1989 VFR750F Carb problem

Hi all,
sorry this is a bit long winded but . This is an Australian 1989 VFR 750F
Saturday morning was cold here so I thought I would warm up the bike for a bit before going up the street . Anyway before I started I noticed the choke was on full ,where I never use it. After turning it off the bike started ok and I went to put the gear on and it started to idle fast . After giving it a couple of guns I had to idle it down but it wouldnt idle under 2grand . So I took it for a ride hoping it would get better . But it got worse . Now its stuck on 3grand . I've never had an engine idle fast before normally its the other way around . So initially I thought butterfly's . So I've had the carbs off 3 times checking that they all closed when the idle screw is backed off fully and it still idles fast. Then I noticed if i sprayed WD40 around the chokes on the carbs it would slow down . Also if I give it a little choke its slows down a lot . Does anybody know the specs or what the each choke is meant to be set at ? I'm also hoping that some kids havent been playing with the choke hence it been on full . But this has got me stuffed. So off they come again tomorrow to check the chokes I've never really checked them so. After checking for air leaks ??????????

 

In my experience a hanging idle is usually due to a lean air/fuel mixture. I would look for an intake air leak, clogged jets or poor fuel delivery from the tank to the carbs.

 

Well after spending all day checking things out ,it turns out its the choke valves are returning to far . You can here the air squeaking when the choke cable is returned all the way. If I turn the choke about quarter of a turn the air squeak stops and it idles where its meant to . Not sure if the cables stretched or what . I guess I'm going to have to put up with it as it is for a while . Which brain wave came up with this system ? At least with butterfly's you can see whats happening, With this what happens when the valves wear ? How much air leaking around them becomes a problem? When I pulled the valves and cleaned the system I put grease around the valves before assembly. But this didnt really make any difference ,so I think I can say that its not from air leaks . And the intake rubbers are good . BTW if you want to protect those rubbers on assembly wet them with WD40 or CRC and the carbs will go in a lot easier plus come out easier . These are easy compared with some of the inline fours I've worked on .

 

Just taken it for a ride . Apart from idle it performs fine so its not fuel delivery .

And the jets are fine.

When i get some more WD40 tomorrow I'll check the air intakes again .

 

Well I found the problem . Those arms that go from one choke to the other , the front one and back can go two ways . Well the front one was 180 degrees out so the choke wasnt closing properly . The whole time I've been riding this thing its had some choke . And I've had it on the road for a about a year and a half . Funny how its only been a problem now . And the miledge hasn't been that bad. Like I said I hadnt really checked the choke setup I just assumed it was ok . I wont be assuming that again . This bike was always serviced by the Honda dealer here . So much for thinking they'd know what they're doing . Anyway after stuffing around with it so much I can idle it down to about 500 rpm and it ticks over just nicely . Plus it changes gears smoothly better now so you live and learn . If you put the back one 180 degrees out it'll hit the rocker cover so you'll soon figure that one out but the front one has more clearance and the control arm is attached to the front . It was only when I checked out a CBR's carby's that I could figure out what was going on .