Re: 83 interstate mix-mathced brake rotors? UPDATE!!

[JSBail]

I'm desperately trying to improve the front brake performance of my 83 interstate without having to resort to "un-linking" the brakes. While looking into options like have my front rotors resurfaced or maybe even new rotors, I spotted something that you would think I would've taken notice long ago (I actually did but didn't give it much thought) and that is the difference in construction between the left front rotor and the right front rotor. Take a close look at the pics and you should easily spot the difference. My question is is this how it may have came from the factory or has a previous owner swapped another rotor on it? If so then what front rotors should my 83 have? I know the right caliper has slightly smaller pistons than the left which is why I never gave a second thought to the differences in the rotors but it seems every pic I've seen so far of 83 interstates show a matching set (or opposite hand) of front rotors while mine is not. Is somebody messing with me?

[sgwilly]

Dat ain't right. I can say my 83 Interstate has the "spiral" type (so does the standard). The 83 Aspencade had a different type but I'm not sure if that's the other one you have. They were different thicknesses as well. I believe the Aspencade rotors had internal channels (were somewhat hollow) to improve cooling.

That all being said, I don't think it's the different rotor designs that is leading to poor brake performance. Things you can do to improve them include: Get new hoses (preferably braided stainless steel) as old rubber hoses "balloon" when under pressure. Flush entire system with DOT4 or 5 and be very thorough about getting all the air out. Rebuild the master cylinder and calipers. These hard SS rotors can't be turned but they can be milled - not any shop does that so you need to check around.

In the end, even with bringing everything back up to snuff it won't have the freakishly powerful braking ability of modern brakes because it's an early 80's design. But you can regain a solid feel and have capable brakes that don't scare you.

And before you ask, the direction of the spiral does not matter.

[JSBail]

Thanks Steve. As it stands now the entire brake system has already been rebuilt including new pistons in the calipers and rebuilt M/C and although it may not look like it, it does have SS brake lines. The lines have a transparent but dark colored protective coating that may make it appear as if they were the old rubber lines in the pics. The bike for the most part stops fine when using both front and rear brakes, the issue is that I have a poor sense of balance and prefer to have both feet on the ground when I come to a stop and that means taking my foot of the brake in that last 5 to 10 feet when coming to a stop and the moment I do that, I lose 2/3's of my braking power due to the linked brakes and rely solely on that left front caliper and squeezing really hard on the front brake lever to do it, squeezing so hard that my arm tenses up and I can loose the "feel" of the bars so to speak because my right arm is tense because I'm squeezing the brake so hard while my left arm isn't. I've come close to dropping the bike a number of times because of it when stopping. I don't expect it to stop with the braking power of modern bikes, I just want that left front caliper to have enough power when coming to a complete stop without having to have a death grip on the brake in that last 5 or 10 feet especially when riding 2up. Right now I'm kicking the idea around of a different front M/C but not sure what to use and what brake pads would be best. If anyone can give me recommendations on that, let me know.

[Rat]

Unlinking is pretty straightforward ... I like to use a double banjo bolt and run a separate line to each front.
Need a 14 mm front master, but this is one place the cheaply available far eastern stuff is good enough ...

Gord(and why I like the '82)Jones

[sgwilly]

Given your circumstances, you may want to look at either de-linking and getting a larger front master cylinder or de-link and get a modern big brake system in there. There used to be a guy doing these big brake conversions on older bikes (fishheadbigbrakes) but his website is no longer active. You can still see some of his work to get ideas of what's needed if you do a search on it.

One path is way cheaper. One is way better.

[flyin900]

That one rotor is off an 82 model of GL or CB series Honda that definitely used that style. Whether it is making a big difference or not is hard to say.
My guess is it isn't your issue and a number of steps already outlined will likely help, yet as noted nothing like a modern bikes braking ability.

100_0037.JPG (212.28 KiB) Viewed 254 times

[JSBail]

Unlinking is pretty straightforward ... I like to use a double banjo bolt and run a separate line to each front.
Need a 14 mm front master, but this is one place the cheaply available far eastern stuff is good enough ...

Gord(and why I like the '82)Jones

I'm trying to avoid un-linking the brakes if I can however I'm not ruling it out either. My question is what length of line did you need for that right caliper and how did you know how to clock the banjo fittings when ordering? Or did you use custom lines where you where able to clock the banjos yourself?

[Rat]

I got custom lines made to my measurements from Apex here in Canada ... ordered the double banjo from him too.

http://www.apexbrakes.com/custom.asp?fi ... ines=black

Gord

[JSBail]

I got custom lines made to my measurements from Apex here in Canada ... ordered the double banjo from him too.

http://www.apexbrakes.com/custom.asp?fi ... ines=black

Gord

I just got in touch with the fellow who made the Apex lines for my cb750. He said clocking the ends isn't an issue because they have swivel ends available. In regards to the right line I'd need just one end to swivel. This just might be the way I go.

[Sidecar Bob]

The linked brake system is designed to work best if you use the foot pedal at least as much as you use the hand lever. If you are trying to use the lever more (as would be desirable on a bike without linked brakes) you are basically trying to stop with only 1 of the front calipers.

Un-linking the brakes isn't quite as simple as plumbing both of the calipers to the front master cylinder.
To start with, if you un-link the brakes you would need to change the master cylinders. A master that is designed to operate 2 calipers needs to pump twice the fluid that a single caliper master would for the same lever movement. This means that if you connect both of the front calipers to the single caliper front master the lever would have to move almost twice as far for the same brake application - at best it would always feel mushy, at worst it could contact the grip before the brakes were fully applied. If you connect the rear caliper to the 2 caliper rear master by itself the pedal would only travel about 1/2 the distance - it would feel "wooden".
And then there's the issue of the mismatched calipers. Honda balanced the work done by the linked calipers by using a caliper with much smaller pistons on the front than the rear. When you connect calipers with different sized pistons to the same master cylinder the smaller pistons will move farther than the larger ones and apply pressure to the disc sooner so when you press the rear brake pedal you are actually using the front brake more than the rear.
This means that the front caliper that is linked to the rear also has smaller pistons than the front caliper that is controlled by the front master cylinder, which means that when both are connected to the front master cylinder the one with smaller pistons will still grab the disc sooner & harder than the one with the larger pistons (in my case the pads on the side with small pistons wore out about twice as soon). Think of it as if you have 1.5 front calipers - better than 1 but not as good as 2.

FWIW, I eventually changed to a matched pair of front calipers (mine came from a CX650E but a matched set from any Honda with calipers that look like the original ones will do) and now the brake has much better feel and the pads wear out evenly.

BTW: The discs on the Aspencade are vented (similar to car discs) so they are much thicker. That isn't an Aspencade disc.

[JSBail]

For now the plan is to get the correct rotor, put good pads on it and see how it works first before I dive into un-linking them. What's odd is that while searching ebay for gl1100 rotors, the majority of the ones I spotted were the same as the left rotor on mine while nearly every picture I see of an 83 interstate show a matched pair like the right rotor. Go figure.

[sgwilly]

83 1100s were a slight stylistic departure from from previous 1100s (80-82) and only lasted 1 year before the major rework of the 84 1200s. So that ratio seems about right.

[flyin900]

That right rotor is correct while the left was used on many different Honda bikes so it is more common for availability. The 80-82 GL's used that left style rotor, or a variation of that design. While the 83 was a one year wonder style prior to the 84 GL1200 changeover.

[MikeNTexas]

Make sure someone hasn’t replaced the master cylinder with one that has a larger bore. That will make the handle firmer but decrease the pressure to the front brake.you will be moving more fluid but with less pressure.

[JSBail]

Just a quick update. The plan for now is to see if I can get the front brake to work better as it is now before I decide to unlink them. The correct rotor arrived today and new brake pads came in yesterday but I'll be gone all weekend and wont be able to work on it till next week. I'll update again on how it works out.