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Cool head question for a stock bike?


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Compression ratio, not cranking PSI determine octane needs.

 

Chariot and Noss are site sponsors, stick with them.

 

Each head has it's pros and cons. Not having to buy longer studs to use either of their products is a nice thing.

 

If you're going to advance the timing, don't go less than 21cc if you definately, positively only want to run pump gas.

 

I know people will state (they already have) someone they know runs 18cc domes on pump gas.

That's great...if the someone they know will pay for a damaged motor if you attempt to do the same, then listen to them.

 

21cc should be safe, give you a nice performance bump with the timing increase....

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Compression ratio, not cranking PSI determine octane needs.

 

Chariot and Noss are site sponsors, stick with them.

 

Each head has it's pros and cons. Not having to buy longer studs to use either of their products is a nice thing.

 

If you're going to advance the timing, don't go less than 21cc if you definately, positively only want to run pump gas.

 

I know people will state (they already have) someone they know runs 18cc domes on pump gas.

That's great...if the someone they know will pay for a damaged motor if you attempt to do the same, then listen to them.

 

21cc should be safe, give you a nice performance bump with the timing increase....

 

 

Famous last words right!....."I want to run pumpgas" lol!! For now, I want to run pumpgas just for the simple fact of availability and cost and also other mods I would have to do the be able to run race fuel. And I just don't have the money right now to do all of that. I thinkthe 21cc domes with the cool head and timing will be a nice gain and let me run the stock crank.

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If Money is that tight, which...for most of us it is, go spend 30 to 50 bucks and have someone mill .015 to .020 off your stock head.

The stock crank is an absolute ROCK, when it's properly trued and welded.

I've seen them separate in stock motors. When you tear it down for a rebuild, or...before you go crazy on some mods...good idea for a true and weld.

 

Till then, you're just playing a poker hand. Could last forever, could separate 1st or second time out.

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Only if the bearings are bad. I'd recommend new seals...

 

If you're going to go that far, save the money on the cool head and get your crank trued/welded, unless you pull it apart and find it's got bad bearings.

 

You can get a good true/weld job done on a stocker for 50 to 100 bucks.

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I have had 2 stock cranks separate on 2 diff bikes. Both bikes at the time had pipes and advanced timing only. One of them did this:

 

grenaded-banshee.jpg

 

I just recently pulled down my other bike and the crank had started to separate. Didnt grenade yet, but god only knows how long it would have been. I had planned on squeezing another trip out of the motor but for some reason got a wild hair one night and pulled it apart, im glad i did. Anyway, long story short, if i ever buy another banshee, i will weld the crank before i do anything else.

 

As far as domes, i agree with dajo, dont go any smaller than 21 cc if you plan to stay with pump gas and +4. No way in hell somebody could run 18cc domes on pump anywhere near sea level, maybe at high elevation. For referencem y new motor kicks 180 psi at sea level with 19cc domes

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  • 12 years later...

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