New to Airheads

[Jacko09]

Hi everyone

Just purchased a 1987 R80RT mono which is an ex-Police bikewhich I am likely to change into a scrambler or flat tracker, wires are all over the place and the bike has been half stripped down, no keys with it so I have already had to buy a secondhand ignition with key!!

I think there will be plenty questions from me in the near future and I will appreciate all the help I can get but my first one is so I can chgeck that the bike runs before going any further with it.

In what order do the wires connect to the ignition switch? I have twin Red and brown, Green, grey and single red wire

Thank you in advance

Jacko09

[Bamboo812]

Haynes shows single red to 30, single grey to 56 (or 58E), green to 15, and double grey to 58 (or 58A) Welcome!

[Jacko09]

Thank you Bamboo812, I will look at it tomorrow, just ordered a Haynes Manual as well

Cheers

[SteveD]

Thank you Bamboo812, I will look at it tomorrow, just ordered a Haynes Manual as well

Cheers

Here's a freebie. Open and scroll down.
http://bmwairheadsdownunder.com/airhead_tech.html

[Duane Ausherman]

SteveD, I wasn't aware of that site. I must warn you, the article on fixing the spun bearing in the hub is both good and bad. First the good part. I didn't know that an insert was available and that is great news.

Now the bad part. However, he makes the BMW mistake in setting up the wheel bearing preload with a wedding ring change while the stack is out. That won't work. That is how the bearings spin in the first place.

I also read the article on swing arm bearings. It is full of errors.

[Ken in Oklahoma]

SteveD, I wasn't aware of that site. I must warn you, the article on fixing the spun bearing in the hub is both good and bad. First the good part. I didn't know that an insert was available and that is great news.

Now the bad part. However, he makes the BMW mistake in setting up the wheel bearing preload with a wedding ring change while the stack is out. That won't work. That is how the bearings spin in the first place. . . .

It's easy enough. With the 'stack' in the hub with your best guess on wedding band thickness, you run the axle into one side or the other. Then you make a spacer to be placed on the outside of the wheel/hub such that the axle nut can be snugged up, simulating what happens with the wheel in the forks or swing arm. What you're going to do is to snug up the nut on the axle and feel for any preload. You don't need to 'tighten' the axle nut, but you do want some torque on it so as to make sure that all slack is taken up.

Now you gently 'tighten' the axle nut, periodically rotating the axle within the wheel with your hand. You will either have too much slack with the nut snugged up or too little slack. That is to say that the 'wedding band' is too thick, or too thin, or just right. You probably don't have a 'collection' of wedding bands, so you might have to order one or two. Over the years I've collected a decent set of them and haven't been faced with having to endure the wait for the one I think I want to try.

I would be very cautious about trying to thin a wedding band. I've never even tried to do it. If you went that direction you would need to mic the wedding band thickness all around the periphery to ensure that the two ends are parallel to each other.

The 'feel' that you're looking for is the axle to be slack at first and then, as the nut is judiciously tightened, the slack goes away as you rotate the axle with your fingers. Further tightening of the axle nut will not markedly make the axle harder to rotate. That's because the spacer and wedding band is just the right thickness. If the thickness is too much then the axle will have some noticeable 'slop' left and right. You won't see it but you can feel it. If the wedding band is too thin then the axle keeps getting harder and harder to rotate with your fingers. You will have to judge when you think the preload is just right. A loose axle is wrong, and a too tight axle is wrong.

As an aside it's been my experience, more often than not, that the new wheel bearings need the same spacer thickness that the old bearings needed.

This particular process is very satisfying.

Ken

[Bamboo812]

Note; it's a real good idea to check that the bearing race hasn't spun in the hub before doing the wedding band adjustments, or you'll spend hours chasing your tail trying to get the preload right...

[Duane Ausherman]

Ken, sorry to start controversy, but your method has a fatal error. One can set up the preload perfectly with the stack out as BMW suggests, but it may still fail. Once the stack is mounted in the hub, the preload is much greater due to the cooling of the hub shrinking the outer race down a whole lot.

Don't believe me, test it. This is why the only test that works is the "shake the wheel" test. It is described on my website and other places now.

[Ken in Oklahoma]

Ken, sorry to start controversy, but your method has a fatal error. One can set up the preload perfectly with the stack out as BMW suggests, but it may still fail. Once the stack is mounted in the hub, the preload is much greater due to the cooling of the hub shrinking the outer race down a whole lot.

Don't believe me, test it. This is why the only test that works is the "shake the wheel" test. It is described on my website and other places now.

Agreed, Duane. Mea Culpa. I wasn't thinking about the rear wheel removable stack. I was thinking of those later rear wheels without the removable stack. And of course front wheels don't have a stack. Thanks for the clarification. I hope I've got all of this straight in my mind now.

Ken