xs1100sf can't find the right brk master cyl kit

[bikerdave79]

Its a 3h3 prefix. Make 10/78 but the title says 79? Is it possibly a 78? Which is what's effing me?

[bikerdave79]

If it's the correct kit for an SF it should be 11/16 or 17mm.

Where do I measure?

[BA80]

Well, a 3H3 is an SF ...VIN codes.

These bikes were built like 6 months BEFORE their advertised model year.

[jetmechmarty]

The rear master cylinder has a smaller bore than the front one.

My two SG front master cyl markings are 4 NISSIN 11/16. The 4 is in a circle.

[bikerdave79]

Here's what I'm working with. Now that I've soda blasted the old paint and corrosion off I can see the numbers better

[bikerdave79]

Notice the new plunger and seals are slightly larger

[BA80]

That's a 14mm master cylinder for a single disc front brake. Someone put the wrong one on there.

It should say Nissin 11/16 on the bottom.

You've got the right kit but the wrong master.

[jetmechmarty]

What you have is an XS650 master cylinder. I have four of them. The XS650 has a single caliper front brake. As Greg has pointed out, it's the wrong one.

You can buy a kit for an XS650 front master cylinder and fix it. You should replace it with a correct master cylinder.

Here's the rub. If you have ridden the bike as is, you won't like the one that's supposed to be on there. It will take a lot more effort and feel wooden. If you stick with the one you have, you run the risk of running out of squeeze before the brakes are fully applied. I know of folks who run them that way anyway. It provides a long smooth pull.

The simple solution is to pm andreashweiss and have him send you the correct one. You already have the kit for it.

[bikerdave79]

I kinda figured that was the case, it looks awefully small. Have never ridden it yet. Got the bike in deplorable condition as the po got sick and left it outside under a tarp for years. Good news is he had taken the carbs and tank off and stored them inside so with a little cleaning I got it fired up pretty easily. Bad news is the aluminum is terribly tarnished, tires are shot and brake fluid turned to dust. Its a work in progress but its all minor because it has a title and runs strong as a bear.

[bikerdave79]

Yes I'd rather have the correct one. I'll pm him thanks!

What you have is an XS650 master cylinder. I have four of them. The XS650 has a single caliper front brake. As Greg has pointed out, it's the wrong one.

You can buy a kit for an XS650 front master cylinder and fix it. You should replace it with a correct master cylinder.

Here's the rub. If you have ridden the bike as is, you won't like the one that's supposed to be on there. It will take a lot more effort and feel wooden. If you stick with the one you have, you run the risk of running out of squeeze before the brakes are fully applied. I know of folks who run them that way anyway. It provides a long smooth pull.

The simple solution is to pm andreashweiss and have him send you the correct one. You already have the kit for it.

[BA80]

Yes I'd rather have the correct one. I'll pm him thanks!

Ha ha ha.......you've already got the kit.

[bikerdave79]

So he doesn't have any and the ones I see on eBay are expensive. Can I get away with a 14mm aftermarket one. I can get a Mc and clutch lever set that looks way better than what I have for the price of the one used master. Will a 14mm be too small? Doesn't seem that anyone offers a 17mm Mc as aftermarket.

[bikerphil]

If you are using SS brake lines, a 16mm or 5/8" bore will have the best feel/stopping for your Special calipers.

http://www.vintagebrake.com/mastercylinder.htm

[jetmechmarty]

If you are using SS brake lines, a 16mm or 5/8" bore will have the best feel/stopping for your Special calipers.

http://www.vintagebrake.com/mastercylinder.htm

That's why the stock one feels so wooden.

[bikerphil]

Yep, the larger bore is OK with rubber lines, once you go SS, the smaller piston is the ticket. I have learned a lot from "MMM", thanks to you Marty.