Monday, March 9, 2009

Motorcycle Season Begins?

It's hard to believe that three days ago Jamie and I dusted off the Magna for a short ride around town. The great thing about the weather around here is that if you don't like it, just wait 15 minutes…

Post-production continues on the film as we log hour and hours of footage. Matt tells me that most of the tape has been captured and he's pumped about turning out that first rough cut. I'm excited as well because unlike our other projects, there is quite a lot of footage that I haven't seen yet (I wasn't present for the shooting), so there will be a lot of stuff I haven't seen yet in the rough.

As the weather turns fair it reminds us that we don't have a lot of time before the spring run (two months?) and neither of our bikes are quite "road ready" yet. On Matt's end he continues to battle the leaking fuel tank issues while mine are less serious mechanically (I'll get into them in a minute) but I'm still uncertain about obtaining a proper title which really grounds the whole project. If I don't make any progress in this regard soon, I'm seriously considering a frame swap…

But on the mechanical end of things, the two highest-priority items I have on my list are:

  • Work out the midrange power problems
  • Figure out (and fix) the back brake "clunking" issue

When I had the bike out last year I noticed, when accelerating through the rev range the bike struggles as the tach climbs beyond 3000rpm. After thinking about it over the winter, I'm pretty confident this is a jetting issue, since I really opened up the intake and exhaust but I'm still running the stock main jets. So I ordered a "jet kit" off ebay that comes with several different sizes of main jets and we'll give this a shot.

The brake issue is something else. I un-intentionally disassembled the rear (drum) brake when I removed the wheel to have new tires mounted. I thought I put it back together correctly, but apparently I did something wrong. When applying the brake, it begins to grab as expected but then it will suddenly grip, make a "clunk" noise and then all but lock-up the rear wheel. If you plan for it, it's not a problem but if it catches you off-guard it's very unsettling. I'm not sure if I goofed something up inside the brake itself or maybe something in the mounting (the torque arm?) but either way I'm going to have to spend some time figuring it out. If I had even one disc up front, I wouldn’t sweat it too much but with (old) drums on both ends, I need every bit of stopping power I can find.

The weather is supposed to turn warmer again this week and I expect my jets will arrive as well. If both these things happen I may charge up the bike, get some fresh fuel and see if I can at least get it to start. If I get that far, I'll try installing some new jets and see what the difference is. It will probably be awhile before I can do another road test, but at least I'll be ready for the next break in the weather.


Anonymous said...

Hey man, did you figure out what the clunking was? I've got the same problem with my bike and I can't figure it out. Forums aren't much use either. It only does it once in a while but my MOT is coming up and I need it to pass!



Jason J. Gullickson said...

Martin, thanks for stopping by.

I described this to Bill at Motorcycle Performance ( and he immediately told me to loosten the rear axle, depress the brake and then re-tighten the axle nut. Apparently there is something inside the drum that doesn't set right unless the pedal is depressed when the hub is tightened.

I tried this quickly by turning the nut "just" loose, holding the pedal down and re-tightening (hard to do by yourself, actually) and I thought I had it licked, but after a good solid stomp on the pedal, it was back.

I wish I could remember exactly what Bill said, because I might have missed a step.

I'm going to give it another try this weekend and if I still can't get it I'll follow up with Bill and figure out what I'm doing wrong. If I find something that works, I'll be sure to mention it in a future post.

Out of curiosity, what year is your bike and if it's a CL, what are you running for exhaust? I'm starting to question my wide-open pipes as I'm having some running issues now...