Shake-Down Rides

So I thought I would finish the "Project RD400 Racer" in one summer, what a joke. I'll never finish, I'll just keep tinkering!

I reset the MZ ignition back to 2mm BTDC and the bike runs fine on hi-octane pre-mix. The powerband is still as extreme as ever, but the 2mm BTDC seems to be a reliable compromise. The RD comes "onto the pipe" at about 4,500 rpm and explodes all the way up to the redline.

Next I'll play will the main-jets on the carbs.

The first couple of shade-down rides have gone well, without any major issues or failures. The bike is a blast to ride and the powerband is exhilarating! I have been keeping the rides under 60 miles in length and keeping the speeds down.

For Sunday's ride I installed some new knee-sliders on my leathers and focused on cornering and handling. The RD is very predictable in the corners and it's quite easy to get a knee down on the sweeping corners. I have a long way to go on the suspension setup, but the journey should be fun!

Fat Tires & Ignition Timing

Currently I have been spending the evenings in the garage trying to stuff the widest tire possible into the rear of my RD. This puzzle is all about finding just the right combo of rubber, chain length, sprocket size, and not have clearance problems between the tire and swingarm. Last night I dumped my box of chains and sprockets on the garage floor and started working out the best "combo". After trying several combinations, I have settled on 98 links, 17T front sprocket, and a 38T rear sprocket. This combo gives me about a 6mm gap between the new Pirreli "Sport Demon" 120/80-18 and the swingarm, but the gearing is not my favorite option. I would rather have a 40T sprocket on the rear! Now the ignition timing..... The 3mm BTDC on my MZ ignition is a bit extreme and I'm more than a little worried about frying a piston. This weekend I am going to experiment and test-ride settings between 1.7mm and 2.0mm BTDC. I just can't reliably get (or afford) the 115 octane leaded race fuel that I need for the 3mm advance. At about $12 / gallon, the race fuel really limits my riding options. I am planning an "epic ride" this summer and I want to complete the journey without melting a piston of seizing the motor! If I get the taxes done this week, I should be testing various ignition settings all weekend. Stay tuned for the results.