Sprockets front sprocket weld

Discussion in 'Transmission / Drivetrain' started by mytreksfaster, Jun 4, 2011.

  1. mytreksfaster

    mytreksfaster New Member

    Ok. Has anyone welded the front sprocket directly to the crankshaft? The slot where the key sits is destroyed from when the key sheared yesterday. I have been welding for a long time as a profession but never on anything this high speed. I can wled it up pretty solid. Any thoughts? thanx.

  2. motorpsycho

    motorpsycho Active Member

    i'm sure you can weld it but i have never done it.
    I would make sure that the sprocket is lined up EXACTLY where it should be and is perfectly straight.
    if it's in the wrong spot or if it's not welded on straight, it will throw the chain all the time. throwing the chain on the engine sprocket is real bad because it can and will jam up inder the cover, causing the rear wheel to lock up and probably rip out some spokes and cause you to crash big time.
    i would think that as long as the crank is steel and the sprocket is steel, you can weld it on...but alignment is crutial.
    i would not weld the entire thing...don't run a bead all the way around the sprocket. I would just put a few short beads on it and don't overheat the steel.
    That's just my opinion anyway.
    Last edited: Jun 4, 2011
  3. Al.Fisherman

    Al.Fisherman Active Member

    While looking for a case to experiment fabricating a engine mount that was unusable to the average person, I got a case that the sprocket was wielded to the shaft. You are referring to the sprocket that is driven by the clutch shaft? Yes you can do it but remember it's there for duration and a cut off wheel will be needed to remove. If I was going to do it I'd put a couple or few (2 or 3) good spot wields. I'd wield before I'd trash the engine, or replace the clutch shaft.
    http://s982.photobucket.com/albums/ae309/Ron-Becker/Broken mount repair/
    Last edited: Jun 4, 2011
  4. Turtle Tedd

    Turtle Tedd Member

    Mytrikesfaster...yes if you are a welder by profession you can weld it..Tig would be best..get it lined up , get, it clean..of course you know about to much heat on one side of the shaft...NO fluxcore wire without gas..right???
  5. srdavo

    srdavo Active Member

    azbill welded a sprocket on the clutch shaft successfully, years ago.

    Three years ago, due to a mangled keyway, I welded the small gear (on the clutch side) to the crankshaft.
    I put 3 small tack-welds on it... as so not to overheat anything & it has held up fine.

    I used my 110 v. wirefeed, with flux-sore wire.