twizted269 Posted January 28, 2009 Report Posted January 28, 2009 getting a cool head and want to get the dome size right. running 93 octane pump gas, bored 40 over, piped and jetted right. elavation is around 600 to 700 im guessing. mostly trail ridding no racing. i think 21 cc would be fine but want the expert opinion here. im just looking for better cooling. engine runs hot and spits a little coolant every now and again. not boiling just a little spurt. any help would be great. thanks. Quote
magz Posted January 28, 2009 Report Posted January 28, 2009 getting a cool head and want to get the dome size right. running 93 octane pump gas, bored 40 over, piped and jetted right. elavation is around 600 to 700 im guessing. mostly trail ridding no racing. i think 21 cc would be fine but want the expert opinion here. im just looking for better cooling. engine runs hot and spits a little coolant every now and again. not boiling just a little spurt. any help would be great. thanks. im running 20cc domes on mine, 700 elev, on 93 octane with no problems, im ported but i had 20's on it when i wasnt ported too... Quote
twizted269 Posted January 28, 2009 Author Report Posted January 28, 2009 im running 20cc domes on mine, 700 elev, on 93 octane with no problems, im ported but i had 20's on it when i wasnt ported too... what compression are you running? i heard that you need to be around 150 or lower for pump gas. just dont wanna blow it again. gets expensive!!! lol. Quote
magz Posted January 28, 2009 Report Posted January 28, 2009 what compression are you running? i heard that you need to be around 150 or lower for pump gas. just dont wanna blow it again. gets expensive!!! lol. mines got 135psi compression, but its cause of my port work. 20's should put you right around the 150 mark, some people say 150psi some people say over 160 some people say 155 to 160....so....its all on how safe you want to play it. id say go with 20s i think youd be fine, if you want to play is safer get 21's Quote
twizted269 Posted January 28, 2009 Author Report Posted January 28, 2009 mines got 135psi compression, but its cause of my port work. 20's should put you right around the 150 mark, some people say 150psi some people say over 160 some people say 155 to 160....so....its all on how safe you want to play it. id say go with 20s i think youd be fine, if you want to play is safer get 21's a buddy of mine has one with 21s that looks damn good for 150 so i think its a great price. just wanted to see how good it would match my needs. thanks. Quote
twizted269 Posted January 28, 2009 Author Report Posted January 28, 2009 also would this affect my jetting? or will it still burn as it is with a stock head? i know it will give it higher compression but dont know what else will need to be done. Quote
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