OzVMX Forum
Clubroom => Bike Talk => Topic started by: mudguard on January 11, 2011, 10:12:11 pm
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Hi,
How can I get the front brake on my 1976 YZ250 to stop the bike within the distance of a footy field? ??? I have fitted a new set of Yamaha brake shoes and a new brake cable, but no matter how much brake I grab, the bike just rolls to a stop. Is this just the way vmx bikes are or can you get the front brake to perform well?
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That's how they are.. you have to drag both feet then pitch it sideways
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If it makes you feel better, they're the best SLS MX bike drum brake out there...
Clean, not overly polished drum?
Good bearings? (Yes, they matter)
Brake lever with the right ratio?
Decent quality cable?
Is the lever coming back to the bars, or is it firm but useless?
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Hey Nathan,
The lever is firm, not going all the way to the bars. It is a cheap lever though. Wouldn't have thought lever types could make much difference? I got some info a while ago that I can take my wheel and brake plate somewhere and they can get the entire surface of the brake shoe to bond to the drum. Don't know who does this though!
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There's lots of different levers out there, and they do make a difference.
The XR Hondah lever will give a bit more mechanical advantage & is easy to get. The genuine Yamaha cables won't fit though, unless you file out the part of the lever blade where the cable passes through - a tedious prick of a job.
Most of the dramas with shit drum brakes that are fixed by matching the shoes to the drum, relate to shit quality components - Yamaha brakes are supposed to work well because they don't have any shit quality components in them...
Try roughing up the brake drum surface with some sand paper and the Honder lever and see how it goes.
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Use an inside Caliper ( like and inside ruler) to make sure the drum is round.If it not it need machining.
Try a Yamaha AG 200 front brake cable and lever (or XR 200 lever )
Match the new shoes to the hub by clouring in with texter or white board maker the shoes to find the high spots.
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Thanks guys,
Plenty of info here to work with. Should get a much better result. :)
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Forgot to add cheap levers and perchs flex at the prech and reduce braking.
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Guys working on Husky,s in Amerika are glueing sandpaper inside the brakedrum and giving the wheel a spin to match the shoes to the drum.
Also fixing the paper to the shoes and giving the drum a bit of a rub.
Never tried it but it sounds good.
Mike :)
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missing some important points. This is not my language, so have mercy and fun ;)
- first check the drum. Should not be konical or not round (if so it needs machining)
- check wheel bearings and seals (no oil- or greasedust on the shoes/drum)
- cam in plate must be in good technical order and easy to turn (no worn out bearing)
- quality cable on its way up to the lever guided as straight as possible
- rough the drum with rough sandpaper (P40-80) and wipe out the rusty ring
- rough the shoes also with P80 on the complete function-surface
- install the wheel, pull the brakelever strong and hold it while tighten the front axle! (really important to center the plate in the drum)
- lever on the plate should be in a 90° angle to the cable when brake is pulled
- go an ride a few minutes with using the brake softly
- back in the shed after removing the wheel you will see glossy parts on the brakeshoes
- remove these glossy parts with a fine rasp and ride again (always tighten frontaxle with lever pulled!)
- work is done, if the surface of the shoes wears over 2/3 (glossy parts growing)
- cutting off the lining 10-20mm on the camside of the frontshoe increases the braking effect on single leading brakes
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frank M has it spot on - works for me,took while on Xl hub but got there
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Hey Frank M.
I will use your advice, step by step, and report on the outcome. :)
Wayne.
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drums are funny. i found that the drums on the front of my PE are useless when i had it going before restoration. havnt had the chance yet to try an resolve this problem but the front drums on a old xl 250 i had worked great. they really grabbed. have got the front drum of the PE in the shed an it has plenty of life left in the shoes. so i scuffed the shoes with a wire brush. i havnt done anything to the drum will probably just give it a sand paper when i get it back, an adjust it. see what happens when i play around with it.
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Quote: "install the wheel, pull the brakelever strong and hold it while tighten the front axle! (really important to center the plate in the drum)"
This is really important however I always get the front end off the ground, give the wheel a good spin in the forward direction, jam the brake on quickly and, while still holding the brake on, tighten the axle and pinch bolts. This will generally turn a spongy ineffective brake into a firm effective brake.
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Quote: "install the wheel, pull the brakelever strong and hold it while tighten the front axle! (really important to center the plate in the drum)"
This is really important however I always get the front end off the ground, give the wheel a good spin in the forward direction, jam the brake on quickly and, while still holding the brake on, tighten the axle and pinch bolts. This will generally turn a spongy ineffective brake into a firm effective brake.
Good one Pete....You put me onto that little tip a while ago and I now do it on all of the bikes and have no brake problems, even the so-called shithouse Maico brakes work great. The difference some of these tips made to my Maico conical front brake was phenomenal. Using the heaviest grade cable and routing the brake the most kink free direct route also add to the efficiency.
Frank M and others have presented some good tips.....
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I lightly machined my hubs on a lathe to make sure they were clean and round. New cable, new shoes and yes, pull it up tight and lock in the wheel. Noticeably smooth and strong compared to original.
Worth taking the opportunity to clean up the hubs if you find you have your wheels in pieces.
Luke
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Another important thing is that standard shoes OD may not be big enough to suit drums that have been machined a few times. I have a couple of bikes that have had so much machined from the drum surface that by the time I have reshaped standard shoes to that diameter, the cam moves too far around to work well. On these bikes I have had extra thick (6mm) linings fitted to the shoes and then machined the linings back to suit the diameter for the drum, so am getting 100% contact area. Lots of trouble despoking and respoking to machine the drum and sending the shoes away for relining, but the results are amazing.
The relining was done by some place in Brisbane. I arranged it through a local (Gladstone) car brake/clutch repair workshop.
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If you have access to a sand blaster clean the brake drum surface ,i have found with all the other tips given you get a good strong feeling brake.