87 Linked Brakes

[Docjava]

Greetings from Knoxville, TN. I hope this is a good place to post this for some info. I just got a real nice loaded 87 Venture Royal. Can do a lot fixens, but the linked brakes I never had before. Seems like there is no rear pedal. I have bled the rear cal and the left front cal and there seemed to be no air. However, the bleeder up by the handle bars has a lot of air. I kept the rear master cyl filled, thru the 14mm bolt hole in the side of the MC (i guess that is a fill hole), and bled a lot of air out of that upper bleeder and got a good hard pedal and wheel stop, but after a little other work elsewhere on the bike, I rechecked the rear pedal and there was not any pedal again. I have repeated the air bleed from that upper bleeder a couple times and more air comes out. I would think that if I got a good hard pedal then Im good-to-go but why doesnt it last? If I had a leak sucking air in, I would think I would also see a leak on the floor, specially under pressure when bleeding. Would love any ideas and direction.

Dennis

[Squidley]

Dennis,

Depending upon how long the bike has been setting and the previous maintenance that had been done, you might want to check the rear master cylinder. Many times on these older Ventures the brake fluid turns to jello and will dramatically hamper the braking system.

The actual procedure that I have done in the past with good results is this. Bleed the rear caliper 1st, this makes it so that you have good pressure to force air up the line to the bleed screw by the upper triple tree. Then bleed it at that steering head bleeder and then go down to the front left caliper. If you dont have a vacuum bleeder you might want to think about getting one as it makes the job a lot easier.

There are a lot of members in Tennessee that would just love an excuse to ride and give you a hand if you so chose. Others will chime in here and give others insights....welcome to the club.

[JoeKanuck]

Speed bleeders seem to have been used with some success.

 

http://www.speedbleeder.com/

[Yammer Dan]

I have taken a couple of those old Masters apart and cleaned them good and got them working. They do crud up easy.

[Docjava]

Thanks guys. I do have a vac pump so I will try that on all bleed points today. It still has me wondering tho why after I hand bled and got a good solid pedal, after sitting a bit, it would loose all pressure and I would get more air out of that upper bleeder. Where is the air coming from. I see no leaks (yet).

[Squidley]

Check all the crush washers on the banjo bolts also, just a little leak will cause problems.

[Docjava]

Well fellas It appears that I am sucking air thur the metering valve on the triple tree. Discontinued from Yamaha. I will have to look for one. As far as not seeing a brake fluid leak, it was catching in the from lower cowl and not on the ground. Also need to replace the o-ring and bolt washer/gaskets on the fuel-cock. Smelled a little gas and found that leaking.

[Yammer Dan]

Glad you found it. That brake fluid is a great paint remover! Don't ask how I know.

[Docjava]

Oh yea, found that out a while back. I fixed the leaking fuel cock gasket. So now Im headed up to Morristown TN to Motorcycle Salvage and try to find one of those linked-brake metering valves. One of the best places iv ever seen. Always had something I needed in the past.

[Yammer Dan]

I think Yamaha still sells that valve. Not sure but might be worth checking.

[Squidley]

Another option is if you can't find one....delink the brakes and you wont have to worry about that bleeder port up top

[Venturous Randy]

So now Im headed up to Morristown TN to Motorcycle Salvage and try to find one of those linked-brake metering valves. One of the best places iv ever seen. Always had something I needed in the past.

 

I have been there several times and he has several 1st gens. My only problem is he wants mucho $ for anything I was interested in. I believe all together he has over 6,000 bikes.

RandyA

[paysaw]

http://cgi.ebay.ca/YAMAHA-VENTURE-ROYALE-XVZ-13-BRAKE-PROPORTIONING-VALVE-/270612539406?pt=Motorcycles_Parts_Accessories&hash=item3f01c3a80e.

Check out this Ebay link.He wants 10buck for the valve.He is in Quebec Canada:bawling:

[jasonm.]

that piece at the tree is NOT A METERING VALVE. It's simply a bleeder at the higheest point. The proportioning valve is by the rear master cylinder. That proportioning valve cannot go bad...it has NO seals or rubber. But anything can get clogged. My experience is you probably have a rubber seal in the master or less likely a copper sealing washer leaking just enough to cause you problems. I have had rubber hoses separate inside and leak intenally. It's a pain to find. But the cure is always ...replace the hoses.You can make your own SS brakelines with a high bleeder...if you look at Galfer , Russell and others. They offer the parts to make any size or shape brake lines. I delinked my brakes and went to SS lines 15+ years ago. I have all the stock parts. But do not feel comfortable selling or giving 20+ year old parts to anyone.

[greg_in_london]

That valve behind the bottom yoke is a restrictor valve to reduce the brake pressure to the front when you stamp on the back brake, supposedly to stop you from locking the front wheel in an emergency stop.

 

Personally I recommend getting a 5/8" front master cylinder, delinking the brakes and removing that proprtioning valve, but that's my choice. Some people seem to like the linked system. (I want to be able to stop !)

[dingy]

that piece at the tree is NOT A METERING VALVE. It's simply a bleeder at the higheest point. The proportioning valve is by the rear master cylinder. That proportioning valve cannot go bad...it has NO seals or rubber. But anything can get clogged. My experience is you probably have a rubber seal in the master or less likely a copper sealing washer leaking just enough to cause you problems. I have had rubber hoses separate inside and leak intenally. It's a pain to find. But the cure is always ...replace the hoses.You can make your own SS brakelines with a high bleeder...if you look at Galfer , Russell and others. They offer the parts to make any size or shape brake lines. I delinked my brakes and went to SS lines 15+ years ago. I have all the stock parts. But do not feel comfortable selling or giving 20+ year old parts to anyone.

 

Attached are a couple of pictures of the insides of a proportioning valve.

 

Last picture is entire rear master.

 

There are two rubber components inside the proportioning valve.

 

If you delink the brakes, the proportioning valve is eliminated.

 

Gary

[CrazyHorse]

Attached are a couple of pictures of the insides of a proportioning valve.

 

Last picture is entire rear master.

 

There are two rubber components inside the proportioning valve.

 

If you delink the brakes, the proportioning valve is eliminated.

 

Gary

You dont have to remove the proportioning valve. You can leave it in.

[Docjava]

Got it fixed. This part is by all sources called a metering valve. The end under the rubber cap can leak similar to a pressure relief valve iv found in auto brake and power steering systems and they can't be fixed. Pull off the rubber cap to check if wet. Mine was and could watch a drip form when pressing rear pedal, then when let off pedal could watch it get sucked back in, thus my air for the spungy pedal. Must be a rare thing for it to go bad. I found the MC Salvge in Morristown TN had 3 Ventures carcuses and all three still had this part. So i got one and it fixed my spongy rear brakes right up.

[greg_in_london]

Yes, Yamaha call it a metering valve and if you know what they mean, that's great, but it is a restrictor, a throttle in the brake feed line, so that if you stamp on the back brake you're less likely to initially lock the front wheel.

 

If you're keeping the linked brakes then I reckon you need it (and you've kept it.) The proportioning valve is a second contraption (I think you know this, but re-reading the thread I think it has become confusing) which detects when you are slowing down and is meant to reduce the pressure to the back brake (or stop you braking more) to make rear wheel lock-up less likely. Without it, the idea must be that during heavy braking, when you ease off the back brake, you'd be easing off the front as well without it.

 

I think I've said before how much I don't like the system. My back brake felt useless (even after cleaning the caliper, SS hoses and HF pads) until I junked the proportioning valve, but I carry quite a bit of weight and often have to cope with traffic.