It's time to approach the gurus again.
On my supposedly 91 LT, when I put the "choke" lever onto position 1 or 2 to start the bike, nothing happens
with the throttle screw on the rail. I can see that the gizmo behind the TPS is pulling up but it is not contacting the throttle rail at all and the idle screw just sits flat on the stopper. If I slip a small screwdriver under the idle screw I get instant start (well, almost) and as I have been trying to adjust the idle (via the manual) this is causing headaches.

I would like to know where to start looking. Here is what I know.
The choke lever moves, stays on position 1, and it lifts the cable end down behind the TPS. I have tried adjusting that but it doesn't seem to have enough adjustment to make the idle screw move at all.
I suspect P O has done a bodgy job on the idle screw setting so everything will be out of whack.
Should I take the TPS off to get better access and work on that end?. I should say that when warm the engine
ticks over at 1,000 rpm so I don't really want to adjust the idle much from there.

RT

In between TB #3 and #4 there is a small roller that works on a cam arrangement the roller very often falls of never to be seen again. Putting a replacement in is to say the least a bugger of a job.  My advice is try to live without it as the game isn't worth the candle.

we have often seen this issue before bob ....

seems to me that every body adjusts the idle by the throttle body bypass screws and forgets the idle adjust screw 

sounds like you need to find klompy or some one who has one of those vacuume guage thingos and get a job done  ?

of corse you could try yourself and mark the throttle bodys  and wind them all in a similar amount .

don't forget that the throttle body screws only need to come out a bout 1.5 turns from closed .

what will end up happening is that the idle will drop lots ....now letting you wind the idle screw back down onto the idle (choke ) adjust rail
but best plan is to have a tb adjust day ?

The choke lever pulls on a cable that draws up a lever, causing a cam to rotate.  The cam mechanism rides on a roller attached to the shaft that moves the butterfly valves.  See the picture of the cam below:



You should see the action of the choke by observing the butterfly valves open slightly when the choke is engaged.  This will be most obvious by watching that the shaft rotates slightly clockwise as the choke is engaged.

If the shaft does not rotate as you engage the choke, the cam mechanism is the most likely culprit.  It is possible that the roller is missing or broken or that the cam is maladjusted.  In any case, the throttle body assembly will need to be removed to service this part.  That is a major disassembly job that you will have to evaluate whether it is worth the effort to regain the function you are missing.

I don't believe fooling with the idle adjust screws will return your fast idle behaviour if the mechanism is at fault.

that pic explains a lot rob

sorry bob I didn't read clearly that there is no movement of the throttle rail

Thank you all, that picture is great, how the hell did you do that Rob?.
Anyway, cool weather has made it a bit more of a bummer but today I see signs of Spring, and Waz from Wollongong is arranging a TB and valve clearance session early Sept (good man him) so if I can get that all adjusted on both bikes I can swap my rego plate over and get some test riding in. (Did I say that) I meant get the black bike registered too. 
Cheers .
RT

RT wrote:Thank you all, that picture is great, how the hell did you do that Rob?.

Easy.  I have a spare throttle body assembly sitting on a shelf in the basement (along with all the component parts of my K75 as I have completely disassembled it into its constituent parts).  Don't worry though; I'm in the process of putting it back together into a new customized form.

You guys must have more time available than me, I've got a whole spare bike in a shed, been there for 8 years now. I think I'm under the thumb.