cold starts

[gkarats]

Hi Guys
yet some more help needed....I installed a aftermarket slip-on and K&N air filter KA-2508. Since then I have been having issues at start up after sitting overnight. It gets cool here now about 4 deg C/39F in the mornings. Whats happening is:
I apply full choke
turn bike on and hit the starter
it fires right up and idles at 1500rpm for about 20 seconds then slowly the rpms drop off and the bike stalls out.

Unless i apply full choke and a little throttle it will not restart, then I have to stay on the throttle for at least a minute before it will stay running with the choke on.

After warm and I have ridden for 10 min everything seems good. It pulls nicely with no hesitation.

Is this a jetting issue? Any Ideas?

[jkv45]

You could richen the idle mixture a bit, as the mixture will lean out as the temps drop. If it's on the edge of being lean when it's warm it will be significantly lean once the temps drop.

Are you sure you aren't using too much choke after it fires? Does it immediately kill if you back it down once it's running?

In those temps (39F) I'd be running a 5W synthetic like Rotella T6 5W-40 instead of a regular 10W. It will give you better cranking, less pumping resistance, and better overall lubrication at start-up. While it's warming-up it also gives you better mileage.

How old is the gas? That's another factor. If you haven't filled it up recently (87 w/o ethanol is always the best choice) you may be running on summer-blend which won't atomize well with cold air. Keeping the tank close to full as the temps rise and fall will keep you from getting condensation, which will make the bike run poorly and rust the tank.

[gkarats]

Originally Posted by jkv45

How old is the gas? That's another factor. If you haven't filled it up recently (87 w/o ethanol is always the best choice) you may be running on summer-blend which won't atomize well with cold air.

When I first got the bike it was near empty I filled up with 94! that was just the other day. I have used about half a tank since. I use 94 all the time in my zxr750 so I thought to do the same. When I got home and I read the manual it suggested 87 as a minimum. Can't see it being the gas but I'm a newbie to this machine and do not know all of its quirks quite yet....we are still getting to know each other

Choke doesn't seem to be operating properly, I could be wrong though. I may shim the jets this weekend and see if that makes a difference.
Cheers

[jkv45]

Originally Posted by gkarats

When I first got the bike it was near empty I filled up with 94! that was just the other day. I have used about half a tank since. I use 94 all the time in my zxr750 so I thought to do the same. When I got home and I read the manual it suggested 87 as a minimum. Can't see it being the gas but I'm a newbie to this machine and do not know all of its quirks quite yet....we are still getting to know each other

Choke doesn't seem to be operating properly, I could be wrong though. I may shim the jets this weekend and see if that makes a difference.
Cheers

It may run better on 87. Sometimes the "Premium" grade doesn't get sold as rapidly as the "Regular" (87) grade, so it's sits in the storage tank longer.

I'd add fuel stabilizer or Seafoam cleaner (includes stabilizer) at this point and fill the tank up with 87. Stay away from Ethanol if you can, so you might have to go to a higher grade.

Adjust the idle mixture screws when the engine is hot and the temps are cooler. Set it to the highest RPM you can get - then open the screw an additional 1/8 to 1/4 turn richer. In the summer that setting will be too rich.

Shimming the needles is a good idea, but it's not going to correct a lean mixture at idle.

[gkarats]

Originally Posted by jkv45

It may run better on 87. Sometimes the "Premium" grade doesn't get sold as rapidly as the "Regular" (87) grade, so it's sits in the storage tank longer.

I'd add fuel stabilizer or Seafoam cleaner (includes stabilizer) at this point and fill the tank up with 87. Stay away from Ethanol if you can, so you might have to go to a higher grade.

Adjust the idle mixture screws when the engine is hot and the temps are cooler. Set it to the highest RPM you can get - then open the screw an additional 1/8 to 1/4 turn richer. In the summer that setting will be too rich.

Shimming the needles is a good idea, but it's not going to correct a lean mixture at idle.

Ok I'll take your advise and adjust the idle mixture screws. ... I'll let you know how it goes