eiger Posted May 4, 2004 Report Share Posted May 4, 2004 I am looking to improve the front brake on our TY175 and am thinking of converting it to disc. I have been looking for a front end off a broken Gas Gas or similar. Have any of you chaps carried out such a mod and have you any advice? Thanks Eiger. Quote Link to comment Share on other sites More sharing options...
woody Posted May 4, 2004 Report Share Posted May 4, 2004 The biggest problem is mounting the caliper. If you know someone who is very good at aluminium TIG welding and does a neat job you can have a mounting bracket welded to the fork leg. It shouldn't distort the leg as I've had an Ossa leg done by a friend who is an exceptional welder, although TY175 legs are pretty spindly. The alternative is trying to fashion a bracket that somehow clamps to the leg. What I did was to make a copy of the caliper bracket of a Marzocchi fork leg as fitted to an old disc braked Beta, Fantic, JCM etc. (air-cooledtype) and mock up a fitting with the wheel and caliper from same bike on the Ossa leg. Only problem is that like the TY the Ossa has its spindle directly under the fork leg whereas the Marzocchis are leading axle so the caliper bracket needs to be shaped accordingly to get the caliper to sit correctly as the wheel and therefore th disc sits further back in the Ossa forks. Once that was done I had a bracket machined properly out of alloy (another engineer friend - what I'd do without 'em I daren't think) and then had it welded on. Then use the wheel and caliper from the same bike. There are a few being broken now. The old type discs and wheels aren't as 'attractive' or efficient as the more modern type but chances of getting reasonably priced modern stuff is slim. Before doing that however, have you tried genuine Yamaha brake shoes in the hub. The friend of mine who is the engineer has a TY175 and his front brake was poor also. He ditched the aftermarket shoes and used genuine Yamaha ones (there are about 4 different compounds apparently) and it worked perfectly. I've bought some for my Majesty but haven't been able to try them yet. They are the same as Yam mono rears, supplied by Steve Goode. Try him on 01938 850544 and ask for the same shoes that I've had - he'll know what you mean. They are around a tenner if I remember. Cheaper to try that first before going the disc route - which may be frowned upon anyway, depends where/what you ride. Dave Quote Link to comment Share on other sites More sharing options...
endo kid Posted May 4, 2004 Report Share Posted May 4, 2004 Eiger i have a Honda tlr 250 and the brakes were crap.I dont know if this will work on a Yamaha what i do is file the brakeshoes flat at the pivot end.This allows the brakeshoes to float in the hub.So that when you apply the brakes the whole face of the brakeshoe makes contact with the hub.This gives you much better brakeing. CHEERS ENDO KID. Quote Link to comment Share on other sites More sharing options...
kevin j Posted May 5, 2004 Report Share Posted May 5, 2004 I have mounted a late GG wheel and 4 piston disc brake to my TY350. No welding either, I floated the new bracket on the axle hole and took the torque reaction through the original lug on the side of the lower leg. It works awesome. somewhat stronger, but PRECISE and good feel. I am pushed for time now, I can send you some pics later. send me an address. Shoes: I think front Ty twin ;shocks and back TY mono are same, can't recall. Anyway I have bought a lot of shoes trying to find a good combination. (til finally the disk.) genuine yamaha vaires a lot. I got some NOS yamaha they were great. nex time Yam sent SBS Scnadinavian Braking System shoes. Hard as nails, wore forever, and very little braking. Vesrah, Japanese, has worked well for me. I get from Dennis Kirk Co. in the US. din't notice where you are. plan on changing offten. Some cleaners reactwith the resins, lose the friction. Some (like ether starting fluid spray) react and and make the shoes shoe sticky they grab and lock up. Another advantage of the disk. have to run, k Quote Link to comment Share on other sites More sharing options...
woody Posted May 6, 2004 Report Share Posted May 6, 2004 I have mounted a late GG wheel and 4 piston disc brake to my TY350. No welding either, I floated the new bracket on the axle hole and took the torque reaction through the original lug on the side of the lower leg. That is a good way of mounting a bracket on the mono, it was an aftermarket option here in UK, but the twinshock Yam forks don't have the lug on the lower leg for the brake plate for the torque reaction. They had bolt on torque arms so this method isn't possible. Quote Link to comment Share on other sites More sharing options...
kevin j Posted May 7, 2004 Report Share Posted May 7, 2004 True. I'll have a look at the 175 this weekend. I think the same concept could be used: avoid welding by pivoting the bracket on the axle. Then either take the bracket in one piece up to the bolt lug, or using a torque arm bar up to the bolted lug, similar to the drum. It sort of defeats the spirit of the twin shock, but the brakes are so much better I would find a way to make it work. k Quote Link to comment Share on other sites More sharing options...
woody Posted May 7, 2004 Report Share Posted May 7, 2004 Yep, that'd be good if it could be done, with the advantage that the fork leg is left unmolested and therefore retains it's original appearance. Can also be transfered from bike to bike as well. Quote Link to comment Share on other sites More sharing options...
woody Posted May 7, 2004 Report Share Posted May 7, 2004 Yep, that'd be good if it could be done, with the advantage that the fork leg is left unmolested and therefore retains it's original appearance. Can also be transfered from bike to bike as well. Quote Link to comment Share on other sites More sharing options...
woody Posted May 7, 2004 Report Share Posted May 7, 2004 It sort of defeats the spirit of the twin shock, but the brakes are so much better I would find a way to make it work.k I agree with you here although it depends what it is being used for. I have started to do one of my Ossas with discs but only to ride in the odd modern event where decent brakes are needed. I'd never ride it in the twinshock championship here in the UK and I don't think it should be allowed although there are no rules yet to prohibit it, but I agree that it is not really in the spirit of the events. Quote Link to comment Share on other sites More sharing options...
eiger Posted May 8, 2004 Author Report Share Posted May 8, 2004 Thanks for the replies. I've decided to go for the cheapest option for now and try endo kid's idea re the brake shoes. I enjoy riding the bike and have also enjoyed building it up but I hadn't expected it to cost quite so much. Sadly my much beloved (until recently!) wife has also discovered how much the bike stands me at and has insisted I spend the same on the kitchen! Their goes my idea for a 320 Majesty! Eiger. Quote Link to comment Share on other sites More sharing options...
endo kid Posted May 8, 2004 Report Share Posted May 8, 2004 EIGER let me no if it worked OK. CHEERS ENDO KID Quote Link to comment Share on other sites More sharing options...
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