GS425 front brake info needed, please.

[TinkerFreak]

Hi, all. New to the site. I have a fun little project I'm finishing over the winter. It is a chopper-like midi with a GS425 front fork. I procured the whole front fork from a bike junkyard but they didn't have the brake parts. The fork has "GS425" still written on the brake disc and it fit the existing race perfectly. It's a fun little scooter to ride.





I am not even sure of the year of the fork to be honest. It's a single caliper fork as you can tell in the pic. I'm trying to procure a complete assembly--the caliper, hydraulic cylinder, line, and brake handle. Once the mechanicals are perfect then I'll move on to stripping the bike to the frame and rebuilding it.

This was a fun way to get my feet wet with a bike build. If someone has a complete brake setup to part with I would love to buy it.

[cowboyup3371]

Very interesting. Will the kids use it to play around with?

[TinkerFreak]

Very interesting. Will the kids use it to play around with?

Not really, but it's still a toy and not meant for the highway. The motor runs on E85 and the bike needs a front brake. I was surprised so little work made it that quick. It's small enough to be some good campy fun and needs to be safer. I'm over 6ft. tall and it's still a comfy scooter combo to actually ride. It doesn't beat me to death and I won't chew a bumper too easily.

+1 for Earl's brake info. Good reading!

http://members.dslextreme.com/users/bikecliff/images/brakes_odds-n-ends.html

[pete]

That does look like a bit of fun!

Most of the twins share a lot of components, so I wouldn't be surprised if the 400, 425, or 450 brakes all fitted, maybe even the 250 and 300 also.

Jump onto Alpha Sports website and pick a 425 model at random (I'm guessing around 1980) and find the caliper part number, then go to Bike Bandit and do a search on it which will tell you what other models use the same caliper.

Without knowing the year it's still a bit of guess work, but that's the only way I could see to do it with any degree of accuracy at the moment.

[Flaming Chainsaws]

That does look like a bit of fun!

Most of the twins share a lot of components, so I wouldn't be surprised if the 400, 425, or 450 brakes all fitted, maybe even the 250 and 300 also.

Jump onto Alpha Sports website and pick a 425 model at random (I'm guessing around 1980) and find the caliper part number, then go to Bike Bandit and do a search on it which will tell you what other models use the same caliper.

Without knowing the year it's still a bit of guess work, but that's the only way I could see to do it with any degree of accuracy at the moment.

The GS425 was a one year wonder. Only made in 1979.

[mriddle]

I would be afraid that it would be too easy to lock that front wheel with so little weight on it.

Cute little ride though .. looks like a blast.

[TinkerFreak]

Hey all. Thanks for the input. I can't even find a local place that stocks these calipers. I don't see why they wouldn't use the same caliper but it's worth trying to verify it before venturing out again to try and find one.

The center-to-center on the fork's caliper mount is 71 or 72mm. The outer distance of these mounting holes is 94mm.

Dual pistons would definitely be too much brake!