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Idle mix screw in high heat and humidity

Posted: Sun Jun 27, 2010 1:54 pm
by bengone1
I picked up and installed the UK cams and carbs. I am currently running into an annoying problem. I have been searching what to set the idle screws to. It seems a lot of you have 2.5 turns, the manual says 1.5 or 1.75. I started with 2.5. The bike would cut out when it got up to full temp. I tried going down turns 1.75 to 1.5. This did not help unless no choke was my goal!

Currently the weather has been Killer. 90 degrees and tons of humidity. Should I be running over 2.5 turns on the screws to keep it running at temp? I am hoping someone can chime in from another region suffering miserable temps.

Re: Idle mix screw in high heat and humidity

Posted: Sun Jun 27, 2010 2:53 pm
by parby81
to be honest, in that sort of heat, next to no choke should be the goal, maybe a tad on startup but then knocked off pretty quick. Warmer air is thinner, therefore less petrol req'd. Mine is set at 1 and 3/4's and we've got 30C today (86F) and it starts on the button with no choke, and revs fine when warm. Is the exhaust and air filter stock?

Re: Idle mix screw in high heat and humidity

Posted: Sun Jun 27, 2010 5:29 pm
by bengone1
Stock exhaust with K&N air filter. The temps I imagine are close but I thought maybe the high humidity could have an effect. If I keep the idle set at 2k it has no problems. Idling in traffic it gets to the 3/4 bar on the temp gauge.

Re: Idle mix screw in high heat and humidity

Posted: Mon Jun 28, 2010 8:38 pm
by parby81
Bikes are generally set up a bit rich to quieten them and get through any testing at certain points in the rev range. With the K & N you are allowing it to breathe in mnore easily but with a stock exhaust it can't breathe out properly. We've had lots of people on here mention bad things about the K&N air filter even when matched with an aftermarket exhaust, so with the standard can, I'm not suprised you're having issues.
Is the "snorkel" still in with the K&N? I'd try going for the standard air filter and see what difference that makes.

Re: Idle mix screw in high heat and humidity

Posted: Tue Jun 29, 2010 12:01 am
by bengone1
I firmly believe in using factory parts for most things. This bike will have a lot of exceptions. I cannot get OE parts very easy as this model was not shipped to the US. The snorkel is in. I doubt Kawasaki would put it in there for the hell of it.

What sort of problems were you running into with the K&N? Any work arounds? I would be surprised to find this bike cannot be made to idle with an aftermarket filter.Thanks for the input.

I guess this is a great excuse for an aftermarket can... I was just going to wait till I wrecked it a few times!

Re: Idle mix screw in high heat and humidity

Posted: Tue Jun 29, 2010 1:39 pm
by RedexRobB
I dont think there anything necessarily bad about the K&N air filter, i think its just a case of the standard one is good enough on its own that even racers stick with them.

Re: Idle mix screw in high heat and humidity

Posted: Tue Jun 29, 2010 2:51 pm
by bengone1
I really didn't expect any performance out of it. I just wanted a filter that was serviceable and didn't need to be shipped overseas. I guess I will keep poking it with a stick until it runs when hot.

Re: Idle mix screw in high heat and humidity

Posted: Tue Jun 29, 2010 2:52 pm
by bengone1
You know it just occurred to me that the Tach may be off a few hundred RPMs when hot. I will check that as well.