No worries phil,
So how much sag have you got when your sat on the bike?thats whats important.
im a bit worried now,i cant recall what your airscrew was on before but im guessing it was in further (a richer setting)?
As if winding the screw out has raised the idle rpm by that much it indicates either>>
There is an airleak in the intake manifold/reedblock rubber area,hence the need for a really rich airscrew setting to bring the revs down or...
the idle screws ar adjusted too high and someone has got confused and set the aircrew really rich to get the revs down.
i would bet its more likely to be the latter,its rare for the rubbers to crack ALL the way through,they just split on the surface generally.
The proper way to set the idle is,
1.Remove airbox (i know its a bastard thing!
).
2.set the slack at the throttle housing end to around 5mm (give or take)
3.Wind both adjusters on the carb sides out so they are not having any effect on the slide.
4.Looking at the slides from the rear and holding the throttle move them very slightly,what your looking for is one slide opening BEFORE the other,adjust til they are exact and working in unison by moving the cable adjusters at the carb tops in or out (make sure you still have slack at the throttle end while doing this,if not adjust)
5.So your happy,everythings working in harmony and they both reach full throttle at the same time,grab yourself a cup of tea and/or a fag now and relax
6.Setting the idle speed is now on the agenda,you cant guess it,it needs setting while the engines running ,your aiming for around 1000 to 1200rpm,any higher and they bang into gear.
You can make a start by winding the idle stop screws in until they move the carb slides around 1mm or so,fit the tank etc and fire it up,run it up on choke when cold and it should idle high (1500 to 2000rpm) for a about 30secs or so,then it should start loading the plugs up (recognised by the revs starting to drop),knock the choke off and vary the revs between 3 to 4000rpm for a minute or so,give the throttle a couple of blips up to say 5000 rpm and let the revs drop,you should now have some heat in the engine and can set the idle.
7.with the right side panel off and maybe the leave the tank slightly loose you should be able to get your hand to the left carb idle screw,wind it in or out along with the right to get a similar amount of back pressure from the tailpipes and the desired RPM.
a low pressure at the tailpipe or a pipe that takes longer to get heat in is generally caused by that cylinder not working due to the slides being out of synch,get this right and it will make for a much smoother more responsive engine.
To recap,a rich low speed setting will sound like like the engines burbling,choking itself and the revs will gradually drop til it stalls.
A lean idle setting will sound very smooth,quiet and when you blip the throttle the revs drop very slowly,also it will get worse as the engine gets heat in it (it may feel fine when cold).
You may have to rcihen or lean the airsrew a bit from the standard setting but not much,if you end up needing more than 2 turns out or further in than 3/4 out something else is not right.
ON the plugs again,check the gap is 0.5mm,there sometimes set too wide.0.7mm is fine for the standard ES type plugs not for fine wire types.
Oh and if your feeling like a bit more fettling you can slot the ignition pick and set the air gap to 0.25mm,tends to help with response.
HTH
