Boxerworks.com

Hello,

New to the forum, I just bought my dad's old bike, 1977 R75/7. It has been sitting for ~15 years

I have got almost everything back and running properly, but the bing carbs are giving me issues.

I can get the bike up and running ok, but I can't get them to stop leaking gas. Of course the gas leaks right on my feet.

Is it worth the money to change over to mikuni carbs? are the 32mm or 34mm mikunis better?

I also live in the foothills of the Rockies, how well do the mikunis deal with elevation changes?

I noticed that rocky point cycle recently sold, Now I don't see any options for the higher elevation carb kits.

I always thought that the Bings did better for transitions from one altitude to the other, but both carbs can be set up properly if your staying in one of the other.

Sounds like you just need to go through the Bings and change gaskets, etc. Personnally, I wouldn't bail on the Bings just for that.

Rocky Point sold, true, but aren't the products still be offered?

Kurt in S.A.

Personaly I would try to get to the bottom of the leaking isue. Once working proprely the Bing CVs are good all round carbs.

The only reason I can see for Mikuni's are for performace improvements. Mikuni's have a huge range of adjustment available and can take a lot of paitence to get right bang on. The correct CVs for your bike are set up almost pervectly at base settings and work quite well from sea level to 10,000 ft.

(This is from someone who has a set on TM32s and cables in a box waiting for a project.)

I have a friend that lives in Denver with a '77 R100S. I picked the bike up for him here in the East, then rode it there. Then we spent 3 days riding the mountain passes in the Rockies without any problems or changes to the jets. Like the others above, I suggest going through the carbs again (floats) to solve the Bing problems before going to Mikunis. The CV carbs work well in the thin air.

Get a gasket set for your carbs at http://www.eubmw.com (cheap and free shipping) but first I would check you float level settings and also let gas run through the carbs with the bowls off to hopefully flush any bits of debris off the float needle seats themselves. A word of caution, I have new stock floats, and the factory setting of "level with the bottom of the carb" did NOT stop it overflowing. Mine had to be hanging down just slightly. It's a touchy adjustment; too far down and you will have fuel starvation at WOT. DAMHIK

After 15 years one could expect things to not work properly.
New gaskets and o rings and new float needles would be my first step.

My dad had done some work on it before I bought it. But last night I found that the float needles are trashed. I ordered a new set, hopefully that fixes it.

nquillen wrote:My dad had done some work on it before I bought it. But last night I found that the float needles are trashed. I ordered a new set, hopefully that fixes it.

Yep, Float needles valves. They need replacing ever few seasons on Bings and will cause the floats to overflow on your foot. These are not to be confused with the needles that control the main jets.