Suzuki GZ125 not starting and rear wheel not turning

[mistermentali...]

Hoping some one can help me figure this out, my 2003 GZ125 stopped working on way home last week and had to be trailered home.

When I try to bump start it nothing happens, the rear wheel locks but nothing else happens and it doesnt try to start in any way.

When I press the starter button there is a whine as if the starter motor is trying (it is a new starter motor fitted after bike stopped working so should be fine) and the lights dim, also the electronic speedo (an after market one added about a year ago) switches off then back on at same time as lights dim.

I am concerned my bike is unfixable and hoping I am wrong as it is my only transport, can any one give me some advice on a possible cause please?

Gears can be changed with the gear lever without issue but I guess my biggest concern is that maybe something has seized.

Thanks.

[jaffa90]

Have you tried putting it in top gear and letting the clutch out whilst pushing it to see if the engine turns over?
Is the engine oil level low?

[mistermentali...]

Thanks for quick reply. I have tried pushing in all gears but wheel stays stuck solid. It had an oil change two days before it stopped working but has full level of oil.

I am thinking maybe piston is seized?

Thanks again for quick reply.

Dave

[neptune8]

I am not saying you are an idiot, but I have met people who think that "Top Gear" means gear number 1, when in fact it means gear number 5 or 6, depending on how many gears you have. So just to be clear, try bump starting in the highest gear you have. When the bike broke down, did it lock the back wheel then?
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Enjoy yourself, its later than you think

[mistermentali...]

It's ok I know what you mean but yes I tried in all gears to bump start but first of all tried in 2nd as is what has worked before when battery went flat.

I was riding down road and the bike just cut out and slowed ro a halt so not sure if wheel locked at that point but probably did as it would not bump start nor electrical start from then on and wheel would not move so I would think that it did stop turning then.


Dave

[jaffa90]

Oh dear dear dear.
What oil did you put in.

[Tamsin]

Does the bike roll in neutral or with the clutch in?

Hate to say it, but sounds like a seized engine to me..

[bladerunner]

if the engine wont turn over..could well be seized ...drain the oil into a clean container and let it settle overnight,see if you have metal particles in it!!

top end off job and new piston/rebore may be on the cards but its not a big job on an air cooled single.

early versions of this engine had small oil galleys that would struggle to feed enough oil to the tope end,usually causing cam failure before seizure but they made them bigger kinda early 90's but were still sensitive to neglect
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Current bikes...cbr929, KDX200's, Rd125lc mk2, RGV250's

[mistermentali...]

Hi, its had small metal particles on the magnetic oil drain nut the past few times I did an oil change. If I do need to replace the piston will I need to use a piston compressor when putting new piston in?

I can change gears and have found that in fifth gear I can now get the rear wheel to move very slightly but when it does so the piston does not seem to be turning so am thinking that piston may be the issue.

Thanks for the advice, I didn't know there had been another reply or would have said something sooner. Thanks again,

Dave

[smegballs]

I'd put it in neutral, whip plug out and try turning the crank directly with a socket.

[struan80]

[struan80]

[mistermentali...]

I did try getting the cover off to crank engine before but the cover doesn't budge. I used a large allen key and even tried tapping allen key with a hammer but still doest budge so unless there is another way to get the cover off I can't try that unfortunately.

Dave

[talkToTheHat]

On the GZ/GN engine there's a steel mesh filter over the drain plug. Undo 3 bolts on the small plate surrounding the drain plug and the plate and screen can be removed.

Did you change the oil filter along with the oil? Did you put the new one in the right way round?

Get some plusgas penetrating oil. It works wonders on stubborn bolts. Spray, have cup of coffee, and boom.

I'm using allen drive bits and a ratchet or breaker bar on stubborn parts. Did the rear stub axle of a mondeo a few weeks ago, 15 years old and rusted to shit. Ok, it was torx bits but close enough. Car owner was swearing and swinging on it, asked me to bring drill and tap set. Spray, coffee, breaker bar and done.

Once diagnosed, you might find it easier to fit running engine from a crashed GZ. Note there are minor but important differences between the megaphone exhaust and cylinder exhaust carbed GZ bikes, the internal tolerances are all different. Final models were EFI and very different.

Please tell me you didn't get advised into buying 2-stroke premix oil? I had this on my older GZ (which used oil a bit), in that petrol station attendants would tell me I needed the 2T oil they sell a lot of, becasue assuming all small motorcycles work the same way. My mum killed a lawnmower this way becasue she failed to heed the giant warning sticker saying to use 10w40 car engine oil and the guy at b&q insisted she needed premix oil.
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Bandit. does. everything.

[mistermentali...]

I have tried some penetrant sprays but not seen the one you mention so will look for it, I use castrol 10w40 for my bikes oil so oil is always good quality.

Cant afford a crashed gz engine as only one I found was 479 pounds so will be trying to fix the one I have.

Will remove engine from frame and that way can work on it when I get in from work.

Hopefully it is something I can sort with the right parts and a Haynes manual.

Dave

[mistermentali...]

I have identified the problem, it needs a new crankshaft which I have now bought but no one even the Haynes manual (unless I have missed it in mine) seems to be sure what flywheel puller I need for a 2003 k3 model GZ125.

Could any one please advise me as I really need to know so I can buy the right size and type.

Thanks,

Dave

[smegballs]

Do you know what caused the crank to fail?

I wouldn't think the cranks just shit the bed and die without an underlying cause....

[mistermentali...]

The big end bearing in it has seized, it is the original so is fourteen years old so maybe it just went althoughit did turn out the camchain tensioner had seized solid and I hadn't realised so unless that affected it I think maybe it just went due to lots of use as I do an average 240 miles a week to and from work so it gets plenty of use.

Dave

[Paulf]

You could measure the thread and look on eBay for a puller, my honda fes 125 was 30 mm and could not find one, 24 mm & 27 mm seem popular. I ended up frigging it off with a three leg puller at £10 off Amazon. Good luck in your search noting that I think I saw 1 and 1.5 threads I.e. 27 x1.0 mm and 27 x 1.5 mm so be careful.

[mistermentali...]

I managed to get a thread puller and got everything back together after putting in all new springs and rollers in starter clutch but all that happens is the starter motor spins but will not start the bike.

The manual says the starter clutch should only be able to rotate one way and that if it rotates both ways, which it does although very slowly, to put new springs and rollers in....but that's already been done.

The starter clutch fits over a large sprocket but there is nothing that I can see that would connect it to that gear (it just sits over its collar which is smooth so couldn't stop it moving) so I'm hoping someone can explain how the starter clutch is meant to work when it doesn't seem connected to the sprocket in a way that would affect it?

Thanks,

Dave