Tuesday, 18 July 2017

Everyday TR1 - rejetting and syncing

Lately I have been playing around a lot with getting the everyday TR1 (the Traktor) dialed in perfectly. It's been 90% there, but still... until I found out, that maybe a year ago or so, I tried a flatter ignition curve, because I had some heat issues. They weren't cured by less ignition advance, but I never got round to setting the curve back to the values, I used before. And as I tend to alter my ignition curves by always choosing the previous one and then make some alterations... well you get the picture. The result was relatively simple: After going back to that old curve, I now had to raise the needle one notch as it was pinging a bit at 3000 rpm. Not shown, but at the same time I also swapped out the mains for #170ies, instead of #175s as it was a bit rich on max rpm and now it revs to 7500rpm in 4th (couldn't go any faster yesterday).

Unfortunately, when you take off the carb tops, you will eventually mess up the synchronization. But as a lot of people asked me, how I go about sync'ing cable-operated carbs, my loss is your gain, I guess.

My setup (sorry for the dark picture, I've used a different camera...) is an old moped-fuel tank hanging off the ceiling and feeding both carbs.

First step is to fire up the bike, open the cable adjuster on the throttle grip and turn that up until the RPM increases. (This way you make sure you're actually sync'ing the cables and not the throttle stops.)

I've drilled holes into the cast inlet manifolds of my cylinder heads, so next step is to unplug the sync ports.

The actual cable adjustment will have to be done via the cable adjuster on top of the carb. 

With the clocks plugged in, you will probably see something like this. (I simply assume you know how to hook up the clocks without damaging them, if not, RTFM.)

Now the only (slightly) counter-intuitive thing you have to know: If you the vacuum is bigger on one port than it is on the other, this means the throttle slide is LOW and you have to raise it. (It's simple physics, if you don't believe me, try it out for yourself.) And after a bit of fiddling, you end with something more ressembling this picture.

Then you tighten down the locknuts on the carb tops without disturbing the settings and you're done.

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