XJ650 brakes

I wanted to know if anyone out there knows where I could get a proportioning valve setup for my 82 Yamaha XJ650 so that I can remove the brake from my handlebars and just have the foot brake. Also, if anyone has any suggested links that might show how to set this up, that would be great as well.

Thanks in advance
Beardking

 

Might be tough to do since the XJ uses mechanical rear brakes and hydraulic fronts. Probably end up having to switch to a hydraulic rear setup by either switching to a rear disc, or rigging up some kind of slave cylinder hooked to the rear drum lever.

 

You know, right after I hit submit, I started wondering about that. Still a little new (alright REALLY new) to this stuff, so didn't even consider that. Oh well, looks like I'll be keeping both brakes.

 

Hey, I was just going to start a new thread, but this is perfect.

What would it take to change to a rear disc brake on a '82 XJ650? Do I
need to swap the entire rear unit (wheel, gear case, etc.) from a shaft-driven 750 or can I just pilfer the brake parts? How hard is this to do, has anyone done it, and what parts would I need to acquire off a donor bike?


If I have to use the entire wheel/final drive unit, is it compatible with a 650 in terms of gear ratios, etc.?

 

You might as well swap-out the whole ass-end ... including the swing. The rear disc set-up has welded-on brackets for the trailing-arm caliper stay. The back end of the trailing-arm connects to the top of the caliper mount. The lower caliper mount serves as a spacer between the inside of the swingarm and rear wheel -- with the rear axle is used as the lower attachment point for the caliper mount.

Collecting all that stuff and trying to fabricate the fit would be a loud bad-words screaming, hair-pulling out, tool-throwing and dog-kicking adventure.

You might very well get lucky with a whole swap. If not ... and you try it ... make sure nobody lets the dog go in the garage!

 

The only XJ's with rear discs were the XJ900 and the XJ1100. The 900 stuff will bolt right up, there's a member here that did it to his Seca Turbo. The 1100 stuff I have no idea about, haven't seen it up close to know if it would work.

I'm planning on attempting a swap from an XS850 triple that I have here, they are rear disc/shaft drive as well. It'll probably be this winter before I try it though.

 

At first, I thought you were trying to get rid of your front brakes, but after re-reading, I see you were looking to make the pedal into an integrated unit (like some new Hondas). I agree it would have to have hydraulic brakes all around, but then it might be feasible.

 

Hey Joel, do you remember the name of the member who did that rear disc swap? I'd like to communicate with him to see what he used, what mods were required, how it ended up working out. Thanks..........

 

Injuhneer did the swap, but he fabricated the stay arm, if I remember correctly.

Actually, the XS1100 Special had a linked braked system and (I believe) proportioning valve to control the back disc and one of the front discs. It's certainly possible to fab something up, but I'm wondering if it's worth the effort. You can chat with the guys at XS11.com to figure out the details.

 

The XS1100 doesn't have linked brakes, at least my 1980 doesn't. It does have a rear disc but then the XS750 and XS850 and even SR500 have them too. The parts off the 750 or SR500 might be made to fit but I wouldn't try it since the drum works just as well and takes a lot less maintenance to keep it working. BMW's have linked brakes but it adds a lot of extra weight and complexity to the bike.

 

That's wired Steve, since every article I Google with "XS1100 Special" and "brake" has a blurb about the linked brakes. I guess somebody changed yours over, or something else is going on.

 

There's a reason that the bike comes with separate front and rear brakes.
Linking the front and rear is unsafe and could cause the bike to spill if both the front and rear brakes are applied in hard cornering or a evasive maneuver.

If a linked system was deemed safer by the design engineers ... the bike would have been made that way.

If you link-up the brakes and lock-up both wheels ... you're likely to lose control and dump the bike.

I do believe that issue is emphasized in Motorcycle Safety Courses.

 

Kinda odd, Honda has been using the linked brake system in its Goldwing bikes for years. Given the number of years it was in production with this design, it must have had some benefit. The Wings were special, we did get told about this issue at instructor training school and were told not to run them in the controled rear wheel skid for that very reason.

 

It is weird since I've had the Special for 8 years and I never heard of any of them having linked brakes and there's no mention of it in the service manuals. They have all had the same separate brakes all along, at least they were all separate up until 1980. The option to have linked brakes must have been added to the last model year that was sold in 1981 since one article I found with Google was from 1981 and mentioned that it was available in the UK. Anyway, it must not have been too popular since it never caught on.