Lightened flywheel

[chasbmw]

sam,

New starter has been fitted, problems lessened but still there.

[SamH]

Ahh. Well, at least you know where you stand now. I did notice that motobins have flywheels on sale for 40 pounds... Not sure if they're for 8 or 9 tooth though. It'd probably be cheaper to get a new one lightened than the old one repaired.

P.s. Your flywheel looks like a photocopy of mine. Did you get it lightened or did it come that way?

[chasbmw]

Sam,

The flywheel was lightened by Jim Cray and then the engine was balanced.............Thats the reason why I dont really want to to go down the replacement route. The engine is really smooth as is. The cheapo flywheels from Bins are 111 tooth, but doubtless I could change the gear on the starter to a 9 tooth.

[Duane Ausherman]

Did you consider replacing the starter ring?

[chasbmw]

Duane, this is a possibility, there are some companies producing new ring gear in the UK, but to date I can't find one of the right size, the other issue is that some of the lightening holes intrude onto the ring gear and will have to be redrilled. I think I'm going to stick with cleaning up the existing ring gear with a file and to see how that works.

[Ken in Oklahoma]

. . . I think I'm going to stick with cleaning up the existing ring gear with a file and to see how that works.

Considering how badly you want to keep a lightened flywheel, I'm betting that cleaning up the teeth will last for life, yours or the bikes. And it it doesn't work, you would have had to have made or bought a lightened flywheel anyhow. The possibility of screwing up the starter gear is a consideration but with the starter and flywheel teeth mating correctly this time I think it's a good bet to make. At least I would give it a shot if it were mine (and i really wanted a light flywheel and I didn't want to spend a lot of money.)


Ken

[mattcfish]

. . . I think I'm going to stick with cleaning up the existing ring gear with a file and to see how that works.

Considering how badly you want to keep a lightened flywheel, I'm betting that cleaning up the teeth will last for life, yours or the bikes. And it it doesn't work, you would have had to have made or bought a lightened flywheel anyhow. The possibility of screwing up the starter gear is a consideration but with the starter and flywheel teeth mating correctly this time I think it's a good bet to make. At least I would give it a shot if it were mine (and i really wanted a light flywheel and I didn't want to spend a lot of money.)


Ken

+1
Is it just me, those teeth look pretty good on that flywheel. Before I went to the post 81 clutch gear and tranny, my original flywheel was way worse and worked quietly and without issue for over 20 years. What sort of issue are you currently experiencing?

[Major Softie]

And IF that flywheel is correctly balanced, then you could have a new flywheel lightened to exactly the same weight, and it would not throw off Cray's engine balancing work.

[chasbmw]

I have cleaned up the ring gear on my flywheel, with a combination of hand file and Dremel.

It looks much better now, just have to wait until everything is done and we shall see how well the starter works.

[Sam LP]

Hello Charles

That looks like a good clean-up job on the teeth, I expect it will make a good fix.
a few years ago I had my bike come back from the MOT test with a broken starter nose-casting - the MOT guys had "road-tested" my bike (I think a bit like the garage attendants in Ferris Bueller's Day Off) so I replaced the starter. The nose casting broke again two weeks later. Jim Cray diagnosed the problem over the phone and I replaced the flywheel with a 2nd hand one, AND another starter, and and the problem was solved.

Sam LP