Author Topic: Rear Brake Help Needed  (Read 13524 times)

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Thumper

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Reply #15 on: March 10, 2008, 12:02:55 am
Actually, I had it adjusted lower to get it out of the way of my foot.  I don't like the idea of my foot resting on the pedal in case the brake light is always on.  I set the pedal back up to the stock position hoping for more braking power.

The rear hub - where I assume the brake shoes are - seems puny.  Not much diameter to it.  If it was bigger the brakes might be better - but it's not so.

Are there any aftermarket shoes that will improve the braking?

As a test, recommend you adjust it back up to reduce freeplay. On the centerstand, adjust it until it engages (binds). Now back off until you have some freeplay (say about 3/4") at the rear pedal. Take it out for a spin and see if it performs as you'd expect. If so, then you'll have to sacrifice convenient foot positioning for working brakes.

Matt


fredgold52

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Reply #16 on: March 10, 2008, 01:40:58 pm
I am assuming these are right side brake pedals with a cross-over?
I find the original left foot rear brake, left side rod really pretty good with only about 950 miles on the clock and done nil to it!
I wonder if there is some torque flex etc in the cross over design?

I think you are right LSM.  I think my brakes could be centered better in the drum, but there is also a considerable amount of flex in the system.  Once the shoes engage, the lever will continue to flex another inch or more. 

When it's warmer I'll take it apart and re-assemble.  Some glaze removal and recentering will probably do it.
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baird4444

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Reply #17 on: March 10, 2008, 08:08:51 pm
Fredgold-
there is considerable flexing or twisting in the crossover rod that goes from the pedal to the brakeside once contact is made giving that spongie feeling. I have read of a couple of fixes...  welding a length of 3/16 angle is one to keep it from flexing.
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cyrusb

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Reply #18 on: March 21, 2008, 01:26:11 am
Your post made me check my back brake performance and it is weak also. It has gone unnoticed all this time because I'm a front braker with slight rear,(braking that is) so who knew? I can tell  you It's not the size thats the problem because a brake just about that size will stop a 500 lb 1977 XLH just fine. People who mentioned the twisting tube I think are spot on. Also the cranked operating rod cant help either,Why cranked? A straighter one would work on mine .
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deepak

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Reply #19 on: April 03, 2008, 10:46:03 am
I join the friends who believe that the Bullet rear brake needs a good improvement.
I am exploring some ways for this.
I think the rear brake could be upgraded from 6" single leading shoe type to 7" twin leading shoe type in which parts from the 7" front brake in current production could be used with some suitable modifications.
This would include following -
1) Modifying the existing rear drum and sprocket unit to have a larger drum with larger sprocket (42 or 44 teeth) on it.
Inner width of the new drum should be the same as the existing which may accomodate the wider(1.25")  7" shoes due to available space . The existing 6"shoe are 1" wide.If required due to space problem , the 1.25" width may be modified suitably .
2) Increasing the gearbox sprocket (18 teeth from 16)) suitably to maintaing the sprocket  teeth ratio, increasing chain length suitably.
3) Repalcing the existing 6" rear brake plate by the 7" Twin leading shoe brake plate with modifications such as removal of the pair of projections  (between which the projection on the front fork tube is accommodated) , Flattening the curved outer surface of the brake plate, ensuring the thickness for suitability for correct fitting etc .
4) The brake operating arms mounted on the brake plates would need to be shaped suitably
5) The link rod between the two arms as well as the main rod connecting with the barake pedal would need to be shaped suitably.
6) The width of the slotted portion on the rear fork plate which accommodated the brake plate connection would need to be increased to enable the two adjescent projections on the 7" brake plate.
I have not attempted the above yet, but a close look on both the assebly of the brakes inspired the idea to me .
Hope, the above idea may be useful.

Regards




cyrusb

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Reply #20 on: April 03, 2008, 04:40:43 pm
Thats a lot of work . The stock size rear brake should not have any trouble at least skidding the rear tire if it worked correctly. Mine will not. I wonder if the bikes with left side brake pedal have the same trouble. The left side being more direct, without the twisting tube. I have not had the opportunity to open up the brake yet, but mine feels as though it has grease on it. Like I said earlier a brake just about that size works just fine on a 500lb XLH. So I doubt its the size thats the problem. It might be just the cam angles are wrong, limiting the leverage that they exert.
« Last Edit: April 03, 2008, 04:43:17 pm by cyrusb »
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Bankerdanny

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Reply #21 on: April 03, 2008, 04:47:36 pm
Rear drums of a similar size hae been used on more modern, heavier, and faster bike than the Bullet.

Besides, the front brake is much more important to stopping power, that's why manufacturers went to front disks land before adding them to the back and why so many cars still have drums in the back.

As long as it is properly adjusted the existing rear brake should provide ample stopping power.
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cyrusb

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Reply #22 on: April 03, 2008, 08:31:19 pm
Fredgold, couldn't you just lower the pedal at the splined connection and still have the brakes adjusted tight? I know this will probably not help the brake work any better but at least it would be adjusted right.
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LotusSevenMan

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Reply #23 on: April 03, 2008, 11:53:34 pm
Have to say my back brake works very well. Really pulls the bike up if required without the use of the front brake (done it just to see if it would). Has much better feel and action than the disc brake on my Honda FireStorm!!!!!!!!!!!!!

Have to say my Bullet has the direct linkage left side brake action  (as it was originally designed) and I'm sure that the additional  torque 'wind-up' of the right side transfer shaft is part of the reason for poor performance and that 'cranked' operating rod. Straight pull is best!! ; IMHO of course!
« Last Edit: April 10, 2008, 07:40:01 am by LotusSevenMan »
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baird4444

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Reply #24 on: April 04, 2008, 05:10:26 am
Thats a lot of work . The stock size rear brake should not have any trouble at least skidding the rear tire if it worked correctly. Mine will not. I wonder if the bikes with left side brake pedal have the same trouble. The left side being more direct, without the twisting tube. I have not had the opportunity to open up the brake yet, but mine feels as though it has grease on it. Like I said earlier a brake just about that size works just fine on a 500lb XLH. So I doubt its the size thats the problem. It might be just the cam angles are wrong, limiting the leverage that they exert.

       cyrusb-  you are right...  the main issue in the leftfoot brake is that there is a ton of mechanical advantage LOST in this bodged up deal. Most of the braking should be done with the front but it would be nice to have more in the rear. The 2 easiest things that we we can do is to reset the arm at the axle to be at a 90 Degree angle to gain the most mechanical advantage. The other is to eat 2 double cheeseburgers a day to give you more mass to stomp on the pedal....     OK, make sure the brake plate is centered.
   I wuz looking at mine yesterday and there is some mech loss caused by the rod having that little bend in it to get it over the rear footrest.  If ya got a solo...  remove the footpegs and straighten the rod. If you are bound to take SWMBO  on a regular ride... I think the plate that the rod fastens to on it's front end could be extended with just a little welding so a straight rod could be used...  taking another flex out of the equation. There is more that could be done but these are the easiest.
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scoTTy

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Reply #25 on: April 05, 2008, 03:36:11 am
er so right now it's kinda like ABS brakeing and it doesn't work and you are looking for the hand brake___i've always been a front brakeR too...  rear brakes are for going down an inclined street in the rain...  and having to stop ...  :o




    and actually my electra's rear brake behaves in the manner it was built for... no problems here... ...  I catch it with my heel anyway since my lower right leg is carbon fiber
 
« Last Edit: April 05, 2008, 03:58:16 am by scotty »


deepak

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Reply #26 on: April 06, 2008, 09:06:49 am
As regads the stopping capacity , and the size of the rear brake, Royal Enfield (UK) did produce a 7" single leading shoe rear brake for some of their models which could be regarded  as a betterment and which is not seen on the bullet model ,probably because by the time the improved version of the rear brake was introduced, the bullet model was either discontinued or about to be discontinued.


LJRead

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Reply #27 on: April 09, 2008, 05:56:50 am
While taking the rear end of my bike apart the past few days, I had a closer look at the rear brake setup.  What is quite obvious is that much of the mushy feel is because of the long lever arm of the brake lever itself.  Putting pressure on it should put great pressure on the brake pads because the mechanical advantage is so great.  I'm wondering if there might also be a small amount of flexing of the lever itself.  I suppose the lever of a left brake lever model must be the same, but wonder if such a long lever arm is really necessary.  What it all means is that there should be more than adequate pressure on the brake shoes when compared with the front brake.  Perhaps a shorter lever could be used, but I'm not sure how difficult it would be to relocate the pivot point forward. so that the brake lever could be made shorter (by taking a section out of it. Anyway, now I well understand why the thing feels so cushy.  Move the lever down one inch and you are only moving the brake adjustment rod forward by a mere fraction of that amount.  I don't think it needs to be that long - the lever I mean.


cyrusb

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Reply #28 on: April 10, 2008, 01:49:24 am
I bet converting to right hand shift is the ticket. Belongs there anyway....imho
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jest2dogs

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Reply #29 on: April 10, 2008, 03:45:19 am
I have an inquiry in this section (re: 5spd right hand conversion) because of this very same concern. The energy and distance lost to the "play" in the right side rear brake pedal is astounding. Have someone else apply pressure to the pedal while you watch from the side. It's like using a wet rope to push a car.

As for the shifting, even tho' designed with a tunnel for the crossover shaft, the outer transmission case of the 5 spd has a "boss" on it for the casting of the shift lever pivot (forward of the right foot peg...it does not mount concentric with the kickstarter as on the 4 spd.).

Also, since I have a "bum" big toe on the left foot, the nail gets damaged easily. Switching to right side shift would alleviate the pressure point.

I can't help but think that crossover linkages and bandy-legged brake pedals aren't lowering the proper "feel" and responsiveness of the controls.

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