I bought my first evo this year with 10k original miles, and it's been like yours from day one. Some days worse/better than others. Options are patience or go back to twinkieland…I chose patience. Still not convinced yet that I need carb work? Differing opinions on here when I too asked.

 

And what Murp said. I'm not so quick to close the choke when I take off. Sometimes pull it back out slightly til she cooperates.

 

That's why I am considering this a problem. For over a year I'd start up with full choke let it idle while I had a smoke push to half choke and go, no problem. Now it's running really rough for at least a mile down the road using the same procedure.

 

If you decide to do work on the carb, please give us an update on what transpires. I would be curious to know. I'm living with mine the way it is.

 

You replaced the plugs recently?....Evo's are funny about plugs....Iridium NGK's work best in my experience.

 

If plugs are in need of replacement, wouldn't bike run rough even after warmed up?

 

Not always, the motor can deal with issues better when its warm (ever heated up the plug on a 2-stroke lawnmower to get it to start?)

Any Evo that comes to me with starting or misfire probs gets new plugs before any diagnostics take place.....cures at least 25% of them straight away. Iridiums will last for ever but any fouling or wear on a non-iridium plug can cause a heap of problems.

Yesterday I did a home visit to a sick 1987 Softie......running on one cylinder....new plugs and it was fixed :-) Then I re-adjusted the S&S carby so it didn't foul the plugs at idle and the customer was 75 bucks poorer (inc labour) but 100% happier....wish it always was that simple!

BTW you can't always clean a fouled plug sufficiently for an Evo to run well on it, so new is always the better option, then cure the fault that makes them foul in the first place.

 

when I fired the bike up today. choke out all the way fired right up but sounded like one cylinder severely miss firing. When I increased throttle the miss would even out. after a couple min. pushed choke all the way in idled okay still didn't sound quite right. Let it idle for 5-10 min. then went for a ride, still ran really rough for about a mile including backfiring when I opened the throttle.

 

Dodgy plugs or air leak would be my first thoughts on that one.

 

Also plugs and air filter were replaced after this first started. The problem seems to be getting worse. I did pull the plugs the other day and there was black carbon on the plugs, so I cleaned them off also pulled the air cleaner and sprayed carb cleaner in tto the carb. Did'nt seem to make a difference.