Two Q's re: bing rebuild

[nhlkats]

... then closed the butterfly in the carb throat and looked for light coming around the edges. When I had it where a minimum of light was visible, and what was there was evenly distributed around the butterfly, I snugged up the screws.

Some light will get through. A complete seal is not achievable.

 

[26667]

pleased w Bing Agency

Just to be fair to the guys in Nebrsaka, after a delay they were kind enough to overnigh the mis-matched jet and we installed the carbs today. Runs like a top!
Thanx, Bing!

 

[bobh41]

Mice in the carbs ??!!

My recent experience with Bing

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Was very positive. I got the right pieces with the rebuild kit. I got everything I needed to do the rebuild - manual, Twin Max syncer and a few other bits. My problem included an unrealized set of mice nests in each carb - which really confused me.

'scuse me - while reviewing this very interesting thread I came upon my own gross typo (more like brain f**t - my editor is out to lunch these days). In case anyone was paying any mind, the mice nests were in the mufflers; they were completely stopped up. I only found out when the engine backfired.

 

[Polarbear]

OK my friend, here's another!

I've been riding the /7,/5's since they were new and these things can be quirky sometimes... I was riding across the USA a lot of years ago and my /7 started doing funny things in the motor, carb department and I rode the better part of two days trying to figure it out. I took the electrics all apart, testing them, etc and the carb bowls, jets out, too,cleaning them along side the roadways with carb cleaners and nothing worked! It was bugging me a lot. I camped, slept on it and early morning came and I had enough, so before hitting the road in Kansas, by the way, I disassembled the "carbs" all the way on a picnic table and I'd be damned if I didn't find it! I found it alright! My carbs are the 32mm variety, with domes that house a slide chamber for the tops of the slides(tubes). These tubes are supposed to slide in and out of the cover assembly effortlessly. Absolutely NO friction should be present there...Mine had developed a bur up inside the cover hole that the slide runs in and this was IT... I could not believe it and without some serious dilligence, I'd never found it. Sandpaper in my toolbox fixed it completely. Your carb issue, story reminded me of that trip across the USA about 20 years ago. If this indeed turned out to be your problem, please be sure to let me know...Seems you've done nearly everything else. I had this same frustration running the highway, far from home and got lucky enough to find it alongside US50 in Kansas somewhere.

 

[nhlkats]

Thanks, I checked that out, it moved smoothly.

What is supposed to happen when turning the mixture screw all the way in on one side? Being overly specific won't hurt here.

 

[beemerPhil]

Bing CV Carbs

Closing the mixture screw completely will shut down that cylinder, unless fuel is coming from somewhere else.

You're not looking for a clogged passage, you're looking for a leak- fuel is getting through somewhere it's not supposed to. Be certain that your idle mixture screw and seat aren't damaged. Check the cold start jet and valve, make sure all your orings went in ok- it's a good idea to lubricate new orings for installation so they don't 'pull' when you screw them in- you can trouble shoot the cold start circuit for fuel leakage by temporarily blocking the cold start jet(it's the one farthest from the main jet off in the corner of the bowl)to see if the problem goes away. The idle and cold start circuits are the only passages that can see vacuum at idle....the main & needle jets are not the culprit.

The butterfly should close completely when the idle screw is backed out- it may not be perfect, but should be a very good fit, and there is PLENTY of play on the butterfly screws to allow it to go in crooked. If you put the butterfly in with the screws loose and play with the shaft a bit, you'll find that it locates itself quite well- unless it's bent or damaged.....be certain that you have it facing the right way- and when you get it right, lightly 'stake' the screws from the threaded side so they can't back out into your intake....this causes noises you won't like.


The two small holes at the bottom of the venturi are transition jets- they're both UPSTREAM(air filter side) of the butterfly at idle, and are exposed to vacuum as the butterfly opens. Fuel/air mix from the idle jet passage flows through these holes when they're uncovered, to smooth the transition from idle to part throttle. (This is a place to look if your bike is stumbly off idle-)


It's unlikely that the float/valve has anything to do with this problem- the fuel would have to be VERY deep in the bowl before it would reach the intake stream!

 

[47744]

Bing bang

The BAD: The bing agency rebuilt my carbs on my 1995 R100RT (the real last edition) and after 4k miles up in Washington State one cylinder acted like it was on idle all the time. Back home in California I discovered all machine screws had backed out of the diaphram to slide connection on the left carb. Opening the throttle butterfly on the left carb would not result in the slide opening. What a tough motorcycle. It had done 3k miles with one carb on idle and the other working ok with my wife and her hair dryer on board pulling a little trailer.
Charlie at the Bing Agency said he had never heard of such a thing. Neither had I.

The GOOD: Prior to sending these carbs to the Bing Agency; I had cleaned the carbs replaced parts, choke plate gaskets, etc and worked on them without success. In desperation I took the 32mm bings off my 1983 R80ST and put them on the 1995 R100RT. Wha-La, it ran perfect. I sent the original R100RT bings off to the agency and after I got them back , they worked fine(until the screws backed out). The only thing done different by the Bing Agency was : they tanked the disassembled carbs. I hadn't done that. There is a Berrymans 1 gallon tank can you can buy at your local auto parts with a basket inside.

Remember to tank your completely dissassembled carbs first.

 

[ISAMEMON]

Bing has been a lot of help for me too........... very helpful on the phone and I did get most of my parts there
however the floats, float jet and bowl gasket were cheaper at my local BMW dealer
however the manual ......to me is just a real good parts listing and technical stuff that was interesting but did not help rebuild the carbs
what was the most useful was snowbums article and the old "ON" magazine of March 2003 with over 40 pictures of how to rebuild a bing
they still might have some of the old copies available at the main office, I got mine about 6 months ago less then 5 bucks........cheap !!!!!!