Reliability factor from high compression?

[450R_lover]

Does raising the compression to 13:1 with port and polishing the engine decrease reliability? I dont wanna sacrifice the reliability if i do this mod. Thanks for your advise

[Snoopy450r]

Im also iinterested in this to. Someone should know this.

[czrider263]

I know that if u have the wrong combo u can have problems but with my wisco and mild port i haven't had problems yet and its been 1/2 a year. BUT make sure your cylinder has the right clearences for the piston u buy. u might have to bore or recoat your cylinder for best performance and reliablity

[bwamos]

13:1 wont have any major reliablilty loss. Once you get much higher than that reliablilty loss increases on an exponential curve though.

Remember molecules and atoms have a negativly charged outer shell. So it's like pushing like charged polar ends of a magnet together. The pressure increases faster than the volume decreases.

[shamisc]

Anytime you increase compression, you lose reliability! I'm not saying it will blow up in 6 months, but it won't last as long as it would if you leave it stock. You can't have the best of both worlds! You have to meet somewhere in the middle. We've got a 13.8:1 Sparks 450r with X2 Megacycle cam, etc, etc, etc and it's been running for almost a year.

[OKTRX450R]

Reliability...ability to get on quad and just ride with nothing breaking.

With a mild comp I do not think you are giving up much reliability at all providing you perform preventitive maintenance routinely. What you are giving up is performance longevity which to me is different then reliability. With the higher comp you are going to have to work on the top end more often to maintain the same level of performance...basically IMHO the higher comps will lose compression faster then the lower. Is it still reliable, yes, but not as powerful. That is why after you install a piston it is important to do a leakdown test for a baseline and then periodically for comparison.

I feel the same about drop in cams...

[Varmit57]

I put in the JE 13.5 to 1 Piston last winter and raced it every weekend all summer with no issues. I run Hare Scrambles and MX.

It does run a bit hotter though. Check out my other mods bellow.