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Idle/Air Fuel Ration Question

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arenaud17453

New Member
Hey everyone... I'm new to the forum and world of HD. I have a 2001 Heritage Softail. I've don't have a lot of experience with carbureted engines much so I'm looking for some advice... I was thinking my idle sounds a bit higher than it should be based on what I've read here. Also the rear cylinder seems to cut out at idle (you can hear in video) but from what I read this is normal for this engine style? I just purchased it and they put a SEII exhaust and air intake on it would need to have the idle mix screw adjusted? The plug is still in place so I don’t think any adjustment was made. Thanks for any help!

I am unable to post the link to the video but if you could check it out my username is arenaudj2

video name is "2001 heritage softail idle"

Thanks again everyone!!
 
arenaud17453 said:
Hey everyone... I'm new to the forum and world of HD. I have a 2001 Heritage Softail. I've don't have a lot of experience with carbureted engines much so I'm looking for some advice... I was thinking my idle sounds a bit higher than it should be based on what I've read here. Also the rear cylinder seems to cut out at idle (you can hear in video) but from what I read this is normal for this engine style? I just purchased it and they put a SEII exhaust and air intake on it would need to have the idle mix screw adjusted? The plug is still in place so I don’t think any adjustment was made. Thanks for any help!

I am unable to post the link to the video but if you could check it out my username is arenaudj2

video name is "2001 heritage softail idle"

Thanks again everyone!!
Click to expand...

The A/F adustment screw behind the plug is not the screw to set your idle RPMS, which BTW should be about 1000 rpms. The idle adjustment screw is up at the carb on the throttle cable. The A/F adjustment screw behind the plug is the low speed/idle circuit for the carb and you might need to adjust it after you re-jet the carb to accomodate for the hi flow mufflers and intake. Did the techs re-jet the carb? If not, you need to rejet before tinkering with the A/F adjustment.

Just listened to your idle video and it sounds good.
 
If it's got a SE exhaust on it, the Harley techs might not have messed with the mixture control. Generally speaking, if you do a minor modification like an exhaust and/or air cleaner, you can get by going to the next higher jet and leaving the mixture alone --- and this is according to Keihin.

The first thing I would do is take the carb off the bike, and take the bottom cover off of it and see what size jets are in it, and then go from there.
 
Typical CV40 rejet for Stage I upgrades is a 48 slow jet and 195 main jet and either the 27094-88 needle or shimming the OEM needle about .050" with small washers. With the SE A/C and SE mufflers, you might get by with the OEM slow but I would go up on size on the main jet and either shim or replacing the needle; that will wake things up. Once that is done, you can expose the A/F adjustment screw and screw in in all the way, softly, and if the motor stumble or dies, the slow jet should be OK. Just slowly back out the A/F screw and find the "happy" idle place and your done.
 
Hello everyone! Thanks for the help, I swapped out the 45 slow to a 48 and shimmed the needle. Runs much better at low speed and light throttle... Huge improvement! Thanks again!
 
arenaud17453 said:
Hello everyone! Thanks for the help, I swapped out the 45 slow to a 48 and shimmed the needle. Runs much better at low speed and light throttle... Huge improvement! Thanks again!
Click to expand...

OK, you got low speed and light throttle. What about WOT? Should go up at least a half size on the main. Do couple of WOT plug guts with new plugs and see what the look like.
 
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