I've developed this problem with my evo. I have a mikuni 42 and a headquarters cam and ignition. The problem started out as a slight hesitation in the throttle from a dead stop and dispite tinkering with air/fuel mixture and accelerator pump setting the problem only got worse. At this point I cant maintain a smooth idle and advancing the throttle causes significant sputtering and hesitation; but with a little throttle play I can get it to accelerate.

Any Ideas?

 

O.k. It's not a carberator problem it's electric. For some reason I have intermitent spark to my front plug.
I have a head quarters hq 21835 electronic ignition and there's sporatic current coming through one lead.
The plug, wire, and single fire coil all check out,

Any thoughts?

 

Since I'm the only person here I'll just say good job graulty for rooting out the problem and making your bike pur again.
Turns out it was just a loose connection at the coil, a timing adjustment, a too rich mixture screw, and a loose upper motor mount.
Next time don't jump for the carberator, just check connections and such!

 

Good job graulty! Thanks for taking the time to post the remedy, even though no one responed. Even when the thread is one sided its super helpful to read the cause.

Ride Hard,

KB

 

Welcome to the club! Thru persistence and drive you solved the problem. American ingenuity is still alive! Now grab a cold-one and celebrate!

Can I get an Amen?

 

Thanks for the tip, My 2005 softail backfired upon start up and since has been cutting out at full throttle...I'll check connections and such.

 

Thanks for the comments gents... This is my favorite HD site, it was very helpfull durring my build and is a great resourse for continuing mainenance.

 

I got caught in a traffic jam and ended up sitting on a hot day in one spot for nearly 30 mintues. I noticed my 01 DWG getting hot bit I didn't think it was getting that hot. Finally I got out of that traffic jam and encountered another one a mile down the road. While sitting in that one the bike was so hot it was burning my inner legs so I pulled off the road and shut it downs. I left it that way about 20 minutes and tried to start it up, it backfired. After about three attempts it started up but the idle was way off, I had to hold the thottle down somewhat to get an idie. I rode it home after that and I haven't tried to start it yet. With a bike getting that hot should I changes out the oil and trasnsmission fluid? And what else should I check? If I turn it back on and it idles rough again I guess I'll take it to a delaer to have it checked.. Other than replacing the fluids I'm not sure what else to check on.

 

Thats a tough one. If it doesn't run fine when you start it again I'd say you need professional help. You could look it over for something obvious but I'd guess you've already done that.
Try posting in another forum, there are many knowledgable members here, sorry I can't give you a solution.