Monday, April 11, 2011

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!


Tuesday, April 5, 2011

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.

Monday, March 7, 2011

Rockers vs Mods 2011

Time flies and now it's almost time for the 5th annual "Rockers vs Mods" event in Dallas! April 1st - 3rd Dallas will be transformed into a cafe racer's gathering, with bands, rides, bar runs, bike shows and assorted shenanigans. I hope to attend, but it will probably be for just Saturday, April 2nd. The RD still looks pretty ratty, dented tank and I still need to get around to painting the bike. Sure hope to make the event!

UPDATE: 3/31/2011 Looks like I'll be in the garage working on the RD while everyone is partying at Rockers vs Mods! A rear wheel bearing failure and dificulty in procuring several parts have made the timeline undoable! Maybe next year....

Spring Is Here, Time to Ride!

Spring has officially sprung and I have sprung into action getting the RD Racer back on the road. This weekend I completed a tear-down of the carbs, charged the little micro-battery, and spent some time puzzling over the rear wheel alignment. Right now the rear wheel is my "big issue".

My quest for more grip led me to install a wider rear tire and now swingarm clearances are an issue. Hard cornering, my 180 lbs, and vintage 1970's chrome-moly all lead to some pretty substantial swingarm flex. After a hard ride with lots of aggressive cornering, I can see where the tire has rubbed the swingarm! I am moving the rear wheel back about 10mm to increase clearances.

Should be test riding this weekend!