Why does my carb slide stick?

[Bullfrog]

All my math and science teachers demanded that I keep track of the "units"

[dcooke007]

Nice to have a little fun on this sight again.

Danny

[admin]

Yes Danny it is !

[hodakamax]

And Paul, Happy Birthday, I hope it's a funny one!

Everpresent,

Max

[Bullfrog]

Paul, have you decided what you want to be when you grow up?

Ed
(Happy birfday!)

[dcooke007]

Paul, have you decided what you want to be when you grow up?

Ed
(Happy birfday!)

Did not know it was going to turn out like this!!! Assuming it really is your birthday, happy birthday Paul.

Danny

[admin]

Thanks guys!! Ed what made you get up so early?? Please do not say it was to celebrate my birthday.
To bad we are not back at Finbars !!!!

Yes I do know what I want to be.... Just like you and almost as old as Kennie.
Have a great days guys

[Bullfrog]

Paulie - you need to improve your aspirations! (Though listening to live Aussie folk music at Finbars again does seem like a good aspiration.)

I went to bed obsessing about Vic's carb . . . and woke up early with the mind still "attacking the problem". The deformation which has accumulated over time is quite impressive - and all of the deformation appears to come from (more-or-less) normal forces. Nut is torqued down, sides of flange are stressed and bend, O-ring holds center of flange slightly away and body structure prevents bending in that area (microscopically speaking) . . . repeat . . . repeat . . . repeat . . . The end result is an amazing amount of metal movement with no evidence that any of it comes from being clamped in a vise.




It SEEMS that the warping of the mount flange must somehow relate to the "ovaling" of the slide bore . . . though I have no clear theory of how that could be. Still, it is quite apparent that the parent zinc is quite ductile/malleable/deformable . . . and there needs to be only some .004" of deformation transferred to the slide bore to result in the ZERO clearance seen in this carb body.

Finally -- DOH! Vic, I just discovered your pilot jet resting on the workbench. It will go out to you today.

Ed

[viclioce]

OK. Glad you found it as it was the only one that size I had! looked like I can save your photos and make a nice mixed collage to hang on the wall with the carb in he middle! I'll even keep your typing on the photos! ; D Victor

[rlkarren]

In my limited experience, no two carbs or engines are identical in regards to jetting.

Victor, I think you'll find that using the same jetting in the new carb won't work as it did in the past, especially since it was "damaged". I'm at 4400 ft and I'm using a 25/125 with excellent results. But I am running a stock 94 125cc. Since we're at about the same elevation, I wonder if maybe your carb was leaking since your 35/140 was running so well? A 35 pilot seems awfully large for our elevation. But then again, no two engines are alike... More or less.


$0.02

Roger

[viclioce]

Roger. I was speaking with Greg about the carb he is sending me. Since he s at 6-6500 feet he's less than 1000 feet lower than me. I agree with you as I could never pull the needle jet, it was stuck and I couldn't get it loose.

I also I never pulled the choke to check the rubber plunger at the end to see if it was dried out or not. The whole carb was poorly configured to begin with, but I may have undercompensated with the main jet to account for other issues in the carb which may have caused it to run too rich. I suspect the needle jet may have been badly worn but I couldn't get it apart. Now I can pull it even if I damage it and inspect the needle jet.

I know running different needles, especially if they are stainless instead of aluminium, can egg out the needle orifice because they are soft and the carb doesn't mount perfectly level. So the stainless needle can start rubbing against the needle jet orifice and wear it out of round. But since I couldn't pull it apart without damaging it, I chose to let it go and work with just adjusting the pilot and main jets. It was a bit funky, but it got the carb to run smoothly. If it wasn't for the slide sticking, I may have continued to try and pull it apart and consider whether the needle jet needed replacement. Now it's a moot point.

The carb which Greg is sending me has a 35 pilot and a 220 main but all the other components work the way they should and are also clean. So I am going to try it as he set it up first, and if it gurgles too much I suspect I won't be going lower than a 170-180 IF needed. So we will see how it goes when it arrives. Heck I may even go smaller on the pilot, who knows!

Greg upgraded his bike's carb from a 24mm to a 28mm and no longer needed it. So he's sending it to me for the cost of postage! I'm going to try the configuration he is sending first and go from there. At least this will give me the opportunity to make the bike have proven reliability and I won't have to screw with the old "wall decoration" any more! ; D Victor

[Bullfrog]

Vic, are you saying you couldn't get the needle jet out of the carb body of the carb I just looked at and sent back to you?

I took it out for inspection and it went back in just fine. Do you need the magic password so you can remove it too?

Ed

[viclioce]

Ed. Package received. Got the carb, just waiting for the pilot jet! ; D Victor

[viclioce]

Uh, no Ed. I just didn't have a good enough small wrench which would fit the brass fitting without most likely damaging the brass. I certainly didn't want to put some vice grips on it. The only wrenches I have that small are inexpensive automotive "ignition" wrenches which would have surely torn it up, and I don't currently have a crescent which would tighten down securely enough to not strip it as well. My best guess is it was varnished up but I ran enough fuel mix through the carb to clean it, and you were able to get it off because I stopped trying.

And, it's a good thing I removed the password from it BEFORE I sent it to you or you couldn't have removed it either. I will remember to set the password on the one Greg sent me to something along the order of 76 characters with extensive non-asci characters and maybe a half dozen Spanish only pronunciation characters as well!

I really wasn't expecting that cheeky of a response in a technical forum question. Oh well... Live and learn. ; p Victor

[Bullfrog]

Attempts at humor sometimes miss the strike zone (sorry about that). (I wasn't sure you new that the small brass fitting had to be removed . . . I've bumped into folks who didn't know that in the past.)

Ed

[viclioce]

Yeah I got the first piece off but couldn't turn the damned jet. But like I said it's a moot point now since it's going to be a wall hanging. Did you notice if the needle orifice was damaged? You didn't say anything about the status of the needle jet. ; D Victor

[Bullfrog]

Umm, mayhaps I was on the right track after all?

You loosen the little fitting (after removing the O-ring) about 1 turn. Then give it a little tap to loosen the needle jet in it's bore. Then remove the fitting and the brass flat washer. The needle jet is now free to be removed straight out the top of the carb - turn the carb upside down and the jet will probably fall out. If not, pressing on the end of the needle jet with a piece of wood dowel should easily remove it. There is no need to turn the needle jet (in fact you can't turn it while it is in place) - it has a slot and guide pin arrangement to assure it goes in only one way. That's the password for removing the needle jet.

I forgot to examine the ID of the needle jet closely, but the top of the jet didn't appear to be obviously ovaled.

Ed

[viclioce]

Update.....

I sent the old carb which was still sticking to Greg McClintock in Prescott. He received it this afternoon and this is the email response I got from him, copied verbatim:

"Received this afternoon. Measured it, and my numbers match Eds. Using marker pen I found where it was sticking, and found a series of two long scratches top to bottom in the rear ( toward the engine). Whatever got caught and made the scratches not only dug grooves, but displaced metal making lips on each side of the grooves. A little light buffing with a wheel inside and the slide now drops free through the bore.

It is also possible that, in addition to the scratches, the slide bore wasn't perfectly round, and it may not actually be so now, but I now show measurements of 27.52mm more or less continuously around the top of the slide bore. The slide itself is about perfect.

I will check the jetting and passages as something may be blocked inside. After that, I may add Venturi dividers just for the heck of it. They do work.

Greg McClintock
Prescott, AZ"

So the carb is now his, he sent me his old 24mm one because he upgraded to a 28mm. Interesting saga to say the least. But it's nice to know what the problem was, and that it was fixable by a great mechanic and he will put it to good use, I am sure! ; D Victor