Squeeze Play
New member
I have a 1998 SRX 700 with trail porting, shaved heads and shaved skirts. I am jetted very conservatively and retain the stock airbox with baffle board. I just noticed when I pulled my powervalves, in cylinder 3 (mag side), the piston crown is melted at the exhaust port side. It did not affect the rings thankfully, but anyone have any idea what could cause this? I did run an MBRP exhaust can last year and it ran like crap, so I put the stock can back on. I wonder if low back pressure from the can or bad gas may be to blame?
Help?
Help?
98srx6
New member
can you get pictures of the pistons and heads?
Squeeze Play
New member
I wish I had time to pull the motor apart myself, but I have a 17 month old child at home. I usually have my work done with a local yamaha tuner. I have not talked with him yet, but I hope to get many opinions so I dont do this again. The melted spot is about an inch long and looks like a waterfall. It is almost touching the ring and it looks like it was not thick enough to touch the cylinder wall. Thanks
Been der dun dat....you were lean even tho jetting seems conservative. Those mods make the engine want more fuel. 1 day with a very high barometer &you will go boom!
Wilson
New member
Turk is right fatten it up I have melted enough pistons to know .First cold day and you are toast .Bigger jets will save you big $
srx74
New member
Too Lean. Do you recall what size pilots, Mains and air jets were conservative.
Squeeze Play
New member
Thanks everyone, I will replace the piston and fatten her up.