carb question

[fritz1966]

I'm trying to get my 80 mid special running, I noticed today after having someone rebuild carbs this last winter that one of the adj screws is missing, this screw is on top in the front on all 4 carbs its brass and recessed, I have a extra set of carbs but i cannot get screw to come out on these either, any hints on this.

fritz

[TopCatGr58]

Hey there Fritz,

I see that a lot of folks have viewed this question, but no responses!!!! It may be because we're unsure of whether you are describing the correct location?

As the carbs sit on the engine, if you look down on the top of them, towards the front of the bike where the carbs mount to the intake boots, there are 4 holes,1 in each carb, with a needle screw that fits into them, it's the pilot/idle circuit adjusting screw. They have very fine needle tips that will protrude slightly into the throat of the carb. IF they are tightened too tight, they can get stuck and then when trying to get them out, they can even break off the tips. There are springs and a few metal and rubber washers under them.

You say yours is an 81, they were sealed with caps by the factory, so apparently someone removed them, as many of us do, to be able to do a more thorough cleaning, as well as being able to adjust the idle!

However, if you are looking at the air filter end of the carbs, into their throat, there are a couple of screws, air jets that are brass and fitted into recessed holes around the curved opening of the carbs, near the left middle more so than the "top" of the opening!

Hope this helps, write back with more info if you need it, being as descriptive as possible!!!!

[newmaac]

Fritz, if it is the idle mixture screw that is missing, It is possible that it was broken when they were re-worked last year.
Are the carbs mounted?
If not, feel the inside of the opening of the carb, where it mounts to the intake boot. Can you feel the sharp point of the mixture screw protruding through the carb body?
Check back and let us know what you find.

[Ken Talbot]

It sounds to me like Fritz is talking about a missing pilot screws on a later-model carb. If this is the case, these would be the blunt ended screws and they are not susceptible to breakingoff like the sharp ended screws on the early model carbs. However, if one is in fact missing, that will cause a problem. Being unable to remove a screw from another bank of carbs can be pretty common. The screws have a very fine thread, and they can easily get corroded and stuck. My advice or this wold be to use an impact driver with whatever adapters it takes to get an appropriate sized screwdriver bit onto the stuck screw. Use just a small hammer to strike the impact driver once you have the slack taken out of the spring and you should be able to budge the screw loose. Be very careful if you don't have an impact driver - it is very easy for the screwdriver bit to climb up out of the slot as you're cranking on it, and this will break off or round off the sides of the slot. Then you'll have to drillit out or grind a new slot with a dremel tool and a fine diamond burr. HTH.....

[fritz1966]

This is the screw that goes into the front intake boot, it sounds like the pilot screw I'm talking about, it looks like screw is missing i can see hole in carb, anyway this is a 80 mid sp i have another set of carbs that just got rebuilt for my other 80 mid-sp, screws will go in and out i just can not get it to come out pass recessed area to get ahold of it, Ialso tried to get them out of my 81 with same results i even tried a magnet to lift it out, but from what i understand the 81 screws will not work, sounds like i need to find something very small to get under the head of screw to finish lifting it out of recessed area, Thanks for all the tips guys I wanted to make sure they do come out.

Fritz

[John]

Try enlarging the opening slightly. Run the screws back down into the bore, and ues a drill slightly larger than the opening of the pilot screw bore. They may be a 'booger' on the the opening where the factory seal was. If you have compressed air available, use that to blow the screws out past the opening. Blowing through the pilot jet in the intake side of the carb with your finger over the pilot hole in the other end of the carb, may help also.

[fritz1966]

broken tip

Thanks for the tips guys, After further investigation I found tip was broke off, dealer never told me, well i got some work to do.

Fritz