Horizons Unlimited - The HUBB

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-   -   86 XL600 Drum to Disc Brake Conversion (https://www.horizonsunlimited.com/hubb/travellers-questions-dont-fit-anywhere/86-xl600-drum-disc-brake-380)

belly 24 Sep 2005 17:02

86 XL600 Drum to Disc Brake Conversion
 
I am looking for somone that might know what the cheapest and easiest way of converting the drum brakes on this old beast to disk brakes. I am an amputee rider and canot use the rear brake pedel. This bike has a bit of sentimental value so it was my intention to convert the drum brakes if possible to disk brakes and run them (intergrate) both off the front brake level. This 86 Model XL600 RMG has 17 inch wheel with cush drive. I am thinking that i may be able to find a wheel that will slip straight. I have looked at a few on the newer model bikes to try and get an idea of how i might be able to do it. I have also exausted all my local wreckers tring to get ideas. The closest thing i can find that i think may slot straight in is the new KLR650 cushion drive 17 inch wheel. Has anyone out there done the conversion or have any hints on how i might be able to get it done.

Matt595 25 Sep 2005 02:33

Hi, it won´t be easy but not impossible, you need to respoke the backwheel and get a new compatible part fixing disc, then you need to attach cylinder with swingarm: usually one bolt and wheel axle.
Maybe you can divide front break lever in 2 giving 50% brake front 50% back, though it can be dangerous as backwheel will slide if braking much.
You'll need to regulate brake pressure, lets say 30% back and 70% front, but I'm no expert.
Regulation can be made with a valves of different sizes.
Make sure master cylinder is ok.
Your best option is to go see a braker who has parts and is mechanically knowledgable, he is capable of adapting something to your bike.
An easier solution is to create a 2nd comand on gearshift side pulling drum brake, like on old bikes behind shift lever.

Good luck,

Matt

JonStobbs 25 Sep 2005 04:26

As far as the mechanical bits at the back end are concerned,if you can find a 1986-on XL600LMF in a breakers,they are disc braked on the back.The swinging arm,wheel and caliper assembly will fit straight on(only reason why you need the swinging arm is for the caliper bracket lugs....maybe get something made-up to do this job then you only need caliper and wheel).I have done this conversion before and for what you are going to do,should work out fine.The biggest problem i had was mounting the brake master cylinder and reservoir to keep it away from the exhaust heat.But if you're going for a linked system this won't be a worry.As for the braking effort,most motorsport suppliers will have quite a few brake balancing/limiting devices to choose from,and with a bit of patience in setting-up you should be able to get it spot on.Even better,if you need to abjust the front/rear ratio(in wet/muddy conditions for example) it's only a fiddle with the adjuster away.Only thing i can't remember about is the rear sprocket of the LMF,if it's the same number of teeth as yours.The conversion i did was on a sidecar outfit and i fitted a special bigger sprocket to gear it down.The standard LMF one has 40 teeth.The pitch is the same though(520).
Good luck,and if i can help,please mail me.
Jon

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Just going for a short ride on my bike....

AZBill 20 Oct 2005 10:19

BY far the easiest way is to go to a MC recycleyard and by the whole front end off of a bike. Triple clamp forks everything. Then all you have to do is change the head bearing in your frame.


Cheers, Bill


Steve Pickford 20 Oct 2005 14:04

Quote:

Originally posted by AZBill:
BY far the easiest way is to go to a MC recycleyard and by the whole front end off of a bike. Triple clamp forks everything. Then all you have to do is change the head bearing in your frame.

Cheers, Bill


I think only the rear is a drum on the 600?

Buying a complete disc brake rear wheel assembly is the easiest way to go - Dominator / XR series etc?

I converted a DR600 with a drum rear to disc rear using an RGV250 rear wheel, sprocket carrier, disc & caliper.

Once I'd machined out the spindle slots in the swingarm from 17 to 20mm, I measured the overall width of the RGV wheel assembly, which happened to be about 10mm wider than the stock DR measurement. I took 5mm off the l/h spacer & 5mm off the outside off the rear caliper carrier. This allowed the wheel to slide in to swingarm whilst retaining wheel alignment.

I welded a lug on to the underside of the DR swingarm & drilled a hole in the stock RGV caliper carrier, connecting them with a Rose jointed torque/brake arm anchor. A bit of messing about was req'd to convert the drum brake lever to operate a rear m/cylinder although you won't have this problem.

I spaced out the front sprocket a little to maintain chain alignment.

Don't be tempted to go too big on whatever front m/cylinder you choose to use or you could end up with brakes that lack feel - smaller can often be better.

Differing wheel bearing size issues can also be overcome by fitting new bearings with the same OD but a smaller or larger ID, bearing stockists can help.


wal750 14 Nov 2006 21:56

I realise this is an old thread but...

I have done this conversion using a Suzuki DR650 rear wheel and caliper.

Fairly easy to do but you will need to weld a bracket on the frame to mount the rear master cylinder.

Spacers may need adjusting on the back (can't remember exactly) but it is fairly simple overall.

Craig

Joe C90 15 Nov 2006 00:10

rear brake
 
It is quite feasible to operate the rear hydraulic brake off a thumb lever on the left handlebar, some of the racing boys do this. speak to any motorcycle sports specialist.


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