I'm being told my FZR400 crank is bad. Honestly, I don't know if it is and am hoping someone can understand my description. The head and cylinder are removed so the pistons and connecting rods are are just hanging there. The number 1 rod is very stiff when trying to rotate it. Gravity pulls the other 3 down to rest against the case. The mechanic says it'll need new bearings and a crank. Is this enough to go on?
You will have to remove the rods and inspect the journal and bearings. Make sure that the journal isn't egg shaped or crowned, but it sounds more like a bad bearing. If the crank is blued or gouged from a bad bearing, you can have it repaired, possibly cheaper than replacing. You will need to split the cases, you can't get to the number 1 rod from the oil pan. The nice thing about Yamaha's is that the bolts on the case are numbered for removal and installation, so splitting the cases is pretty quick and easy. Until you can't find the two bolts under the cylinder or the one bolt under the oil pump (assuming the 400's are the same as the 600's).
No more cranks are available from Yamaha as far as I know, so many blew up that they ran the factory right out of parts. You will need to send the crank to Falicon and have it repaired or find someone who is hoarding them.
Last I checked Falicon advises against their submerged arc welded pins for high performance (read racing) applications. Street engines are okay, but if you stress the repaired pin too hard it will shuck off the weld.
You may want to have it balanced too. I had one that was a streetbike crank that I was putting in my racebike and just happened to have the machinist balance it while he was checking it over. It was WAY out of what you would want to use in a racebike. It ended up being the smoothest running engine that I ever had in the bike. What passes muster for the street is not automatically good to go at the track. I was very happy with any and all of the work that Falicon ever did for me. Just be prepared to write the check when the bill comes due.
