highroller355 Posted September 22, 2008 Report Share Posted September 22, 2008 what do you think stock 421 4 mil cub, clean up port with all gooodies 39 pwk billet bowls and so on shold i do it Quote Link to comment Share on other sites More sharing options...
Bansh-eman Posted September 22, 2008 Report Share Posted September 22, 2008 you ride on asphalt right? any noise restrictions? If not I would say go for it. I wish I had done it along time ago. Quote Link to comment Share on other sites More sharing options...
yfzdunejumper Posted September 22, 2008 Report Share Posted September 22, 2008 It will be faster with out of frames no dought about that. Quote Link to comment Share on other sites More sharing options...
okbeast Posted September 22, 2008 Report Share Posted September 22, 2008 Yes and sell me those... :biggrin: Quote Link to comment Share on other sites More sharing options...
highroller355 Posted September 22, 2008 Author Report Share Posted September 22, 2008 Yes and sell me those... :biggrin: you might have a set of in frames soon okbeast. just have to find out whats a good brand and so on. anymore input welcome, thanks again Quote Link to comment Share on other sites More sharing options...
wacko2000 Posted September 23, 2008 Report Share Posted September 23, 2008 you have stock jugs on that bike? if so how do you get 421? I think im confused..lol Quote Link to comment Share on other sites More sharing options...
okbeast Posted September 23, 2008 Report Share Posted September 23, 2008 OOF shearers, CPI's, RDZ, GRR, etc. etc. All seem to make great pipes. Quote Link to comment Share on other sites More sharing options...
Bansh-eman Posted September 23, 2008 Report Share Posted September 23, 2008 talk to who ported the motor and see what they recommend Quote Link to comment Share on other sites More sharing options...
dajogejr Posted September 25, 2008 Report Share Posted September 25, 2008 I'm going to go out on a total limb here.... I say CPI or RDZ. I love my Shearer pipes... But he's moving a heavy bike down the pavement, more hook, etc. CPI and RDZ make more power in lower RPMs than Shearer....if you believe all the dyno sheets you run. Seeing as you have over 200PSI, this motor, IMO, is not going to rev to the moon, so...get a pipe that will make more power in the RPMs it will turn. From what I've seen and read, RDZ or CPI would be a good choice.... Quote Link to comment Share on other sites More sharing options...
J-Madd Posted September 25, 2008 Report Share Posted September 25, 2008 I've got RDZs on a 421 Cub, and Shearers on a 392 Cub. I love both of them. Can't compare the 2 on those different motors b/c they (the motors) rev and pull completely different. Buy the ones you can find the best deal on. I bought the RDZs new, bare for $550(?), and you can find chrome, used RDZs, CPIs, Shearers, all day long in the $400s. 200 psi? Isn't that a little much for a drag racing engine? I like 180 psi, some guys even like 160 psi. Quote Link to comment Share on other sites More sharing options...
highroller355 Posted September 25, 2008 Author Report Share Posted September 25, 2008 not to sure if its alot for a motor, my motor has really no port work, just a quick clean up. 1st 1 im building jeff told me to run his 20 cc cut domes and it would have around 200 to 210. not to sure whats what, or what im suppose to have. still wet behind the ears, all input welcome and appreciated, also i need small bore correct, Quote Link to comment Share on other sites More sharing options...
okbeast Posted September 25, 2008 Report Share Posted September 25, 2008 I'd be really surprised if you had 200+psi with 20cc domes. Definately depends on who cuts the domes, but I have some 18cc domes with a .020 base gasket and only have in the 165psi range, definately shows a difference in who cuts them. Quote Link to comment Share on other sites More sharing options...
dajogejr Posted September 25, 2008 Report Share Posted September 25, 2008 I have about 185PSI on 20cc domes with very generous squish (.056 ) It is very possible. But check for yourself...take NOTHING for granted. Quote Link to comment Share on other sites More sharing options...
J-Madd Posted September 25, 2008 Report Share Posted September 25, 2008 not to sure if its alot for a motor, my motor has really no port work, just a quick clean up. 1st 1 im building jeff told me to run his 20 cc cut domes and it would have around 200 to 210. not to sure whats what, or what im suppose to have. still wet behind the ears, all input welcome and appreciated, also i need small bore correct, My 421 is from Jeff,with minimal porting with his 20cc domes. 180 psi with fresh rings, 155 with worn out rings. 300 ft elev. Quote Link to comment Share on other sites More sharing options...
highroller355 Posted September 26, 2008 Author Report Share Posted September 26, 2008 200 to 205 comp. with i think 48 squish. check it last night. jeff talked to my friend and said he would like me to have less comp also. i have a race on sunday, if it holds together i will be changing things up afterwards. Quote Link to comment Share on other sites More sharing options...
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