440 compression

[95xcr]

What should a 440 Trailfire have for compression to run good.

[WinnipegStPaul9]

120 psi or higher. Both cylinders need to be within 10% of each other.

DA

[95xcr]

I have 105 and 110 comp.It seems like its low on power should I put in new pistons are just a set of rings. Any help

[WinnipegStPaul9]

That's low. In my opinion you start by tearing it down to see what all is needed. As rule, we replace the pistons, not just the rings.

DA

[95xcr]

Thanks for the input on this I also adjusted the choke cable and it does run better sometimes when you get on it out of the hole it really takes off then the next time it wont hardly spin the track so does this sound like a low compression issue to you guys. Thanks for any more help.

[WinnipegStPaul9]

How new are the crankshaft seals?

DA

[95xcr]

Everything on this sled is original it starts on the second or third pull when cold otherwiseit starts up fine usually if the seals r out they wont start is what ii've been told unless u prime the system so you are thinking the seals vould cause this boggy issue I have at times.

[Matt]

Everything on this sled is original it starts on the second or third pull when cold otherwiseit starts up fine usually if the seals r out they wont start is what ii've been told unless u prime the system so you are thinking the seals vould cause this boggy issue I have at times.

Completely untrue about not starting with bad seals. It can start, run, overheat, and melt a piston. 105/110 isn't too bad IMO but if you want it to run like it should then it's time for a complete rebuild.

[JDT]

Crank seals before anything else.

Bad seals are the source on unlimited issues.

[95xcr]

Thanks Todd I may just try those just thinking the compression was a little low also.

[sledhead16]

I usually like to see 120+ as well, if you want to invest time and money in it, get all new gaskets and seals and a set of spi pistons kits for it. Piece of mind is a wonderful thing.