Intake boot clamp question

[Anonymous]

Hey all-

I was wondering if its normal for the intake boot clamps to be clamped all the way down?

I think I still have an air leak of some sort on my bike, as its still running lean on 3 of 4 cylinders, despite shimming the needles and going a full turn and a half out on the pilot screws.

The bike has stock airbox and filter, and aftermarket exhaust that should be no less restrictive than stock. The intake boot o-rings are new.

I'm running out of ideas on why this thing keeps wanting to run lean. (except for cyl no. 4)

Help! 8O

[KEITH KRAUSE]

The clamps aren't that strong so it's easy to bottom them. They usually get over tightened and this pinches the rubber boots too much. The pinched boots then require more tightening and before you know it, they're bottomed.
Warm up the bike first and spray a fine mist of water on the boots. If the rpm's drop a moment, you have an intake leak.
Are the carbs "popped" into their boots all the way? Does the stock air box still have its lid? Has the airbox had any extra holes cut into it? Are the carbs clean inside? Have you tried adjusting the mixture screws for the highest rpm possible and then re-set the idle with the idle screwknob? Are the carbs synched correctly? Are the floats adjusted correctly? Did you replace all/any spacers on the jet needles in the same order?
If everything else checks out, try the mixture screw adjustment followed by a GOOD carb synch.

[Anonymous]

Keith:

Are the carbs "popped" into their boots all the way? Yes.
Does the stock air box still have its lid? Yes. Seals well too.
Has the airbox had any extra holes cut into it? No.
Are the carbs clean inside? Yes.
Have you tried adjusting the mixture screws for the highest rpm possible and then re-set the idle with the idle screwknob? Have not adjusted while running - but they're already 3 turns out - way more than should be normal.
Are the carbs synched correctly? Have not been synched. When I asked a local bike mechainic about this, he said it is unlikely to cause a lean condition like I am experiencing - just rough running.
Are the floats adjusted correctly? Yes. Dead on to service manual spec.
Did you replace all/any spacers on the jet needles in the same order? Yes, including a 1/2 mm shim to raise each needle that I got from a local Suzi dealer.


I'll try the water on the boots thing. I think its probably the boots, even though it is QUITE tough to get the carb rack in and out of the boots as they seem so tight. They're still soft, BTW ..

[KEITH KRAUSE]

Well, do the intake leak check first.
Synching carbs is adjusting the amount of vacuum so all are close to even. Too much vacuum results in a rich mixture and too little results in a lean mixture. I would still adjust the screws FIRST as I said, see what the plugs say, then follow that with a good carb synch. If it's been a while, then the bike probably needs the synch anyway.
Also, is it possible some of the diaphragms are not seated correctly?

[Anonymous]

Yep - it's the boots not sealing around the carbs. I called the stealership today and they said the original clamps are discontinued.

Since the original boots are still quite flexible and not cracked, (just compressed I guess) I'm going to try and build up the surface that the clamps clamp to with a few layers of electrician's tape trimmed down to the proper width. That way the clamps won't bottom out before they can clamp down firmly enough to get a good seal on the carbs.

I know, it's a hack, but I'd rather have a hack that works and an engine not overheating than not be able to ride because I can't outlay the cash for a new set of boots and clamps.. Providing it works.

[KEITH KRAUSE]

That might work, never tried it. I know electrical tape wants to "move around" when near heat. Another thing that might work is adding rubber.
Most hardware stores sell small sheets of rubber in various thicknesses. If you could find some 1/16" thick, you could make a liner for each clamp. It may be a little fun lining everything up. The liners would have to be a little wider than the clamps so the clamps won't slip off the edges of the liners so easily. If your clamps rest in an indentation, you'll have to make sure you stay in that indentation. I would also spray the rubber liners with a silicone spray to help stop cracking, or at least some other protectant and do this once in a while.

[Anonymous]

[quote="condensr"]I'm going to try and build up the surface that the clamps clamp to with a few layers of electrician's tape trimmed down to the proper width. That way the clamps won't bottom out before they can clamp down firmly enough to get a good seal on the carbs.[quote]

Will that tape stand up to fuel vapor? Some tapes do nasty things when exposed to solvents. Or is that location not exposed to it? The sheet rubber trick might be a better idea if it is. Maybe a ring cut from an inner tube would fit around the carb's output and not leave a gap the way the ends of a flat straight piece could.

Dave

[Anonymous]

Well, the tape should stand up to anything THHN wire will, and THHN wire is gas/oil resistant.

That, and this paricular location, if this does the trick, should not be exposed to any fuel.

I like the rubber idea, Keith - I think while I still have the carbs off I might just go get some .. oh, and the spot where my clamps go is an indented channel..

Thanks all!

[dgeorge]

Do you have an old bicycle inner tube that would work for the rubber?

[Anonymous]

did your tape "hack" work? If so I might bust out the tape!

[Anonymous]

did your tape "hack" work? If so I might bust out the tape!

I'll know tomorrow. I would seriously consider the rubber or inner tube idea though - If I didn't already have the tape on and want to get the bike back together to ride tomorrow, I'd have have searched out some rubber instead..

The tape build-up did definitely make the clamps tighten up before bottoming out, though, so I think it'll be OK. I'll check the plugs tomorrow and see if I'm still running lean.