Sunday, 23 April 2017

Helping friends with XS750ies and Honda CB125 Twins

Now you may wonder, why my progress on the sidecar is a bit slow? Well I tend to be a friendly guy and help other people. This time it actually was two on the same day:

First I met my friend Carl and helped him dial in and service his XS750. First step was to adjust the valves, which were basically all set up incorrectly by the p.o., because the stock valve settings are: 0.15 - 0.20 on the inlet and 0.20 - 0.25 on the exhaust valves, which is quite a bit wider than what you'd normally find on a bike (so can't fully blame them).

Now here's a little trick on how to do the valves on a Yamaha Triple, if you forgot your shim-tool at home: You losen all the bearing cups and remove the cam-chain tensioner and you can actually tilt them out of the way, making the whole process quite bearable.

Blessed is he, who hoards shims...

There's no pictures on how to use a strobe-light or how to sync the carbs, because there's nothing too special about it, but to hear a well tuned XS750 Triple go through the rev-range, well they are special.

 Second step of the afternoon was close to being even more fun. Never worked on a CB125 Twin before and with it being the smallest production fourstroke twin available over here, I was indeed expecting a little buzzing bee, but in all fairness... It revs to the moon and back and then you're only in second gear.

Should you ever have to swap out the carbs on one of these for a set of 110cc dirtbike Mikuni clones, the kind of jetting that seems to work (half decently) with some cheap pods is: #12.5 pilots, #100 mains and the mix-screw (unlike the real Mikunis these have mix-screws and not air-screws) 2 turns out.

Still, mighty fun for a basically guttless bike, but after an afternoon of dialing those carbs in, she finally rev'ed to 12,000RPM again and did the uphill test pulling a steady 80 to 85.

Oh and just in case you're worried... there's news on the sidecar as well, but that's for the next post.

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