Vintage Motorcycle Eccentrics

Leif and I are going to try out the Mighty 500 brake mods and see if it is up for Matawa in March. Anyone care to join us? I may even offer to loan you a bike! Sunday noonish, let me know, Doug

Dang, I'll be heading to the big city.

Have fun up there!
(Let me know if the trail to Angeles is open)

Good news and bad news. I did 3 things to the '85 KTM 500 a couple months ago to try to make it more fun and usable. I changed out the original Bing carb which was getting sloppy with a Keihin from a '90 cr250. I put yet more extra base gasket under the cylinder (now up to .045) to lower the compression to make it easier to kickstart and I fit up a rear disc brake from an '86 model, which is a fairly straightforward swap, to replace a poor o-e drum. The carb is mostly good, it is great up to the main jet and then goes a little flat- I think lean. Starting is still brutal but better for sure except that it kicked back a couple times (ouch), my older son fiddled with the timing a while back and I think it is still a little advanced. The brake was disappointing, I did the same mod to my '85 KTM 250 several years ago and it has been a great upgrade but I seem to have a few bugs in the 500 conversion. It seems kind of soft so maybe I failed to get it bled completely but the disc also seems glazed even though I sanded it when I was putting it together and used new pads. Mark- last time I was up there (Oct.) we found our way over to Mount Angeles road but that trail was blocked today and we didn't look too hard for another since Leif was getting cold. So the Mighty 500 is headed back to the rack but I still think I can get it dialed for Matawa in March.

Did you think about putting a thinner base gasket (lowering ports) and thicker head?
But probably not as easy to find.
Of course lower ports mean more corrected C/R...

Sounds like a fun project.

Mark

I took the trials bike (GasGas 280 Pro) up to the Foothills.
Had a blast!
It took me a bit to figure it out, the steering is really quick and not much suspension travel. Plus I am all goofed up with that silly rear brake operated by the foot. Whats with that?

But after a bit I got a pretty good pace going. Lots of fun doing little jumps over everything- tossing it way over turning Super late in a corner, running in 5th gear on trails I'd bein 3rd on my 300.
The gearbox has really low gears down low, then a huge jump and some high gears. But it is so torquey I could slip the clutch a bit if it got too low and get going well.
My 300 will feel like a pig!

I even found a couple of new little trails. The steep, rutty one was a bit of a challenge, sine the rut is way over the footpegs. Sort of hard to stand on pegs that are folded up.
But I found a cool reroute around one section- with some root sections I had to attack to make.
Oh yeah, had to hop several logs- one group of logs someone left a couple of bridge planks nearby, so I could go up one plank, down the other.

The only real issues I had- the bars need to be higher for extended riding and the radiator got a lot of mud in it. Plus it is a tiny radiator- so I think a mudflap on the front fender would solve it.

Mark