KZ750 LTD Choke - Fast Idle Adjustment

The carbs on my new-to-me KZ750 LTD are working fine, and have a good idle when warm, however starting is a bit of a pain. The mixture enrichment works well, and starting up the bike isn't an issue, but to keep it running I need to hold the throttle open a little. The fast idle of the choke doesn't seem to work.

I've looked at the manual and had a look between the carbs, and I can see where the fast idle link connects to the choke shaft. However it doesn't connect with the valve pulley to open up the throttle as it should. The manual states to adjust the clearance, however I can't see any obvious way of doing so.



I can remove the carbs if need be, but I don't want to if I don't have to. So how do I adjust the idling link gap? Can it be done with the carbs in place, and if I do need to take them off, then how do I do it?

I think you have to bend the Fast Idle Link so it opens the throttle a little more when the choke is actuated. I've never had to do this before but from the look of the diagram it seems the notches in the link down by the Pulley are to facilitate bending.

Nessism wrote: I think you have to bend the Fast Idle Link so it opens the throttle a little more when the choke is actuated. I've never had to do this before but from the look of the diagram it seems the notches in the link down by the Pulley are to facilitate bending.

The link is quite thick. I guess it could be bent, I can't see any other reason for it to be that shape. If that's the case it looks like it's a carbs off job - I guess if there's another way I'll see it once they're off.

can you upload some pictures of your fast idle mechanism with choke in zero, half and full position???
Have you checked the carbs are running synchronized when the engine is warm?

Scirocco wrote: can you upload some pictures of your fast idle mechanism with choke in zero, half and full position???

I can try - I had the tank off to change my valve gasket yesterday, so I'll see if I can still get in enough to take a picture this evening (I'm in Australia, so it's morning now).

To describe it using the image I posted above, the fast idle link (3) does turn clockwise as expected when the choke it engaged, however there is too much of a gap between the fast idle link (3) and the pulley (5), so it never turns the pulley. So either the the bottom of the fast idle link needs to be bent so that it is closer to the pulley (as Nessism suggested) or the top needs to be moved closer to the fast idle cam. I was expecting an adjustment up the top, but I couldn't see that even with the tank off.

As Nessism said,something in the fast idle mechanism must be bent.
Choke = (more fuel,less air) = you must hold the throttle butterflies open by hand till the engine is warming up.

Scirocco wrote: As Nessism said,something in the fast idle mechanism must be bent.
Choke = (more fuel,less air) = you must hold the throttle butterflies open by hand till the engine is warming up.

The enrichment part works fine - I can see the choke link move and it's easy to start. It's just the fast idle mechanism. I think the previous owner just bumped up the idle so that it would run when cold (it was running at over 2000rpm when warmed up), when really the fast idle just needs to be fixed.

Some pic´s or a short video are very helpful to solve your problem.
I have seen many carbs cleaned, rebuild and adjust with the result that bike runs worse than before.

Michael

Some photos showing the linkage with choke on and off. I think you need to bend the linkage as shown with the screwdriver if you want to increase the idle with the choke on.

That's exactly what I needed. I presumed that there was an adjustment up the top (like a screw or something) that would bring it further away from the choke cam.

By the looks of things I think I'll need to take the carbs off for this. Even if I can access that slot with a screwdriver, it would need a fair amount of pressure, and I'd be worried about breaking something doing it at arms length.

I guess my other option in the mean time is to add a spacer. I might try making a small aluminium clip to sit on the pulley and reduce the clearance between the pulley and the fast idle link. I'll have a look when I get home to see if that's realistic.

No screw adjustment in the system. Only way to adjust is to bend the tab as shown. The bracket bends pretty easily. I think if you remove the tank you will have a reasonable chance of reaching it.

Before bending double check my bending location suggestion.

before bending something