Melted piston?

[pattheriault]

 

 

What can cause this piston to be as bad and the other one to be in perfect shape?

 

id say around 300km on the 4mil rebuilt

 

Could a bad spark cause this? on my last ride the terminal nut came loose on the plug and it ran on 1 cyl for a short period of time.

 

 

[sheerider11]

That's a lean condition. Need to figure out why. Air leak or carb issue

[pattheriault]

yeah kind of what I figured... will need to find out why.. 

 

Would you guys go ahead and split the case to inspect for metal shaving in a situation like this? crank seems tight and in good shape.

[RagunCajun]

Did you do a leak down test before disassembly?

[pattheriault]

No i did not..

 

I suspect an air leak as my carb were cleaned when i did my rebuild but ill inspect them tomorrow

[J-Madd]

Should've done a leak down test before tear down, but we've all probably been hasty to tear one down and forgot at one point. If the bore is ok you can run a hone through it and put a new piston in there. Test for air leak before starting and also report your mods and jetting specs.

[pattheriault]

4mil, fast dune port, shearer, pod filter,.20 over,24cc dome,+4 degree, vforce 4,

 

360 main 30 pilot

[pattheriault]

Ill try to clean the jug tomorrow but they have a bit of material from the piston on them. I think ill have to bore to 65mm

[J-Madd]

Ill try to clean the jug tomorrow but they have a bit of material from the piston on them. I think ill have to bore to 65mm

May try some muratic acid on the bore. It will take the aluminum off. But I bet you're bore is scarred if that happened.

[pattheriault]

is there a trick to take the screws out to take out the little plate behind the clutch (Bearing stopper plate)?? 

 

they are in there pretty tight and im afraid to strip them in..

[sheerider11]

#3 tip and impact driver

[pattheriault]

Thanks! worked like a charm