Should this even be running?

[Barry]

I thought the adjusters control air flow instead of fuel flow.  A bad oring can play havoc.

As CV carbs they are primarily considered to flow fuel so turning them in weakens the mixture and out richens which is the opposite of what air screws do on slide carbs.

To be pedantic, due to the auxiliary air jet they actually flow a pre-mix of air and fuel.

[wilcom]

thought the adjusters control air flow instead of fuel flow.

I'm going back over that now... I have two YOUTUBE animations , one shows CV carb with the idle screw metering the fuel, the 2nd shows the idle jet metering at a point where you have both fuel and air,,,,, have not found a R65 BMW Specific diagram yet. I do not have the patience for Snow Bums site right now. I'll continue searching the Web for a  understandable diagram.

[Barry]

No question that A Bing CV mixture screw flows a pre-mix of fuel and air. This isn't actually a Bing but it shows it nicely with a colour legend and I guarantee a Bing works the same way. 

[wilcom]

A bad oring can play havoc.
                   

Barry thanks for that diagram, that was one of the animations that I had seen on youTube(very close).

R65Guy.... the O-rings could be my issue. I had a hard time trying to figure out what O-ring went where. None of them seem to fit nicely anywhere, all wanted to be stretched to almost breaking to go on. I might have flubbed the rings. I will get another set and replace them b4 I go any farther.

Thanks Guys

[georgesgiralt]

Hello,
Check your idle needles for wear.
Then gently screw them in, and open them a little (1/2 turn if my memory serves me right).
The idle srew have to be opened t'ill you can see a wee bit of day between their tip and the butterfly flat, then gently go to contact and give them a half turn (again from memory).
Then you will have the base setting for the bike to start and adjust.
Your situation was that a mixture screw is giving way too much mix and the engine is apt to run on this one alone.

[wilcom]

Your situation was that a mixture screw is giving way too much mix and the engine is apt to run on this one alone.

My situation in my mind is........ If it's idling perfectly at 900 rpm and I can't vary the RPM or quality of idle with either idle adjustment screw, am I actually idling on that ckt?

I've checked the butterfly's for daylight, I have backed off the adjusters for choke and throttle so there is no input with those ckts. I have agonized with the assembly of my enriching devices to make sure I have them correct. (thank you Barry for the most understandable instructions for their orientation in one of your posts)

A lot of my "head scratching" is that I really DO NOT HAVE A PROBLEM, it idles correctly, no off idle lag, seems to pull well thru the gears at all rpm's(during my around the block testing under 65mph)....... the PROBLEM is that it is not acting correctly to adjustments. A similar situation would be a doctor telling a patient to take deep breaths while listening to his chest and detecting NO abnormalities. and as the patient puts on his shirt the Doctor notices that the patient has Duct Tape covering his mouth and nose. :-? Maybe the Doc and I should just go have a beer.

R65Guy did hit on a fact with the O-rings. I had a devil of a time trying to figure out what O-ring went where. I could have the WRONG O-ring on BOTH idle screws(making both sides act the same or in my case NOT ACT AT ALL.  I'll look for new O-rings next.

Anyone have a source for O-rings where I don't have to buy gaskets and Diaphragms too ?

I'll be checking for information (got to go to O-ring school)on the rings as it looked like none of the rings I had, fit properly on any shaft that I was trying to put a ring on, either too lose or too tight. If anyone has a link to "O-ring school" I'd love to go there.

[Barry]

Anyone have a source for O-rings where I don't have to buy gaskets and Diaphragms too ?

I'll be checking for information (got to go to O-ring school)on the rings as it looked like none of the rings I had, fit properly on any shaft that I was trying to put a ring on, either too lose or too tight. If anyone has a link to "O-ring school" I'd love to go there.

In the 12 years I've had mine I've only ever use standard NBR O rings from a 400 piece Metric O ring Kit.  I use whatever seems to fit and have never had problems. But I do have the specified sizes and part no's for reference.


 

[Bob_Roller]

Joe, so your situation, is that you get no rpm response when adjusting idle mixture ??

[wilcom]

Joe, so your situation, is that you get no rpm response when adjusting idle mixture ??

exactly:
Idling perfectly but unable to effect any change with idle mixture screws, screwed closed or fully open4-6 turns, no detectable change in the idle speed or quality at all

Video here of bike idling away 1 hour ago
https://www.youtube.com/watch?v=A_9NIlrdlFc

[Bob_Roller]

I have had this happen, the idle jets were clogged .
The metered orifice at the end of the jet is almost impossible to determine if it is clogged or not .
If you take a can of carb cleaner, with the extension tube on the nozzle, place it on the end with the screwdriver slot .
Then cover the two sets of holes in the jet body to contain the cleaner, fluid should come out of the end if it is clear .

[wilcom]

I have had this happen, the idle jets were clogged

Let me give that a try in the morning, as I gotta work tonight.

I have had these guys apart 3-4 times, initially soaked in Berryman's and squirted thru every orifice I could find. But you have a point there. When I squirt in the orifice and I see it coming out somewhere else I assume it's OK...... but with multiple paths it could be squirting out 2 holes and there is a 3rd clogged. Good call, makes sense.

I'll report back.............

[wilcom]

. but with multiple paths it could be squirting out 2 holes and there is a 3rd clogged. Good call, makes sense.

I'll report back.............

Took awhile to get the O rings for the idle jet and mixture adjust. But I have 20 of them now!. I didn't want to pull them apart again til I could replace the suspect O rings.

I pulled them off agai9n and checked all passages in the idle ckt, Air in, Mixture out, jet and adjuster screw. All passages are open.

I checked the jet in the bottom of both bowls while I was at it and all running clear..... However.... when I blew back up the pipe that feeds the choke ckt I had a pin hole about 3/4 way up the pipe pointing at the float. I checked the other carb and it is the same way...... is this supposed to be? How would the enrichner pull fuel from the bowl if the pipe had a pin hole in it?  Maybe I'm not understanding the flow. I took a picture of the pipe and where the screw driver is pointing is where the pin hole is ON BOTH CARBS.

Is this normal and can I go back to worrying about my idle issue :-/

[wilcom]

Is this normal and can I go back to worrying about my idle issue :-/

Evidently this is a normal thing to equalize pressure??/ got a response off facebook and all looks ok then and I can reassemble.

[wilcom]

I am comfortable with " what is that hole in that pipe and should it be there" so I reassembled the little carbies with fresh O rings and clean passages in the idle ckts and back on the bike. (again)

I fired it off and it was idling at 900 rpm( 200 more than before). i adjusted the idle screw on the left and it acted as it should, I was able to tune to a sweet spot. I moved to the right carb and no love, still the adjuster would have no effect on the idle.

I rechecked the choke and throttle cables and there is no input at all either side. as I was checking cables I lifted the choke cable on the left side and killed the motor immediately. I went to the right side and pulled up the choke cable and it DID NOT kill the motor. It hiccuped a little bit and gained rpm. WTF

I was meticulous when I reassembled the enrichening devices. I went to Snow Bums site and few other web spots, and finished it off with Barry's concise explanation here on this site. With all this, it seems I have still found a way to foul the stew.

The right carb will go on the bench again to see what evil lurks in the choke ckt

[wilcom]

Choke assembly checked out per all the online info. But did notice a slight "halo" of light at the top of the throttle butterfly, hmmmm.

I did not have the shaft out of the carb because I didn't wan to go thru the Peening process, but looks as if I'm headed in that directiojn. But air running past the butterfly would make it react differently to the added fuel when I yanked on the choke cable.

As I look at it the bevel looks like it is heading the right direction. I will source some new screws and take it apart.