CG125 rough transmission on engine over-run

BusterGonads · Trackday Trickster Joined: 18 May 2018 Karma :

Hello.

I am a late returner to biking, having ridden thousands of miles in the seventies and eighties on a few different bikes of various sizes. I gave it all up about 1995, but lately bought a quite low mileage CG125 BR for pootling about the country lanes of a summer evening. It has only got 11500 miles on it and is a 2000 model Brazil CG.

The engine works great for what it is and the gearbox, but as I run along a slightly downhill road at say about 50 mph, when the engine is kind of balanced between pulling the chain and being pushed around by it, I am getting a rough vibration through the footrests, which I think is likely the chain going tight and loose alternately on the top and bottom run as the engine sometimes is pulling and sometimes being pulled over by the rolling bike. If I shut the throttle or open it, the feeling goes.

Obviously I have adjusted the chain in the time honoured way with about 3/4 inch of slack at the tightest point on the bottom run, but this doesn't stop the issue. It feels like the chain is rucking up slightly. It is properly lubricated and defo not too tight or loose. There are no fouling marks in the chain guard and the sprockets look good.

The guy I bought it off had it laid up a good while before I got it and he said he had replaced the chain and both sprockets just before it went out of use. Looking at the chain, it looks a bit of a cheapo one with pretty rough looking rivets punched into the links.

I'm not used to the cush drive in the rear hub (I mean I can't remember them being on my old bikes) and the sprocket only looks to be held in by the circlip as I can just make it move by gripping the sprocket and wagging it. Only the movement allowed by the circlip though - not falling apart or anything.

I don't remember my old bikes doing this rough over run if the chains were adjusted so I don't think it is normal......

Any ideas Lads??

neptune8 · Nova Slayer Joined: 22 Nov 2016 Karma :

The chain may actually be tighter in one place than another. with bike on center stand [if fitted] check chain tension at different places by rotating rear wheel. Rear sprocket is as you say retained by a large circlip. A tiny bit of side play is OK, but there should not be much radial play [ hold wheel still whilst trying to turn sprocket] if there is excessive radial play the cush drive rubbers need renewing. They are a barstward to get out. Only use genuine honda ones, as pattern parts last about five minutes.
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BusterGonads · Trackday Trickster Joined: 18 May 2018 Karma :

Nobby the Bastard · Harley Gaydar Joined: 16 Aug 2013 Karma :

Modern(ish) bikes run much longer chain runs that older bikes, necessitating rubber/plastic guides above and below the swing arm so that the chain doesn't eat into the metal. Thats what you can feel the chain rubbing on.
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trevor saxe-coburg-gotha:"Remember this simple rule - scooters are for men who like to feel the breeze on their huge, flapping cunt lips."
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BusterGonads · Trackday Trickster Joined: 18 May 2018 Karma :

Tamsin · World Chat Champion Joined: 07 Mar 2014 Karma :

Get yourself onto cg125 UK owners on faceache (My group)

Crush rubbers do go on these bikes quite often but are relatively cheap and easy to replace. I can't see that they would cause the issue in question though,

I'm inclined to suggest that the chain could do with being slackened off slightly (I tend to run about 1" slack when on the stand) and checking wheel alignment. The other thing that comes to mind is that I've heard tell of some crap Chinese front sprockets that did the round a few years back which were sloppy as hell.

Edit to add, there is a "rubbing pad" on the top of the swingarm on a cg125 but a correct length and tension chain shouldn't be hitting it really

MCN · Super Spammer Joined: 22 Jul 2015 Karma :

Cheap chain has tight links/pins. If it has a split link, remove the chain and check it off the bike for tight links. You could try to oil it and work any tight links but do not be to surprised if they tighten up later.
A new chain has still to be maintained. Fitting and then storing means the chain lube can dry up.
Recommended advise for storage would be to zlobber the chain with chain lube. (Acidic Used Engine Oil as some say is not the greatest lube)
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Disclaimer: The comments above may be predicted text and not necessarily the opinion of MCN.

BusterGonads · Trackday Trickster Joined: 18 May 2018 Karma :

BusterGonads · Trackday Trickster Joined: 18 May 2018 Karma :

Tamsin · World Chat Champion Joined: 07 Mar 2014 Karma :

A new DID chain and sprockets set for the CG is less than £30 from wemoto and it's less than 30 min to fit it all without specialist tools. Stupid not to if there's any query about it really.

BusterGonads · Trackday Trickster Joined: 18 May 2018 Karma :

neptune8 · Nova Slayer Joined: 22 Nov 2016 Karma :

Well pleased you got sorted. I ride a 2002 CG for the same reasons you do. Been riding since 1963, big bikes and small. I LOVE my cg.
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Enjoy yourself, its later than you think

stephen_o · Spanner Monkey Joined: 02 Aug 2011 Karma :

I have fond memories of my CG125, the bike I did my test on and I had the same problem as the op but I passed my test the following week and then sold the bike. 20 years old it looked like it had been at the bottom of the sea but what a runner, drum brakes, stopping in the wet from 40 was not for the weak willed.
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current scoot 2009 Yamaha YBR250 + Current Pootle 2013 Nissan Leaf

Teflon-Mike · tl;dr Joined: 01 Jun 2010 Karma :

Err.. the chain's not 'new', it's just 'reportedly' little used.... there's a primary presumption to mother all effups.... It probably WAS a pretty low grade crappy chain when new, but?! Another bit of presumption....

CG's is also something of a victim of thier own reputation, that you cant go wrong with one, and they is so low maintenance... no-one does any.... 'low' is not 'no'.

Enclosed chainguards... should a 2000 model still have the fully-enclosed enclosed chain-guard?... ponder point.... OTMH they removed it about the time they went e-start only on them for cost-cutting.... and later models without cant easily have them retro-fitted.... if so, there's a can of worms there if some-one has tried.....

Meanwhile, that ruddy fully-enclosed chain was an effin pain in the arse from the off, adding to this stupid idea that 'low' is 'no'... and out-of-site-out-of-mind folk didn't bother adjusting the chain tension or adding lube until the chain was so loose it was rattling the tin.. and even then!!!! But still....

QUESTION that sprung instantly to mind, and the pertinent was.....

MCN · Super Spammer Joined: 22 Jul 2015 Karma :

You will need a new chain by the time you have read/rode all the way to the end of The Tef's post/dissertation.
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Disclaimer: The comments above may be predicted text and not necessarily the opinion of MCN.

BusterGonads · Trackday Trickster Joined: 18 May 2018 Karma :

Teflon-Mike · tl;dr Joined: 01 Jun 2010 Karma :

I'll take a guess you are probably closer to my Dad's age than mine... but curiously it was a BSA C15 that first inspired my motorcycling.... I was three, and it was red, and it had a big plastic star on the petrol tank,. and my Uncle had procured it, because 'big-bruv' kept moaning he couldn't get to and from college... 'cos my gran had told him he wasn't insured on her car anymore.... after he'd written two of them off driving under the influence.... of what... we still speculate!!!!!

My Dad hated the thing..... Given one in the 80's to chop for trials, I can empathize some!!!!! But still....

Family legend recalls that it was stolen three times, and as it wasn't suitable for carting a wife and kid around, and he was about to leave college and aught be able to afford a car.. never replaced.

In as moment of inebriation, in my 20's... the truth came out!!

The first 'Theft'... was actually that he'd parked it outside a pub in camden... got very under the influence (it was the 60's/early 70's remember!)... and a week later a helpful bobby turned up on my gran's door-step, and asked if her son would like to collect his bike from thier cop-shop! Only THEN was it reported stolen!... He couldn't remember where he'd parked the thing!

The second one, seems similar... he'd popped round to a mates and asked them to have a look at its distributor... got side tracked.... or more likely wasted.... and hitch hiked back to his mum's when he had run out of money! The thing 'may' havce been stolen from outside his mates... and may have been pushed far enough up the road to discover it wouldn't 'bump' before being dumped in a hedge.... and his mate might have reported the theft...

But dearest daddy was most disheartened to get the thing back, and within weeks it was stolen again.... this time, allegedly from outside his college, where it was allegedly chained to the iron railings....

I say alledgedly... after quarter of a century he admitted that actually he had pushed the thing into a canal, so he'd NEVER have to see the thing again.... and Mummy would have to take pitty and give him her car-keys!

She didn't!

WONDERFULLY though.... I found photo's, in my Mum's Mum's attic... actually slides, so none of the family had ever seen them.

My mum's Dad, had in 1967 bought a huge rambling old farm house on the Stratford-Birmingham road; in the summer before the shot-gun wedding, Mum & Dad had created a 'Bed-Sit' on the top floor, and Dad had left the photo's behind.

Among them, were some wonderful shots of Packwood-House.... a Nat-Trust property interesting for its priest-hole.... but I guess, since they were married at Packwood Church... shortly... very shortly.. nay, mere WEEKS before I was born..... Dad was visiting the reverend there, and they made a day of it! Church is the other side of the house's 'moat'.

Among them, though was my Mother, in a very hippy knitted... err.. I probably need say little more than 'hippy' really... Jacket? Coat? Poncho? Shawl? Who knows!!!!!!

Are you gagging at your own memories of the era's fashions yet?

Anyway, Mother-Dearest was sprawled on this red BSA C15.... with L-Plates..... oooh... naughty boy... no full licence to take her pillion....

NO!!!! There's a powder blue Vespa 90 in the back-ground!!!!!

That was my mothers... I thought she didn't get that until 1972 to commute to night-school (To do the A-Levels I made her miss out on!).. but NO! she got it that summer when she and my dad set up... well, attic together!

Curiousely, there's a photo of my father, in VERY big flares.... you know the ones where they look like jeans, but have a ruddy great triangle of corduroy or purple velvet... with gold cowboy braid sewn on!!! Inset in the leg to make them 'flare'.....

You are almost certainly feeling queezy recalling the era's fashions now!

Anyway, pre-farce-broke, when I used a slide-duplicator to make prints from all these lost slides.... THOSE disappeared from the envelkope incredibly quickly!

But not before mother revealed that actually, my Dad with Quadraphenia allussions would find reason to ride my Mum's Vespa, rather than the Beeza, quite often.... and that when she tried riding the Beeza... all hell broke loose that it wasn't 'seemly'!!!!!!!

She loved the Vespa though, and it was an early target for my learning mechanics; pulled out of a heap of scrap at the back of the garage at my Grans rambling barn-house, where it had been ignominiousely 'dumped' after my Auntie had borrowed it and been SMIDSY'd, bending the fork.

Another anecdote recounts how Auntie, after being brought off, was whisked to Solihul general... a 38DD at the age of 14, we only guess how big her assets were at 17..... when, the radiologist, asked her, in good Brumigum.... "Kin yaw tek Nikk'liuss off, luv!" cos X-=Rays and metal neclaces dont mix.... and Auntie, obligingly pulled her skirt up and removed offending 'nik-liss'!!!! Lol

But, almost a decade later, I pulled the thing out the scrap-heap, and tried to fix it. Astoundingly with some fresh petrol mixed with two-stroke in the tank, and the spark-plug cleaned the thing started up on I think the third kick! Then caused consternation, when I found the replacement forks for it, and tried to steal the wheel back off my Grandad's wheel barrow! Lol!

Beeza A65..... oooooh!

That was what the uncle who procured both the C15 and the Vespa rode..... Other attic, at other grand, had a wonderful collection of duplex primary chains hung of nails ion the rafters for one of them, as I recall!

He got it shortly before his 16th birthday as a fixer-upper, on principle he could ride it when he was 16, with the chair attached..... he was 17 by the time it ran further than the end of the drive.... and the chair relegated to lawn ornament.... until he decided to move house, when with a sofa tied on with bailer twine.... it became the favoured means of getting all his mates back from pub!

And village Bobby, apparently commented that he couldn't arrest them.... it was far too funny to watch!!!!
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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?'

BusterGonads · Trackday Trickster Joined: 18 May 2018 Karma :

Quite a tale there Taff....

On the C15 - it was fine as long as you changed the oil and didn't drive it wide open for too long. I never changed the oil, reasoning that since it leaked out pretty quickly, none of it was that old anyway, but there is a fault in that logic - mostly, that if I had drained the tank, I would have noticed the blocked up gauze oil filter and probably might have avoided a seizure of the piston one summer day while driving home to Newcastle from London at an indicated 60mph all the way to seize up - about 180 miles. The later C15 was a better engine and I had one of those too. It had a proper bearing on the timing side main instead of a bit of bronze tubing and also a roller big end. I think reliability increased a lot after they made those changes and someone at Beeza Central thought with a decent crankshaft arrangement, they could make a B25, which they did.

Vespas never appealed to me at all after my first frenzied go on a motor vehicle - an old vespa, in a back lane in Scotswood when I let out the clutch on one and opened the throttle and it lurched off with me - wildly out of control until it crashed into a bin. It was 1966; I was fifteen; uninsured; no license and not that popular with my mate afterwards.

Seventies fashion? DON'T GO THERE. You couldn't buy anything but those clown outfits, no matter how hard you tried. I did try. It was either that or go naked.

Teflon-Mike · tl;dr Joined: 01 Jun 2010 Karma :

I gave up on my C15 as a bad-job. It had a high crown piston and a lumpy cam, and consequently mashed valves; the rest of it was a right mish-mash of starfire and Street-Scrambler bits and bobs, and I recall a rather leaky two-tone glass-fibre tank, none of which fitted together properly, probably because of some notion of 'De-Lugging' going on, and substitution of atatchment points with coat-hanger wire... were't zip ties a miricle of technology, eh?

The Vespa.. I have to say was AWSOME.... it filled me with Awe every time I looked at it, and I still feel pretty awful remembering it now!

An automotive anathma, it was aparently designed by a chap at Piaggio who hated motorcycles with a loathing, and told to design one after WWII when they couldn't make bits for fighter-planes... legend suggests he sat down with a clean sheet of paper, and listed all the things that a good motorbike should have.... like big wheels... an engine in the middle... a stiff triangulated frame... and wrote "Nope" in italian next to each item! Then when he ran out of REALLY bad ideas... JUST incase 'management' persisted.. decided that if making the engine the back swing arm wasn't bad enough... off-setting it a couple of inches was obviousely a great move... and if that meant that the wheels didn't run on the same axis? FANTASTIC! No-one would be daft enough to take such an idea seriousely! Would they!?

Err... Porshe 911.... you want to make a well balenced good handling sportscar you do NOT start by chucking the engine behind the back axle in the boot! A Triumph of development over bad engineering!

So they decided to build it... and in honour of the Aeronautical connundrum of the Bumble-Bee, that defies all laws of aeronatical engineering, but flies... 'cos no-one has told the bee... translated into latin... called it the 'Wasp'

I had hours of fun from that Vespa 90.. usually plotting how to get the front wheel off the wheel-barrow without my grandad noticing.... but just looking at the thing, and wondering "WHY!?" and "How!?" the thing just should NOT have been, and most certainly shouldn't have ever worked!!! Yet, like the bumble-bee... some-how it did!!!

If it makes you feel better about crashing into the bin.... family lore recounts how my mother decided to take her motorbike test on the thing...... SOMEHOW managed to do her emergency stop on it, when the examiner stepped out infront of her (silly, SILLY man!) and told her to put it into Neutral, whilst he gave her the next set of instructions... where upon, the cable-operated gears slipped' and it jumped into drive, and WHEELIED... straight over the examiner!!!! Lol!

Funnily enough.... she failed!

AS for 70's fashion.... y-e-a-h.... I was like five.....

There aught to have been a LAW to stop anphetamine fueld hippies sticking thier kids in Kafftans and telling them they look like Jimmi Hendrix... when they are white, freckled and have bright red hair! MORE to avoid such consternation as being stuck in a check lunber-jack jacket... and bright red shorts.... with yellow piping round the pockets!!!!

And then taking PHOTO'S of them!!!!!!!!!!!!!

And FINDING said photo's forty years later.....

A-N-D showing them to 'the grandkids'!!!!!!!!!!!!!!!!!!

Care homes.... I am reading the reviews with relish!!

Vengence is mine sayeth the lord.... but I dont see why I cant get a bit of payback in the meantime!! He He He!!!
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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?'

Ste · Not Work Safe Joined: 01 Sep 2002 Karma :

Tamsin · World Chat Champion Joined: 07 Mar 2014 Karma :

For the record, from Tefs doctoral thesis on cg125 chains.....

A 2000 bike should absolutely have a fully enclose guard, only the ES 2004 on had a partial guard.

Tony, it's really very unlikely to be a total dog so don't be disheartened, the thing about cg125s is that although they are oft bodged by younguns they really aren't expensive to sort out properly.

It really does sound like a new c&s and a proper oil change (including the centrifugal oil filter inside the clutch side casing) will work wonders!

BusterGonads · Trackday Trickster Joined: 18 May 2018 Karma :

Tamsin · World Chat Champion Joined: 07 Mar 2014 Karma :

Accelerator pump is slightly fiddly but pretty straightfowards to disassemble and tidy up, that said I've never seen a perished membrane...

BusterGonads · Trackday Trickster Joined: 18 May 2018 Karma :

BusterGonads · Trackday Trickster Joined: 18 May 2018 Karma :

Fitted a new chain and sprockets with DID chain got on fleabay from Swansea Moto.

It's like a different bike.

Part of the difference is that they guy who had it before had recently fitted a chain and sprockets and had changed the over all gearing lowering it about 7%.

This was deliberate. He was a big lad and his wife was a big lass and to help out the CG he put on a 14 tooth front sprocket instead of the standard 15 tooth one. The bike is now back to CG125 Brazil W standard gearing with a 36 rear and 15 front. It has much longer legs and rides along in a much less busy fashion. Of course, I am more frequently dropping to fourth on the hills along the Military Road by Hadrian's Wall where I live. No problem with that though. I like the bike far better the way it is.

Beats me why people mess with things like gear ratio. Maybe they think the people at Honda are stupid and need some amateur bodging to make the bike good. I think the same about people messing with loud pipes and blindly re-jetting carbs which I've seen people on here suggesting would make their bike better....