'77 R100 High Rev at Start After Handlebar Change

[Steve in Golden]

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!

You just need motorcycle boots with steel toes.

[melville]

Now just wait a minute. And another minute. I'll get this bike stopped sometime......

I had more for the last post, but was called away prematurely. I have some photos of brake cable routing mockups using white housing for clarity in case our new member wasn't getting it from the text of my last post. Here we go:

As BMW sets it up for high bars:



And how they set it up for low bars:



It works a treat--when initially set up with the high bar routing, there was substantial cable movement with handlebar motion. Moved to the other side, nearly none.

It's not clear to me from OP if he's made any correction to the throttle position as to its engagement with the gear--the teeth on the throttle tube do not go all the way around, and it is possible to get it in a spot where it binds before fully releasing the cables to idle. There are supposedly reference marks on the cam and tube (I may even have seen them), but the crucial thing is to make sure that the cables can get to a spot where they've got just a wee spot o' slack. And of course, that full throttle is possible, that one may enjoy life at WFO.

[Norm T R100T R1150RT]

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!

You just need motorcycle boots with steel toes.

The fastest way to stop my old Panhead is to run over another motorcycle - been there /done that - or in the extreme, lock up the rear, lay her down and get the hell away - the under tank master cylinder on my Airhead works fine as far as I'm concerned - saved me from "broadsidin" a car early on - but I do keep an eye out for the handlebar mounted set up on ebay - the front brakes on my Oilhead are superb.

[JeramyN]

Ok, I'm going to take remove the cable from the master cylinder under the tank and re-route it.
I've never removed a cable form the master cylinder so if there is anything else weird i should know, or expect, i appreciate a tip. I was afraid to attempt it before not knowing brake fluid would start pouring out....

I'll report back over the weekend once i've done it.

Thank you all so much for the pro tips

[JeramyN]

I did not have a chance to get to the brake over the weekend but i did go for a ride and noticed that after i put the lower bars on, my bike is idling WAY to high... Like close to 1500 RPM.

Can I get some tips on adjusting either the carb or the cables? I did re rout the cables so they are no extreme bends... So should i start by screwing in the idle screw all the way and then back out 1 turn? Or i noticed the cables may be adjustable down where they hit the carb...

Any advice here would help.

Thanks y'all,
Jeramy

[melville]

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's this bit that has me concerned. Have you verified that the cables are allowed to go full slack? Just pull the cover off the throttle and verify that the gear is not binding before the cables go slack. If it is binding, then monkey around with stuff until it doesn't.

Yes, it's a bit of a many-fingered dance to put it all back together. Worth doing, though.

[JeramyN]

Yeah well, I messed with it a lot actually. without knowing exactly what to do, i put it back together in such a way that the chain is extended as close to the cable holes as possible. This gives the cable the least amount of pull and when I turn the throttle, it pulls the cable immediately with zero play. would really like a photo of the exact position of the throttle sprocket if possible.

[Slashsevenpig]

Foot dragging is how the Harley riders do it, I have observed.

To match their knuckles, of course!

[Duane Ausherman]

Yeah well, I messed with it a lot actually. without knowing exactly what to do, i put it back together in such a way that the chain is extended as close to the cable holes as possible. This gives the cable the least amount of pull and when I turn the throttle, it pulls the cable immediately with zero play. would really like a photo of the exact position of the throttle sprocket if possible.

You may have negative play, or another way of saying it is that they are pulled up a bit. You should run the adjuster on the top of the carb in a bit to get definite play.

[Jean]

The sleeve at the top of each carb cable should move about 4mm (3/16 inch) without affecting the carb throttle lever.
If it worked OK before you changed the bars and took the throttle mech. apart, it might be some binding in the throttle control.
I think there is a discussion of how to set-up the handlebar throttle parts (sproket/chain) either on Snowbum's site or Duane's site. It must be in one of my books, but I haven't found it yet.
CAUTION.
Mother noise coming: Be careful when taking things apart. Make photos before disturbing little parts...The "choke" on Bing carbs comes to mind especially. Likewise arrangement of the insides of the headlight shell...