Mr-unorigonal Posted April 19, 2023 Report Share Posted April 19, 2023 So I've had this bike for about a year. It's the only quad/bike I've owned and although I've leaned so much just from research and hands on I decided to take what I found and get some more experienced opinions. So this is what you are dealing with. Cheetah Cub 443, 7mm stroker. 110 octane 32/1 yamalube. 35mm TMX Mikuni carbs. 27.5 pilot 310 main on the richest clip setting. The problem is it only makes 140psi compression (cold). Being that the bike was built to run race gas those numbers seem a little low. I don't know what size domes it has but regardless it just doesn't seem right. Also the past few times I've taken it out it had started running pretty poorly (Rich) which from what I read can mean the compression is dropping. I've raised the clip 4 slots and it finally sounds happy in the mid range. I've ordered some mains and will update once I get it happy on the top end. So my question is is it possible that the bike always ran lower compression (unlikely) or is my top end going out. (Likely) This is the bike (first clip was when it was running good) and the first 3 gears were slow, was on sand geckos. The other bikes were 450's https://youtu.be/XYoRKYh0qaA Also put pictures of the pistons and the bike in there. (To big to attach) Any input would be appreciated. Thanks in advance. Quote Link to comment Share on other sites More sharing options...
caleb90 Posted April 20, 2023 Report Share Posted April 20, 2023 Did you have the motor built? It is possible some one put smaller domes in to run lower compression Quote Link to comment Share on other sites More sharing options...
Mr-unorigonal Posted April 20, 2023 Author Report Share Posted April 20, 2023 45 minutes ago, caleb90 said: Did you have the motor built? It is possible some one put smaller domes in to run lower compression The motor is built but the person who built/had it built passed away so I've had to figure it all out myself. I didn't want to pull the head if I didn't have to but I might. Are there markings on the domes that would tell me what they are? Quote Link to comment Share on other sites More sharing options...
caleb90 Posted April 20, 2023 Report Share Posted April 20, 2023 (edited) Should be marking on the domes. 24,23,22 ectect. Those numbers are the cc size of the dome. Will help figure out what your compression should be Edited April 20, 2023 by caleb90 Quote Link to comment Share on other sites More sharing options...
Jereme6655 Posted April 21, 2023 Report Share Posted April 21, 2023 Don’t be worried about pulling the head, if it has an aftermarket head there is almost a guarantee it is using o-ring style gaskets….. which are reusable as long as not damaged. Most builders who make the domes usually mark the dome size on them. Either way, you need to pop the head off to verify the domes/rebuild it if it’s tired. but depending on a few other factors, I will say 140 is low for 110. Shit I was kicking over 150 on 93pump fuel when my motor was fresh. Quote Link to comment Share on other sites More sharing options...
ClaudeMachining Posted April 21, 2023 Report Share Posted April 21, 2023 UCCR ffs!!!Envoyé de mon SM-S908W en utilisant Tapatalk Quote Link to comment Share on other sites More sharing options...
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