Sorry. This is my first post and I sent it without any text, so this is a reply to myself. I have a 1992 XLH Hugger 883 converted to 1200 and belt drive. Since new, I have put on 22,450 miles and everything is great except it sort of surges and jerks at low, constant speeds. It idles well and has good acceleration but a constant 30 or so in town is jerky. I changed from a 42 to a 45 low-speed jet but that did not change much. Otherwise, I have a K&N Screamin' Eagle air cleaner, Yost Power Tube, and stock pipes. The chief mechanic at the dealer rode it and said it seemed OK to him. Am I just a nitpicker, or can you give me some advice on this?

 

Have you checked the primary Chain tension?

 

Yes, I have checked the primary tension myself, and the dealer checked it at the 20,000 mile service. To me, it seems that if the low-speed jet is OK, and I am below the speed for the high-speed jet to kick in, that it might be the slide and the needle but I have not had experience with that before and I am a bit reluctant to take it all apart to check it. But, you have a good point. If it is jerking at 30 mph, I can get rid of it by gently accelerating. But, in town, that leaves me cycling up and down to keep out of the constant speed zone. I wonder if others have had this problem or if they say it is just a characteristic of the Sportster and the CV carb.

 

Are you lugging the engine? Try down shifting a gear.

 

I had the same problem. Check your low jet. Stock for mine was a 40/170 and I have a 42/180 in there now. Also I had a slight jerking at slow speed and a slight surge at cruise that went away after I readjusted the primary. Tim

 

I had the same problem but thought it was due to the cams (490 lift Andrews).
I changed the front pulley from a 27 tooth to a 29 tooth and that changes the rpm range. It defiantly made the bike "more civilized" around town. You can run in a lower gear without winding out.

Rick C.

 

I checked the primary chain again today and it was a little bit loose. My book calls for 3/8 to 1/2 inch of slack when cold. Mine was 5/8 or a tad more. It was supposed to have been adjusted at the dealer 20,000 mile service but it either got off in the 2500 miles since then, or they did not get it quite right. I set it between 1/4 and 1/2 and it is much better. It still hunts a bit at those lower speeds but the jerky part is greatly reduced by the tighter chain. A bit more RPM also helps although I was never near lugging it before. This bike was born an 883 with a 40 slow jet and a 160 main jet. When it was converted to a 1200 we went with a 42 slow jet and 165 main jet. I have since gone to a 45 slow jet to smooth that low speed running but I am not sure it was necessary.

Thanks for the comments. If I ever get running as smoothly as my Dad's old PowerGlide Chevvy, I will let you know. But it sure beats the PowerGlide on get up and go.

 

92XLH: Check your float level. It just might be too high. If everything smooths out at higher speeds the high float level is likely. Also check for intake manifold leaks. Good Luck! Let us know what cures it. The symptoms are not "normal" for the CV carb or the Sportster. ............ BC

 

I had the same problem on my 05 1200C and after I got my pipes and it was rejetted the problem went away.