TRX250R.ORG

Workshop => Engine and Bottom End => Topic started by: Johan on December 06, 2014, 12:02:12 PM

Title: 87 stroker motor build help
Post by: Johan on December 06, 2014, 12:02:12 PM: We are trying to get compression down on an 87 stroker build and wondering if anyone knows of thick head gasket that i can order? Compression is at 205 at the moment and we dont want to run race fuel. We have had the head machined to hotrods specs and still too high.
Title: 87 stroker motor build help
Post by: Usmoneylover on December 06, 2014, 12:11:37 PM: You should tell us what setup you have right now. Hard to offer advice otherwise.
Title: 87 stroker motor build help
Post by: DnB_Racing on December 06, 2014, 12:32:24 PM: just because your at 205 psi that's not the only factor in determining your fuel what's your UCCR
http://www.macdizzy.com/compress.htm
Title: 87 stroker motor build help
Post by: Johan on December 06, 2014, 12:33:24 PM: hotrods 4ml crank, 68mm wiseco piston. stock head milled as per hotrods instructions, kranit porting, ct full exhaust (midrange)
Title: 87 stroker motor build help
Post by: Johan on December 06, 2014, 12:39:29 PM: when we put it together, it broke up top end badly no matter what jetting we ran. dumped a half can of Klotz octane booster in it and runs mint. but would like to drop compression a bit so it will stay together a little longer. im guessing the high compression is the culprit for chewing the pin bearing within 20 to 25 hrs
Title: 87 stroker motor build help
Post by: Pumashine on December 06, 2014, 01:34:20 PM: Quote from: Johan;47173
We are trying to get compression down on an 87 stroker build and wondering if anyone knows of thick head gasket that i can order? Compression is at 205 at the moment and we dont want to run race fuel. We have had the head machined to hotrods specs and still too high.

Thicker head gasket is the same as cutting your head a little deeper. If you have access to a lathe this is probably easier than finding a thicker head gasket.
Title: 87 stroker motor build help
Post by: F-Red on December 06, 2014, 04:11:40 PM: Why does Hot Rod, instruct the head milled? To increase compression?
Title: 87 stroker motor build help
Post by: Rupp250 on December 07, 2014, 01:58:33 AM: You could try a place like this. Never used them personally but have heard good things. Yes they are in Thailand. Whats the squish?

http://www.gasketstogo.com/

http://twostrokeperformance.com.au/measuring-squish-clearance/
Title: 87 stroker motor build help
Post by: C-Leigh Racing on December 08, 2014, 04:29:37 PM: Cometic Gaskets, can cut you a copper head gasket in several thicknesses. I think they can go up to 0.080".
I just dont like them though, never had good luck with them on a water cooler engine. Now an old air cooled engine, dont want to use anything else.

205 compressions not that bad, you could probably get by with a 50/50 race/pump mix, maybe less than that.
Do you understand the benifits of race gas. You dont have just any ol 4 wheel atv, man thats a TRX250R, best sport quad ever built & sold & needs to be treated as such.
Neil