hi all ,
new to this forum,my name is Stavros and I come from Greece.
A couple of months ago I installed a ev13 cam in my 1993 ultra classic, and although I'm very happy with its performance, the bike jerks or bucks(not sure if these words are correct) only during deceleration below 1800 revs. It is as if you constantly blip and release the throttle, as if someone rearends you.
Other than that, when you open the throttle even slightly the bike accelerates smoothly even with 1000 rpm.
there is no popping or coughing, bike starts easy and runs awesome apart from decel. Changed several pilot jets and replaced manifold and carb flanges and seals but problem persists.
any ideas would be much appreciated.

 

What kind carburetor and ignition module are you running?

 

Cv carb, stock ignition

 

what jet sizes are You running?
Wize people on here could tell You if the carb is jetted correct for what you're running.

EV13 cam so I presume You also are running
Slip-on mufflers and an Open Airfilter?

 

46 pilot(have also tried 48 with no difference) and 180 main jet

 

I would check float level and needle and seat if you have not done so yet.

 

I dont think its carb related, ive also changed the carb, no difference at all...

 

So perhaps there is no problem with the carb then.
Seems as if you tested everything and even tried a different carb.

Have you checked the ignition timing?


Did the problems show up after You installed the new cam?
Did it run without problems before the cam swap?

If so, then I would check the timing of the cam.
Did You reuse the cam gear from your old cam, and if so did you press on the cam gear in the exact correct position?

 

The problem was from the day i swapped the cam. I put the cam with its own gear, did not swap gears. As far as timing, i marked the ignition in the cone and put it back at the same spot

 

Also i matched the timing marks of the cam with the pinion gear and breather...i assume that if they where not properly matched, the bike woulnd run. The bike works perfect apart from this low rev bucking under decel, ie under no load. Under load its perfect even at 1000 rpm