'94 Carb Work
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Thread: '94 Carb Work

  1. #1
    Senior Member Omega Man's Avatar
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    Hi Guys, even before I got my TW I knew that some carb work would be needed. Last year the TW ran pretty good on about 1/8 to 1/3rd choke. This year it was pretty crappy at 3/4 choke so I thought I'd go in. I had been reading the pinned threads here and looking at the pictures and come to find out, the '94 has a different carb. I got (kinda ugly) through it and it seems like it's the next generation of the throttle cable out of the top style carb.

    Anyway, it's hard to tell what the previous owner did as there were a bunch of spare parts that came with it but I installed the new 118 main jet- that is what was in it, put the "splash ring" on it and shimmed the needle up 3 washers.

    I haven't ridden it yet, but this is the first time it has sat at idle with the "choke" off. I can "blip" the throttle and the bike doesn't die. I had already removed the brass plug and I think the idle circuit will need a little more tweaking but at least it looks like I'm on the path to improved driveability.

    Gary
    "It's more fun going fast on a slow bike than going slow on a fast bike" UK

    1994 TW200, 2009 F800GS loaded,

  2. #2
    Senior Member silverhead's Avatar
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    114 was the original main jet size. I'm running a 116 main jet in Iowa. The 118 might actually be too rich depending on your elevation and causing the bike to run crappy once you're into the main circuit 33% to 100% throttle range. Especially if you have the needle shimmed up a bit you might experience an overly rich main jet circuit that acts like trying to drive with the choke out slightly. Or you might be totally OK. I'm not sure how quickly the carb fattens out and starts to act up.



    What brass plug are you speaking of that you removed? I have not removed anything from my carburetor, or do you mean the anti-tamper cover over top of the pilot jet adjustment screw under the carb? If so, I am running my carburetor at 3 turns out of that screw.



    Fortunately nobody had ever taken my carburetor apart. Another handy test is to check fuel height using clear tubing out of your fuel drain on the bottom.



    Loop the tubing up and see how high your gasoline sits in the float bowl (with the bike upright.) It should be sitting at 8mm below the lip on the float bowl. If it's lower or higher you adjust your float to compensate. The bike runs great when fuel height is set dead on. This measurement is more important than measuring your float height.



    Your pilot jet should be a 40 size. I tried a 42, but it didn't help me. 40 works great for me.



    I have to start my bike with varying amounts of choke and then I can go off choke completely on even cold days at about 1 minute of driving.



    I have a smooth transition from idle to wide open throttle and my settings are: 40 pilot jet, 3 turns out on the pilot screw, 116 main jet, and about the equivalent of 1.5 mikuni carb shim washers. I made mine out of pop can pull tabs because I'm a tight wad.



    My bike is a '93 so the carb is identical to yours. When I got my bike the rubber intake boot to the engine was cracked and was leaking air. I had to buy a new one. I sealed the old one and it worked, but the new one is ideal. Check for air leaks since they like to crack or come separated from the metal part.
    1993 TW200

  3. #3
    Senior Member Omega Man's Avatar
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    Quote Originally Posted by silverhead View Post
    114 was the original main jet size.
    That's good info, there was a 118 which was a little corroded and a new one in the "spare" parts bag so I put a 118 back in.

    I'm running a 116 main jet in Iowa. The 118 might actually be too rich depending on your elevation and causing the bike to run crappy once you're into the main circuit 33% to 100% throttle range. Especially if you have the needle shimmed up a bit you might experience an overly rich main jet circuit that acts like trying to drive with the choke out slightly. Or you might be totally OK. I'm not sure how quickly the carb fattens out and starts to act up.
    I haven't got a chance to ride it yet so I will have to see how it runs. It was kinda hairy as there was no telling if there was going to be a stall at an intersection.

    What brass plug are you speaking of that you removed? I have not removed anything from my carburetor, or do you mean the anti-tamper cover over top of the pilot jet adjustment screw under the carb? If so, I am running my carburetor at 3 turns out of that screw.
    Yeah, that's the plug. I had drilled it out while it was on the bike last year to try to get it to run better. I don't know the turn-out but I think it's close to the talked about 2.5 turns.



    Fortunately nobody had ever taken my carburetor apart. Another handy test is to check fuel height using clear tubing out of your fuel drain on the bottom.

    Loop the tubing up and see how high your gasoline sits in the float bowl (with the bike upright.) It should be sitting at 8mm below the lip on the float bowl. If it's lower or higher you adjust your float to compensate. The bike runs great when fuel height is set dead on. This measurement is more important than measuring your float height.
    That's interesting, I just set it to the dim. mentioned in the maintenance manual. Nice trick with the tube.



    Your pilot jet should be a 40 size. I tried a 42, but it didn't help me. 40 works great for me.
    I didn't see a number on the pilot jet but as it looked clean and OK, I left it alone. I did have a 42 in the spare parts.

    I have to start my bike with varying amounts of choke and then I can go off choke completely on even cold days at about 1 minute of driving.



    I have a smooth transition from idle to wide open throttle and my settings are: 40 pilot jet, 3 turns out on the pilot screw, 116 main jet, and about the equivalent of 1.5 mikuni carb shim washers. I made mine out of pop can pull tabs because I'm a tight wad.
    I have had very little smooth running with this bike, so I'm hoping for the best. I was able to find some washers at the local hardware store.



    My bike is a '93 so the carb is identical to yours. When I got my bike the rubber intake boot to the engine was cracked and was leaking air. I had to buy a new one. I sealed the old one and it worked, but the new one is ideal. Check for air leaks since they like to crack or come separated from the metal part.
    I had a time of it getting the slide out finally deciding to take the "E" clips off the linkage and slide it by. The second time around I took it apart while it was on the bike and now that I have a better understanding of the goings on, a change wouldn't be a big deal. I did take a look at the rubbers and although not perfect, I think they are still usable.

    One bright spot it that this was the firs outing for my Harbor Freight M/C lift....it made the job much easier.

    Thanks for the response. Gary
    "It's more fun going fast on a slow bike than going slow on a fast bike" UK

    1994 TW200, 2009 F800GS loaded,

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  5. #4
    Senior Member Omega Man's Avatar
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    I need to add a correction....I was trying to pick up the tools and while going through the packaging, I realized I installed a 116 size jet not the 118 I had mentioned. I still don't know what the outcome will be until I get it off the lift. OM
    "It's more fun going fast on a slow bike than going slow on a fast bike" UK

    1994 TW200, 2009 F800GS loaded,

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