Pistons! Help!!!!!

RS125_Tecky · Trackday Trickster Joined: 20 Apr 2005 Karma :

I know i already posted a topic on this but this is a different Q.

I was on my RS 125 after a recent new piston kit had been fitted, when it started loosing power (going really slow in all gears) then within about 2 minutes is cut out.

It didnt cut out INSTANTlY it sounded like a bike sounds when it runs out of petrol where it gradually cuts out.

What im trying to say is, if the piston came of the conrod wouldnt the bike of cut out straight away, instantly.

But as it gradually died out could this mean ive only NIPPPED A PISTON RING.

Kickstart you will prob know Thumbs Up

Cheers

R4nger · World Chat Champion Joined: 05 Jan 2005 Karma :

Sounds like a serious engine problem like when I seized my instructor's bike. Laughing

Kickstart · The Oracle Joined: 04 Feb 2002 Karma :

Hi

It the piston came off the con rod then there would be one hell of a mess, and it would stop very suddenly and very noisily.

Was it overheating when it stopped?

All the best

Keith
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RS125_Tecky · Trackday Trickster Joined: 20 Apr 2005 Karma :

Kickstart · The Oracle Joined: 04 Feb 2002 Karma :

Hi

It could have nipped up, but hopefully not (as that would trash the piston and might trash the barrel), but doing it slowly would tend to happen from overheating and that does not seem to have happened from what you say.

Personally I would start looking through the fuel system. Open the fuel tank and check it you hear air rushing in (ie, blocked breather hose). Check for kinked fuel hoses. Clean out the fuel filter. Check nobody has turned the fuel off on you. Drain the tank just in case there is water in there (this would probably be most likely if the problem happened just after going onto reserve).

All the best

Keith
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pipnet11 · Brolly Dolly Joined: 17 Sep 2004 Karma :

You do know your supposed to run in a new piston right.......

If the piston comes away from the conron there is a VERY big bang and you can feel your wallet getting lighter by the second and your trousers filling up if you were going at any speed.
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Frost · World Chat Champion Joined: 26 May 2004 Karma :

Could you have put the ring on upside down?

You can thrash a brand new engine to hell and the chances of it seizing are very low provided it has the correct amount of oil. Running in is just good for long term engine reliability.

RS125_Tecky · Trackday Trickster Joined: 20 Apr 2005 Karma :

binge · Emo Kiddy Joined: 02 Jul 2004 Karma :

This happened to my scooter when my bottom end bearing split and was pulled through the piston. I heared a clang. Thaught nothing of it. then a few seconds later it felt like I was running out of petrol.

Can you take the barrel off yourself?

If you can. Remove the cylinder head, have a look for any bits of metal stuck to it. If the cylinder head looks clean. then pull the barrel off.
Check it, if it all seems ok, then you will probably need a new gasket kit. Although today I got away with it. I took my cylinder head off, cleaned it and put it back on wthout changing gaskets. And its running fine.

When you got the new piston put on, was the engine split and cleaned of any debre from the previous piston. (If it seized / blew up that is?)

<|Ben|>