1979 GS 425L Dual Disc?

[Guest]

I'm going to look again but it looked like my front wheel had holes on the right side for a second brake rotor. If that is the case would I be able to get another rotor on the right hand side find onother left fork leg and a caliper put it on the right side and flip around and have the brake caliper in front of the fork for a dual disc setup? Would it be worth the effort?

[Midwest FZ Rider]

Would I need a new master cylinder?

[pete]

While I'm not 100% sure it sounds a bit risky doing it that way. The fork legs and calipers are designed to deal with braking pressure pushing into the fork leg, not pulling away from it.

In addition, you may find some weird handling with that setup as well with one side pushing and one side pulling... I expect it might want to pull to the left during braking.

If you want dual discs, you'd be better off finding a 550 front end and swapping the whole thing. Someone on here did it and it's a straight swap apparently.

I think it may have been CDC who did it but not 100% sure...

[Midwest FZ Rider]

Do you think the issue would be because one of the brakes is leading and one is trailing?

[GateKeeper]

Do you think the issue would be because one of the brakes is leading and one is trailing?

yes

that is what pete was saying in his post above

[Suzuki_Don]

Not to disagree with Pete, but a lot of the early super bikes had the caliper in front of the forks. e.g. the Kawa Z900 and the Suzuki GT750. A mod in "the day" was to swap the fork legs around so the weight of the caliper was behind the fork leg instead of in front of it.

The other point about the bike pulling to the left or right is not valid, that can happen on a four wheel vehicle where one wheel will pull the vehicle to the left or right, but the two calipers are working on the one wheel and if one is exerting more pressure than the other it just means one disk is slowing the wheel more than the other, but both in combination are slowing the wheel more rapidly.

I have seen bikes with the calipers mounted fore and aft with no problems, it just doesn't look that great.

If the 450 forks are 35mm then 550 or 650 front forks will fit.

[Midwest FZ Rider]

That was kind of what I thought too. I knew I had seen it in older pictures of bikes. I should have stated that this isn't something I am going to run out and do tomorrow. It's just been rattling around in my head for a while and I wanted to see what other input this group could add.

I think that maybe what Pete was getting at would be that there would be a mismatch of forces on the fork legs? Not really a pull in a specific direction like a car would. Though if the forks deformed enough there could be an effect on the steering. Really my ideal setup would be to find a fully adjustable USD front end for my SV650s and the swap the standar front end with its race tech internals and emulators to the GS. But that would be more $$$ than a fork leg, caliper, rotor and possibly a master cylinder.

[pete]

Not to disagree with Pete, but a lot of the early super bikes had the caliper in front of the forks. e.g. the Kawa Z900 and the Suzuki GT750. A mod in "the day" was to swap the fork legs around so the weight of the caliper was behind the fork leg instead of in front of it.

The other point about the bike pulling to the left or right is not valid, that can happen on a four wheel vehicle where one wheel will pull the vehicle to the left or right, but the two calipers are working on the one wheel and if one is exerting more pressure than the other it just means one disk is slowing the wheel more than the other, but both in combination are slowing the wheel more rapidly.

I have seen bikes with the calipers mounted fore and aft with no problems, it just doesn't look that great.

If the 450 forks are 35mm then 550 or 650 front forks will fit.

I stand corrected Don... it just didn't sound like something that would be safe to do to me... and I probably should've put in big capital letters... I'm no expert!

Perhaps I should keep my pie hole shut? Hahaha

I think the most valid point here is your comment that it just doesn't look that great

Personally I think the 550/650 front end swap is a better deal still... just my 2c though

That was kind of what I thought too. I knew I had seen it in older pictures of bikes. I should have stated that this isn't something I am going to run out and do tomorrow. It's just been rattling around in my head for a while and I wanted to see what other input this group could add.

I think that maybe what Pete was getting at would be that there would be a mismatch of forces on the fork legs? Not really a pull in a specific direction like a car would. Though if the forks deformed enough there could be an effect on the steering. Really my ideal setup would be to find a fully adjustable USD front end for my SV650s and the swap the standar front end with its race tech internals and emulators to the GS. But that would be more $$$ than a fork leg, caliper, rotor and possibly a master cylinder.

That's sort of what I was thinking, but again I'm no expert... I thought the push/pull effect would be bad for forks not designed for it... maybe not?

There was a guy on here (Billy T) that had a modern USD front end bolt straight onto his 450 and another guy Scottychop did a similar thing with his 450, so it's definitely doable, but yeah there will certainly be some $$$ involved...