gordo Posted January 13, 2008 Report Share Posted January 13, 2008 Hi Folks, I'm looking for a disc brake conversion kit for my 85 Yamaha TY 350. I'm told they're out there, but have never seen one. Can anyone out there help me out. I'de be happy with just the front brake kit. Thanks. Quote Link to comment Share on other sites More sharing options...
eddie_lejeune Posted January 13, 2008 Report Share Posted January 13, 2008 the white frame yams, 90ish , some people had a talon one i think, but this was for the front brake only, i dont think there is one for the back brake maybe im wrong Quote Link to comment Share on other sites More sharing options...
mollygreen Posted January 13, 2008 Report Share Posted January 13, 2008 the white frame yams, 90ish , some people had a talon one i think, but this was for the front brake only, i dont think there is one for the back brake maybe im wrong I had a Talon rear disc conversion as well as the front on my Yam TY Mono. It did'nt work that well and was a pain to set up right. Quote Link to comment Share on other sites More sharing options...
kevin j Posted January 14, 2008 Report Share Posted January 14, 2008 I put a 2000 gasgas front brake and wheel on my TY350. way easeir and cheaper and works great and easy to get parts. Actually was spare parts that I had for kids bike, and just got to thinking it might owrk. Way easy. should be an earlier post on here with some pics and dwgs. if not, send me a message and I'll email pics and details. I would like to hear from someone who has converted the back though. Don't need disk there, but want to get tubeless tire.....disassembly and patching a tube type is a PITA. kcj Quote Link to comment Share on other sites More sharing options...
rory Posted October 12, 2008 Report Share Posted October 12, 2008 Would love to know how one could get a gasgas brake caliper to fit on the drum fork leg of a TY350 ?? Quote Link to comment Share on other sites More sharing options...
kevin j Posted October 16, 2008 Report Share Posted October 16, 2008 Rather than weld or epoxy to the fork leg, I made a floating bracket that rode on the axle shaft, and had a slot that fit around the lug for the drum brake. The caliper bolted to that. (It was steel, as prototype, and a bit heavy. My intent was to make from aluminum after making necsessary changes. It worked great, and I never spent the $$ to have it made in alum.) The axle has some shims and spacers to fit the larger bearings, and to cewnter the wheel properly. I just used shim washers and bits of tubing, but dwg had the dim to make one piece spacers if you have a lathe. I posted pics on TC somewhere in the past. Search for those first please. If can't find, PM me and I will send pics and the scan of the bracket dwg. kcj Quote Link to comment Share on other sites More sharing options...
swooshdave Posted October 16, 2008 Report Share Posted October 16, 2008 Rather than weld or epoxy to the fork leg, I made a floating bracket that rode on the axle shaft, and had a slot that fit around the lug for the drum brake. The caliper bolted to that. (It was steel, as prototype, and a bit heavy. My intent was to make from aluminum after making necsessary changes. It worked great, and I never spent the $$ to have it made in alum.) The axle has some shims and spacers to fit the larger bearings, and to cewnter the wheel properly. I just used shim washers and bits of tubing, but dwg had the dim to make one piece spacers if you have a lathe. I posted pics on TC somewhere in the past. Search for those first please. If can't find, PM me and I will send pics and the scan of the bracket dwg. kcj I searched hi and lo for the post. Can't seem to find it. Went back to 2003. Saw some post where you mention posting and went back from there. Quote Link to comment Share on other sites More sharing options...
kevin j Posted October 17, 2008 Report Share Posted October 17, 2008 May have some pics here at work... how do I post pics? tks, kcj Quote Link to comment Share on other sites More sharing options...
swooshdave Posted October 19, 2008 Report Share Posted October 19, 2008 Host the pictures on somewhere like Photobucket or Flicker and then post them here. Quote Link to comment Share on other sites More sharing options...
kevin j Posted October 20, 2008 Report Share Posted October 20, 2008 greek to me..... PM an address and I will send them email. kcj Quote Link to comment Share on other sites More sharing options...
kevin j Posted October 21, 2008 Report Share Posted October 21, 2008 The notes document in Word .doc format sketch is not posting well. Add also the pics in dig pic file, and the pdf of the CAD dwg. GOAL: -Disc front brake for Yamaha TY250/350 monoshock, 1984 to 1986 ORIGINAL PLANS: 1. Disc kits from that era. Brembo, Talon, etc. Either aftermarket conversion, or front end from TYZ in the 90's. Adv: made to fit Disadv: impossible to find. Obsolete for parts, and they are 80's technology. Some were not any better than the drum. 2. Fit fork tubes from disc brand of that era; Adv: may be easier. Disadv: Fork tube diameter did not match any of the disc brake parts. 3. Fit entire front end from a disc 80's bike (Fantic, montesa, etc.) Adv: ?? Disadv: hard to find, major project including machining, and geometry could be all hosed up with frame angles vs the front end angles from another brand. 4. Fit MX hub and disc Adv: parts available Disadv: heavier, have to lace up a wheel, much work, disc is much larger, and caliper is often behind fork tube where it can be damaged in trials. 5. Weld caliper mount to fork leg. I can't do it, it may destroy the leg, and cannot be converted back. 6. Epoxy the bracket to fork leg? Commonly done with the kits. Must be perfect fit to work. 7. Clamp a bracket to fork leg? Commonly done with the kits. Must be perfect fit. All of these were dead end paths for a couple years. Then, while moving around some spare wheels for the modern bikes, I thought, what if. . . . Ultimately, the GasGas front wheel and disc were far easier to fit than I ever imagined. All parts used for this were from 99-2000 GasGas trials bike, maybe common to later TXT also? I used the 4 piston AJP caliper and master cylinder. This caliper loads the pads from the top, with one single holding screw, without removing caliper from wheel. This choice was accidental, as they were the parts I had on hand and they fit well. Others would likely work also. 98 & prior used 2 piston calipers, but would probably work also. Older (and newer) 2 piston AJP calipers have to be removed from the wheel to change pads by pulling them out the bottom. That fact alone would sway me to the 4 piston parts. However, Travis' 96 with 2 piston caliper has stiffer and better brakes than the 4 piston ones, so I would recommend doing this conversion with any wheel and brakes available. I also used the GG wheel, disc, disc plastic guard, caliper mounting bolts, master cylinder, hose, etc. and the Yamaha axle. Original fork leg can be refitted with the drum brakes if the bike is sold, or if I need to rob the parts back for the modern bike. The caliper mounts on a plate the fits on axle on inner end, and takes the torque reaction through the original fork lug for the drum brake. GG wheel hub has floating disc, so the caliper mount is not so critical. Trials specific disc is very light and small. I would like to try this with a later model wheel with the smaller yet wave rotors. Total project took LESS THAN 5 HOURS for the prototype (not including turning spacers). Should take less time with these instructions, and is an incredible improvement for the time spent. I have a welder. A mill would be nice, but I did all work with hand tools and electric drill. BRACKET -I have dimensional sketches but cannot scan at the moment. I am trying to put into cad. -Disadvantage: the bracket is steel, because I can weld that. It is heavy. I would prefer to machine one from aluminum, Second choice would be to weld up the steel parts as shown, then machine the caliper mount pads for more accurate locating and square mount. -Bracket is a flat plate .188 inch thick. A hole at bottom floats on the original Yam axle. Slot in the plate flits over the brake lug on the inner side of left Yam fork leg. This takes the torque reaction. The Yam axle tightens on the fork leg and clamps the bracket between spacers and fork leg. Bracket does not move at all. -Around the axle hole is a stack of washers .285 thick, tack welded to the plate. -Along front top edge of plate is a flat 1/4 x 1 x 3 long. Two bosses weld to that to mount the caliper lugs. Bosses are 3/4 OD shaft material, .700 to .725 long. .352 hole to fit 8 mm bolt is drilled through the boss offset .050 to .065 from the center of the round shaft. This produces a drilled hole a bit offset from center, to locate the holes close to the flat bar. This offset was necessary for the brakcet parts to clear the curvature of the caliper casting. LOCATION -Wheel was originally about 6 mm to the right of being centered in the forks. While I could not feel this in handling, I know it has an effect. -I removed the (6) hex head disc mounting screws, kept the small cup washers in place, and used (6) M6 x 1.00 thread x 20 mm long button head allen screws. My local hardware store had them in the assortment drawer type displays. The thinner heads gained 2 mm in space. I also trimmed about 1 to 2 mm off the original brake lug on the left fork slider, on the inside edge. I trimmed only in the area the bolts will pass by, so most of the lug is still stock. The original drum brake backing plate can be refitted. -After this, wheel is NOT quite centered in front end, maybe 2 to 3 mm to right. This is not noticeable at all to me, but I think the wheel could be moved the last couple mm by adjusting the spokes and moving the rim to the left. Since it is not noticeable to me, I don't have the time to mess with the spokes, and the potential is there to make things worse not better, I just run it as is. The space and dimensions below match the final hub location. Adjusting the spokes would not change the spacer dimensions. SPACERS FOR AXLE AND BEARINGS -GG had aluminum axle, larger diameter than the steel Yamaha axle. -I used the GasGas aluminum wheel spacers (to fit the bearing ID)+ washers as noted to take up the left and right space. -Left side=GG spacer, .436 long + washer stack of (1) US 5/8 hard FW, + (1) metric FW + (1) machinery washer. Total stack of washers is .307 thick. -Right side GG spacer .944 + (1) 14 mm FW which is actually 15 mm ID and .104 thick. -Dim as noted below don't add up to the numbers above. I am not sure which is in error. I need to measure all parts again before having spacers machined to dimensions below. -Inside the ID of the GG spacers, but over the OD of the Yam axle, I used a copper coupling/splice for 1/2 water tubing, just because it was in the junk drawer. I cut about 1/8-3/16 out of the side making a C shaped bushing, and filed out some of the ID to fit the axle. By squeezing it inward, I filed and fitted it inside the GG spacers, and over the Yam axle. It's not perfect, but its not a100 mph application either. The original intent was a mockup to just see if the parts would fit. They fit better than I thought, so I went further to make it driveable. They worked great, I have ridden it for 2 years on the mockup parts. -What I have in now is a stack of washers to get the side to side distance correct, and some bronze bushings to fit between ID of the GasGas bearings and the OD of the Yamaha axle. I think another bearing will be available with ID to fit the Yam axle and OD to match the GG hub. I have not taken the measurements to my local industrial bearing supply house to find out, and probably never will. If I change bearings, the wheel won't fit back to the GG axle as a quick spare change. The washers and shims work fine, but it is a real pain when the wheel is taken off, with all the loose pieces to get out of order. I just haven't had time to have the spacers made from aluminum and verify the dimensions. -Crude dwg in Word. D1 is OD of the round alum shaft used to make the bearing. It is not critical. D2 is the turned down portion of shoulder. This is the ID of the wheel bearing. D3 is the ID through the spacer. It is the OD of the Yamaha axle. L1 is the spacer length between wheel bearing and the inside of bracket/caliper. L2 is the length inside the wheel bearing. It is not ciritcal. Break all edges and corners. Use aluminum. L1 D1 L2 D2 D3 Two spacers are required on the outboard side, one per bearing. One on the left (caliper) side, and one on the right side against the fork leg. The original inner GasGas spacer between the bearing inner races (inside the wheel) is used, and MUST be in place as it takes the axle load from tightening the axle in the Yam fork leg. Notes: 4/06. These dimensions don't match my sketches, Need to be verified before fabrication. Quote Link to comment Share on other sites More sharing options...
kevin j Posted October 21, 2008 Report Share Posted October 21, 2008 (edited) ok, loaded to photobucket, now how do I psot pics or links here? pdf of bracket dimensions I cannot load here. kcj edited 22 Oct (pics are dark, tried to lighten a bit) THANKS DAVE! learning something every day. overall view bracket inside view, bracket floating on axle and slotted to the fork leg lug. Edited October 22, 2008 by kevin j Quote Link to comment Share on other sites More sharing options...
swooshdave Posted October 22, 2008 Report Share Posted October 22, 2008 ok, loaded to photobucket, now how do I psot pics or links here?pdf of bracket dimensions I cannot load here. kcj Here's the link I finally found for the instructions on posting. Let me know if you have any questions. Here's the PDF file (converted). Plus a smaller pic for reference. Brake_bracket_TY350.pdf Quote Link to comment Share on other sites More sharing options...
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