FYI, check BDC piston/lower port clearance.

[socalscott]

Never mentioned it after discovery. My Bros. '04 300 requires a .095" base gasket set to get the piston @ BDC to fully clear the transfer ports. He used a full gasket set, + an extra big green one, a hand made one(same as the green) and still re-used some!
Man, that's quite a bit of material to remove from the head.
Later, there's plans to make a spacer, as to allow the use of only two gaskets.

Not sure how the cylinder deck specs came about. Presumed to be stock actually.

Bro. went and matched cylinder/cases, exhaust valves/ports, whittled on the main flaper, matched the exhaust spigot and polished it all up. The case/cylinder surfaces were off 3/16", cases being the issue. Better than the cylinder side.
This thing should be a 450 slayer. Gonna install the G2 throttle strait away.

[fury1]

your bros bike must have been assenbled on a holiday weekend,Ive had three motors apart from a 2000, 2003, and a 2006 and havent had to run more than the thinest gasket on any of them

[widebear]

Interesting that you should mention that Scott. A few weeks ago when I did the 300 to 250 conversion I noticed the same thing on my engine when I was checking the squish clearance. I started by stacking two gaskets, a green and a really thin yellowy one to use just as a referance point, thats when I noticed what your saying re: the port timing. Problem was even with the jug that low on the deck I still had 2mm squish clearence so I binned the thin one to up the compression, I was in a hurry because I needed the bike for the next days ride. It ran ok But I know what your saying about the potencial from blueprinting. Are you going to cnc a spacer, I'd def be interested in one or even two if you can do a batch. I'll be doing my mc engine this winter. P.S. Will you tell us what your final corrected comp ratio is? Thanks Rick

[socalscott]

Widebear,
Follow the link below, this guy actually has custom gaskets @ .057"(paper) and .035" neoprene coated aluminium! Looks like someone found an issue.

I can tell you, full correction may not be to everyones taste. A proper woods bike? no The positive here is, we are afforded broad tunabilty. The key is, getting GG-ers the heads up, so they can easily extract the P/B they desire.

http://stores.ebay.com/NORTH-TAHOE-M...dZ2QQpZ2QQtZkm