Vintage Dirt Bike Q & A

I picked up a spare cylinder and head for my CR and was hoping to get it worked over before i sent it off for chrome and piston. I race this bike regularly and was hoping you guys knew of a good porter with experience with these motors who could do a mild port job on my cylinder.

Thanks!

You could always go with the factory specs for the center port barrel off of Tripes's bike that was claimed in 79 and broken down by cycle. I suspect any decent port guy could replicate it.

http://www.vintagefactory.com/Cycle6.jpg

Then maybe top it off with an "E" series ignition set up from the 79 bike, which is what Tripes ran.

hmmm, i dont have a 79 ignition. I actualy dont want to make a top end ported out motor either, i was just hoping to find someone with a decent amount of experience with the 78-80 motors that could clean up my spare cylinder before i had it re-plated.

I have a CR500R and on the http://www.bannedcr500riders.com forum, Glen Howell gets great reviews. I discussed doing a clean-up on my '79 CR250R cylinder - particularly addressing some mis-matching between the ports and the sleeve. Not done the work yet.

GSS Race Porting
Palmdale, CA
(661) 609-9272
Glen Howell
mailto:gssraceporting@aol.com

Much further back I had a conversation with Sam Alexander - who I contacted via Jastco. He will do major porting work and carb mods to make the CR250R and 40 HP 104 octane-only engine. I am sure he'd do minor work, too.

The John Astleford Company
2146-E/F West Park Court
Stone Mountain, GA 30087
USA
Phone 770-469-3926
Fax 770-469-3926

Hope this helps.

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Michael Stiles
1979 Honda CR250R Elsinore | 2006 Husqvarna SM510R | 2007 Service Honda CR500R-AF

Thank you very much!! i will run these leads down this week!!

http://www.EricGorr.com is a great and inexpensive place for porting work, crankshaft rebuilding, head mods etc...

Eric is one of the premier tuners in the United States/World and has bikes racing the Nationals, Supercross and GP's in Europe.

He's also very economical too...

He doesn't just lop 20,000ths or 30,000ths off your head, he can redesign the squish band, alther the porting in the cylinder to suit your needs etc...

A trick or "poor mans" tip is to take about 20,000ths off the head, and then run two base gaskets. It lifts the exhaust port giving more upper midrange and top end, and the milling increase the compression or returns the compresion so that the bike still pulls down low.

Peace...
Mikeee P

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The Race Isn't Over Until YOU Cross The Finish Line!