Platinum Posted March 8, 2008 Report Share Posted March 8, 2008 I have a 06 banshee with T5's dual k&n filters and jet kit, I have a cool head on the way and was wondering what domes i should run? Quote Link to comment Share on other sites More sharing options...
rubberneck Posted March 8, 2008 Report Share Posted March 8, 2008 (edited) I have a 06 banshee with T5's dual k&n filters and jet kit, I have a cool head on the way and was wondering what domes i should run? I think in general if your crank is not welded they dont recomend smaller than 21cc domes. Smaller than that you will need to run race gas also depending on elevation Edited March 8, 2008 by rubberneck Quote Link to comment Share on other sites More sharing options...
Snopczynski Posted March 8, 2008 Report Share Posted March 8, 2008 I run 18cc domes at 184 psi compression with an unwelded crank. Quote Link to comment Share on other sites More sharing options...
scooter6101982 Posted March 8, 2008 Report Share Posted March 8, 2008 whats ur elevation snop im runnin 19s at about 600 above sea level and have 200psi of compression im thinknin the tester was aoff by some but anyway im unwelded and run 110 race fuel Quote Link to comment Share on other sites More sharing options...
rubberneck Posted March 8, 2008 Report Share Posted March 8, 2008 I thought i read somewhere that you run the risk of crank separation the more you jack the compression. I have been resisting jacking the compression on my second bike becuase i was worried about this. good to know Quote Link to comment Share on other sites More sharing options...
peak-j Posted March 8, 2008 Report Share Posted March 8, 2008 Been running 20cc domes @ 1000ft. for about year and a half, crank is not welded, and 150 psi. I run pump gas. Quote Link to comment Share on other sites More sharing options...
siksykorx7 Posted March 8, 2008 Report Share Posted March 8, 2008 (edited) i ran 19cc domes with a k&n air lid,toomey t5s and stock reeds and vp c12 race gas at about 800ft for a year and had no problems top end looked beautiful when i tore it apart,my crank is at fast now ill let ya know if anything was wrong with it when i talk to him again. Edited March 8, 2008 by siksykorx7 Quote Link to comment Share on other sites More sharing options...
Snopczynski Posted March 9, 2008 Report Share Posted March 9, 2008 My exhaust port is raised over stock, thats why my compression is lower. Crank twisiting isn't a result of compression build up. Its actually a result of popping the clutch at high rpms. Quote Link to comment Share on other sites More sharing options...
flotek Posted March 9, 2008 Report Share Posted March 9, 2008 high static compression is hard on crank bearings and worn bearings will have play and ultiamtly make an untrued cran k come apart prematurely Quote Link to comment Share on other sites More sharing options...
GASSRX Posted March 9, 2008 Report Share Posted March 9, 2008 high static compression is hard on crank bearings and worn bearings will have play and ultiamtly make an untrued cran k come apart prematurely in that case wouldnt any power mod case this problem. building more power/torque doesnt it push down on the crank harder,, timing could be an issue .. just my 2 cents Quote Link to comment Share on other sites More sharing options...
rubberneck Posted March 9, 2008 Report Share Posted March 9, 2008 high static compression is hard on crank bearings and worn bearings will have play and ultiamtly make an untrued cran k come apart prematurely So basically, if the crank and bearings are in good shape, you feel raising the compression is ok to do. I guess the only problem is in order to inspect everything and make sure it is in good shape i have to tear it down anyway. At that point i may as well true and weld it. LOL Oh well maybe ill just wait till she needs a rebuild and do it right. Quote Link to comment Share on other sites More sharing options...
rubberneck Posted March 9, 2008 Report Share Posted March 9, 2008 Crank twisiting isn't a result of compression build up. Its actually a result of popping the clutch at high rpms. That makes sense to me. Im sure all the clutching I do while hill climbing doesnt' help matters. Quote Link to comment Share on other sites More sharing options...
jmd0346 Posted March 9, 2008 Report Share Posted March 9, 2008 I run 18cc domes at 184 psi compression with an unwelded crank. I know your bike is setup for as much low end as "Banshee" possible. Did you see much topend loss with 184psi? I made a thread about this a while back but didnt get any decent answers. From my research, 150-175psi seems to be the sweet spot. Just wondering how that 184 runs. I run about 150psi but want to bump it up to 175 or so. I want to see some data or atleast some educated opinion saying its worth the difference. Quote Link to comment Share on other sites More sharing options...
Banshee Roost Posted April 19, 2008 Report Share Posted April 19, 2008 I run 19cc domes with VP 110 Leaded Race Gas! Quote Link to comment Share on other sites More sharing options...
Animalman294 Posted April 19, 2008 Report Share Posted April 19, 2008 Its the compression that determines the use of race fuel not the dome size. Now don't get me wrong the dome size mixed with the rest of your mods will increase compression requiring higher octane, but some of the responses above state that if you run this size dome you have to run race fuel. NOSS had a compression chart available and if you searched on here you would find it and it stated what elevations and what size domes put your compression over the edge for pump gas. Even 20cc domes at 3500-4000 ft would allow pump gas still, but you still need to do a compression test.............. For example: T-5's and a NOSS head with 20cc will cause you to run 50/50, because it puts you at about 150-160 and to keep it from detonating you need to run higher octane fuel, but you don't need to jump straight to 100% race fuel either. If you don't need to run race fuel it is a waste of money until you get higher compression and need it.................... Quote Link to comment Share on other sites More sharing options...
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