Question for the Mikuni gods

[fairmountvewe]

Are there different slide lengths for Mikuni carbs? The reason I ask is because I am working on an 80 Trailfire 440, and when I set the carb up so that the slide is flush to the top at WOT, and I release the throttle, the slide doesn't fall down far enough to come anywhere near the idle adjustment screw. Conversely, if I set the throttle cable low enough so that the idle screw has some effect on the slide, then WOT only raises the slide half to 3/4 of the height to flush. I cannot increase the amount of cable "length" because that is determined by the throttle lever throw. So I am wondering if I have a short slide. Is that even possible? I believe it is an original part, but I do not know for sure. I can get the sled to run, but I am not at the full test stage yet, so I don't know if this is even an issue. If I can I will grab some pictures tomorrow.

Peter

[Matt]

I'm not aware of different slide lengths. Is it the original throttle block?

[sledhead16]

Peter are u making the bottom of the slide flush on the motor side when at wot and not the airbox side and is your eclip on the needle jet in the 3rd position?

[sledhead16]

None of the venturi should be obstructed by the slide at wot on the engine side of t h e carb

[JDT]

Check the throttle cable at the grip block on the handlebars. Make sure that the barrel end is fully seated in the throttle block hole.

[fairmountvewe]

Thanks for all the feedback. The needle is in the third position, the throttle cable is fully seated, however after talking to some of the local guys, I have erred on the side of caution and have adjusted the throttle cable all the way down so idle is fine, but WOT will be affected. I haven't had a chance to run it at speed yet to see what happens. I have a day off on Thursday, so I will try it then. It does run and idle (2500-ish rpm), and it doesn't sound rough or laboured. I will let you know what happens. Thanks again.

Peter

[mwking]

I ran into the same thing a few years back. The guy I bought my '84 Sportfire from had complained that it wasn't very fast. Among other things I found that the slide was not going to wide open throttle. I replaced the cable with the correct one and that problem was solved. Who knows what the cable on it was meant to fit or where it came from. Tend to find that a lot of these old sleds have had parts replaced over the years with whatever seemed to fit.