Triumph Rat Motorcycle Forums banner
1 - 8 of 8 Posts

·
Registered
Joined
·
62 Posts
Discussion Starter · #1 ·
So my bike rolled easy for a bit and then got real hard to roll. I suspect the front hub is out of round. The back brake behaves the same way. I will measure the hub tomorrow with an inside micrometer. If I have to have it turned to true it up, do I have to remove it from the wheel? This involves removing the spokes and rim. UGH! What say the experts? Where do I get the work done to turn the hub? I am in Huntsville, AL and lovin it!

Fred
 

·
Registered
Joined
·
4,484 Posts
Hi Fred, Generally out of round brake drum will feel "jerky" while applying brake. Rather like you were pulsating the lever rapidly.

What do you feel when you spin the wheel by hand on the center stand? Do you feel a dragging spot? If you back the brake adjuster well off does it go away while spinning wheel by hand? If so your drum is out of round & needs turning.

If the shoe adjustment is well backed off & you still feel binding in spots, it has other problems, such as wheel bearings. Could be you have both wheel bearing problem & out of round drum at the same time. Often a bad wheel bearing will sound & feel like it's grinding before it binds. If wheel bearings are very bad, replace then retest drum before sending out for turning.

It's better to turn the drum with the wheel laced & spokes tensioned & rim trued. That gives you the best roundness after turning.

I have no idea who can turn motor cycle brakes in your area. That seems to be a lost art these days. However there is a need for that service. Even if you could ship wheels to a know good shop it would be worth it. You may need to remove wheel bearings for the process.
Don
 

·
Registered
Joined
·
2,930 Posts
in addition to Dons advice - check for any "foreign" matter that may be floating around in the drum -- brake linings can come loose too

for skimming the drums - although a brake shop is the best bet , its also a simple job for a good machine shop
 

·
Registered
Joined
·
62 Posts
Discussion Starter · #4 ·
So I went to measure the drum but could not use my inside mics as the brearing races stick up too high and my 6 inch caliber is too small. So I went by Harbor Freight and pick up a 12" caliber and measured the drum. Best I can tell it is only 0.010 in. out of round. That should not be enough to cause a problem. So I will order new sealed bearings and some other small parts today. Whew, that's a load off my mind.

Fred
 

·
Registered
Joined
·
1,131 Posts
Sometimes when this happens the shoes need to be centered. Loosen the nut that secures the brake plate. Put the brake on, and while it is on tighten the nut. It's worth a try.
 

·
Registered
Joined
·
4,484 Posts
Hi NASA, I have some experience on brakes. Generally on these small dia. brakes anything near .005" will give a decided pulsation. A good drum will be .0015 or less. .005 is max for bell mouth or taper or barrel shape wear. Taper or barrel will not cause pulsation though, just weaker stopping.

The drum should be concentric to the axle, but that is slightly less critical than roundness.

Often drum can have dip or high spot which pulsates even worse than simple oval shape.

Hot spots can also cause mild pulsate. On these turning will cure temporarily, but the metal has changed so they often wear out of round soon.

Still I'd turn them with hot spots & see how it lasts.

For sure turn them with spokes laced & trued.

No brake or machine shops in my area can mount a laced wheel. Either the spindle is too fat or it can't clear the rim.
Don
 

·
Premium Member
Joined
·
1,074 Posts
Hi NASA,
You have the twin leading front brake, right?

Did your problem just start recently or have you had the front wheel apart recently?

I had a bad front brake pulse on my tls and found the big nut that holds the brake plate on was loose and that caused the major pulse problem. Mine still pulses a little bit but not near as bad as it used to after tightening the nut. I don't think the nut is suppose to be real tight but plate should not be able to rock back and forth. If you grab the outer edges of the plate and try to wiggle it back and forth and you feel it rock then tighten the nut a little more until the rocking stops. That's what I did and hope it works for you....Gary
 

·
Registered
Joined
·
62 Posts
Discussion Starter · #8 ·
Thanks everyone for all the comments. Just so you know, I just got this bike about a month ago and have not actually ridden it yet. So the saga continues....
I cleaned up the front axle and bearings this weekend. One of the front bearing has chunks missing out of the inner race! I have new ones (sealed) on order. I was working on cleaning up the axle last night and found where it had been clamped in a vice on at least two different occasions and someone went after one end with a pair of vice grips and displaced some metal. Sot I was able to tap a lot of the displaced metal back into place and was buffing it up with some 400 sandpaper and noticed the ends where acting a bit weird. I can see hammer marks on the end of the axle but then took a caliber to it and found both ends are mushroomed out pretty bad. One is swolled up a little over .020 over nominal diameter. Crap! I hope to find a lathe I can use today to dress the ends up.
 
1 - 8 of 8 Posts
Top