RD350 engine noise, cant locate

[teazer]

That is detonation for sure. I have pulled a few Wisecos out like that. Not a fault of the pistons but old ones were a bit tricky.

Please show us a picture of the other one for reference

 

[kopcicle]

Did that piston come out of the clutch or ignition side ?

~kop

 

[Spoonz]

Clutch side, it wasn't caused by the crank seal

 

[Spoonz]

There was a pin when it went in, not much of one when it came out

 

[teazer]

It has clearly overheated and detonated through lean mixture and/or too much ignition advance. Poor fuel and too little boreiston clearance could have assisted too.

Were the seals leak down tested before it ran?

Can we see the other piston please. My money is still on the wrong rings not sealing and gas blowing by and overheating the crown and skirt.

On an RD350 with too much squish clearance (unless the cylinders are machined) that's a problem.

 

[crazypj]

I had a few like that out of my Maico 490 (in the 80's)
It's when I learned a lot about racing two stroke carburation compared to modified RD400, Suzuki 250's, etc and started to become a carb 'expert' :
Mahle race pistons are way more expensive than Wiseco to replace ;D

 

[Spoonz]

That happened about 3yrs ago if I still had the other piston I would post a pic, but when the one went I tossed both to the scrap pile and chocked it up to a loss.

 

[bradj]

Spoonz if you want ill build your motors from now on

 

[Spoonz]

Brad, thanks for the offer, but I like my lower end to stay in my cases. Haven't had any problems since this other than a blown head gasket last year.

 

[teazer]

While we have been enjoying chatting with Spoonz about his meltdown, any word form the OP?