Twinpot Brake upgrade on 78 Skunk

[salty_monk]

Calipers are right.... The rotors might be a bigger dia. The RR came with bigger dia some years.

[carusoat]

I ended up going with a different set of rotors off a 93/94 900rr. They measure 296 and have a different hole pattern than yours. I was wondering if you had any of your bracket kits available?

[salty_monk]

Yes I have some. I can get you some out over this next week no problem. I'll PM you.

[salty_monk]

I got some more bracket kits for anyone that is in need...

[erickson_ron]

I noticed that my left caliper sits 1/4 or so higher from axle then right side. Pad is too high. What am I missing?
IMG_0007.jpg

[salty_monk]

Let's have a side on pic too if you can. I would say your left leg is off a single brake model and the other one is off a dual brake model.

[Chuck78]

Yes, what Dan said, & measure from center of axle to center of lower caliper mounting bolt on each fork slider. The 2 measurements should be the exact same. If what Dan says is the problem, one side would be 10mm further than the other (half of the difference between 275mm & 295mm OEM dual disc vs dingle disc brakes).

Measure both rotors to make sure they are identical. They should be, but some Honda models with ABS have one rotor that works for us and one that wont. The difference should not be in the diameter in that case as far as I have seen, but in the offset of the rotor.

[erickson_ron]

Yes it appears that in this bike's previous life someone fitted a single disc lower on the left. It is a small enough difference that I didn't pick up on it until finishing the brakes. Amazing the demons you will find hiding in old bikes. Thanks all and if you have a spare GS1000E lower left leg I am in the market.

[bobtail84]

Just a quick up date..

After I completed the twinpot upgrade I was never 100% happy with the feel of the brake lever.

So after a little bit of investigation I decided to use the master cylinder from a 96 Suzuki Bandit GSF 600 which cost me ?25.00 from eBay which is about the same in $ at the moment.

My main reasoning was the availability of the initial M/C, spare and service parts. The M/C also is a very good fit on the bars with regards to the switch gear and throttle cables and it also is very aesthetically pleasing meaning it looks like it should be there.

The GSF M/C has the mounts for the wing mirrors, again this was what I was looking for.

After a strip down and clean with a change of rubbers the whole conversion took all of half an hour including re-bleeding the brakes.

The end result is what I was trying to achieve with the original but didn't. The brake feel has gone from OK to absolutely spot on with a true 2 finger breaking with low effort for maximum effect and feel.

[Guest]

That's great, detailed info for people. Great post.

[goldbike]

Gs1000E brake upgrade

Dear sir, I have a 78 GS1000E. Have purchased the CBR900 rotors and the EX500 calipers. Do you sell the brackets that mount the calipers to the forks? How much? And will you accept a money order.
Thanks, James Shinault Goldbike 864-677-4630 evenings 864-677-5630

[80GS850GBob]

....I decided to use the master cylinder from a 96 Suzuki Bandit GSF 600 ...

I love the happy ending, but have to ask, what was the previous MC that you didn't care for? {Just as a reference point for us}

[bobtail84]

I love the happy ending, but have to ask, what was the previous MC that you didn't care for? {Just as a reference point for us}

It was the standard item circa 1980.
I just couldn't get a good feel on the lever even after bleeding the system many times. I put it down to the age of the M/C and how much it had just generally worn over the years even after replacing the rubbers.

[Grimly]

Just a quick up date..

After I completed the twinpot upgrade I was never 100% happy with the feel of the brake lever.

So after a little bit of investigation I decided to use the master cylinder from a 96 Suzuki Bandit GSF 600 which cost me ?25.00 from eBay which is about the same in $ at the moment.

My main reasoning was the availability of the initial M/C, spare and service parts. The M/C also is a very good fit on the bars with regards to the switch gear and throttle cables and it also is very aesthetically pleasing meaning it looks like it should be there.

The GSF M/C has the mounts for the wing mirrors, again this was what I was looking for.

After a strip down and clean with a change of rubbers the whole conversion took all of half an hour including re-bleeding the brakes.

The end result is what I was trying to achieve with the original but didn't. The brake feel has gone from OK to absolutely spot on with a true 2 finger breaking with low effort for maximum effect and feel.

The Deauville (NTV 650) m/c is another useful 5/8" / 16mm one to bear in mind, and sits flat on the bars. Amazing what difference a generation or two of design makes to the feel, yet it's superficially the same thing.

[80GS850GBob]

Any brake conversion has it trails and errors in a refit....just because the oem had twin discs doesn't mean the new calipers area is a match. The needed volume..or wanted volume...when activated, may vary. Too big a volume and the brakes are touchy and hard to modulate....too little and they're soft, not very responsive and not much better than what you started with. A tweener is best, leaning on the side of a a tad more volume.

Some folks think the oem brakes are fine...
I figure these folks are; ham handed and can squeeze harder, never rode a bike with responsive brakes to compare to or just figure they're just supposed to be that way. I'm just not one of those folks...and given this thread, I'm not alone in the want for better braking.