Twinpot Brake upgrade on 78 Skunk

[salty_monk]

Got it. Will send them early next week.

[Jamie]

Great, looking forward to getting them.

[RustyStuff]

Do the brackets fit the Single brake GS450's?

[tkent02]

Do the brackets fit the Single brake GS450's?

It should, I used it on my single brake 550, the caliper on the 450 looks like it mounts the same. I have not taken it off to measure anything.

[bwanna]

Do the brackets fit the Single brake GS450's?

I have one on my 82 gs450 and it works very well

[tkent02]

I have one on my 82 gs450 and it works very well

Did you find that 450 needed better braking? I'm just curious, mine seems very good just pushing it around, rolling it down a hill and trying the brakes, but I haven't ridden it yet.

[bwanna]

Did you find that 450 needed better braking? I'm just curious, mine seems very good just pushing it around, rolling it down a hill and trying the brakes, but I haven't ridden it yet.

I commute through city traffic before getting to country roads. I find the stock bashes didn't give me the confidence to stop immediately in the city. In those times I got caught in the rain the stock brakes didn't have enough pressure regardless of the type of pads I used. The 2 cylinder brakes provided me a stronger grip and this more confidence in all situations.

[philosopheriam]

Salty,

Do you know if anyone has had any issues with the CBR900RR rotors - the center bore on these rotors is 62mm - larger than the stock hub bore.

This will cause the rotor to no longer be hub-centric.

These are the rotors I purchased:

http://www.ebay.com/itm/140957390853?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649

[philosopheriam]

Picture of rotor and hub

[tkent02]

The bolts will hold everything in place just fine.

[salty_monk]

The bolts are shoulder bolts & as stated above appear to hold everything in place just fine.
We are going up from M6 to M8 on the bolts for a start & the forces are around the axle not across the hub so the bolts take all the forces whether the rotor is tight to the hub or not...

Many people on here with lots of miles on this upgrade. As ever fit at your own risk, if you are not confident you can send them back to me no problem.

[philosopheriam]

Salty,

I did not mean to cast aspersions on your work - I was simply concerned with the possibility of radial runout.

I suppose the key here is to make sure that the bolt holes are drilled/enlarged correctly and proper torque is applied to the rotor bolts.

Also, you mentioned something else which is important - the stock bolts have a shoulder on them, and thus, the shear surface is distributed on the shoulder, not the threads.

[salty_monk]

No problem & no offence taken, response not meant to sound defensive just honest.

The key is:

1. Make sure the rotor spacer is fixed centrally to the rotor when you drill the holes.
2. Drill the holes straight & true to size.

In honesty I have measured these & I have also drilled some I've used personally where I have "eyeballed" it & then put a hand drill through. No problems experienced either way. I have a reasonably calibrated eye. There is some room in the caliper for minimal run-out at the edge so although not ideal I don't think it would cause too many problems. I usually balance the wheel with the rotors fitted (although again I suspect it would have minimal effect that close to the hub).

For sure the shoulder bolts are important. All rotor bolts I've seen to date have some kind of shoulder - presumably because that takes the torque on the rotor when the brake is applied.

[philosopheriam]

Also, for my own edification...

Your spacer + the new rotor seems to have the same thickness as the original rotor (approx 10mm). So, in this instance, I'm assuming that the speedo dust cover doesn't need to be trimmed. Right?

[tkent02]

I had to trim mine quite a bit on the '79 550. Didn't at all on the '82 1100G.