Lightened flywheel

[chasbmw]

The flywheel on my R90/6 has been lightened, it weighs 2.380 KG, here are a couple of photos





This works very well and the engine has been balenced to suit.

However, I do have a problem wear of the starter ring gear. This wear was caused by fitting an 9 tooth starter on a flywheel meant to have an 8 tooth one, coupled with the starter relay sticking on twice, and each time it took me too long to get the tools out to disconnect the battery. as a result I have a very noisy starter, which does not always properly engage and disengage.

What is the solution?

[sabre2]

CLANG !!! Got to be brave admitting that.Hope you get it sorted.Blue skies,KC.

[chasbmw]

I was told by the starter motor supplier that a 9 tooth would fit, I stupidly took their word for it without checking the number of teeth on the flywheel. The supplier was good enough to refund me for the starter even though it had had approx 500 miles use.

[Deleted User 287]

I hope you haven't hurt your ring gear! That would be a shame.

So you are going to get a 8-tooth starter, especially now that your old one may be damaged? (Yeah, I know, anything can be fixed).
I'd get me one of those fancy, lightweight Nippondenso starters, if I were spending your money!

The starters are also available for all 1970 thru 76 Slash 5, Slash 6, and R90S models that have an 8 tooth drive gear!

[chasbmw]

I'v got the fancy 8 tooth starter...........but don't want to bugger it up with the knackered ring gear which is sharp and pointy and worn on the starter side of the flywheel.

[melville]

The ring gear can be pressed off and replaced (if you can get the part) but it looks like the lightening holes cross the border from the main flywheel to the ring gear. At the very least, you'd need rebalancing when done.

[Garnet]

If the ring gear comes off, then turn it over and use the other side.

[robert]

If the ring gear comes off, then turn it over and use the other side.

The teeth are chamfered on the engagement side.

[chasbmw]

Can anyone post a pic of unworn ring gear?

There is a very old school workshop here in Bristol called Pistonbroke, I'll take it in to Steve to see if he has any suggestions on how to clean it up.

Thanks all

[SamH]

Install the new starter and try it out? You could de-bur the fly wheel first. I wouldn't think there's any point in changing anything till you know it doesn't work.