compression is down on the sled. ring gaps are out of spec. trying to decide if i should put in some pro-lite wisecos or just re-ring the stock pistons. any advice?
M7 wiseco or re-ring stock?
- Thread starter JordanWilliams
- Start date
OEM or SPI full piston kit! not just a re ring.
X2 what he said! If the rings are actually worn that badly you probably have enough miles on it to start worrying about fatigue on the pistons. You could re-ring them, but if a piston skirt breaks off you could be in for a much more expensive fix than the cost of a couple pistons.
New OEM pistons and rings please.
why not wiseco? just wondering. put a wiseco in my dirtbike and had over 100 hours on it. I know you must let them warm up properly because of cold seize. just curious if they were any better than stock or not. never been a fan of spi...
Wiseco in a bike, no problem all day long. I don't know why, but they just never jive well with a sled. We use them once in a while, like in a big bore application where you don't have an option, or in a boosted race application because when you have a boost induced failure, they usually don't wreck the cylinders like the cast pistons do. In your case stock is best.
^^^ what he said. the Wiseco is a real nice quality piston but the oem one is way better for the job and almost all the time less money.
W
What was your compression out of curiosity?
M
pistons
Wiscos sure seem to work good in our 1000s.
Wiscos sure seem to work good in our 1000s.
S
Pro-x pistons. Just as good as oem.
compression is down to 120. id like to get it back up to 130 or higher. and yes i did a proper compression test.
S
Where are you located elevation wise? I'm at 120 a side with an Racinstation head and 13:1 domes at 5000ft in Denver.
H
You are correct the Wiseco is a very good piston and i've never had a problem with them, you are also correct about the OEM pistons, you are also correct about the cost, just paid 200.00 each for new D&D 901 pistons.
P
OEM use cast pistons because they expand and contract closer to the same rate as the cylinders that way they can run closer tolerances without cold seizure issues. It just works best for sled applications so just stick with cast OEM for best results. Back in the old days when we build race motors with forged pistons my boss used to say -- build them loose and give em juice -- longevity was not the object of the game. The pistons would expand so much at race pace that you had to go to the outer limits just to not get seized pistons. Right now we get many times the milage out of motors than what we got back in the good old days.
S
120
at 120 I would run it another season, these motors go at 5-6 on original pistons
at 120 I would run it another season, these motors go at 5-6 on original pistons
D
Maybe just time for a new sled 
:face-icon-small-ton
:face-icon-small-ton
E
^^^x2 new axys.
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