I've never checked durations before. What would I adjust for? I usually set the piston flush with the transfer ports. Then raise the exhaust port 1-2mm, then check compression and adjust head gaskets to dial in the compression. If I remember correctly on my new, untouched, replica cylinder I had 155psi with the full circle rhq crank (kickstarting it till it maxed out- and the last time I checked after lots of use it is running strong at 135ish ). Where should I be compression wise with this cylinder? This is intended as a street machine, running Ethanol free 91 octane(best pump gas available, where I'm from)
Last Edit: Apr 24, 2015 5:12:23 GMT -5 by mauibird
There's a good write up in the tech section on checking durations. I use the alternative calculating method explained at the end. 130-132 and 190 is what I was recommended on my 103cc build. Had to do some porting and shaving to get close. It would make me nervous to start opening up a port on an aluminum cylinder. Nickasil chips.
I asked my scooter guru, and he'll port the cylinder for me. He's done 100's of aluminum bore's and has built most of the fast bikes on the island. I don't think he uses a degree wheel though, but I trust him.
Cool. I'm not sure how you'd know how much material to remove without a wheel but I'd be real interested in learning his process for porting an aluminum cylinder. A member told me he used diamond burrs on his but I wasn't comfortable trying it on a new cylinder. Anyone got a junk aluminum cylinder I can practice on?
It looks like he uses a 1/2 head, carbide with a rounded end. I asked if he turns down the speed, he said he just rips em. Could be a guru secret though or decades of experience. I'll be involved with the porting process. I'll probably find 190 exhaust duration and mark a line for him. Then I'll play with the piston to get transfer durations dialed in.
I THINK I'M GOING TO ORDER A BRAND NEW LOWER/BOTTOM BEARING RACE INSTEAD OF USING THE OLD ONE OFF THE ELITE FORKS THAT I HAVE. IT WAS TOO HARD TO GET THE LAST ONE OFF. PLUS, I DON'T WANT TO HACK 'EM UP TO GET TO IT. I LIKE HAVING THEM FOR MOCK UP REASONS. SO I WAIT ANOTHER WEEK FOR THE MAIL. THATS HOW MY PROJECTS ALWAYS GO, 1 WEEK AT A TIME.
Senna1Rossi: Thanks renagade281!
May 23, 2016 14:59:12 GMT -5
Fox: I don't really know how to say this but straight. I am Dave's Girlfriend Kellilee and bluntly and VERY SADLY he passed away early Tuesday morning. I know he would want ya all to know this. Thank You Brent for befriending my love he was very happy on here!
Jun 18, 2016 16:26:04 GMT -5
Fox: www.gofundme.com/29mgf6b8 I hope it is ok to pass on his gofundme page link. If not you will un-post it I'm sure. Thanks again all!!
Jun 18, 2016 16:31:18 GMT -5