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'77 R100 High Rev at Start After Handlebar Change

Posted: Wed Jul 31, 2013 1:10 pm
by JeramyN
I just put on lower bars and now when I start my bike it's idling around 3,000RPM. Any idea what might be causing this? The cables all look to be fine as even though the bars are a little lower, they are a tad bit wider so it compensates a bit.

I took the throttle off to see if the something happened in there but it looked fine. Unfortunately though now i'm not sure how the piece was supposed to fit back on the sprocket.

Could the throttle slide/s have gotten pulled and stuck up?

I took the tank off and it had zero effect. I pushed and pulled throttle cables also with no effect. Twilight Zone if you ask me.

Re: '77 R100 High Rev at Start After Handlebar Change

Posted: Wed Jul 31, 2013 2:37 pm
by Kurt in S.A.
I was going to say be sure that the ferrule at the carb end of the cable is seated in the little "cup" on top of the carb, but if you pulled the cables, that should have cleared that up.

Not sure if this is related, but I was out on my R69S a few weeks ago after messing with the throttle housing...I had the tank off, too. At one point in my ride, I came up to a stop and the engine was revving high...I couldn't close the throttle down. I killed the engine and got off the inspect. Then I realized when the tank went back on it pinched the cable where it disappears under the tank. I cleared it and made it home. At home, I repositioned the cables under the tank...not a problem now.

Kurt in S.A.

Re: '77 R100 High Rev at Start After Handlebar Change

Posted: Wed Jul 31, 2013 4:17 pm
by JeramyN
I actually ran my bike with the tank completely off. I just filled the carbs and letter run. I was thinking that same thing but no bueno.

Maybe i should re route the throttle cables and see if that fixes it.

Have you ever taken the throttle sprocket and chain off of the switch housing? I accidentally did but don't see any marks to line it back up? i just guessed on how it should be back on. I would post a pic but not sure how to do that here.

I didn't even thing about this. maybe i should detach the the cables from the switch completely and see how it idles. I've never done that before.

Re: '77 R100 High Rev at Start After Handlebar Change

Posted: Wed Jul 31, 2013 5:28 pm
by Major Softie
JeramyN wrote:I actually ran my bike with the tank completely off. I just filled the carbs and letter run.
That is no way to be delivering the mail.


It's almost certainly a cable issue of some sort. Keep messing with them and I'm sure you'll figure it out. Let us know when you do.

Re: '77 R100 High Rev at Start After Handlebar Change

Posted: Wed Jul 31, 2013 8:14 pm
by SteveD
JeramyN wrote: Have you ever taken the throttle sprocket and chain off of the switch housing? I accidentally did but don't see any marks to line it back up? i just guessed on how it should be back on. I would post a pic but not sure how to do that here.
It can be a bit fiddly to set the throttle cam & cables to correct position. The cam needs to align correctly to the throttle handle cam.
http://www.largiader.com/articles/throttles/

Have the cables been lubed? They shouldn't be, as that can attract dirt etc and cause the cables to hold up.

Re: '77 R100 High Rev at Start After Handlebar Change

Posted: Wed Jul 31, 2013 10:21 pm
by Duane Ausherman
The very first thing to do, and you didn't comment doing it, is to check the free play of the cables. They must have some free play.

Re: '77 R100 High Rev at Start After Handlebar Change

Posted: Thu Aug 01, 2013 11:00 am
by JeramyN
Thanks for all of this guys!
I think i got it last night. I re routed the cables and it seemed to help. I cranked her up after and she seemed to be running like normal. And no, I have never lubed the cables. I hear graphite does not gum up but i have never used it on this bike...

Now though, i have a new problem :x . When i cut the wheel hard right, the front brake engages. If i cut left it is fine and in the center it is fine. the only thing that looks like it could be the culprit is the short brake cable that runs from the lever to the reservoir under the tank. It gets pushed a in an awkward way when i turn to the right.

Assuming this is it, How do you remove the cable from the lever? it looks different than all of my other bikes (hondas).
Or would i be able to detach it from the reservoir? Or would brake fluid pour out?

First time BMW owner issues :?

Thank you guys so much!

Re: '77 R100 High Rev at Start After Handlebar Change

Posted: Thu Aug 01, 2013 12:37 pm
by melville
JeramyN wrote:Thanks for all of this guys!
I think i got it last night. I re routed the cables and it seemed to help. I cranked her up after and she seemed to be running like normal. And no, I have never lubed the cables. I hear graphite does not gum up but i have never used it on this bike...

Now though, i have a new problem :x . When i cut the wheel hard right, the front brake engages. If i cut left it is fine and in the center it is fine. the only thing that looks like it could be the culprit is the short brake cable that runs from the lever to the reservoir under the tank. It gets pushed a in an awkward way when i turn to the right.

Assuming this is it, How do you remove the cable from the lever? it looks different than all of my other bikes (hondas).
Or would i be able to detach it from the reservoir? Or would brake fluid pour out?

First time BMW owner issues :?

Thank you guys so much!
Believe it or not, but there is just one cable for high and low bars, on the undertank MC bikes. You'll need to reroute the cable around the left side of the steering head, running by the fork lock. It may be easier to disconnect it at the master cylinder--force the hook forward and free the cable, then knock the brass piece off the end of the cable. Then you can pull the cable through the barrel adjuster and reroute it.

Re: Undertank MC

Posted: Thu Aug 01, 2013 12:52 pm
by Steve in Golden
Or he could just drag his feet to slow down, that will work about as well as the front brake with the undertank master cylinder.

Re: '77 R100 High Rev at Start After Handlebar Change

Posted: Thu Aug 01, 2013 2:35 pm
by Jean
Foot dragging is how the Harley riders do it, I have observed.
I don't recommend it tho. Beemers are higher and you'll stub your toes!