I am thinking of buying a coolhead but I don't know what size domes to get. I want to increase power but not decrease engine life. I run 92 octane gas, FMF gold fatties with turbine core 2 silencers, K&N filter with no airbox lid. My crank is not welded. Thanks for the help.

 

I run 21cc domes in mine with no ill effects. If you go to a 20cc or smaller dome, you will have to run race gas. The power gain is noticable in throughout the powerband, particularly in the bottom end. Is it worth the money for a coolhead? I dont know, I just got it mainly for the extra cooling effect. On a nearly stock engine like yours, you can get away with just having your stock head recut without worrying about over heating, but if you plan on getting porting or larger displacement kits, the cool head is a good idea.

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Jayson Blough '99 Banshee, '97 Warrior, '96 Blaster Yes I like Yamaha

 

I have the trinity stage4 head on my 87 w/ a 16cc dome and I run 98 octane and 40:1 klots r50 oil, and a pro design coolhead w/18cc domes on my 92 (same fuel). stock is 22cc so you wont gain much by dropping to a 21cc.my 92 has 150 lbs compression and my 87 has just over 160. some times when I know Im going to be racing up the mountain (sand mountain) I will buy some 110 octane and mix it with 92 octane 50/50. it just burns clean. but I have ran strait 92 in it and had no problems but if I do need the extra I will have It. they cool better too.


Bruce 87,92 banshees

 

I was in the same boat as yourself not long ago. Through a local dealer here in Utah, we contacted Pro Design and asked how small a dome we could go without a welded crank. They told us no less than 21 without the crank done. I bought it for the cooling more than anything, and it has worked great. I also noticed a bit more power. Hope this will help you.