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Posted

I need some help here with my NOSS head setup!

First off my compression is reading 110 on each cylinder, is that normal for stock motor?

What domes would be appropriate for my compression? I'm keeping it on high octane pump gas. I have a new set of Orings on the way. Do I also need to replace the copper washers? Do I need other gaskets or silicone where all the Orings sit & cylinder surface where the head sits? Here's my mods:

 

Stock 2002 motor

Toomey 5 Pipes

V Force 3's

K&N Pods replaced the airbox

300 jets [dropping it to 290]

Temp - 75 Degrees & up!

Sea Level - Los Angeles: I ride Glamis, Dumont, Pismo Beach.

:thanks:

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Posted

Stock compression is 130, so your ok for now, some say anything below 100 at sea level and its time to think about a rebuild. 22cc domes are standard compression, i have 21's, they run fine on pump gas... i ride the same places you do :thumbsup:

Posted
Stock compression is 130, so your ok for now, some say anything below 100 at sea level and its time to think about a rebuild. 22cc domes are standard compression, i have 21's, they run fine on pump gas... i ride the same places you do :thumbsup:

What's your compression with 21cc Domes?

You making it to Pismo this weekend for the HQ gathering?

Posted

I dont think i will be able to make it.. we just went last weekend :blush: , it was a good time down there, the most rails i have seen there in a long time. I havent tested it (or run it as a matter of fact with my cool head) the other bike that i bought has the 21cc's and they run fine. i dont know compression tho, sorry lol. Have a good time out there!

Posted

Sometimes i wish i had 20 cc domes :down: these 18s steal the 55 gallon drum at $7.00+/Gal 110 seems a little low to me? but maybe i'm wrong? been so long since a had a stock motor i wouldnt know but 135 sounds good to me... have you ever redone the top end? I would use 20's in your case also. Keep us updated

 

Eric

Posted (edited)

Climb,make sure you are using a good guage sometimes the cheap ones give a false reading.I would use the 21cc domes you already have. After my last rebuild, with the 21cc domes I was at 150# on each cylinder.If your compression is actually 110 you are getting close to a rebuild.

Edited by MDS2106
Posted

I run a 20cc dome at sea level and my compression once broken in is 155psi. Compression usually drops 5-10 psi after the motor has broken in.

Posted
I run a 20cc dome at sea level and my compression once broken in is 155psi. Compression usually drops 5-10 psi after the motor has broken in.

 

I will have to disagree here, the rings are not seated when not broken in = less compression. Everytime i do a rebuild it goes up 5-10 psi if anything...

Posted

Hmmm, well that is not true. Stock I brought the bike home, put a cool head on it and started it, once warm I checked the compression with a mac gauge. Compression was 165 psi in both holes with 20cc domes. Ran it a summer and checked it again warm just before I took it apart to get ported and it was 157 psi both holes.

 

Had the bike ported and reassembled with wiseco pistons, ran it and checked it 162 psi both holes. Ran it for a weekend and checked it last saturday warm and it is 155 psi in both holes now.

 

Dont even tell me the rings are seated, I know they are.

Posted
Hmmm, well that is not true. Stock I brought the bike home, put a cool head on it and started it, once warm I checked the compression with a mac gauge. Compression was 165 psi in both holes with 20cc domes. Ran it a summer and checked it again warm just before I took it apart to get ported and it was 157 psi both holes.

 

Had the bike ported and reassembled with wiseco pistons, ran it and checked it 162 psi both holes. Ran it for a weekend and checked it last saturday warm and it is 155 psi in both holes now.

 

Dont even tell me the rings are seated, I know they are.

 

Sounds like you arn't breaking her in properly then eh? :biggrin: Nah, just always had experience with it going up, makes sense though doesnt it? When you first do a comp test before you even start her up, the rings are not seated yet, which means the rings arn't holding compression to their potential yet, after they seat (properly that is) they should infact increase your compression. To each their own opinions, no one can ever agree with eachother when it comes to engines.

 

Eric

Posted (edited)

I dont ever do a compression test without running the bike and warming it up first.

 

When I pulled the stock pistons out they had zero blow by on the ring lands.

Edited by Snopczynski

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