these cheetahs are slow.....

[demonic shee]

I recently bought some used cheetah cylinders without the powervalves and bolted them on. my crank is 7mm my carbs are 34pjs, fmf sst's and my elevation is about 1000ft. my mains went from 135 to 178 since i upgraded the cylinders but the power is the same or less than my mildly ported stock cylinders. My builder said something about case porting wihich it doesnt seem to me that that would slow me down that much, and he also said my pipes which seems more logical to me, but im no expert any ideas anyone? it feels like about 60-65HP one other thing, i got the 68m pistons.

[banshee370]

My first question is Are those cyls set up for a 7 mil rank? Are you running a spacerplate? Whats your compression at?

[lowriderb]

it sounds like your not feeding them enough through the carbs the pipes.. also are they the big cheetah's or the cubs (just making it clear because the cheetah's can come without the power valves and the cubs dont have them at all)..

Edited March 29, 2006 by lowriderb

[rsheppick]

1 vote for your pipes needing to be replaced.

[Big Blue]

Pipes and your jetting seems rich, just because you go to a larger motor doesnt mean you jetting will need to go way up.

[NYUK]

sst `s are strangling your flow. you need som cpi. are your cylinders ported for your stroke?

[2bzy2p]

i agree with ny those are terrible pipes for that and im thinking bigger carbs than 34s

[demonic shee]

they are the actual cheetahs, the original owner of the cylinders bought them without even having the powervalve holes machines in i guess so it will be cheaper, and my thoughts were to buy them and have trinity machine powervalves into them, well i called them and they said what done is done, that sounds like a crock of shitake to me. they are 7mm cheetahs. my compression is 180lbs. i dont know the thing just feels like it doesnt have enough carb but it goes both ways because it could be the pipes, but i know the carbs are big enough to atleast get 80+hp.

[creamsickle]

your carbs are way too small. I didnt think there was a 68mm cheetah. I thought they were 73mm. I bet if you go to some duel 38s or even 35s you will gain a good 10 to 15 hp. and new pipes will give you another 10 I bet.

[lonestar]

On the stock cases the deck, did your builder fill in the voids with devcon epoxy? If he didn't that's your problem more than likely. Yamaha cut's water jackets that matches the stock cylinders on the top of the cases about a 1/4 deep they have to be filled in with epoxy. The top of the cases must be flat completely to match the cylinders. Between the cylinders on the top of the deck on the stock cases theirs water jacket wright in the middle that looks like a football that has to be filled in also thats the important one. Especially if your transfer ports are open up in that area. Your gasket will not cover that football completely.Theirs alot work to be done with the cheetha cylinders thats why they came out with the cubs. I wouldn't run it any more till you found the problem.

Edited March 29, 2006 by lonestar

[Wicked98Shee]

would go with some 38mm carbs and go with either shearer or cpi pipes .. just to be sure on the set up, ya can pull ur head and make sure the bottom of the tranferports are even with the top of the piston at BDC then check out ur squish LOL trinty is about lame as they come

Edited March 29, 2006 by Wicked98Shee

[lowriderb]

come to think of it, why not call calvin pollet (cpindustries) and talk to him about them since he is the person that makes the cylinders he can point you in a better direction..