Tunrsover but not start :(

ben5883 · L Plate Warrior Joined: 08 Oct 2010 Karma :

So I hae replaced the piston, rings and all gaskets but the old cg125 back togther and it tunsover perfectly, everything seems to be working, fuel, compresion, spark. But it just wont burst into life. When using the electric start it does make a high pitch whine whilst turning over which I wasnt expecting, like something is spinning round really fast. Any ideas?

N cee thirty · Banned Joined: 31 Jan 2010 Karma :

omg there such a bastard to start when being put back together

its got a kickstart i assume,keep going for it

the starter pinion hasn't come off has it ?
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'00 Aprilia RS50 > '92 Honda CG > '99 Yamaha Fazer > '91 Yamaha RXS > '79 Suzuki X5 > 01' Honda Cg > 07' Honda Cg > 82' Kawasaki Z200 > suzuki gsxr 400 gk73a > honda vfr 400 NC30 Mod 2 Passed 09/06/2011

Jewlio Iglesias wrote: I actually did vote BNP once

ben5883 · L Plate Warrior Joined: 08 Oct 2010 Karma :

yes to the kickstart Smile

starter pinoin ? now youve lost me Embarassed

stonesie · World Chat Champion Joined: 04 Jul 2010 Karma :

Mine was a complete Arse when the carb had been off, are you sure it is getting fuel?

Also check that you have the choke off, it will never run with it fully on Thumbs Up

ben5883 · L Plate Warrior Joined: 08 Oct 2010 Karma :

as sure as i can be on the fuel, gonna try draining the carb in the morning to double check, unless u have a secret trick?

stonesie · World Chat Champion Joined: 04 Jul 2010 Karma :

Remove the spark plug and see if it looks wet, if it does then leave it out for a few minutes then re-fit and try again.

While it's out plug it back into the plug lead and hold it against the engine (insulated pliers are recommended) and spin it over to check for a spark.

P.addy · Red Rocket Joined: 14 Feb 2008 Karma :

a high pitched whine, sounds like either a duff motor or its stuck.
Could be you haven't put it back together properly.

Try kickstart and bump start anyway, also did you adjust timing? Timing on my KH125 was slightly out, albeit a 2t...it was enough to make it turn but not fire up Thumbs Up

bootsbiker · Traffic Copper Joined: 07 Jan 2009 Karma :

why did you replace the parts in th first place??
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ben5883 · L Plate Warrior Joined: 08 Oct 2010 Karma :

the ole man blew the gasket when he last rode it, and the piston was not in great shape Smile

bootsbiker · Traffic Copper Joined: 07 Jan 2009 Karma :

Did you check the cylinder head for warping.. Don't know if I am going down the wrong ally..
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ben5883 · L Plate Warrior Joined: 08 Oct 2010 Karma :

re-stripped the top again today to check all was ok, it was Sad

no cylinder warp, piston is fine and all moving spark is perfect with a new plug, all oiled valves all seated ok and offering reasonable compressiononly tested with thumb over the plug hole), carb is taking fuel. but still no start, any further ideas or do i need to be looking for a friendly garage Smile

bootsbiker · Traffic Copper Joined: 07 Jan 2009 Karma :

what does the petrol look like.. maybe water has got in the tank..
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P.addy · Red Rocket Joined: 14 Feb 2008 Karma :

change the spark plug..it may be a duff one.

How much compression has it got..a thumb test might suffice, but as its not starting id get it checked properly.

N cee thirty · Banned Joined: 31 Jan 2010 Karma :

put it back together and try to start it again,mine needed about 20 mins full on kicking it over to get it started again
____________________
'00 Aprilia RS50 > '92 Honda CG > '99 Yamaha Fazer > '91 Yamaha RXS > '79 Suzuki X5 > 01' Honda Cg > 07' Honda Cg > 82' Kawasaki Z200 > suzuki gsxr 400 gk73a > honda vfr 400 NC30 Mod 2 Passed 09/06/2011

Jewlio Iglesias wrote: I actually did vote BNP once

0ddball · World Chat Champion Joined: 15 Jul 2005 Karma :

FreshAL · Sir Crashalot Joined: 04 Jul 2005 Karma :

Start ya Bastard
https://cgi.ebay.co.uk/Nulon-Start-Ya-Bastard-400ml-Easy-Engine-Starter-SYB400-/320534712232?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item4aa15b8fa8

If that doesn't get some response, then it's likely a spark/compression/timing problem.

If it does cough, then it's probably fuel related. Did you have the carbs apart? Mixture screw in the right place? I think the CG has an accelerator pump, anyone know if that is used on starting? I'd guess no, but haven't really got a clue.

Let us know if you get it sorted

rob_scott92 · Could Be A Chat Bot Joined: 28 Mar 2009 Karma :

Did you adjust the valve clearances when you did all this??? I did mine too tight on my Honda the other week and it wouldn't run at all.

Worth checking I suppose.
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First bike: 1982 Suzuki Gs 125 'The beast MK1' Wink

> 1988 Honda Cb 350's' FOR SPORT! (Good ol' oil burner!) > 2001 Suzuki Sv 650 's' Made it out of the 80's! > 1997 Honda Cbr 600f :p

tahrey · World Chat Champion Joined: 07 Jul 2010 Karma :

The whining sounds like either starter not engaging or lack of compression to me. Have you tried bump-starting it? Pop it in 1st and see how easy it is to wheel with the clutch engaged - answer should be "not very".

Starter whizzes the crank on both my car and bike beautifully fast, smooth - and whininly - with the plug(s) out. Could be it's lost compression somewhere else - as mentioned, the head, the valves etc.

ben5883 · L Plate Warrior Joined: 08 Oct 2010 Karma :

AWESOME she lives again, put some new valves in, in the end adjusted clearances etc and started first time Smile

thanks for all the advice people. now just to get a new stud put in to secure the suspension been as i snapped it whilst putting it back together Sad