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1986 Venture Royal Rear Brake Problems?

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Right about the beginning of the COVID madness, I bought a 2006 RSV and my '86 was put into storage. When we bought the new house, a little over a year ago now, I pulled it out to ride it to a storage unit closer to the new homestead. I found the rear brake pedal was mushy and went "to the floor" with little effect on braking. 

I looked for sings of leaks, found nothing. The rear reservoir was completely full. I figured the rear master needed rebuilt. I didn't have time then to do anything with it.

BTW, it is still the factory, linked configuration.

I just got around to rebuilding the rear MC and it definitely needed it. With everything back together, using a Mity Vac and brake bleeder kit, I cannot get fluid to either the rear caliper or the bleeder at the steering neck. When I crack the banjo nut that feeds the front line, I get a rush of fluid when pressing the pedal. With the banjo nut tight, there is no pressure built up at all when pumping the pedal and the reservoir level never drops when pulling a vacuum on either bleeder fitting.

Any Ideas?


Edited by luvmy40
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Knowing you I am assuming you have a pretty good idea of what is required. From my end not getting pressure would indicate air in the system, somewhere. Or you could have restriction with the reservoir tank flow into the master. The left front caliper is the one for the rear pedal eh.

Here's what I would do: open the rear caliper, better yet take it off first and clean it as well as the front left. With the calipers off see if you can pump clean fluid through the system, then with the calipers in place and open try to pump fluid through them one at a time. Make sure you let the pedal pop back quickly, not slowly and keeping pumping quickly  until you get fluid. Once you have got that far go to your regular way of brake bleeding.

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Couple question here first..  have you delink the rear brakes from the left front brake caliper or is the brake system still stock?

If it is stock you will need to bleed the rear caliper first, making sure you get brake fluid to come out. Once you have clean brake fluid out of the rear caliper, move to the left front caliper and repeat the process till clean brake fluid is coming out. Of course make sure to keep the reservoir for the rear master cylinder full while bleeding. Next you need to remove the false tank cover and you will find another bleeder valve up by the triple tree tubes. You will need to bleed this one last as it is the highest point on the rear master cylinder lines. If there is a lot of air in the system, this is where it most likely is.

If you are not getting any fluid or pressure out of the rear master cylinder, then you might need to remove it and rebuild it or clean it. There is a small hole in the master cylinder that does get clogged and will effect operations of the brakes. In my humble opinion with the age of the bike and it has been sitting a while I would look at rebuilding the complete braking system and replacing the rubber hoses. You might have issues of the hoses deteriorating and cause the clogging issues but I and sure you will find that they will swell when pressure is applied in them.

I had the swelling issue on my 89 about 10 years ago and replaced all of there with steel braided hoses and havent had any braking issues since.

If you have delink brakes then the rear caliper is the only thing connected to the rear master cylinder..

Let us know what you find please..

Rick F.




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I think I'll talk to Earl about the delinking kit. I didn't want to get that deep, iJust wanted to get them working so I can sell it. I only have room to keep one long term and the "06 gets far more ride time than the '86. As much as I love both, one has to go.

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  • 2 weeks later...

Hey Guys,

This is just an FYI, NOT a shameless plug for the S.S. De-Link KIt! Rebuilding one portion of a 37 year old braking system on ANY motorcycle just puts excess pressure on all of the other elements of that braking system, in my opinion! My "Guess" is that the rear proportioning Ball Valve is stuck, and not allowing fluid to pass to the rear caliper. That valve was such a hassle that Yamaha doesn't make it any longer for any of the First Gens. (And stopped making it almost before the end of the run of the First Gens!)  It was a good idea...on paper, but the nature of brake fluid makes it a sticky mess if you don't maintain the flushes of the brake fluid. Along with the proportioning valve getting "Glued" in the closed position, are the caliper pistons on your 37 year old brak system. With the position of the rear caliper behind the engine, and trapped between the rear bags, overheating was a real issue. This is why the rear M/C looked so bad, I can't tell you how many First Gens. I have received at the shop and had to go through the entire braking system, even without adding the De-Link Kit Upgrade just to get the calipers functioning again. Almost every one! The major design element of the De-Link Kit was to take the proportioning valve out of the system every bit as much as it was to convert the bike to the right hand brake lever working both front brakes and the foot pedal working the rear brake. 

There is NO rebuild kit for the proportioning valve, BUT a good disassembly and cleaning of the front left and rear caliper, as well as the proportioning valve without replacing any parts is the very minimum you are looking at here. You don't need to do the De-Link unless you absolutely can't get the proportioning valve functioning again. Also DO NOT get BrakeKleen on the Seals inside the Calipers!!! The seals will swell, and you will never get them back into the caliper bodies again! 

I have ONE final tip for bleeding out the brakes on these bikes, and that is if you are not cracking EVERY Banjo Bolt and EVERY connection point starting at the Master Cylinder and proceeding to the proportioning valve, and then to the rear caliper, (or in the case of the left front caliper, the M/C, then the connection up by the steering head bearings, then to the left front caliper) you have NO idea where the blockage is and i can guarantee that there will be AIR trapped in the braking system somewhere along the line! Period!! To simplify this, crack the first banjo bolt closest to the M/C, briskly compress the foot pedal or brake lever, close the banjo bolt, do it again until ALL of the air is gone at that joint. Move to the next connection, repeat. I find this works best with a "Helper". My wife's right leg is twice the size of her left leg from stomping on the foot pedal of First Gens!! LOL!! I have several Vacuum bleeders here at the shop, and NONE of them work on these bikes! NONE! I do use a positive pressure bleeder on Autos and Trucks that works very well but I haven't been able to adapt it to the different motorcycle master cylinders. YET!

Because of my shop here in South Central Pa. I buy direct from Yamaha and am happy to share my discount with the forum members. I also offer the De-Link Kit for the members that are going to keep their bikes and want to upgrade their braking systems.

I fully understand it is very hard to justify spending hundreds of dollars on improving the braking system on a 30+ year old motorcycle that you most likely paid $800 dollars for. BUT the fact remains that you need to be able to STOP that motorcycle or you are NOT going to be able to ride it safely OR sell it safely. That's why I suggested just cleaning everything up without buying new parts and bleeding the system properly. 

I haven't added it to the "Member Vendors" section of the forum yet, but I also offer a direct bolt on S.S. Line Set for the Second Gens. as well. If I can help you with new parts, or if you have other questions, or you are interested in the De-Link Kit I offer, please feel free to PM me. 



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