Saturday, April 3, 2010

Vintage Motocross Project: 1972 Husky CR400

Note: I wrote this on Thursday, but am just now posting it...

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Back to working on the motor, I picked up where my break down during warm-up (a DNF would sound almost better somehow) problem started. After waiting over a week for the replacement woodruff keys to come in I finally start the work on it. First step was to lap the flywheel to the crankshaft, hopefully this will help prevent it from coming off in the future. Timing the motor was a bit of a process, but not too tricky over all. After getting all of the tools I needed, which in and of its self was the biggest pain of the process. It seems no one stocks a 25mm socket locally, I ended up using a 1", I will find the proper tool later. Anyways back to the job at hand, the threaded spark plug hole insert for the dial indicator that I borrowed from my friend didn't work. The combustion chamber on this motor was just too tall. Pulling the head off the motor I was able to get the dial indicator on the piston and timing it was not a problem. All said and done the timing had been set to far advanced before, which could have cause the problem with the flywheel coming loose.

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Dial indicator measuring the distance before TDC

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Everything in the right spot, the flywheel with the timing pin inserted.

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The marker lines are where the timing was set, a noticeable difference from the correct setting.
After getting all of the covers back on and the oil filled back it I went to start it. After a dozen kicks or so it started... But the throttle was jammed WFO and the motor revved all the way out of a few seconds before I was able to reach the kill button. *BANG* The drive gear coming off the crank shaft fell off, but the flywheel was still on. I remounted the gear, making sure the tapered shaft and the inside of the gear mating surfaces were clean. The motor is jammed, I am really crossing my fingers that it is not seized, but it is not looking too good. I can stand on the kicker and it does not move at all.
I'm going to pull the head and probably the jug too. Hopefully this can be worked around and I can still make the starting grid.

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