steven Posted September 8, 2009 Report Posted September 8, 2009 i got a 421 cheetah cub with 22cc domes in it.. i run c12 racing fuel in it, not a 50/50 mix.. i was wondering if the compresion would change if i put 21cc domes in..? and if i would get more power..? Quote
Building my First Posted September 8, 2009 Report Posted September 8, 2009 I think its about 12psi per cc. What compression is it at now? Quote
bbcmudtruck Posted September 8, 2009 Report Posted September 8, 2009 You would see about 10-12 psi raise in compression. You may notice a little bit more bottom end power, but thats it. Quote
johnny boy Posted September 8, 2009 Report Posted September 8, 2009 hate to hijack your tread,but were you at pismo this weekend?I raced a bike that looked alot like the one you have pictured there. Quote
steven Posted September 8, 2009 Author Report Posted September 8, 2009 hate to hijack your tread,but were you at pismo this weekend?I raced a bike that looked alot like the one you have pictured there. yes i was at pismo...i went sunday.. i was there only for the day... what bike were you running?? oh and my compresion if i could remember was around 165.. Quote
quaddad817 Posted September 8, 2009 Report Posted September 8, 2009 yes i was at pismo...i went sunday.. i was there only for the day... what bike were you running?? oh and my compresion if i could remember was around 165.. so who won??????? Quote
Flo Jo Posted September 9, 2009 Report Posted September 9, 2009 so who won??????? Ever lose any shoe laces? Quote
dajogejr Posted September 9, 2009 Report Posted September 9, 2009 It'll probably raise you compression to around 180 or so PSI. What is your timing at? Don't be afraid to crank up that timing. With race fuel and the domes you have I'd be going 9 to 10 on timing... Quote
johnny boy Posted September 9, 2009 Report Posted September 9, 2009 I had the Blue banshee.Black and white jersey,tan pants,fox blue/white helmet.We raced a couple of times.Not to be rude but if you are running a 421 cub,my bike is running extremely well. Quote
steven Posted September 12, 2009 Author Report Posted September 12, 2009 It'll probably raise you compression to around 180 or so PSI. What is your timing at? Don't be afraid to crank up that timing. With race fuel and the domes you have I'd be going 9 to 10 on timing... my timing is at +4. an wow i didnt know ican go that high on the timing.. thanks everyone for all the info... and jonny yes your bike was running crisp... i got a brand new topend and i was there to jet the bike... but it kinda ran like crap.. and i lost a pod out there so i got to tear down the topend and make sure everything looks good.. hopefully its all good.. Quote
dajogejr Posted September 12, 2009 Report Posted September 12, 2009 Cubs love timing and compression. Put 21 cc domes in it. Put the timing at 7 to begin with. Should be a very noticeable difference. You will probably have to richen up the jetting a size. More compression and timing cause more heat....need more fuel to cool that. Quote
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