Idle When Hot

Crud in the carb idle circuit?? Vacuum leak at the carb intake manifold boot??

the bike needs a lean mixture when it's hot after a race. if it's too rich it'll stall when hot but not when you simply put heat into it from cold starting.

you need to lean off the idle so half a screw in with the pilot screw methinks.

Taffy

lesmoto said:

I have the idle screw almost all the way in.

Click to expand...

To asked a stupid question:

Which screw are you referring to? The mixture screw or the idle speed screw?

Do you know what size jets you already have in the carb?

Cheers,
Simon

lesmoto said:

The idle screw is almost all the way in. Air screw is 1 turn out. Pilot is a 33 with a 190 main.

Click to expand...

Now, unless you're riding around with a completely clogged up airfilter, I would guess you're not suffering from running too rich (on the idle circuit anyway).

Because you have the idle speed screw almost all the way in, I suspect the vacuum is causing the main circuit to come into play - e.g. because the slide is held so far open even when the thottle is closed.

It may also be a worn needle, so check this too.

Here's what I would suggest after you have confirmed and written exactly what your settings are now so you can go back:

1. obviously check all connections as suggested above to make sure there's no leak or similar in the intake, as well as check the airfilter and clean the carb - but you've probably done this already.

2. after starting the bike take the idle mixture screw out to 1.5 turns and then screw out the speed screw, noticing the difference in engine revs.

Set when you get to a good even idle at around 1800rpm.

Hope this helps.

Simon

are you, like i was; always adjusting the tappets open? you may have "tuliped" valves? also your camchain-if not replaced already-will be shagged out by now so go check it.

Taffy

les

i'm not sure you know how to set the carb.

you must set the mixture screw to the level that makes the bike rev the highest. turn the idle down, adjust the mixture screw AGAIN for highest revs and then again set idle screw.

when all this is done on a nice warm engine you can now go for a ride and do it again.

then if you have a cough you should find that 1/4 to 1/2 turn of the mixture screw gets a smooth bike on the gravel.

keep the screw driver in ya pocket-no gloves = 10 minutes work.

sorted.

Taffy