Thursday, May 19, 2011

YZ134....Version 3.1?

Actually, it's hard to figure which version we're looking at right now. It started out as a motocross bike. Then it was lowered and raced as a flattracker, with a 19" spool wheel on the front. We bought it in that phase, with the original 21" front wheel and brake as spare parts.

As Scott grew, we raised the suspension a little, but he still grew out of the bike, and it became a little obsolete as a flattracker, so we thought we'd try some Super Motard racing with it. I pieced together some 17" rims and hubs, sent them off to get laced up and reinstalled the front brake. It became a fun little supermoto bike. I guess you could call that phase/version 3. We raced it successfully in both supermoto and some indoor shorttrack events.

But that only lasted for a little while before we realized that we wanted to use the bike for some woods/moto riding. On went the 21" spare wheel and a proper pair of dirtbike tires, the suspension was returned to full length. Back to phase 1, but with some mods.

After that I got interested in ice riding/racing, so a spare set of wheels was obtained through ebay, and ice tires built. I tried a few different tires, and in fact I'm still working on that set-up. The engine was due for a top end, and I decided to go with an overbore kit from Eric Gorr's Forward Motion. We'll call it phase/version 4.

As you may see from previous posts, this has been the most difficult phase in terms of jetting and performance. I've managed to blow the top end several times, whereas previously the bike didn't seem to care too much about what it was doing. Riding/racing in cold temps requires much more attention to jetting, and I'm afraid I wasn't attending to the finer points as much as I should have been. Live and learn.
Anyway, after the last episode, Eric Gorr very kindly honed the cylinder for me, and sent it back with a fresh piston and gasket set, and some sage advise about proper jetting. I put it back together and decided I'd mount the S/M wheels for now, since we may want to race it in June with that set-up.

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