Camshaft Identification

[SamH]

Yup, just read the ADV post. So that's cool! Now I guess I've got to figure out if it's timed straight or 3* advanced. That means very little to me, I've probably misinterpreted something already.

[mattcfish]

Yup, just read the ADV post. So that's cool! Now I guess I've got to figure out if it's timed straight or 3* advanced. That means very little to me, I've probably misinterpreted something already.

I could be wrong, but I think the keyway cams designed for points, were mostly if not all 0 degree "strait" cams...same as a stock 308.
This should give a little more top end....the 3 degree cams move the curve a little lower. Your cam is unobtainium, a lucky find.
If you decide to use it make sure you read up. You need to make sure you have proper piston/valve clearance. Some have had good luck doing nothing, I deepened the intake pockets on my aftermarket pistons slightly just for a little breathing room.

[mattcfish]

So, what other "performance" bits do you have.

[Garnet]

I hope this link works:
http://www.google.ca/url?sa=t&rct=j&q=i ... 4169,d.cGE

[SamH]

Actually, now I think about it, that's really one of the main ones. The heads are dual plugged, the airbox is drilled, the swingarm is gusseted (and bent, probably because of the welding), the flywheel's lightened but that's probably stock 90S, there's 6 pistons with the bike, 2 stock and 4 new OEM. I don't think they're high comp ones though.

[SamH]

just checked the 336 cam and it's .05 out of round at the oil pump end. I'll take it to a local engine shop and see if they can build it up and true it. If not... 308 cam I guess. Or just use it as is.

[chasbmw]

Sam,

You have a typical 1970s/80s airhead hotrod. Dual plugged lightened flywheel, 336 cam, with any luck the heads may have been ported by someone who knows what they were doing.

If it all has been done right you will get a bike that is much nicer to ride than stocks and nearly as reliable.

Dual plugging requires some changes to the ignition advance curve to work properly, there are a number of modern electronic ignitions that have the correct curves available. Wossner make lightweight pistons in various oversizes at 9.5:1 CR to fit R90 barrels, which is a lot more reliable than the lightweight piston pins that may be with your bike.

It sounds fun