Idle Air Adjustment R25/2

Begonnen von Kurt in S.A., 28 Juni 2020, 19:27:08

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rolf

flammable....the gas or the cleaner?
SPRAY A LITTLE BIT ON THE GROUND AND THEN TRY TO  :kopfhau:  made it burn with a match...only for sure

rolf


Kurt in S.A.

OK, you made me do it!!  Play with fire!!  Yes it does burn.   :waffen093:

Kurt
Kurt in S.A.

rolf

so....now it becomes a miracle....it must be "Nebenluft"...but where????
I´ll think about it.

rolf

Kurt,
paint konic part of the idle mixture screw with an Edding.....screw then the screw into his hole until you ment it is full screwed in.....then screw it out.....is there any ring visible on the Edding marking?

Kurt in S.A.

rolf -

Not sure what you mean by "edding".  Are you referring to some kind of blue-ing compound?  I guess you're wondering if the screw actually seats.

Regardless if the screw seats, it seems that turning it 1-2 turns from the starting point (about 1-1/2 turns out) resulted in no RPM change.

Kurt
Kurt in S.A.

strichzwojan

Kurt, what Rolf meant is: use a broad permanent marker to check, if the tip of the idle screw is touching the bypass correctly.
BTW, edding could be used too, to mark breakpads to ensure correct position and wear in the break drum...

Jan

rolf


Kurt in S.A.

OK, I googled Edding and see that it is a German company that makes writing and marking pens!  Now, if you had said Sharpie, I would have known right away!   :D

Kurt
Kurt in S.A.

rolf

Kurt,
paint konic part of the idle mixture screw with an Sharpie.....screw then the screw into his hole until you ment it is full screwed in.....then screw it out.....is there any ring visible on the Sharpie marking? :P

Krottenkopp

Gruß Heiko/2

Kurt in S.A.

I'll give it a try in due course.  I'm currently 1000 miles away from the bike!

Kurt
Kurt in S.A.

Kurt in S.A.

Got back around to it.  Here are two pictures of basically opposite sides of the screw after seating it.  Looks pretty normal to me...I didn't turn it too hard but figured I got a good seat.  Any insights?

Kurt
Kurt in S.A.

rolf

#42
hey Kurt....looks good....what a pity....it seems to get contact roundaround whn screwing in....however witha VERY thick ring....normal is a small line
once again....no idle changement when you screw in the idle screw? And also no "Nebenluft"? It cannot be so!

Kurt in S.A.

Rolf -

As for a thick vs thin ring, could be that the interior hole in the carb has worn a bit over the years.  I did not retry the screw to see if it made a difference in the idle speed...I had done that before with this very same screw and it made not change.  One thing I would say is that after my ride, the surging I have been getting when returning to my neighborhood was absent.  So, I'm not sure what to make of that.

One other "funny" thing happened on that ride.  I keep track of my gas mileage and use the results of a fill up to calculate when the tank will go to reserve the next time.  I write that number on a piece of tape on the gas cap.  When I left home this time, I noticed I was relatively close to the number on the tape so I headed straight for the gas station.  Less than a kilometer from the gas station, the bike stumbled and stopped running.  I have a clear plastic filter and could see there was no gas in it.  I was shocked because the odometer read earlier than my piece of tape!!  Hmmm...  I was on a hill down to the gas station so I just put in neutral and coasted to the pump.

When I got home, I rechecked my calculations.  Turns out the number I wrote on the tape was "exactly" the distance to reserve. Typically I write a number that is say 20 kilometers before reserve so I have a bit of cushion.  So, I goofed this time in picking my target mileage for heading to the station.  I could have turned the petcock to reserve to get another couple of liters of fuel...but I generally don't drive deep enough into a tank to need reserve so I didn't think of it.  Plus I had the downhill coast to the pump so I didn't have to push the bike for that distance!!

To complicate things, I have been doing some tweaking of the idle screw and checking for leaks which meant that I burned up fuel sitting in the driveway.  That's why I burned the fuel in the main tank earlier than I had predicted.  Live and learn!

Kurt
Kurt in S.A.

rolf

kann mir das jemand übersetzen....mir ist das zu englisch ;D


Kurt....I ask for a translation to the forum....my english is not good enough

4Taktix

...irgendwas mit "Tank früher leer als errechnet" und Motor aus und bergab auffe Tanke rollen.
Nix, was zur Problemlösung beitragen würde - zumindest kann ich das nicht erkennen.
Think outside the box !

Kurt in S.A.

No, nothing to help solve the problem!  It was gas related and just thought I'd share!!  :prost:

Kurt
Kurt in S.A.

rolf

Sascha:
As for a thick vs thin ring, could be that the interior hole in the carb has worn a bit over the years.  I did not retry the screw to see if it made a difference in the idle speed...I had done that before with this very same screw and it made not change.  One thing I would say is that after my ride, the surging I have been getting when returning to my neighborhood was absent.  So, I'm not sure what to make of that.

Kurt in S.A.

Since it appears that air is getting into the idle circuit some way and not from the outside connections, is it possible that the slide is worn or the carb body is worn on the inside?  Is there a way to confirm this?  I will likely need to remove the carb and physically look at the looseness of the slide.  I've priced a replacement from my US source at around $35 which seems pretty cheap.

Kurt
Kurt in S.A.

4Taktix

Hi Kurt,
very simple: detach the carb - slide in idle position - one finger into the intake-side, one other into the outlet-side, then try to move the slide back and forth.
Repeat in various positions. I suppose you will notice that the sideplay decreases, the higher the slide-position.
If so, there is definitelty some wear. Replacing the slide is easy, but the wear will also be in the carb-body, which is harder to eliminate.
Maybe for 35 bucks it's worth a try - depending on the quality. Does the internet have rumours about that replacement carb or that dealer ?
Another possible root cause may be a crack in the carb-body. But you'd have noticed that by rpm-change while spraying with the cleaner or whatever flammable you tried.
Also check the cable-inlet on the top-lid - there's a rubber sleeve available to prevent air from bypassing the slide that way.
You could pre-check this by wrapping tape tight around the cable-inlet.

Regards,
Sascha
Think outside the box !

Kurt in S.A.

Nice weather outside so I decided to investigate further.  The slide is not the problem.  It fits very tight in the bore.  I do recall having some sticking issues in the past and had done some light "buffing" on the outside of the slide.  It moves up and down with throttle easily.  But the slide can't be the problem.

I verified that the hole from the air bleed is open to the throat of the carb.  But there's another hole upstream of that.  This is a bad picture...best I could do.  The air flows from the bottom of the picture to the top.  What you're seeing is the top of the atomized in the bottom of the chamber.  I've circled what appears to be a hole downstream of it.  Note that the hole from the air mixture screw is a little further downstream of the hole that I've circled.  I sprayed cleaner in the circled hole but didn't see where any of it came out somewhere else.

Lastly, I thought I should check the flatness of the carb flange.  It looked flat!  But I rubbed it on pieces of 600 grit sandpaper with some acetone, going each direction a number of times.  It did appear that it wasn't flat.  I continued until I got shiny material all the way around the main throat opening.  Lastly, I put some blue hylomar sealant on both sides of the carb spacer as well as around where the carb cap screws onto the cap.  I'm thinking that maybe air was leaking around this flange.

Kurt
Kurt in S.A.

rolf

#51

THE "Mischkammereinsatz" is in right position?

ps
danke, Sascha :-\\

Kurt in S.A.

I believe it is, Rolf.  As I recall, it only goes in one way.

Kurt
Kurt in S.A.

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