Give Me A Break

Howdy all,

So I'm trying to get this relic of a bike road ready and just a few things left. I seem to have run into a road block in the brake department though. I'm trying to find a replacement front mastercylinder for a Yammi '79 XS 750SF. I have tried Bike Bandit and Dennis Kirk to no avail. I can get the part# from Yammaha's online parts catalogue but it tells me that part is discontinued. Is there an aftermarket dealer that can handle this? I sure could use a little help from some of you avid bike restorers out there.

Also, I can get her started some times, ha, and when I do she runs fine for a few minutes and at a steady rpm starts to back fire a little. Spit and Sputter type stuff. I have rebuilt the carbs already but have not tuned them yet if that helps any. What Gives?

I'm surprised they already discontinued it. Have you talked to a dealer? No one wants to, but when all else fails, they are the best source for new parts for old bikes, the after market has likely abandonned it. You might find some XS forums, I know the XS650 has quite a cult following, some may know something about the 750. The other thing I do is research what other bikes shared the same or similar parts. Things like brake parts are rarely specific to one bike, chances are they used it on another. If all else fails, you may have to find a rebuildable master from another model that won't look too out of place on your bike. Hope that helps.

Try this:
XS parts on ebay

As far as the popping, sounds like a lean condition. Try richening the pilot or low speed jet, usually a screw at the bottom of each carb. make sure they're the same.

As the engine warmed up, the popping was not as loud or as frequent. The triple sounds really nice All he needs are the brakes fixed up and to get the new tires mounted. Then he should be good to start playign around and getting used to the bike. We'll drag him down to the bike nights as the ride is great between here and there.

There are basically 4 things that can cause popping or backfiring.

1) A lean condition. Incorect jetting, idle mixture adjustment, air leaks ( ie:through the intake manifold, etc.)

2) Leaks in the exhaust system, particularly where the header enters the head.

3) Incorrect ignition timing (unless it has electronic ignition)

4) A sticking, leaking or burnt valve. Have you adjusted the valves?

It's most likely 1 or 2.

Unless you really want to keep the machine original...you can always go with a later year model master cylinder...one that looks close enough.
Several companies have generic master cylinders for both 1 inch and 7/8 inch bars...I think Dennis Kirk has them.

But if you really want original.....our Vintage Japanese Motorcycle Motorcycle Assoc. (VJMC) representative for South Texas should be able to help you out. He's good at finding almost anything that is vintage jap. I think he plans to be at Bike Week at PO's next week.

I think inexpensive is the operative word here

Odd....

Yamaha only manufactures parts for their bikes for three years after the model is discontinued. Honda used to make replacement parts available forever, but they recently changed to 10 years after discontinuation (I have heard of exceptions to this recently!). The others have not announced a time limit.

Even if they are not manufacturing the part, chances are that there is a warehouse full of 1979 master cylinders laying around somewhere in Japan. Also it was more than likely made by Tokico instead of Yamaha in the first place.

Iffin 'twer me, I would look for any M/C at a junkyard that looks like it would work without rebuilding. Just remember that if your bike has two discs then get a M/C from a two disc bike. The same goes for a single disc setup.

Is this bike the "Midnight Special"?

-=Tim=-