe carbon fouling is the diagnosis, quoted from one of the links, Over rich fuel mixture. Check Carburettor mixture settings, float level, choke operation, air filter. Now obviously this isn't good, I have my long weekend coming up, bike isn't going to be used friday and saturday, so i'm thinking its time to get my socket set out to play and open up the carb to check for crap and the float?

Please tell me i'm on the right lines with this one?

I have the haynes manual now, still need to get a new plug as halfords didn't have any in stock. Ebay here we come!

Can get a picture up of the plug if this will be of any use in getting to the bottom of the problems....

Cheers for the help guys.
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Ex: GZ125HS, Current: Yamaha xv535 virago, Suzuki GSF600.
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Teflon-Mike
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PostPosted: 09:54 - 31 Oct 2012    Post subject: Reply with quote

stoke-gaz wrote:
Hi guys,

Right, I got as far as removing and inspecting the plug and found it to be black! Now looking at the plug links this leads me to believe carbon fouling is the diagnosis, quoted from one of the links, Over rich fuel mixture. Check Carburettor mixture settings, float level, choke operation, air filter. Now obviously this isn't good, I have my long weekend coming up, bike isn't going to be used friday and saturday, so i'm thinking its time to get my socket set out to play and open up the carb to check for crap and the float?

Please tell me i'm on the right lines with this one?

I have the haynes manual now, still need to get a new plug as halfords didn't have any in stock. Ebay here we come!

Can get a picture up of the plug if this will be of any use in getting to the bottom of the problems....

Cheers for the help guys.


You are on the right lines, and PROBABLY correct...... BUT.... before you dive in and start pulling the carb to bits......

Get a new unused plug, or soak the on eyou have in petrol for twenty minutes then scrub with a toothbrush to get it clean of carbon before cleaning contact & electrode with medium sand-paper...... GAP the plug you are going to use to correct electrode distance, & put it in.

Stick plug spanner in your pocket and go find a quiet road to play on.

Get the bike up to about 40mph under hard acceleration, throttle wide open, and while the bikes still accelerating, flick the kill switch or turn ignition off, to kill the motor, dib the clutch and coast to a halt.

Remove spark plug, have another look.

This is called a WOT Plug chop, or Wide-Open Throttle, Plug-Chop.

Colour NOW will tell you what the engine is running like WHEN you are actually riding the thing.

Taking the plug out the hole, after the bike has been sat idling on the drive, well, all its going to tell you is what its running like on idle jet, with the throttle closed & carbon fould plug could simply be saying that the chokes still on!

Proper diagnosis by plug colour needs a number of plug chops under different conditions, WOT, under acceleration, part throttle steady speed, but fast enough to be on main jet, another slow enough under load or acceleration to be on the idle jet, and then plain idle.

Corrolating results from variouse tests gives you better clue where to go looking; if ALL tests give fouled plug... you check choke linkage first!

THEN if thats fine, or after adjustment you repeat and get all black again.... you look at float height.

IF the plug colour changes under different conditions, then you are looking at worn or gummed jets / needle, maybe air-leaks, depending on colour.
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My Webby'Tef's-tQ, loads of stuff about my bikes, my Land-Rovers, and the stuff I do with them!
Current Bikes:'Honda VF1000F' ;'CB750F2N' ;'CB125TD ( 6 3 of em!)'; 'Montesa Cota 248'. Learner FAQ's:= 'U want to Ride a Motorbike! Where Do U start?'
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willopc
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PostPosted: 19:21 - 04 Nov 2012    Post subject: carburetor air intake on gz 125 marauder Reply with quote

what is the size of the air intake on the gz 125 marauder ie 35mm,36mm,38mm etc plus will it make any difference to speed and performance is their also any need for tuning what else can i do to get more topend speed and better performance
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bladerunner
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PostPosted: 01:38 - 07 Nov 2012    Post subject: Reply with quote

Teflon mike Thumbs Up
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rossi5585
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PostPosted: 14:21 - 25 Mar 2013    Post subject: Help Me - What was the Outcome Reply with quote

Dear All

I have just been reading this and was hoping for the resolution as it may be the same problem i am having.

my background ....... i have been riding for 12 years (since 16) and i now track a GSXR 600, I also have a retro NSR 125, and 2 ZX6R's (J2 & P7F) and a custon cb650 hardtail chop so its safe to say i thought i knew my way around a bike.

I purchased a 2004/5 GZ125 for my girlfriend to see if she likes it or not and booked her CBT, i got the bike as a non runner very very cheap. Within 30 mins i had the bike running and has been ever since .


Original problems (when purchased)
- Dead Spark Plug
- HT lead copper had broken down
- HT plug cap had no continuity
- but worstly the airbox was full with oil so i drained eveything 5 litres of oil and petrol mix come out of the engine, the bike has a capacity of 0.850 litres!!!!!!!!!!!!

I have now :
- changed the pug
- made up a new HT
- installed a new cap
- changed the oil filter, replaced the oil to the right level (mid way on the window when verticle.
- Changed the air filter

The bike now starts and ticks over lovely.

when riding its great in 1st and 2nd as much pull as i ever think it would have, and then looses all power it struggles to get 30-35 mph and stutters even at that.

I have checked all the obvious, brakes, clutch, spark, filters, fuel flow, any blockages air and exhuast, carb initial inspection.

still exactly the same, have tried different plugs and leads still the same.

Last night i went back out to the garage and had a nother look at the oil, its now way above full!! Petrol is making its way to the crank.

I will be checking the float tonight to see if thats stuck ipen and allowing the petrol to trickle through the system.


Any Ideas?
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stevo as b4
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PostPosted: 19:02 - 25 Mar 2013    Post subject: Reply with quote

I'm not sure what a GZ125 is? If it's some fat tyre'd custom heavy thing, then your 50-55mph might be all your going to get.

The CG125 I had a few years ago was not as fast as my mate's earlier Brazilian one, but I didn't need to rev it until the valves bounced in every gear to get an indicated 62-63mph at least on the flat. (Im 11.5st). It would hold 60mph in top on the flat and make 65mph downhill. On a long up-hill stretch on a motorway it would usually sit a 50-55mph depending on how windy it was. I don't ever remember it being down to 40mph anywhere, but then It's not that hilly in the midlands compared to some places etc. All that was with 11bhp, and I know the indicated speeds could have been 5mph or so out, but it always went alright for what it was IMO.
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FirebladeRuss
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PostPosted: 09:19 - 26 Mar 2013    Post subject: Reply with quote

I had a GZ125 initially, and looking back, it definitely wasn't the fastest thing in the world by any stretch of the imagination, but I did use it for a trip up the A3 towards london at least once a week, and I had no issues getting to 55-60 mph, and it seemed quite happy at that speed too. Confused
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dungbug
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PostPosted: 14:36 - 26 Mar 2013    Post subject: Reply with quote

I had similar problems with my old GN (same engine), is the diaphragm in the Carb OK? These do get small holes in them which buggers things up, also is the fuel flowing from the fuel tap freely? Switch the tap 'Off', pull the fuel line off and open it back up (with a cup/bottle underneath to catch the fuel), it should be a consistent 'flow' coming through.....If not the tap could be gummed up. Are you getting a nice fat blue spark from the plug as well? If the plug is black then it could be that the spark isn't strong enough, possibly duff spark plug cap or HT lead.
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paddlesat16
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PostPosted: 16:46 - 27 Mar 2013    Post subject: Reply with quote

From what i can gather with the gz125 they have been downtuned. The valve sizes are way small , i've got a K9 it has the smallest valves out of all these GS, GN and DR.

GZ valve head diameter inlet= 25.5mm exh= 22.5mm
DR/GS/GN valve head diameter inlet=30.000mm exh=26.000mm

So it's underpowered for a start and also having smaller wheels can't help. I suppose opening up the exhaust port a little might help or swapping the head from one of the other models.
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LRGy
L Plate Warrior



Joined: 21 Apr 2013
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PostPosted: 20:27 - 21 Apr 2013    Post subject: Lack of power Reply with quote

Hi

Just noticed your post about the lack of power issue - I have just purchased my wife one to do her CBT etc on and I am having exactly the same problem - did you manage to sort your problem? or have any pointers for me. I have changed the oil and filter, stripped and cleaned the carbs, cleaned the air box, checked air filter, still no joy. It climbs up to about 25 mph and then struggles, it feels like either something is holding it back or it can not get enough fuel/air.

On the side of the carb there is an electric gizmo - do you know what that does? and could that be affecting it?

I know that this bike is not going to be a speed demon but it is not running right - any help would be gratefully received. Very Happy

Thanks
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