open carb tops on bike

[crowesnest3]

Picked up an 84 Interstate over the winter, running rough, actually thought it was only running on 3, not the case, but I do suspect # 3 carb has a problem, spark plug reads different than the others, all light tan to gray, but #3 is almost like its just clean (?) .... haven't checked the plugs for about 500 miles now, need to do that! Been running ATF and Seafoam with high octane / non ethanol gas doing some 80 mph/ 150 - 180 mile loops and its continually getting better. Issue is she just doesn't want to take a handful of throttle, easy throttle, lower rpms and she is smooth actually starting to get strong. Can actually feel the motor at 75/80 when giving some throttle do some rpm lurching as if she wants to break out of the box she's in! The carb rack probably really needs to come off for a rebuild, but in the mean time, I was wondering what if I opened up the tops and gave the diaphrams a once over, maybe shot some carb cleaner or ATF into the body let it soak and pull the bowel drain and dump it? Any thoughts you might have I'm all ears. Really irks me knowing there is a lot of power there I can't touch! ........................... and boy I do like riding the 84 compared to my 80, whole different feel, but if I'm not mistaken my 80 would eat up the 84 in a head to head!? ..... Crowe .... :Egyptian:

 

[slabghost]

Probably not a bad idea to check the diaphragm and maybe clean them with soap and water. Check the sliders move easy too. Especially on #3.If you do use carb cleaner be careful not to get it on any gaskets or O rings. Does it idle well? At what rpm?

 

[crowesnest3]

idles smooth @ 1000, forgot to mention I did sync the carbs .... using a single guage 4 manifold unit I put together this spring, just requires a lot of back n forth but seem to all balance out @ 5 - 6. Thinking its the high speed jet plugged up, just not getting enough fuel to be who she is! Maybe just use ATF rather than carb cleaner, aren't the diaphrams made of rubber? ..... Crowe .... :Egyptian:

 

[slabghost]

Yes the diaphragms are made of a rubber like material. Which is why you use only soap and water to clean them. No carb cleaner. It will eat them. Check them carefully for any pinholes or cracks.

 

[crowesnest3]

thinking would be a GOOD idea to pick up that carb repair manual I see connected to Radnaak's rebuild kits, which if I could put off a rebuild till this winter I would, anyway, let me pose a a question having not ever opened the lid to a carb on a 1200. Pulling the cover exposes the diaphram which then can be gently removed, inspected ,( replaced if comprimised) and given a soap and water bath ( pine sol too much?) Once diaphram is out would it be possible and/or worth the effort to fill the carb body with ATF or PineSol mix, let soak for a while and then drain this out thru the bowel drain maybe with the gentle persuasion of some compressed air ...... even give the carb "ultra" shake with the random orbit connected via flat bar or 1 x 2? Gotta beware of my over active imagination ...." we can fix this!" ...... Crowe ..... :Egyptian:

 

[slabghost]

I'd try this first before opening. Since it is running well enough to ride. Access the air filter intake. Rev the motor up to about 3000 rpm and holding it there cover the air intake choking it.Don't choke it until it dies. If there's a little junk in the high speed jets this should force the fuel mix through and may clear them with several tries. If you haven't adjusted the air / fuel mix screws you may want to do so. If #3 is still uncooperative then it's probably time to pull the carbs and clean them carefully. I wouldn't use anything stronger than dish soap on the diaphragms. Check float heights carefully. If you want manual information I think backlander has it. Unfortunately I don't have a 1200 rack here to open and give you specifics on it.

 

[backlander]

I'm in slabs camp on the cleaning of the diaphragms crowe. I went out to my bike and looked and removing the float bowl on the #3 would be one tuff job, two of the screws sit almost over the water tube to the head and it's pretty tight quarters there. It is possible that the slide is not working properly, the diaphragm is damaged or simply not enough vacuum available to make it work. The 1200 carbs are cv type and use vacuum to alter the position of the slide/needle to allow more or less air flow, pulling the amount of fuel required on demand by the engine. Damaged diaphragm means not enough or no fuel through that carb. That's what I would do first. If you don't find a problem there my suggestion would be to pull the carb rack, flip it over, remove the bowls carefully hoping to save the gaskets, clean the jets and all up, check the float height, reassemble, bench test for leaks. I wouldn't adjust sync screws or air/fuel mixture until they were back on the engine, if it doesn't run exactly right.

 

[crowesnest3]

................wasn't thinking of removing float bowels, just pulling top to inspect diaphram and with that out pour a little ATF into carb body than drain it out thru bowl drain. Will give the air intake choke approach a run, have run up the RPMs in gear and dropped of the throttle for some back pressure. Also, will try to get the plugs pulled out tomorrow and get a read off of them after running pretty hard for about 500 miles. As always appreciate the input ..... Crowe .... :Egyptian: