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20cc domes on pump gas?


jacowils

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Yeah, tell him to fucking re machine that shit. And don't pay him due to inconvenience. Guys seem to think its ok to agree with you on what you need, then just send you what's left on the shelf and hope you don't know so they can save time. If he says yeah I have "X" you damn well better get X in the mail. If he wanted more money for a custom dome he no longer stocks then it's on him to say " I don't have, it costs this much to make"

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  • 2 weeks later...

Compression Ratio=Cranking pressure. If you are 150 or lower pump fuel is fine. 160 on up you need to be careful, time for higher octane to combat DET. This is also timing based, and this part works both ways. If on the border, high compression can be offset with retarded timing, and visa/versa. 20cc may just be fine-depends on these other variables. If you think you are close keep the timing stock (don't advance it). Keep in mind 20cc is the border and can go either way for you at your elevation. The above suggestions are awesome when you are not sure- "Better safe than sorry". If you can't get 21's, then get 22's and then advance it like 4 degrees-will still run just fine for you.

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Let me see if I got this straight. Earlier you started a thread asking what kind of head you have. It was determined that it is a White Knuckle head and White Knuckle gave you their phone number. So, you ordered 21cc domes that are specific to their head, and they sent you 20cc domes, because they don't make 21 cc domes for their head anymore? That's BULLSHIT! That would be like going to McDonalds, ordering a Big Mac and have them hand you a bag with a McChicken sandwich in it because "They don't make Big Macs anymore"

It was a mistake on the machinists part and i sent them back and they had him specially make me 21's and just shipped them out to me today so it was resolved. They are good guys over at white knuckle

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Now that i have my 21's the question is how close am i going to be? Going off the noss chart it would be about 147-148 which is pretty close, but those estimates are based on a stock bore which mine is .030 over not .020 sorry for the typo, but im not sure how much that will raise the compression.

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Would you guys recommend me getting a play/dune port with my shee? How well will it pair with fmf fatty's, boyesen power reeds, .030 over with wisecos, and my cool head with 21cc domes. Deal fell thru with some dmc's so i picked up a pair of fattys and silencers for dirt cheap. Or would a trail port be better with fattys?

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^ that is a solid plan. You will have a lot of details to deal with but it doesn't all have to be done right away. However if you can manage to be patient enough to start from the cases up on the rebuild it should be more reliable and perform better.

 

Those pipes will be fine. Down the road you may wanna swap them for something else.

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dune port and fmf's/stock carbs works pretty well, was an awesome dune bike when mine was set up like that.  Word of caution though, if you decide to get it ported, get the crank welded so it doesnt seperate and machine your cases/blow out bearing's and crank seals.  i got maybe 6 trips before mine fell apart.

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I have the a VERY similar setup to what your wanting to build.....only real difference would be with me running 20cc domes as opposed to 21cc domes like you.  YOU WILL LIKE IT ALOT.  When I say its a total different beast.....it really is a totally different beast.  just make sure you get the crank welded.....I think its about $65 to have the work done.....which is serious peace of mind considering if you wipe out a crank and have to replace it you're talking at least $300 if you find a deal and it didn't hurt anything else. 

 

I wont lie.....after you get it ported....its not going to be something your just willing to pass off to a friend to give it a lap and see what he thinks.......it will make you have to say "no" to the majority of friends.  Not just cause it may be too much for them.....but because it will and can get them hurt in a hurry.  But if you run really tight trails then you're gonna be more interested in the trail port......if you run roads or fire roads or wide open trails......dune/play port from Jeff at FAST all the way.

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Would you guys recommend me getting a play/dune port with my shee? How well will it pair with

Whoever if porting your cylinders will best answer how it will work with any set up. The engine porter and you should discuss how you ride and what you want out of the bike/port work before even mailing the cylinders off.

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Whoever if porting your cylinders will best answer how it will work with any set up. The engine porter and you should discuss how you ride and what you want out of the bike/port work before even mailing the cylinders off.

My cylinders are at his shop as we speak. Jeffs a great guy and does great work.

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