Kelhin 40mm cv carburettor harley 1200 xls

It could be caused by carbon build up on the valves or worn valves or worn timing chain as the bike is 25 years old, and is the bikes exhaust standard if not the carbs jets will need to be changed to suit

Check for leak's on manifold rubber between cylinders!
Try to squirt a Carbu cleaner inside the manifold when running,if the idle going fast or dropped, then you have a leak,.

make sure choke has come off , the carb could have dirt inside also so strip and clean the jets etc

I suspect you have a blocked jet. Strip the carburettor down and clean thouroughly.
Hope that helps.

I would say you have a blocked or damaged jet. I would strip down the carburettor and replace any badly worn jets and clean thoroughly. When refitting the tick over mixture screw , screw it home and back out about 2 1/2 turns. That will be somewhere near it.
Hope that helps.

Sounds like the bike has been sitting for awhile or trash has gotten in the carb and the slow speed jet is plugged up. This means that not enough fuel is getting to the engine. You need to remove the carb from the bike and go through it completely.

This is not a job I recommend for an amateur mechanic on the original Keihen CV carb. There are several areas where you can get into trouble when reassembling the carb.

Now, if you disconnect the fuel hose, the throttle and idle cable and the choke cable at the knob end, you can take the carb to a qualified mechanic, have it cleaned, and then reinstall it.

Good Luck
Steve

This is the CV 40mm stock carb? What is the problem? Do you want to tune the carb to the exhaust.. this is a common thing to do when owners change the pipes.

The first thing to do on this carb is to be sure there are no air leaks at the intake and you can check the slider by lifting it gently and then letting it go. It should "drop" with some resistance, it it does it is probable OK. Don't take the top off the carb.

Next is the idle jet.. what is in your carb? #42? They make a 44(after market) or 45 and 48, This will make the carb "fatter" at idle only. Next is the main jet.. going up in the numbers makes it run richer.. bigger pipes usually need a little more fuel. I recently bought jets and they were about $7.00 a piece from my local Indy..

Do small changes at a time.. learn to read your plugs.. a rich engine is OK.. a lean engine is BAD.. get the timing spot on and get an ext set or two of cheap plugs and dial the bike in.. always put the filter back on when dialing it in.. here is a great site for further reading..

http://www.harley-performance.com/harley-davidson-carburetor.html

Jim

If you're talking about simply adjusting the idle mixture screw, you need to turn the screw inwards to lean it out. But, if you can get to the idle mixture screw, your carb has been modified as this screw has a "anti-tamper" plug covering the screw. The mixture screw is on the back side of the float bowl facing upwards.

More than likely, it sounds as if someone has rejetted the carb. That year model CV carb came with a a #42 slow jet in the carb. The modification to make them run better was to go to a #45 slow jet. This was in the original Keihen 40mm CV type carb. You can try to adjust the mixture screw and see if that allows you to pass. If it doesn't, repost and let us know. Maybe we can help you rejet your carb. Good Luck!

The idle jet is located in the bottom of the car. it's the recessed one in the bottom of the body. Remove your air cleaner assembly. remove the four screws. Be careful because it will be full of gas. ( well vented area.) You'll have one jet sticking out. That's your main. right next to it is a recessed jet . That is your idle. you'll have to use a small flathead screw driver to get it out. Make sure you have god pressure on the jet to break it loose. The jet itself is brass, and you don't want to mess it up. You should probably have a 45 jet with your combo. if you've been messing with the mixture screw it should be set around 1 & 1/2 turns out from lightly seated.

Sounds like the needle jet on the carb is messed up, the low speed idle jet, just buy a new jet. it should idle at 950 to 1000 when warm without the choke