I bought this bike last fall. It had been in a collision with a deer. After some cosmetic repairs had it back on the road. It shows 95K on the odometer and has been running good. Last week left on a ride after about a 30-45 mins (warmed up) it died pulling away from a stop sign, restarted then as I upshifted it did not want to take any throttle and back firing along with rolling black smoke. We nursed it home no codes. and I ckd the plugs OK, replaced anyway.Checked inj. for puddling,shake rattle and pull test on all assoc. wiring then a ck eng light 56 crank sensor. Replaced and tested on ride today and on way home same thing. The fuel pump is pretty noisy and have not noticed it before. I can order the fuel press test adapter from HD but if it is not acting up I dont how good it will do. Any ideas or help would be appreciated.

 

This information is from a carburated bike, but may still be helpful and I will explain why at the end.

I have had my 74 XLCH do nearly exactly the same thing you describe, sudden loss of power, backfiring thru the carb and pipes etc, etc. Did all the tests as you have (outside of sensors and fuel pump) and it all checks out. After going through all the motions, turns out that some little piece of whatever made it into my float bowl and got lodged in the low range jet. Cleared that out, and problem solved.

Now obviously you did not have something get lodged inside of one of your jets. But maybe something made it into your fuel lines between the pump and the injectors? Maybe the line itself is starting to deteriorate and broke away and is now lodged in your injector[s]? Fuel lines only last so long, especially with all the crap that is mixed into the gas today.

Good luck to you, and if you do figure it out, please come back and let us know. Thank you.

 

Thanks for your ideas. This did start after I replaced a check valve for a fuel leak on the return line. So might warrant further investigation. I also found while looking in the factory manual that my high and low idles are out of adjustment. As soon as I get the adjustments and lines checked for debris I will do another test ride. I will get back to the forum to let you know what happens.

Thanks again.

 

The fuel pump on my 98 RKC is noisy too with 1/2 or less fuel in the tank. Normal, I guess. I don't think your problem is related to the idle speeds. Maybe it's related to the check valve you replaced. If not, you might have more fault codes. Funny as it sounds, double check your negative battery cable on BOTH ends for tightness.

 

Sorry for the delay, that work thing coupled with lousy weather means no time to ride less time to repair. I did reset the high and low idles per the manual and the bike is running a lot better. still seems fat as backfiring on deceleration. The main problem now is that even with the warm up in weather it still takes this thing idling in the garage for 15 - 20 minutes to get to normal idle. then if I shut it off for more than 10 minutes on a ride it takes another 10 mins to settle down again, and if I don't wait for it to get to normal idle and I ride anyway, it won't. This is making me think I have a bad engine temp sensor. Still not throwing any codes. Any ideas. Thanks again.

 

Mine takes quite a while to warm up too. If I shut mine down for a few minutes it will go back to high idle at startup but settle back down quickly.

Sure sounds like a bad temp sensor. Cost you $75 - $100 depending on where you get it and about an hour's job. Not hard, just annoying. DON"T pull your tank off. Take the bolts out, push the crossover tube around the coils and hold the tank up and out of the way with a block of wood or a bunch of rags. You can get a deep well socket down in there to get the sensor out. Tight, but not too hard.