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Flywheel?

Featured Replies

does anyone lap the flywheel on the shaft with grinding paste?

i sheared the little key that holds it for the timing!

also what is the handiest way of locking the shaft to torque the flywheel down?

When the mating tapers become corroded, I have used fine grinding paste with oil, then finished with Brasso to gently lap in the flywheel to the crank shaft. Don't lap in for too long, as there is a difference in the two tapers of approx 1 degree to allow the tapers to lock together. I have done this on many bikes over the years, from Villiers through to Gas Gas motors, never been a problem and stopped the flywheel from breaking loose on the taper.

Bye, PeterB.

  • Author

thanks peter,just i was chattin to a gent at the weekend and i was telling him about my flywheel bother,shearing the key,

and he told me to lap it on!

  • Author

easiest way to torque up the flywheel,anty easy tips to lock it in place while i tighten the nut!

  • Author

ahhhhhhhhhhhhhhhhhhhhhhhhhhhhh!

right i got 2 genuine beta woodruff keys on friday,there both now sheared

so i found a piece left of a decent one of something else,i think its finally seated and working now i hope1

just took it round the block,seems fine,suppose i should torque it down again tomorrow after a ride?

theres very little key left holding the flywheel in position,but i gues its not the key that holds it,its the flywheel tightening on the crank!

i got a 2 legged puller and put it on the flywheel to hold it while i tightened the nut up,should work i hope!

Just out of curiousity..what are the symptoms when a woodruff key shears?...will the bike cease to run, or run badly..etc??

  • Author

well its ther to set the timing < so if the flywheel has slipped on the crank and sheared the key it has moved and knocked the timing out!

non running bike! instant

Could be both Stu, depends on how far the flywheel moves from the correct timing point

Hi fastandyc,

You'll need another new woodruff key. The crank nut must have a lock washer between it and the flywheel otherwise the engine vibes will shake the nut loose. The key is only there to locate the flywheel in the correct position and the locking action is fully dependant on the connection between the two (almost) matching tapers. The nut must be tight. If you haven't made up a strong flywheel holding tool (a steel flat bar with two accurately placed spigots that locate in the flywheel holes) then you can use a ring spanner on the nut, holding it into the flywheel with the left hand while at the same time holding your hand around the flywheel then belt the spanner with a heavy leather faced hammer - this was standard practice with the old Villiers motors - they even supplied a "Hammer tight Spanner". I still use this method. Can be frowned upon by purists who advise that the crankshaft can twist, maybe so but in over 30 years this has never happened.

Bye, PeterB.

  • Author

cheers peter,prob will need a few more keys lol!

i had a 2 leg puller that i just slide 2 m8 bolts into and in turn screw the 2 m8s into the flywheel,and i can hold the puller with visegrips while i tightened the nut!

so i hope it lasts a while to i get a few more keys

  • Author

ahhhhhhhhhhhhhhhhhh

flywheel has slipped again!lolfeck it!

how much do you torque the flywheel to?

You can hold the flywheel by winding an old leather belt or similar round it, and attaching the other end with vice clamps to the foot rest. As you rotate the nut the belt tightens on the flywheel stopping it rotating. To tighten be sure to wind the belt in the opposite direction.

Having just changed a stator plate I was faced with the challenge of torquing up the flywheel nut. I have done this many times in the past, I used the impact method, socket extension arm, impact socket

  • Author

can ya not just get some sort of tool for holding the flywheel guys?

I sheared mine whilst trying out different advance settings (270) when I put the new one in used a bit of threadlock on the nut and an air driven rattlegun to tighten it holding the flywheel with my hand. That was a year ago and its been fine since. There's a lot of inertia in that flywheel couldn't believe how heavy it was!

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