Back on an Airhead - 1975 BMW R90/6

[tete]

Well. I re-did the timing. The turn the crank and test light method. It was off a bit. Then I advanced it by turning the plate counterclockwise slightly.

Re-assembled everything and the bike starts now. I still won't hold idle but it will start. I can take it for a spin but it will die if I let go of the throttle.

I'm still debating over electronic or booster. I am really leaning toward electronic for the idea of leaving points as a "back up" system in the event of break down.

Since my advanc is ok and all, I still feel like eliminating the point would be beneficial.

[Kt-88]

Have you cranked up the idle screws? How is your pilot jet? Your mix screws? Will it idle on choke?

[tete]

Cranked up those screws a bit like 4 full turns. Nothing.

I'll play with the mixture screw tomorrow and see where we are at

I haven't tried to see if it idles on choke but will do tomorrow as well.

[Kt-88]

Cool. I'm anxiously awaiting. Lol.

[tete]

Looking to find BMW black paint or alternative that wont breal the bank My buddy is setting up a booth at his house this weekend and all I gotta do is bring the paint.

Thanks.

[Lornce]

Great project bike.

That's a '77 R100RS tank and fenders you've got there. Nice pedigree.

With points, I like to static time them at full advance. Jam the advance weights open with a piece of pencil eraser or fuel line or a small piece of wood etc. and use the full advance timing mark. Leave the plugs in the high tension leads and laying on the heads (so they're grounded) and listen for the plug crackle while you watch for the timing mark. (It's easier than it sounds, and once learned - you can time your bike anywhere).

Always fun to add to the opinion soup in Old School.

[dmftoy1]

Originally Posted by tete

Looking to find BMW black paint or alternative that wont breal the bank My buddy is setting up a booth at his house this weekend and all I gotta do is bring the paint.

Thanks.

Don't know about breaking bank, but ken holt @ holt BMW can set you up with proper paint. Fwiw

[tete]

Originally Posted by dmftoy1

Don't know about breaking bank, but ken holt @ holt BMW can set you up with proper paint. Fwiw

Yeah I'll have ot look into it a bit more tomorrow when shops are actually open. I may just find a paint store that sells ... plain black, no pearl or metallic. just plain ol black. I'll put a really have high gloss finish to it and call it a day. If anyone has any recommendations please chime in

@Lornce

Im not sure what you mean? You advance the timing all the way, and then just let it be? how does that work? if static timing is spot on, then advancing it would cause it to hit 2500 much quicker no? keep in mind, you are talking with a complete novice.

I found the Dynatek, online relatively close for $59.99 shipped. Reputable dealer and would be here by the weekend, which would be the soonest I would replace all the wold be parts.

I figure I can order it and then have BMW store get me the new points and NGK wires. I would rather have the Dyna booster, new wires and points and have a fresh start, than risk breaking down 300 miles from home. I can afford these parts, I can't afford to break down.
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will not idle.

I tried to turn the mixture screw 1.5 turns. 1 full turn and now have it set at 3/4 turn currently non helped. Also tried with chokes mid way up, or all the way pulled. nothing, bogged out the way It always does when I release the throttle.

I also played with the idle screws 1turn , 2 turns 3 turns, 4 turns. nothing.. didn't get any better. I imagine if I keep turning it at some point it will idle but pretty high.

[disston]

tete,

You need to find a Tech Day where somebody can look at your bike with a different eye. Are you a member of the ABC? That's the Airheads Beemer Club and they are the most active in promoting Tech Days where you can learn much easier than trying to do this on your own.

The ABC cost $25 a year and is worth it. They issue a monthly news letter that has Tech Questions answered by Oak Okleson which are the best answers to the most often answered tech questions. Find more info at;

http://www.airheads.org/

The idle speed screws are the larger of the two screws that adjust the Bing carbs. They do the same thing as the throttle cables so you should be able to raise the throttle speed with the idle speed screws. Notice the throttle cables pull the throttle levers on the carbs up. This turns the throttle shaft in the carb that opens the butterfly.

The point of reference for the idle speed screws is where they first touch the shaft on the side of the carbs. They have to push the shaft to turn it and open the butterfly. Make sure you have the idle screws touching the butterfly shaft. From that point the screws are turned in to raise the throttle speed. If twisting the throttle in your hand will keep the bike running but it dies when you let the twist grip go then you need to turn the idle speed screws on the carbs to raise the idle.

[tete]

Originally Posted by disston

tete,

The idle speed screws are the larger of the two screws that adjust the Bing carbs. They do the same thing as the throttle cables so you should be able to raise the throttle speed with the idle speed screws. Notice the throttle cables pull the throttle levers on the carbs up. This turns the throttle shaft in the carb that opens the butterfly.

The point of reference for the idle speed screws is where they first touch the shaft on the side of the carbs. They have to push the shaft to turn it and open the butterfly. Make sure you have the idle screws touching the butterfly shaft. From that point the screws are turned in to raise the throttle speed. If twisting the throttle in your hand will keep the bike running but it dies when you let the twist grip go then you need to turn the idle speed screws on the carbs to raise the idle.

@disston - I definently plan on joining a club, once I'm able to go to a meet... on my bike.

I understand the concept clearly of the idle screws in relation to the butterfly etc..

I have throttle cables since mine are rubbish. I think I will start there. Once installed, I guess what I could do, and please feel free to suggest whatever.

1. Install new cables.
2. start bike and turn throttle to lowest point it will stay on and hold there.
3. while someone holds the throttle in place, turn idle screws to meet that setting and let go of throttle.

I imagine this should work. If this at the end, the bike starts and holds idle, I can now adjust the timing using the light gun. Since I cannot idle I haven't been able to accomplish this. I also need to find a suitable tach....

VDO or something similiar as mine is rubbish and I dont care to rebuild it. This bike is on the other side of trying to keep it all original.

[disston]

That sounds like a good plan.

The Airheads Beemer Club don't have meetings. They do have Tech Days in most localities. Here in Maryland we used to have rides once in awhile to meet at some place we had lunch. We seem to have stopped doing that. And some of the local clubs host weekend Rallys.

You join the club on the Web at the Web site. You will be able to find out who your Air Marshall is and you can contact him to find out when and where the next Tech Day is. It is probably a good idea to do sooner instead of later because most places only have One Tech Day a year. Some have more but not all. And some will through together a Tech Day just because it sounds like it's time. This organization is very loosely run.

There is also the online Tech Support of the Air List. This is an Email Club on the Web. It was started by members of the ABC but it is not a part of the ABC. Sometimes the lines get a little blurred but you won't be a member of the Air List just by joining the ABC. In fact it costs nothing to join the Air List. (once, or is it twice, a year the site that runs the Air List will ask for donations, you are not required to donate) The people that run the Air List are Micapeak. You sign up with them and will receive the Emails that are the only function of the Air List. There are a few steps to go through to find the correct place to join on the Micapeak site but you should be able to figure it out. You are looking for the Airheads;

http://micapeak.com/preview/index.html

[newride]

Dont have points in mine, Switched to electronic ignition 10 years ago. Runs real nice!

[disston]

Originally Posted by newride

Dont have points in mine, Switched to electronic ignition 10 years ago. Runs real nice!

That sounds really nice. If it breaks down on the road can you fix it? Or by pass it to get you some where to fix it. I have had the Dyna III. I carried the points and plate in a plastic bag thinking this would cover break downs. I eventually got rid of the Dyna III and when I looked in the plastic bag the points and plate were a rusty mess.

So each system has it's good and bad points. I hope you are happy with yours I know I like the system I have, points with a Booster.

[Bluebone]

threads like this make me all jittery and anxious....

[tete]

Charlie,

One concern I have is, taking the advance unit off and on. Eventually this will mess up the repaired end. I would like to set the timing once and walk away from it for any decent period of time.

With electronic ignition, such as a Boyer system, I imagine I will still have to mess with the timing and such? Or does the electronic ignition find it's curve and time itself? No timing light needed? Only to Check it initially to make sure it's working?

In an ideal world, I want the one I mess with the least. 95% of my riding will be locally. 5% will be long trips. When I need it working best.

I'm cool w the booster system if it means setting the timing once and calling it a day for any extended period. However that's assuming i know how to set time properly. If the electronic ignition like boyer requires install only and sets the timing that is very appealing. As I'm sure it will be more precise.

I don't expect to have it work magic, but I don't have the means or time to
constantly be addressing timing. I want to ride my bike more than work on it. Just like the rest of you.