'80 Bean Can

[daz]

I don't want to contaminate the '79 bean can post so I started a new one. I've had several air heads but this ignition is different. 1980 R100T. Bike runs just fine. I may not have to adjust points for several thousand miles which may take some time. I had the front cover off and got a peek at the points. So is there some trick to get in there and adjust those contacts? I read the manuals with no help. I don't suppose I can remove the bean can and adjust the points on the workbench. Just something I've been thinking about and was too ashamed to ask! This bike is new to me and a good runner. Can't wait to ride it in the Spring.

[Kurt in S.A.]

Never been around one of these bean cans, but I think you can mark the can relative to the engine case, then remove it. Overhaul might help here:

https://www.flickr.com/photos/getproduc ... 751098893/

Kurt in S.A.

[Zombie Master]

Excellent link Kurt!

[daz]

I wonder what year that was from. The '79 and 80' were different from later models. Did I read that the tang at the back was offset so you can not put it in wrong. The '79 and '80 had points and from then on it was electronic. I don't suppose the later can be interchanged with the points type?

To be truthful I'm out of the country for a few more days so I don't have access to my manuals. It's well below freezing at home and I'm kinda wasting time thinking about that bike. I don't see any points in those photos. From memory both manuals tell how to adjust the point plate. As if it was in front of you. Just wondering if there is some trick that I'm ignorant about.

[barryh]

I wasn't aware there was any difference between a 79 and an 80 points can.

I think the question might be how do you get easy access to the points. The outrigger bearing plate is in the way but if you remove it to set the points the adjustment will change a couple of thou when you put it back again. With practice you will get used to setting the points through the slots in the outrigger plate but what I used to do is remove the whole can and do the adjustment on the bench as you suggest. With good light it's so much easier. If the points need adjustment then the can would have to be moved to set the timing so you are at no real disadvantage by taking the can off completely. As Daz said the drive tang at the back is off center so you can't put it back wrong.

Now for the the really fussy there is another possible reason not to remove the outrigger plate. It's purpose is to support and center the cam so that timing will be identical on both cylinders and it's pretty good at that but in my case at least, not perfect. The plate sits in a rebate at the end of the can and ideally should be a perfect fit but on mine there is a thou or two clearance which means the plate can be fixed a thou or so off center which can result in 1 or 2 degrees difference between cylinders. We fuss about everything else on an airhead being in balance so why not timing. What I do is check the static timing on both cylinders very carefully to check they are the same and if not shim the plate a little until they are. With that done I don't want to move that plate again until a points change which for me will be ten years as I have a points amplifier fitted.

[Rob Frankham]

1) Yes you can adjust the point gap with the 'can' off the bike. You'll need to time it again after refitting, even if you mark the location on the can as resetting the points will alter the timing... but then, that's the same with any points ignition

2) The Hall Effect type can will fit straight on to the earlier engines. The biggest problem you have to resolve is where to fit the ignition module that has to be used with the later can. On later machines, there is space provided under the tank but, on earlier machines that space doesn't exist (or is taken up by the undertank master cylinder) so you have to make it up as you go along.

Rob

[daz]

Well heck! You guys have made my day. Thank you. I think the term is ruminate. I sit here ruminating a problem that doesn't exist. Can't wait until I may be faced with it so I can solve it. Thanks again.

I should probably get in there and lube the ignition advance anyway.

[hal]

So- barmounted MC- ignition under tank! For us willing to compensate to get the gear working..

[Rob Frankham]

So- barmounted MC- ignition under tank! For us willing to compensate to get the gear working..

Sounds like it should work... but I'd want to check the shape of the space under the tank to be sure... tricky fellows, BMW.

Rob