Ok it's not a real GP machine, but an Aprilia Cup RS250. I need to get the crank trued before rebuilding the engine, any suggestions? Plus what's the opinion on welding them after truing, some claim that it weakens the crank. Kevin Murray of MCE Racing was going to do it, but he was injured and I don't know when he will be able to get to it. Vito
When I had my Aprilia, I heard that a new crank and rods with bearings for the cup bikes was right around $400. If this is true, might be worth it to start there.
You may consider Blackmans Cycle in Pa., home of the Himmelsbachs. I don't think Bill is doing the TZ cranks anymore but since they are a high profile Aprilia dealer I'd say it's a good place to start. Blackmans.com or some combination, their phone # is 4-1-1 and they are near Philly somewhere. Monty
Vito, The last crank I did in a TZ, I sent a brand new one to Kevin Murray. He trued it to a magnitude on 1/14 of the of the accepted deviance that it left Yamaha with. It will make a difference in how the bike runs and the life of the cases in any two stroke. I hear Kevin is healing pretty well, my hopes are with him. Rocky Stargel
That's about the right price, I bought a new crank. The first I got was 4X the allowable runout out of the box. I basically want to true it for the reason's Rocky stated. Has anyone ever used Falicon in Florida? Any thoughts on welding the pin after truing? Vito
Has anyone ever used Falicon in Florida? Any thoughts on welding the pin after truing? Falicon does good work, but I was under the impression that they had become "diesel only". Rick Schell is the best, but he's very busy and very expensive.(best crank I've ever had)]
I've never trued an Aprilia crank, but have trued lots of TZ cranks to .01mm. Might be able to true the Aprilia crank - would just have to look at it. Do not weld the crank pin. Per Kevin Cameron, that is the last resort on a crank that is basically shot.
Vito, just curiuos, how many miles do you have on your crank? Have you pulled the old one out yet and checked it? The reason I ask is because I've gotten very different opinions from people on how soon to replace it. Kyle BTW Did you run the duck in clubman this weekend? If so how'd you do?
I haven't removed the crank yet since it appears to be a pain on an Aprilia (waiting on the parts in case I get a wild hair to race it as is). I have somewhere between 3000-3500 miles per the overly optimistic speedo/odometer. I've heard numbers from 1500 miles to +8000 miles with the most common about 3500 miles. No, I had to work at the house to hopefully get ready to move in in a couple of weeks. Vito [This message has been edited by VitoDuc19 (edited 08-27-2001).]
Everyone used to weld the old TZ parallel twin cranks, but on the new ones, I'd listen to the concensus and not weld on it. Heat tempering is important on crank pins, I'd think. Even a spot weld CAN'T be good for temper. Didn't Yamaha used to use some sort of a glue, like loctite, on the crank pins? Anyone know where one can get a decent truing stand for a decent price? Guess I could build one, but I hate to waste time on such projects. Maybe this winter I could do it, though. Pretty simple to build. If I build it, though, it'll probably work but might look like caca. Jack
