Throttle Cable Adjustment

[hudson]

When properly lubed, the throttle tube (grip) on a /5, /6, or /7 shouldn't "snap' back, it should creep back. If it snaps back, it either means it's not lubricated properly (dry) or the springs in the carbs are too stiff. If your throttle grip isn't even creeping back, check that the grip isn't pushed too far onto the handle bar and is dragging on the end of the handle bar itself.

I was replacing my throttle cables on my 71 R75/5. I re-greased the cam, lined up the markings and attached the new cables. When I roll the throttle and release, it doesn't "snap" back, but slowly creeps back. Pretty much have all the slack out of the cables. I read the above on another forum, which says this is normal. I have mikuni VM carbs and the slides snap down when pulled up at the cable where it goes into the carb - so no hangup there. The stop screw underneath the throttle tube is loose (not grabbing), so that too is not holding the tube from returning to the idle position.

Bike hasn't been used in over a year due to recovering from an auto accident (old cables stretched), so I can't remember if this is correct or not. Is this right? Or the throttle suppose to snap back?

What else do I need to know?

Thanks...

[Zombie Master]

Not sure what you are asking, your quote pretty much tells the tale. In my experience the air head throttle are never that smooth. Perhaps they are designed for touring, where it takes less hand strength to hold a throttle position if they don't snap back.. Then there is the screw in damper that controls that even more.

BTW if you are using OEM cables: do not lubricate.

[hudson]

Ok, thanks. just making sure this was the norm. Much appreciated...

[logangranson]

Are the Mikuni Carbs worth it? I have a 1974 bmw r75/6 and i was told my Bing carbs are bad. I want to get it on the road as soon as possible and all i need is replacement carbs. Would it be better to try to buy used bing 32mm carbs on ebay and hope for the best or brand new mikuni carbs?

[Ken in Oklahoma]

Hmm, bad in what way? Unless we're talking crash damage bad, the stock Bings work well for most everybody. Going to Mikunis will take a considerable effort (and more than a little money) as you swap out all of the parts it will take to make the conversion. We're talking about the 'engineering' you will have to do as you sort out the throttle cables, the carb to head connection, and the carb to airbox connection. Plus you will have to make decision about just which Mikunis will work best in your application.

Oh, and did I mention the money?

Ken

[Rob]

Are the Mikuni Carbs worth it? I have a 1974 bmw r75/6 and i was told my Bing carbs are bad. I want to get it on the road as soon as possible and all i need is replacement carbs. Would it be better to try to buy used bing 32mm carbs on ebay and hope for the best or brand new mikuni carbs?

Welcome to the forum. You could have started a new thread of your own.

What Ken said.

[Zombie Master]

Then again it's according to what type of Mikuni you are talking about. The Bings are CV and use a diphram to open up the piston. If you want a more immediate response you might want a pumper carb. I recently swapped out a CV for a Mikuni flat slide pumper. It transformed the engine in that big single. IMO you are best using the bike as designed for the purpose intended use. If BMW wanted you to go fast it would have installed pumper carbs. And on some models it did.

[logangranson]

Thank you for the quick reply, I have had this bike for a few years and really want to ride it only to get it back and learn that the carbs are bad. Rocky point cycle has an already upgraded kit that should just go on my bike that is a CV. From what I could find i could only find 2 bing carbs for 100 less that may or may not work and that is why i was thinking of the mikuni. Also the bing carbs are for a r90 and would have to be adjusted, and i am not very good with.

[Zombie Master]

Thank you for the quick reply, I have had this bike for a few years and really want to ride it only to get it back and learn that the carbs are bad. Rocky point cycle has an already upgraded kit that should just go on my bike that is a CV. From what I could find i could only find 2 bing carbs for 100 less that may or may not work and that is why i was thinking of the mikuni. Also the bing carbs are for a r90 and would have to be adjusted, and i am not very good with.

Really hard to understand this post!

[SteveD]

@logangranson..The 75/6 and 90/6 both use 32mm Bing's. Jetting might be a little different. I'll look that up later.

It might be worth just removing the carbs, removing, cleaning and renewing the o-rings on the jets, cleaning the passages, replacing diaphragms..etc. There's really not much you can do too wrong there as long as you don't overtighten anything.

There are videos on U toob to guide you. One carb at a time, take your time...
You'll save yourself a bit of money and learn a couple of things along the way.

Re: cables, there's also a couple of simple steps to get the settings in the ball park to get the bike running. There's bound to be a dozen or so Airheads in Ohio that can help out. Hook up with a local enthusiast via the Airheads list who might help. The fine tuning is the bit that's more difficult.