Carb balancing

**Steve Pickford** · #1 12 Aug 2003

Need some advie re:carb balancing on my R80GS Paralever. I have some Davida gauges but am unsure where to conect the gauge hoses? The Haynes manuel is of no help at all.

Thanks in advance

Steve

**nobby** · #2 12 Aug 2003

hi stevw
look underneath the carbs and you'll see 2 screws one is flat headed which is in a recess this is your mixture screw and and flat headed screw which the head sits on top of the carb body take this out and fit the tube to the gauges
cheers nobby

**Steve Pickford** · #3 12 Aug 2003

Thanks for the advice, I'll be trying this in the next day or so.

Steve

**Richard Jakobek** · #4 13 Aug 2003

Hi Steve,
The bit for attaching the vacuum gauges on my bike is slightly different to Nobby's. It's still next to the mixture screw, but it is just a little spout which is normally covered with a rubber boot. You have to pull this off and then you can put the rubber tube from your gauge onto the spout.

**Steve Pickford** · #5 13 Aug 2003

Thanks, I took the carbs off last night and found no screws - assumed they'd fallen out but could not work out why the bike had not been running rough. I've now covered them with rubber caps.

My girlfriends GS is different again -it has a connecting tube between the carbs, with a small cut-out in the lower corner of the airbox on each side for the tube to run through. Is this is worthwhile mod?

Steve

**Grant Johnson** · #6 14 Aug 2003

Connecting tube - interesting!

What year is hers?

Mine (86) has a connecting tube running through a notch in the airbox - but it's for gas/petrol, not to the intake spigot. I've seen the tube you're talking about on OTHER bikes - non-BMW's - and it's a balancer, supposed to smooth intake pulses and make it run smoother. NO idea if it's an improvement on a GS or not. Try it! Disconnect on hers and see if it's worse.

------------------
Grant Johnson

Seek, and ye shall find.
------------------------

One world, Two wheels.
www.HorizonsUnlimited.com

**John Ferris** · #7 14 Aug 2003

In most cases the vacume port has a small screw in it. Or sometimes they use a small rubber or plastic cap. Those caps aren't listed as a Bing part. They are a "K" bike part. I have read of people putting in a crossover hose from one vacuum port thinking that it will help to balance the carbs. But I don't think it worked any better than the stock set up.
If a screw is missing or a cap is cracked the bike run but you will notice that something is wrong.

**Timo** · #8 14 Aug 2003

I think my 88' had that connecting tube......

**Timo** · #9 14 Aug 2003

I think my 88' had that connecting tube......

**Steve Pickford** · #10 14 Aug 2003

Both are R80GS Paralevers, mine is 1993 & my partners is 1994, also originally fitted with the clean air system - tubes from airbox to exhaust port.

Steve

**Story Leavesley** · #11 15 Aug 2003

The tube you see connecting the vacuum ports on both carbs connects to the clean air system in the airbox. The vacuum is used to activate the clean air system solenoids to inject air into the exhaust upon decelleration, thereby igniting unburnt vapors in the exhaust (I think that's how it works).

If you've removed the clean air system, you should remove these vacuum lines and plug the ports with small screws. You can find the BMW part numbers for removing the clean air system and plugging the vacuum ports on the IBMWR web page, or contact me for the part numbers.

Story