how to ID a dome?

[EXtreme-]

I have a cool head in my hand....how can I determine what dome is currenty installed? Also, I'm told it needs new o-rings where it fits together.....part number, where to buy?

[HiperEX]

what does the dome look like if its like stock without any work done to it its probably a 21cc if it has some type of riffling its a 19cc, or take pics so we can see for sure

[HiperEX]

also push the dome out and there should be some type of numbers

[EXtreme-]

ok...found a stamped number 21 on the bottom circumference. so...21cc I assume.

the two o-rings need replaced....can I just match em up at the hardware store or is this a major ordeal?

[HiperEX]

you could probably go to a hardware store and get them id assume if they do have higher temp ones get those to be safe but i dont think it would really matter those orings are pretty tuff

[EXtreme-]

thanks...you've been a great help.

lastly....I did a search and didn't find the answer. I see the head gasket for the 86 is different from the 87-89's. Is this a thing of the past, or must they be year specific? I don't want the cr gasket either...want to run 93/94 octane. The 21cc should get me around 170lbs....right? I have an 87 and just aquired an 86. Thoughts?

[HiperEX]

not sure on teh gasket but they should all be the same and as far as what gas to run 93 is fine the 21cc dome is for pump gas, i just recently put a coolhead on my 87 with a 21cc dome and it runs like it should with 93 octane im running an athena topend kit, alot of people will say go for oem topend gasket

[koh0001]

OEM won't fit aftermarket cylinders / big bore. And most aftermarkets use the o-rings not paper.

[machwon]

I would re-use the o-rings if there not broken. The hardware o-rings for faucets will not stand up to the heat.

[dsaint77]

you can get the O-rings from Denniskirk.com

They ship to you in like 3 days with their standard shipping it would cost a total of about 30 dollars.



now I also have a question about this.

I purchased a ported cylinder off ebay and was thinking of installing a cool head for better performance. Will these cool head 21 cc domes work for a stock cylinder and run on pump gas?

I just want to install a cool head on this cylinder which a stock cylinder.

any help appreciated,

Adam