kevin j Posted August 15, 2017 Report Share Posted August 15, 2017 (edited) TY350 MONO FRAME QUESTIONS I've had this TY350 mono (I am in US) for 15+ years. I rode it quite long as the kids got the modern stuff, but it has been parked about 5 years. I want to get it going for a 'reunion trials' this weekend. Beyond the usual carb, fuel, fluids, etc,, what started out as 'I should check and redo the dog bone bearings' became 'this is really thick dirty greasy and needs cleaning' became 'I found a frame break under the gunk' became 'I may as well lower the foot peg mounts while I have the engine out.' I would do the Chris Johnson frame mods to bring the front wheel back, but don't have the money or time to buy a shorter shock that is a part of those changes. So, just lower the pegs at least. CRACK It is the crosstube under the left side rear of engine, outboard of the motor mount and inboard of the frame gusset for swing arm mount and pegs. It has been brazed, so has broken before, The rubber pad is under the engine over the skid plate, and I watch all motor mount bolts for tension. I assume others have seen breaks here, and it appears to have been broken quite a while. I ride low skill level and low obstacles. I would like to grind out the bronze, pull it back closer to alignment, and weld. Questions: -Is the frame mild steel or 4140 or other alloy? -No access to TIG. Can I MIG weld it? Access will be difficult, but possible. (Engine is out.) Edit: I could bronze braze it. -Can I MIG cold rolled or stainless tubing to the frame material to reinforce? -Any ideas about reinforcing? The outboard end of cross tube is tapered and welded closed, so I can't put a sleeve inside to back up the weld, although I think could grind open the end and plug weld it back closed when done. FOOTPEGS While apart, I may as well lower the pegs as planned for 'someday'. The TY feels SO tall as stock. My thought is to weld two thin plates per side, with tube spacers in between at bolt points, and use some sort of bolt on removable plate with peg clevis welded to that. That is extra weight compared to welding clevis mounts directly to the frame, but then I can move pegs around, or use different clevis/bracket dimensions if needed. Questions: -Frame material and weld questions as above -I will go as low as possible, staying maybe 1/2 inch (1 cm) above bottom of skid plate or cross tube, whatever is the lowest point. I will go where it mounts well, and was not intending to move front or rear, but I would if readers think I should. -I want to use modern wider pegs. -I have a 2003? Beta in the garage I could rob for pegs and mount brackets. Beta has a U shaped bracket one plate outboard and one inboard of the frame, and looks pretty sturdy. Has anyone used the Beta assemblies? -Are the Beta clevis dimensions 'modern' such that I can use any pegs? Beta pegs aren't real wide front to rear, but much better than the TY nails. I'd like to go wider later. -I'd like to make the changes without cutting loose and lowering the TY plates, or cutting the TY studs off the frame, until I know the new mounts work. (i.e. I want to ride it next weekend and may have to keep TY pegs in place if I don't use the Beta parts.) -Does the brake pedal pivot point need to be relocated down, or just turn the lever on the splines to move the tip down? It seems like it would feel strange with tip being well below the pivot point (the sine/cosine stuff), but I really don't want to get into relocating if I don't have to. However, if I need to do something to the new brackets to plan ahead to relocate later, or ideally to change to hydraulic rear brake and wheel (mainly so I can use tubeless wheel with obtainable spokes, that I have sitting in the garage), I would make the brackets planning ahead. MISC: -I have the needle bearing and seal interchange data for the dogbones, and am getting data for swing arm pivot area parts. -Has anyone modified the swing arm pivot bolt and sleeves to add grease fittings? Not so much for lubrication, but for purging out dirt and moisture more frequently than the complete teardown every 10 years….. -Anyone have sources for the sleeves/pins and bolts? Mine are ok. I am just changing bearings and seals, but eventually they will get pitted. Maybe not in my riding lifetime, so maybe it is a moot point. Thanks, Kevin J Minnesota USA Edited August 15, 2017 by kevin j Quote Link to comment Share on other sites More sharing options...
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