Brake won't release

[pofarm]

I have an 82 XV750 and I have installed the front suspension from an 86 XV700. I can't get the either one of the brake calipers to release on it. I'm going from a one, single piston caliper system to a two, dual piston system. I'm using the master cylinder from the original one caliper system, since the master for the two caliper system is trashed. I checked the calipers before installing them and they both checked out ok. All pistons are free and the seals are in good shape. I have no leaks and the brake lever feels solid when applied. I'm wondering it the master is just too small for this new system? It worked fine with the original system, but is almost half the size of the dual caliper master. Thoughts??? Thanks

[bstig60]

I think you will find that the master cylinders are different. If you wish you can go to www.bikebandit.com or www.stadiumyamaha.com and click on OEM parts for the years in question and check the part numbers. Check Mark's Cycle Store in Grass Valley, CA. He had an '86 700 and he might still have the master cylinder. Phone is 530-273-8337.

Bill

[pofarm]

Thanks for the info and phone number. They are definitely different. The 700 master is almost twice the size of the 750. I thought I had the problem fixed and took it out on a 10 mile run Thursday. The brakes were almost smoking when I got home. I went out yesterday to work on it and the brakes were free. I tried them several times and they worked fine. I've ridden it about 20 miles since and no problems. Someone else suggested cleaning the return port in the master and I did that, even though they were working. It may have been the problem and whatever had it blocked finally came out. There was some sediment in the bottom of the reservoir that I also cleaned out. I'll keep an eye on it and see what happens. This bike is a project. I've swapped motors from an 82 XV750 to an 89 XV1100 and am still working the bugs out. It's coming along nicely.

[grizzlyrider]

Check the return spring in the cable by the brake handle.
It can get out of position and jam up and not allow the cable to release.
It will act just like you're driving around with the lever pulled.