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Weak front brakes


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Greetings, new member from the eastern shore of MD. I have been riding and wrenching for 20+ years, just added a 2000 RSV mm to the stable and had it out for the first real ride today.

 

The front brakes on this bike are very weak -- the rear brake is great and oddly feels 5x as strong as the front. The fluid looks clear and the master cylinder seems to actuate cleanly.

 

Before I pull the calipers off and check out that side of the equation, I figured I would check the wisdom of the list on any potential common problem(s) to look for. I did a quick forum search, but didn't find anything that stood out to me.

 

Thanks in advance,

Israel

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You're right. The Venture front brakes are weak.

However, first lets assume a couple of things. Lets take for granted that your pads are in good shape, that the calipers don't have any frozen or sticky pistons in them, and that your brake lines aren't deteriorated and spongy.

If all of those things are in good shape and you still have weak brakes, consider going to steal brake lines. That will give a little better braking feel

 

All of that said, I think the best fix is to go to the R1/R6 four piston calipers. It's a bolt on conversion. Skydoc here on the forum sells a complete ready to bolt on kit with rebuilt/painted calipers/pads/bake lines, or any combination of. I bought mine off of Ebay and did the entire conversion for under $100.

 

The improvement in braking with the new calipers is nothing short of amazing. Even with my stock rubber brake lines, the front brakes on my Venture are now all that I could ask for.

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I have never considered the front brakes on my RSVs to be weak. Since we do not often see people complaining about this, I do not consider it a typical problem with this bike.

 

On the other hand, the rear brake is considered too touchy by many owners - very easy to lock up that rear tire - TOO easy in a panic situation.

 

Can't say if your issue is a problem with your bike or simply that you expect something different than most of us do. I'd suggest you try and find another owner to get together with and compare the bikes.

Goose

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I also have never thought the front brakes to be weak but I know there are some threads about swapping them out.

I have slid my front brake a couple of times so there are definitely enough brakes to do that.

The rear brake is very touchy but with a little practice using the front and rear brakes together the RSV will stop just fine and give you a little change.

BOO

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Many of the members will use EBC HH pads, they are sintered and give a bit more biting performance. I too dont find the front brakes terrible with the right pads and deciding to get into the handle. The lines are 11 years old on your bike and may be deteriorated a bit, hard to say, also something to consider is if there has been regular maintenance done to the brake fluid, and braking system.

 

You might want to swap out the pads, and put a new set on for a starting point for your maintenance schedule :2cents:

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I first found the front brakes on this bike not to be 'weak' per se but not aggressive would be the term best to describe the feeling. Keep in mind this is a 900 lbs bike with a rider on it and that is a lot of weight to bring to a stop compared to a VStar 1100 or similar smaller bike.

 

I've since installed HH sintered brake pads on which really helped and installed black braided steel lines to the front brakes. I didn't not add braided steel lines to the rear brake as I found the rear brake to be prone to locking up. The rubber line tends to absorb a lot of near panic induced stomped on braking when someone cuts in front of you, or if your bike has a tendency to nose dive during heavy front braking which raises the rear of the bike taking a lot of weight off the rear wheel, causing the rear wheel to lock up and skid.

 

But with the progressive front springs installed, the bike doesn't dive as it used to, and braking is rather quite aggressive without that feeling of locking up.

 

Proper braking technique, like everything else, is something you need to practice so it becomes second nature for when it really counts..

 

Fun fun fun..

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Nah, this is beyond just a simple "weak". I have owned 50+ bikes and while some are better than others, this is the worst out of any bike I have ever ridden. To put it bluntly, even going 30 mph, grabbing a good handful of lever, I can't stop in any reasonable amount of distance without using the rear brake.

 

Just checked, pads look new. Bled out a little fluid from each caliper and it was clean, as was the fluid in the reservoir. No bubbles in the lines that I could tell. Calipers slide on the pins. Lever is still just a little spongy, but I'm gripping on it pretty well -- weak rubber brake lines could be one possibility, although when braking, I am getting a good solid feel at the lever, but no corresponding grab at the rotors.

 

I'm thinking something along these lines... in no particular order

1. swap pads for a known brand (just got the bike, no idea what the PO used for pads)

2. get a steel line kit

3. rebuild master cylinder

 

Thanks for all the input. Even though its a new-to-me bike, I have to believe that this weakness is just plain wrong -- no way a bike of this weight would ever survive with it like it is.

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Well Iz,

 

By now I think you should have concluded that the oem brakes on your MM need some attention. I have no idea why Yamaha chose to put 2 piston calipers on the front and a 4 piston caliper on the rear, which is completely opposite of most other heavy bikes like ours? But they put 4 piston calipers on the Road Star in 04 but not the Ventures...go figure? Since your scooter is over 10 years old, the brake lines are most likely getting a little spongy. So, if I were in your situation I would:

 

1. Install EBC HH pads on the front and oem (not HH) on the rear

2. Install stainless lines on the front (not on the rear)

 

These 2 changes will make a world of difference. And the front lines are not the easiest lines to bleed, where there will always be a bubble that will hide at the juction. So when you get to the point that you think you have all the air out of the lines, continue pump bleeding, but this time get ugly with the brake lever before you hold it and loosen the bleed valves. There is one other trick that I use to make sure all air is out of the line, which is to tie the brake lever down (with a long piece of double edge Velcro) and let it sit for a while with just the rubber cover on the reservoir. This will allow any bubbles to rise to the top of the reservoir. Then most of us us a synthetic Dot 4.....your choice of brands.

 

Hope this helps,

 

Rick

 

Nah, this is beyond just a simple "weak". I have owned 50+ bikes and while some are better than others, this is the worst out of any bike I have ever ridden. To put it bluntly, even going 30 mph, grabbing a good handful of lever, I can't stop in any reasonable amount of distance without using the rear brake.

 

Just checked, pads look new. Bled out a little fluid from each caliper and it was clean, as was the fluid in the reservoir. No bubbles in the lines that I could tell. Calipers slide on the pins. Lever is still just a little spongy, but I'm gripping on it pretty well -- weak rubber brake lines could be one possibility, although when braking, I am getting a good solid feel at the lever, but no corresponding grab at the rotors.

 

I'm thinking something along these lines... in no particular order

1. swap pads for a known brand (just got the bike, no idea what the PO used for pads)

2. get a steel line kit

3. rebuild master cylinder

 

Thanks for all the input. Even though its a new-to-me bike, I have to believe that this weakness is just plain wrong -- no way a bike of this weight would ever survive with it like it is.

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What you describe is exactly how I would have described the front brakes on my Venture. When I bought my bike, it didn't need pads but the previous owner gave me a complete set of HBC sintered pads (front and rear) so I changed them all out.

 

The front binders were still the same with the new pads, so after a few thousand miles I picked up a set of HBC non-sintered pads. Same thing. I was getting ready to rebuild the calipers when I ran across a deal on the R6 calipers, so I put them on instead.

 

After just a few miles of run in, it was like a different motorcycle. Where I had to lean hard on the lever with the old stock 2 piston calipers using all 4 fingers, I can now bring this thing down from any speed with just 2 digits. Brake lever feel has increased as well.

 

Since the only thing that I changed that resulted in markedly improved braking, was the calipers/pads (I put on non-sintered pads this time and kept the old rubber brake lines) I have to believe that my problem was the under powered 2 piston stock calipers. When I removed the stock calipers I could find nothing wrong with them. The pistons all were free and the calipers floated freely in their brackets. No fluid leaks anywhere, and I had changed the fluid shortly after I bought the bike.

 

I too, have owned many dozens of motorcycles and short of some old vintage bikes with mechanical drum brakes, the Venture has been one of the poorest stoppers of the bunch. I will concede that this is the heaviest motorcycle I have ever owned, but it should still have brakes commensurate with its weight.

The only concern I have is, riding in the rain with these new anchors will require greater attention until I get used to it. Yes, I am a big fan of the 4 piston calipers. lol

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I've wondered about the same thing. As a comparison the front brakes on my '98 RSTC take way less pressure on the brake lever than on the '99 RSV to get the same results. This is not to say the RSV front brakes won't bring it down, it just takes a lot more pressure than the RSTC. I don't know what brand/type of pads are on either bike as they are what I inherited from the previous owners.

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Shortly after buying my 05 RSTD i installed sintered pads and S/S brake lines the type that go straight to each side caliper from the resivoir made a huge difference as i to was dissapointed in the stopping power.I did not know the R6 calipers would bolt straight on Mmmmm never have to much stopping power.

 

Do all year models fit in the R6 R1 notice some cheap on Fleabay

Edited by teza51
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I agree. The stock front brakes on this bike are very weak. Braided lines help, but the real solution is R1/R6 calipers and a 14mm master cylinder. Don't do the calipers without getting the properly sized M/C. This brake setup also brings the front to rear braking power into balance and suddenly the rear brake doesn't feel touchy anymore. These are the brakes this bike should have had from the factory. Why does Y's heaviest bike have the weakest brakes?

 

I don't remember years anymore. The previous generation of R1 calipers is what you want. If they look like they will fit, they will. The current R1 calipers are a completely different design and it's obvious that they won't fit. Calipers of this same design but with a different look can be found on later model Roadstars, Roadliners and Stratoliners.

 

The only bike with a 14mm master cylinder of a style that matches our stock ones is the later model Roadstar. It will have a 14 cast into the front of the housing where the stock ones have 5/8. Don't do this brake conversion without the 14mm M/C.

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Good explanation. It creates the wrong leverage ratio between the M/C and the calipers. Actually I think I'd say the analogy the other way around. It would be like trying to drive a framing nail with a trim hammer. The small hammer won't have enough power to drive the nail. The stock M/C does not have the leverage to operate the R1 calipers properly. Oh it will work, but barely and with no improvement over stock. You'll wonder why those of us who have R1 brakes rave about them.

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Hmmm, interesting.

But My experience has been exactly the opposite. Stock master Cylinder with the R6 calipers has givin me an 100% improvement over the stock setup. If anything the stock M/C may be overpowering the 4 puck calipers, as total brake lever travel is around half of what it was the stock Venture calipers. Still a vast improvement and very managable.

 

If the recommended M/C is 14mm, what is the stock size?

If the stock M/C is 5/8" that is .62". 14mm is .55". I don't see that as being enough difference to create a real world detriment.

Edited by straycatt
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It may not seem like a big difference on paper, but in practice it's huge. It will feel like you added power assist to your brakes. I tried the stock M/C with the R1 calipers too, and I thought it was horrible. That lasted just as long as it took me to procure a 14mm unit. Y always uses a 14mm M/C in conjunction with the R1 style calipers, no matter what bike they're on, and I recommend not using anything else but that.

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Below are how the two master cylinders compare numerically.

 

14 mm = .9544 sq. inches surface area.

 

5/8" = 1.2762 sq. inches surface area.

 

When looking at a hydraulic brakes, there are two sides of the system. The driving side (the master cylinder) and the driven side. (the calipers).

 

The 14mm M/C will provide more force against the calipers, but it will in turn be able to move them less distance, due to lower flow output. Where the less flow becomes a problem is when a 2 piston caliper is replaced with a 4 piston caliper. The 4 piston caliper takes more volume to displace the 4 pistons.

 

The smaller the master cylinder bore, the higher the imparted pressure on the driven side, this is considering the same input from the brake lever on the end of the master cylinder piston. (this is the leverage part of the equation). This smaller diameter creates less volume though.

 

Below is a drawing detailing the two components of a braking system hydraulic circuit.

 

There is also attached a spreadsheet which shows comparisons for the MKI's, MKII's, RSV, 2003 FJR & R6 (not sure of year) brake systems.

 

Gary

 

http://i1007.photobucket.com/albums/af193/gdingy101/hydsystem-1.jpg

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Coming from a Vmax that had the R1 calipers and master as well as lighter wheels and radials. I think the brakes are great on my 08 RSV. The back brake is damn strong but my Vmax was was running a 4 piston R1 caliper/rotor as well so I am used to a sensitive rear brake. I would still consider doing the 4 piston fronts cause its about the mods to me. :)

 

Frank

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Guys,

 

The real point of this issue is that our bikes (the TD included) need 4-piston front calipers and probably a 1 piston rear caliper. But Yamaha will never make this change because of the liability they would face from a law suit. I've lost count of how many of us who have gone down from a rear wheel lockup and I know personally of two who have died because of this issue. They know this, and if they made a change to the caliper configuration, they would be admittimg fault. This is the main reason I chose to develop an adjustable proportioning valve to keep rear wheel lockups to a minimum.

 

However it is interesting to realize that Yamaha had this same 2-piston front, 4-piston brake configuration on the Road Star in the 1999. But more interesting is the fact that they changed the front calipers in 2004 to a 4 piston design.....the very same calipers they used on the early R6 and R1s. But.....it is even more interesting that when they designed their big hp Road Star Warrior, it came with these same 4-piston R1 front calipers that they later put on the standard Road Star......and even more interesting is they used a 1-piston rear caliper.

 

So based upon these facts, what would be the best brake caliper configuration you would choose to be on our Royal Star Ventures and Tour Deluxes? Especially when it is well known that 70% of a bikes stopping power comes from the front brakes.

 

Hope this helps with this conversation,

 

Rick

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Update:

 

I pulled both calipers back off last night and removed the slide pins. They were lightly greased already, I added a little more and reassembled. Then I moved up to the master cylinder. I removed the lever, greased the pivot screw and added a little dab to the contact point at the plunger.

 

Huge difference this morning. When the brake lever previously would hit a brick wall and I still wasn't slowing down, I believe I am now up to the "RSV just has weak front brakes" level -- at the very bottom end of acceptable.

 

At least I didn't fear for my life riding this morning like I did the first outing. The R1 caliper upgrade is still in the works, but I'm a whole lot happier today than I was a few days ago.

 

Thanks for all the input,

Iz

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