Carb tune/balance

[79beem]

Yes! i know I'm being a topic hog...

How do i tune / balance my carbs without sync do-dads?

She seems / sounding a bit rough and sorta bogs out for just a split second when accelerating and then occasionally stalls when stopping downhill or stopping quickly.

A friend has a cx500 ( sorry! sorry!  ) which he tunes / balances  by ear, taking out one spark plug to tune the opposite carb, but his description was a bit flaky

Can anyone please describe the procedure for my beloved 79 r65 [smiley=bmw_smiley.gif] flat top bings ?  

[nhmaf]

Have you tuned an engine before - not meaning to be derogatory, but if this is your first time, without tools, it can be 'shooting in the dark' unless one has a good feel for it already.

A crude but highly sensitive carb balancing device is pretty easy to make if you can get some clear  vinyl tubing, meter stick and some fork/suspension oil.

[79beem]

I've had the carbs apart, fiddled with idle adjusters, had the forks,calipers in bits,adjusted valves  but i havent tuned or balanced before, but Im  keen and tooled up. I have since found out how to build a MANOMETER ( sounds like something from a b grade sci-fi movie ) So i just need the procedure. Please.

[Lucky_Lou]

Ok a rough "idiots" guide it wont be perfect should be close.
1 Make sure the engine is fully warmed up, most recommend 10 miles.
2 Slacken off the lock nuts on both carbs throttle cables.
3 Screw the cable adjuster in until the cable shows signs of being slack.
4 Put  a feeler gauge in to the throttle stop make sure you have the same gap at both sides (i did it at 10 thou).
5 Now set the idle screws at between 3/4 and 1 turn open test the tick over and set at between 1000 and 1200 what ever is best for you then turn off the engine.
6 Take up the slack in the throttle cables feeling for the 10 thou gap then tighten the locking nuts.
It should not be far off but you will need a vacuum gauge to test the mid rev range properly and if you have old cables you may need to change them, also check the enrichers (chokes) are fully shut before you start.
If you dont get a satisfactory tick over from the idle screws you can increase it on the throttle stops having set the cables by screwing both in the same amount say 1/2 a turn at a time but that would indecate a problem in the idle circuit.

[montmil]

I believe I've posted this excellent article regarding the El Cheapo Grande Manometer and Bing carb synchronization procedure several times. It's the absolute best Barney-style DIY technique. My Bing mentor, Hugh Kenny ABC #6051 outta Cheyenne, Wyoming, keeps my R65s tweaked perfectly.

I think this helpful link/article really needs to be posted in our Tech Section. I also recommend membership in the Airheads Beemer Club.

Monte
ABC #12411

http://www.airheads.org/content/view/183/98/

[79beem]

Thanks all for your responses.

Lou, the rough "idiots" guide. How does this differ to the "non idiots" guide?

I would like to get it as sweet as possible.
Im making a manometer next weekend using the article monte posted ( cheers Monte ).

  Has anyone made a manometer for an R65? if so, is the tube size the same as in the article from Monte 3/4" -  1/4"?

[Vegasrandall]

It's mostly the thin tubes that give the best reaction.i used some mineral oil with dye in it.

[Lucky_Lou]

I use Hydraulic oil in mine it is green and doesnt stain the plastic tube
(oh and its free which is a big+).
A rough Idiot is one that forgets to shave, non idiots are a rarer breed and more likely to be found riding an Airhead but because they are used to fending off dumb questions from idiots they will have a working knowledge of the lingo
Lou

[Barry]

Has anyone made a manometer for an R65? if so, is the tube size the same as in the article from Monte 3/4" -1/4"?  

The vacuum take off points are 6mm OD so you need slightly smaller ID tube for a good push fit say 5mm or 3/16" depending on whats available. Don't make the tails of the manometer too short or it will be difficult to drape the tubes either side of the engine without them touching on something hot. I use red auto transmission fluid which works well.

[montmil]

What Barry sez...  [smiley=thumbup.gif] Match the tubing i.d. to fit the vacuum take offs.

Just about any fluid can be used... as long as it's fairly compatible with being drawn into the carb and burned in the combustion process.

If the Bings are w-a-y out of balance, be prepared. Light fluid will be immediately sucked into the engine and the odd smoke cloud can result. Mineral oil -dyed to your color preference, ATF, MC fork oil -mine is purple, hydraulic oil, lighter engine oils or even virgin olive oil... for an Italian flavor.

Monte

[Lucky_Lou]

What Barry sez...  [smiley=thumbup.gif]
If the Bings are w-a-y out of balance, be prepared. Light fluid will be immediately sucked into the engine and the odd smoke cloud can result. Mineral oil -dyed to your color preference, ATF, MC fork oil -mine is purple, hydraulic oil, lighter engine oils or even virgin olive oil... for an Italian flavor.

Monte

And they laughed when i developed the Mark 3 "Texas" manometer it being 10ft tall and bigger than the rest, it gives you time to shut the engine off before you lose the oil.The connecting pipe i used was 6mm ID braided and the guage section is 6mm OD.
Lou

[Ed Miller]

"Just about any fluid can be used... as long as it's fairly compatible with being drawn into the carb and burned in the combustion process."

I use two stroke oil just for that reason.  The stuff I bought is greenish and is easy to see in the clear tubing.  

[79beem]

just for clarity but hopefully not sounding like a ''stupid rough idiot'' . do i follow Lou's procedure first + then attach the manometer, or will i get a better result starting with the manometer using the procedure from Monte's article?

[Lucky_Lou]

If its miles out i would do the rough guide first.
Lou

[nhmaf]

Do the rough adjustment at idle first without the manometer connected, it is very sensitive to slight imbalance, and if your carbs are significantly off to start with, one or the other will suck all your fluid into itself VERY fast if they aren't starting off closely matched..