Carb question

[wingnut]

Has any one swapped the diaphragms, slides, needles and emulation tubes from a early model set of carbs into a late model set? Will it work? The parts should fit but I was wondering if there were performance problems. I’d like to have adjustable needles so I could get this 81 to run a little richer.

[randy]

You can adjust the needles by installing washer(s) under the clip.

[wingnut]

“.A box stock 80-81 Eleven Special will respond nicely to simply raising the needles .025,turning the idle screws out 2.5 turns from fully seated and leaving the stock mains at 110.”

Sorry I can’t remember who posted that but it is what I planned to do. I pulled the carbs off of the ELEMENT and took them apart. The outsides looked like hell but inside they were as clean as a running set. So rather then sell them I was going to keep them for spares or put them on the 81. Hence the question

[TopCatGr58]

No Go on the Swappo!

Sorry Dave,

"I can't let you do that" . . . in my best 2001 space odysey voice!

The slides are not the same diameter, and so you can't swap them! However, I don't know if you might be able to swap out the adjustable needles in the earlier slides for the non adjustable ones of the later carbs!?

T.C.

[wingnut]

Thanks TC, I'll look into the needle swap and report back.

[Ken Talbot]

Re: Carb question

Originally posted by wingnut
I’d like to have adjustable needles so I could get this 81 to run a little richer.

You can achieve this effect by raising the floats a couple of milimetres fromtheir current height. (That means you adjust from, say 25mm, to 23mm, when you have them upside down)

[Incubus]

I don't know if switching the needles is such a good idea. The parts fiche shows them to have different part numbers. Using a needle with the wrong taper could really mess up your air mix. That's why the needles from carb rebuild kits never seem exactly right. The emulsifier tube is worn, the new needles aren't. I had worn needle jets in the carbs from one of my other bikes and it made it really difficult to dial in the carb settings. When I replaced them the carbs tuned very easily.

Patrick

[prometheus578]

T.C. and the HAL9000 are truly the voices of experience.
I seem also to remember that the emulsion tubes themselves are different and are matched to the needles used.
None adjustable needle can be made to run richer by putting small thin washers underneath to lift them up a bit.

[red bandit]

I worked on a 80 carb w/ 78-79 emulsion tubes. Got it to run pretty good (tried a few diff jets) but it wasn't just right. Maybe if I'd have spent more time on it??? Don't know if it was cause the tubes didn't match the needles or the # of holes in the 79 tubes just doesn't work with the 80 carbs. It was real doggy on top end. 5th gear 5000rpm wouldn't hardly pick up speed. That was the before. After wasn't to bad.