I posted this over in the Carb section as well. Hopefully Y'all can help me out with this one.


I have a 1984 Electra Glide with a 1996 Road King engine in it. The guy I purchased the engine from says it is bone stock. The bike has a Crane HI-4N ignition system. I keep having an issue the bike will start and idle good and has excellent power but when I am cruising I have noticed that the bike will run good and out of no where is will stumble and pick back up running right where it was. This is been an on going problem with this engine and the original engine with an EV27 Cam. I have noticed that if I keep the engine revved up some it doesn't seem to happen as much. trying to figure out which way to go with jetting and such. It currently has a 167.5 main jet and a 27.5 pilot and the needle is set one slot down from the middle slot. I had a 25 pilot jet in it and when I went to the 27.5 it seemed to get a little better but is still doing it. I don't want to go too crazy in jet sizes. Has anyone had these kind of issues and what was your fix?

Any help is much appreciated.

 

A good cleaning and check the carb float height. Is this a butterfly or CV carb?

 

its a Mikuni HSR 42 Flat Slide Carb

 

Please disregard previous post.

 

You don't say what you're running for pipes and air cleaner, but that setup sounds a bit on the rich side for a stock Evo. What kind of fuel economy are you getting? What air cleaner? What exhaust? I'd also check to be sure you're not trying to compensate for a manifold leak.

Are you sure the stumble is carburetor related and not an ignition issue?

 

I was thinkin too rich for a stock evo as well. It has an Arlen Ness Big Sucker stage 1. Pipes are a set of true dual headers with Samson slip ons with baffles. Pretty sure it's ok the carb. Brand new ignition module and I have tried two different coils out on it.

 

I'm thinking not carb.

 

I pulled the carb and tore it apart and re-cleaned it. The vacuum port covers on it fell apart when I pulled them off. Wondering if that was causing it to lean out and needing bigger jets?

 

Call the Mikuni guru (forgot his name, but he will be the one who answers the phone) at Fox Distributing in St. Charles, Illinois. He will know exactly what jets you need for your bike and he carries everything for that carb.
(630) 513-9700

 

This! They set me up with the Mikuni "mileage kit", and my Evo Softail has never been happier.