i have a 75 xlch that i am resurrecting after it sat for about 5 years. I replaced the old carb with a harley cv carb. The carb has recently been rebuilt and cleaned. I have the 78 electonic ignition system on my bike for the last 15 years. I have cleaned the tank and replaced the petcock.

now what is going on. My bike kicks over and starts good and idles nice. but when I give it more throttle it will not accellerate. the engine will backfire from either the carb or exhaust. I could leave it all day idling and it sounds smooth.

what could make it do this? I am currently confused.

 

1978 came with points ignition not electronic. Does it have the original points or a newer electronic ignition like Ultima, Hi-4, CompuFire, Dyna or whatever? If you are uncertain post a pic of whatever is behind the round ignition cover.

If it is points they will need to be dismantled, cleaned and inspected. I am not familiar with the details of refurbishing points ignition so someone else will have to chime in on that.

Here's some help on that ...

My Harley is retarded - auto advance rebuild (&pics)
http://xlforum.net/vbportal/forums/s...d.php?t=317401

When you say that "The carb has recently been rebuilt and cleaned" i assume that you did not do it yourself. In my experience this is never satisfactory regardless of how much of an expert the guy appears to be. If the problem persists after the points are determined to be proper then the carb is the next suspect. Could be the accelerator pump.

All of the CV carbs have an accelerator pump except for the first-year ones which i believe was 1989. 1990-on all have the accelerator pump.

Could also be an assembly error or a torn diaphragm or float level way too low. Take off the air cleaner and watch the slide as you advance the throttle - observe if it rises smoothly.

 

what jets are in it - the low speed is too small my guess