Gurtner Carb Project

Okay i have a 1980 motobecane moby and it has a 50v gurtner carb on it and the jets are clogged, I am going to be cleaning it out this weekend. Does anyone have any tips for me on taking it apart ro can anyone give me an idea on how the choke and throlle cables dissconnet fromt he carb? Any help would be greatly appreciated. Thx

Re: Gurtner Carb Project

I have a '80 Honda express NC50 so I don't know how to do your cables.

How to clean a carb well:

First take it apart and remember where everything goes. Make drawings and notes if needed.

Once you have it apart you should take off all the rubber and plastic. Remembering to take note of where they all go. Take out all the screws and then spay it with carb cleaner. You want to spray through the jets. spray and clean all of it, but focus on the jets most of all.

Some people feel confident using the high E string for a guitar, but you should be careful because this is dangerous. The metal the carb is made of can scratch pretty easy. If you don't feel confident then use a nylon stub from a nylon brush to physically remove the junk inside.

Blow through all the tiny jets as hard as you can and then spray it again and repeat this process until you think its definitely clean and then do it two more times to make sure.

Soak the carb without the rubber and plastic parts (screws if you want) in carb cleaner over night.

repeat the spraying, picking and blowing again. If you have an air compressor this helps a lot. spray some compressed air through the jets.

then put it back together. Get used to it because you should clean your carb every six months AT LEAST.

Good luck and get scrubbin'

Gurtner Carb Project

Steamboat Aka J. R. Stevens /

Here is an exploded view from MA photos. Jim

Re: Gurtner Carb Project

It's pretty straightforward. Both cables just attach to a small plate on top of the carburetor, you loosen the screw that holds that plate on, pull on the cables, and the plate, throttle slide, and choke slide will all come out. When you re-insert them later, be sure to have the little nub on the throttle slide in the keyway properly! You don't want to have it out of the keyway when you tighten down on that plate, you could shear the nub off.

As far as cleaning goes, Francis' directions are generally good. You will want to push a wire through both of the holes in the inside of the bowl... the lower one leads to the main jet, and the upper one leads to the choke circuit. With the jet and choke slide out, you will see the wire come out the other side once you've pushed all the gunk (if any) out of the way.

I've attached a drawing with some pointers about the main jet. There is no gasket between the jet and the carb body, and I've found it necessary to wrap Teflon tape around the jet to prevent leaks here. You can probably ignore the last tip, it's just a paranoid compulsion of mine, but I like to align the hole through the side of the jet with the passageway from the bowl.

Don't try to remove the brass parts you'll find after removing the jet (there's a diffuser and something else in there...), I stripped the slot on my diffuser trying to get it out. You can just push a wire through, if necessary.

Make sure you have the pointy end of the float needle pointing up when you put the bowl cover back on. Good luck!


Re: Gurtner Carb Project

the high hole in the carb brings gas to the "choke" (enrichener) circuit, as well as the idle circuit which ends as a small hole next to the diffuser.

Make sure you can get cleaner to pass all the way through the idle circuit. if it does not go it is probably clogged at the point where it passes around the outside of the diffuser. It is a little strange, and you do not really need to understand it if it is not clogged, but if it is, you must take the diffuser out.

If you need to remove the diffuser, make sure to use a screw driver that fits the diffuser holder perfectly. if you try with a screwdriver that is not a perfect fit, you will strip it out (like Anthony Did, and I have done) and you will NEVER be able to remove it.

Re: Gurtner Carb Project

Also some gurtners have the choke cable entering the bottom of the carb, you can change this so it enters at the top, thus making future carb work MUCH MUCH easier.

Re: Gurtner Carb Project

Thanks for the help guys ill try your techniques this weekend and let you know how it goes.

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