Front Brake strength

[cabreco]

I have a question regarding the 1st Gen front brake. My Venture stops fine using bothe the front brake & the linked rear/front pedal but if I try to stop my Venture with JUST the front brake it struggles . I'm not saying stopping from 60 mph but say a 25 mph stop. is this normal?

 

The reason I ask is my CB750 has only 1 front rotor & when I hit that front brake I can easily stop...even if I had no rear brake.

 

My Venture's front pads look ok, as do the rotors. So is this just because of the weight of the Gen 1 that it needs both rotors or do I need new/better pads?

[DragonRider]

You are trying to stop an 800 lb bike with one disc and 2 pads, thats a lot of bike to be stopping, I know, I used to use the front brake only on most my other bikes, but after trying that with the Venture I wore out the right front pads pretty quick. Now I use both front and rear, besides the front brakes on the stock Venture are not all they could be, There are mods you can make to the MK II with R1 calipers and discs that make it really stop well. Not much can be done for the Mk I , they have different mounting points for the calipers than the MK II (86-93).

 

 

I have a question regarding the 1st Gen front brake. My Venture stops fine using bothe the front brake & the linked rear/front pedal but if I try to stop my Venture with JUST the front brake it struggles . I'm not saying stopping from 60 mph but say a 25 mph stop. is this normal?

 

The reason I ask is my CB750 has only 1 front rotor & when I hit that front brake I can easily stop...even if I had no rear brake.

 

My Venture's front pads look ok, as do the rotors. So is this just because of the weight of the Gen 1 that it needs both rotors or do I need new/better pads?

[bongobobny]

Yes, the weight of the bike does play a huige role in the stopping power of any bike. It's a lot easier to stop a 500 lb bike than a 900 lb any day. There is also another factor though, the MK! ('83 - '85) have inadequate brakes to begin with. The MK2 brakes were a vast improvement with the 2 piston calipers and larger rotors, along with the anti dive being converted to a solenoid instead of the brake power robbing hydraulic setup! It costs a lot to convert as the front forks have to be changed out along with the rotors and calipers but it does make a night and day difference. Add stainless steel brake lines that don't flex like the rubber lines do which robs braking power and you will notice even more improvment in braking! The final step is to install calipers from an R1 which are 4 piston calipers. Of course you can always delink your rear from the front and have 2 brakes working with the front brake instead of one...

[Squidley]

When using your front brake only on a 1st gen, you probably are only using 35% of the bikes braking power with the right front caliper (which is what the front brake handle controls). The front calipers are designed to be used in conjunction together, where your 750 was designed to have the majority of the braking force used on the front. I'll wager that 750 doesn't weigh over 700lbs, the Venture's weight is a couple hundred lbs more atleast. The diameter of the rotors plays a big difference also in stopping power.

 

I dont know what pads you have, but a vast many of us here use EBC HH sintered pads. They work very well and many folks when they change to them are quite impressed. Another question that begs to be asked is, do you have any leaks in the fork seals or calipers. Obviously is you get brake fluid on the rotor the brakes are going to suffer greatly. The brake lines are also 20 years old, swapping to SS lines makes a big difference in stopping power. 1 more thing while I'm at it, when was the last time you bled the entire brake system?

[JohnT]

Especially after riding my GS today I am underwhelmed by my VR brakes. this winter I want to delink front and rear, change to SS lines and upgrade the pads. Unless of course I can find R1 calipers on the cheap, then they will be added.

But for the time being I am going to change oil when needed, check it over from time to time, keep it clean, and ride the shnot out of it.

I am already stock piling stuff like HID head light, a bunch of LED lighti9ng, and trying to figure out what I am going to do about the stereo. This winter while the riding sux.

 

Going to g ride it to dinner at a Quaker Steak and Lube somewhere in Ohio next week. Can't wait for that.

[cabreco]

I just wanted to make sure the brakes were not defective. I figured that the weight of this was going to bee a factor. Comparing it to my CB750 was like night & day.

Lots of good stuff here THANKS!

 

Squidley,I did bleed & changed the fluid in December when I rebuild the master cyl, but I did have a fork seal leak the did in fact hit that caliper.

So for the time being some frugal improvements are change the pads to

1.EBC HH sintered pads

2. stainless lines

 

bongobobny, what I get from you is the anti dives rob braking power? So since I installed progressives up front, disconnecting the anti dives from the system & installing the block off plate would improve braking? If so it it significant?

[bongobobny]

Significant enough to notice a difference. Inside the anti dives is a piston/plunger that restricts hydraulic flow in the shocks limiting the travel of the shock tube. Although a lot smaller in diameter it still represents a load on the applied force from the master, and requires moving a slight additional volume of brake fluid. I am assuming Yamaha realized that the brakes on the Venture needed improving so that is probably why with the MK2 they went to bigger brakes and went with the electric antidives...

[frankd]

When I bought my 83 new, I also was never impressed with the front brake. I lived with it. While I was fixing 2nd gear, I did a lot of other mods, including braided brake lines and because I already had Progressive fork springs installed, I disconnected the anti-dive. This made a night and day difference. Now I had a very firm front brake lever, and it worked....real good. Now my front brake was very effective and would flat out stop the bike. BTW, I left the brakes linked.

 

 

However there are other things to consider. Look at your right front disk brake pads and see if they are wearing evenly. If they arent, maybe you have a frozen caliper piston. When I bought my low mileage (meaning it sat unused for a long time) 89, the brakes took a lot of pressure to stop fast. You had to grip the front lever with all of your might, and the back (and left front) also took a lot of pressure. I found that I had frozen pistons in the back caliper and the right front. Fixing this made the brakes a lot better, but not good. It still took a firm squeeze on the hand lever and a hard push on the rear brake pedal. But at least it was safe now. I rode it this way for a couple of years, and then a month ago, my wife and I rodea little aggressively through the Smokies (including the 'Dragon again), and with the hard usage the brakes started getting better and better. Finally I had a panic stop in Myrtle Beach and this made a big difference. It looks like my brake pads never seated. Now my 89 has what I'd call good brakes, and they are still linked. Make sure you are using good pads, EBC Double H brake pads are supposed to be the "grippiest" accoding to their ad.

 

If you have a problem with your brakes not working as designed, de-linking won't help. You may not like the idea of linked brakes, but fix the problem before you delink them.

 

Frank D.

[cabreco]

...and because I already had Progressive fork springs installed, I disconnected the anti-dive. Frank D.

 

Frank I kind of like the linked brakes so I do plan on leaving them alone, but disconnection the antidive units is on the top of my list. Am I correct in assuming all I need to do is remove the hose extensions from the calipers to the antidive & reattach the line to the calipers using the shorter banjo bolt which are on the antidive lines?

Andy

[frankd]

Yes, that's all it takes. I seem to remember putting a short bolt with a copper washer into the anti dive valves to keep the dirt out.

 

Does your brake lever go all the way to the handlebars OR is it too hard to pull?

 

Frank

[cabreco]

Yes, that's all it takes. I seem to remember putting a short bolt with a copper washer into the anti dive valves to keep the dirt out.

 

Does your brake lever go all the way to the handlebars OR is it too hard to pull?

 

Frank

 

The brakes engage at about 1/2 travel towards the grip & if I really squeeze down hard I can get the handle to about 5/8" from the grip.

 

The "feel" of the brake lever feels right, I'm just use to the front brake being able to pull the load better. The plus to the linked brakes is that I can stop ok if I use only the rear brake, (I tried that test) but I always use both out of force of habit.

[frankd]

If you're sure you have all the air out of your brake lines, then disconnecting the anti-dive units will make your brake levers a lot firmer and they'll engage with less lever travel. However, the right front brake won't stop much harder. Because of the different position of your fingers now, you may be able to pull a little harder. Also make sure you don't have frozen caliper pistons. To do this, look at your brake pads and make sure they are wearing evenly. Then colapse the caliper and pump it back up a couple of times. If the piston is binding or frozen you will feel it. NOTE

 

 

Frank D.

[jasonm.]

Yes, the weight of the bike does play a huige role in the stopping power of any bike. It's a lot easier to stop a 500 lb bike than a 900 lb any day. There is also another factor though, the MK! ('83 - '85) have inadequate brakes to begin with. The MK2 brakes were a vast improvement with the 2 piston calipers and larger rotors, along with the anti dive being converted to a solenoid instead of the brake power robbing hydraulic setup! It costs a lot to convert as the front forks have to be changed out along with the rotors and calipers but it does make a night and day difference. Add stainless steel brake lines that don't flex like the rubber lines do which robs braking power and you will notice even more improvment in braking! The final step is to install calipers from an R1 which are 4 piston calipers. Of course you can always delink your rear from the front and have 2 brakes working with the front brake instead of one...

FYI... I thought R1 calipers are not a direct swap to a 1200....just for 1300? ANd yes, as stated above. Those little antidive hoses are not a big help. Remove the hoses and swap the bajo bolts w/new washers. Also the 1200's are difficult to get all the air out of the lines...because there is not bleeder at the steering neck...which the 1300's have. SS lines a another BIG help.

[GaryZ]

The MK2 brakes were a vast improvement with the 2 piston calipers and larger rotors...

 

Yes, yes, and no

The MKll has two-piston calipers and smaller rotors on the front;

298mm x 8.5mm for the MKl

vs

282mm x 7mm on the MKll

[gscbertrand]

I got all 8 hoses in SS for $150.00 at my door from apexbrakes.com. All new banjo bolts and washers and a colored cover of my choice.

[dingy]

When you start getting into replacing brake components on a Venture, there are many variables that will effect the results.

 

Attached is a PDF formatted chart that I have made up with quite a bit of information in it.

 

I have highlighted a few areas that have a large impact on braking.

 

The master cylinder area is shaded in red, the formula for this is R²*pi=Area (R being half the diameter of the piston).

 

Total caliper piston area is shown shaded in green. Total caliper piston area is calculated by using the formula above for all the pistons in the calipers that are driven by the master. Note that some calipers have pistons of different diameters.

 

Ratios are highlighted in blue. Using the total caliper piston area divided by master cylinder area a ratio can be determined for the interaction of the brake components. Ratios for 1st gens are shown in a linked and delinked configurations, yellow highlight.

 

Linked is a brief site going into these ratios.

 

http://www.vintagebrake.com/mastercylinder.htm

 

There is a very basic picture attached I did showing the dynamics in a basic hydraulic setup.

 

One of the key elements in braking force that most of us as casual tinkerers will probably not change is the braking lever geometry. This ratio between the pivot point and the driving arm for the master piston is a key element in the operation of a brake system.

 

Attached chart does not take into account the surface area of the pads or the diameter of the rotor which will have a great influence on braking.

 

Gary