Carb rebuild new cables....

[montmil]

...now that you mentioned it this morning I did notice (when it finally started) the right cylinder fired before the left?

Must be something else, Ampy. It was my left cylinder.  

Monte

[drgnfli]

bjamesw,

Bought the bike with the Mikunis already installed by PO.  He gave me the Bings that was previously on the bike.  He said his foot got soaked with fuel one day and he just decided to replaced the carbs.

Mikunis are alright,  had to play a lot with air and idle screw and different jets to get optimum performance.  It's great right now but  still wondering if "I got it right " now.  I haven't balance the carbs
yet.  I need to buy or constuct those cheap manometer and I think
drill and tap some hole in the Mikunis where the balance tube will go in.  Didn't do it yet because I have no idea where to drill and too afraid to screw it up.  I guess to find out the best setting/adjustment on the carb is to put in on Dyno but I again I dont know if it is worth it and I dont want to spent any more hard earned dollars.  So right now, it's my ear and test ride that determine if the adjustment/setting are  optimal.

Reason for why I want to put back the Bings is, I dont know how the the bike run with original carb.   I am wondering may be it's better
than the Mikunis.  I don't know, I do not have anything to compare right now.  Just wondering how the bike will behave will original Bings.

Drgnfli

[weasel01]

Yep...I have some problem here I'm not seeing?

I get a perfect balance on the manometer ...idle is perfctly smooth and riding rpm is smooth and even take offs are smooth unless it idles for more than 30 seconds (like at a light) then it stumbles when I twist the grip...

I have to blip the throttle to get it to go ...or hold the rpms slightly above idle.

I found my hard to start remedy to be a readjust on the choke cable...it now starts immediatly idles great but studders off the line?

I noticed the right carb doesnt have as much rpm change as the left but thats the only difference?

I'm going to build a plug shorting setup today so I can hear each side independantly....

[Barry]

If the rubber sleeve connecting the carbs to the head is too long there will be a gap between the carb and inlet stub.  This can fill up with condensed fuel and cause a rich stumble off idle that would probably clear after being ridden and maybe happen again after a period of low speed /idle .  

Does this fit your symptoms ?  

I remember reading about one guy who machined brass spacer rings to fill the gap.  I just shortened the rubber sleeves a little and it seemed to help.

[weasel01]

Thanks Barry, I installed new BMW inlet hoses as part of my overhaul.
The carbs seem to sit perfectly? No gap.

I made shorting pins for my spark plugs and the cylinders sound the same?

I rechecked my timing (just replaced timing chain recently) and both settings are perfect too?

I pulled the carbs again just to check for any unseen blockages and everything looks just right?

I'm really baffled...it does "OK" for about 15 minutes of riding (this already hot after manometer adjustment) then slips back to the studder thing again?

[bjamesw]

When I replaced my carb cables I noticed that one of the weak points was where the ferrule end connects to the carb body.    The ferrule is rigidly held at the body, and the cables tend to flex right at the ferrules and the cable within has to make a sharp bend.  Good spot for some strain relief.  For each of the throttle and choke cables (all four) I cut a (approx) one inch, a two inch, and a three inch section of black electrical shrink tubing.   Shortest (inch) one first,  covering the ferrule all but the male section that mates with the carb body.   Heat it tight.  Then do the two and three inch sections likewise.   Even better, if you  have it, is adhesive lined shrink tubing.  When I don't have the adhesive lined stuff,  I wrap a single thickness of Scotch double-sided  clear adhesive tape over whatever I'm putting shrink tubing over.   Waterproofs and keeps everything ultra tight.  

Worked out beautifully!   I posted a pic here somewheres a few years back.  

[weasel01]

Hey Bjamesw,That's a cool suggestion...however I have visions of a heat gun , gasoline and me.

That could be a bad combination!!

[weasel01]

ok here is my new question....at what rpm is the charge light supposed to go out?

[Bob_Roller]

I would say around 14-1500 rpm, it all depends on the state of charge of the battery .

[weasel01]

Well....I'm having a bad time with this.

 I have adjusted readjusted re re adjusted re re re adjusted re re re re re adjusted and get the same result..

I pulled the spark plugs and they look fine.

I've started at 1/2 and at 3/4 turn on the mix and end up at the same sweet spot  ...I've set the cable mix at 1300rpm 1500rpm and 3000rpm

I've set the idle as low as 1100rpm and as high as 1250

I've gone as lean as possible and as rich as possible I've balanced and rebalanced between each step.

The end result is perfectly smooth idle perfectly smooth mid and top range even smooth take off if it's within a few seconds.

What is escaping me is if I'm idling for more than 10 seconds there is a studder when I roll the throttle on (there is a "too rich" crakle that happens only then)

Most of the time it's minor but more than a couple times it has stalled at a traffic light which is not cool at all.

My best result is a higher idle rpm but I can still "sense" the studder spot as soon as the throttle is rolled on.

It's very even smooth and pleasant except for this .......

any suggestions appreciated! ...except anything chicken related!!!

[montmil]

In trying to visualize your off-idle stutter... Engine is at operating temperature and everything is fine except for the engine stutter as you're attempting to pull away from a stop sign, etc.

As I've followed most every line you've written about your R65, it sounds as if you have done everything per specification. But your concern continues...

When you worked on the Bings, did you remove/replace the butterfly valves in the carbs? There are older posts on different sites that discuss the importance of centering each brass plate within the bore of the carb's throat. If a throttle plate drags, it could create symptoms as you have described. If one butterfly is dragging -even a tiny bit- that Bing will be delayed in beginning the fuel delivery and create a stutter until it unsticks itself. Then, all's well until the next stop. At operating temps, heat expansion could be affecting the brass butterfly. Yes, I may be reaching here...

Pulling the carbs and shining a bright light into the throat should reveal an equidistant gap around the valve's circumference and the throat bore. If the butterfly drags, loosen the anchor screws a bit and re-center the valve.

This may be a stretch but I'm about stumped. Anybody?     Monte

 

[Bengt_Phorqs]

The only thing that I can think of is perhaps the auto advance springs in the bean can might be sticking momentarily causing the stutter.  I'm reaching too, but just give 'em a quick shot of WD40 as a temporary fix.  It won't hurt anything and may isolate the cause.

[Bob_Roller]

Yet another 'shot in the dark', how do the pressed in caps on the upper cover of the carbs look ?

They come loose on rare occasions .

Was this hesitation present brfore you worked on the carbs ?

[weasel01]

When you worked on the Bings, did you remove/replace the butterfly valves in the carbs?

 

Yes, I did remove both of them and had a real bear of a time getting them back in place.

I just looked at them again when I had it apart for thwe 2nd time last sunday and they looked equally seated?

Like I've said before give me a soldering iron and watch me go... stick a wrench in my hand and watch me fail....

That is a reasonable suggestion so I will pull them back off a look again with a light this time.

[weasel01]

Bengt and Bob, Thank you for the suggestions but this all happened immediatly following the carb rebuild?

And except for the tiny tear that aprreared in the diaphragm everything was fine as wine?