The bike is a 2000 ultra classic fuel injected. has cobra speedster exhaust and k&n air filter. The bike runs perfect. I can ride all afternoon and she runs good until I have a stretch where I go 55 + for 2-3 mile or more but usually starts feeling weird after 2-3 miles, bike feels like it is restricted. doesn't skip just feels unsettled. Pull in the clutch and it sounds and acts as if it is running on 1 cylinder. I can rev it up and she will straighten up until I go 55+. I have spark at both cylinders when this happens.temp sensor ohmed out good. front plug is a little more tan than the rear which looks like a new plug very little tanning on it. any suggestions. i am thinking injector acting up??

 

I would start with the fuel filter.

 

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Simple things 1st before going into much more expensive diagnostics @ the shop etc so if the plugs/wires/coil truly chk out ok then try this.

Are you sure their isnt an issue with one of the 16+ yr old plug wires (or old spark plug with low miles that may have a bad resistor in it) either of which could be going bad that could send you chasing your tail on this for a long time?

Just for ha ha's when you get home with bike hot at night look for arching from plug wires to ground on frame,fuel tank etc.

Fuel filter ever been changed,if not that could cause partial fuel delivery restriction at times leading to pwr / perf loss issues too.

To be safe you should remove & clean both elec connectors on the injectors to ensure there isnt an issues with corrosion causing an intermittent elec connection issue on 1 of the injectors causing signal issues to & from ecm.

Also,when was the last time you ran a healthy dose quality injector cleaner like chevrons Techron (Concentrated version) thru the bike thats something most riders dont do but should a min of 1x-2x yrly?

Run a full tank of fresh fuel dosed with a min of 1.5oz Chevron Techron per gal fuel thru the motor & see if that helps.

Could also be an injector going bad that cleaning cant correct

If that dosnt cure it & being a 16+yr old bike it could Also be an issue with bad oring seal on an injector & or bad intake seal causing excessive lean mixture at times too.

Good luck.

scott

 

When the bike starts acting up, try loosening the gas cap. My RK gas cap vent was plugged causing a vapor lock. A new gas cap all was good.

 

I did check for arching, I did not see any arching. Bike has 56000 miles. I will pull the injectors and check, clean them and add fuel additive and run a tank of fuel thru it. I checked for intake seal issue by spraying a light burst of carb cleaner around the intake seals and it had no effect on idle, but problem wasn't existant when I did this. To duplicate problem, I haven't been able to keep it running in the poor running condition to try spraying when hot I was going to mist it with water, but it dies, and upon restart it runs better.I will check for o ring issues. I have tried the gas cap idea it did not change the way the bike was running. I thought vacuum restricting fuel flow, was exactly how it was acting. It runs so good to run so bad.and then right back to good. I will also get new plugs and check into wires also. 1 wire has been replaced before I got bike. thanks for the good ideas I will check them and report back

 

Fuel system in the tank seemed fine, But fuel filter replacement is a maintenance Item and I do believe I will change that. I will get one ordered in. thanks

 

Could also be the fuel pressure regulator. I had one go bad on my 2000 FLHTCI.

 

OP, have you tried to duplicate the problem at slower speeds? Maybe try to start off in second. Does it break up when you rev it up while sitting?
Sounds like it is breaking down under load. As others have suggested, 2 things; primary ignition (plugs/wires) or, fuel filter partially clogged.
Kind of interesting that past owner only replaced 1 plug wire.
Seeing the age of the bike, I would suggest a basic tune including the plugs, wires and fuel filter just to eliminate them.
If the problem still exists, you will need to check the coil, the output voltage at the battery, the grounds, compression etc.
Good luck bro.

 

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16+ yr old stock original plug wires with 56k miles on them too ,REAPLACE THEM NO MATTER WHAT!

Or you said 1 plug wire was replaced prior to you getting the bike which was the wrong cheap thing to do so maybe the other plug wire is finally crapping the bed.

And old plug wire can check ok with ohm meter but when vibrating on the motor can have issues with the carbon impregnated core being brittle & cracked from age & heat that can go partial open at times during running cond leading to reduced voltage/current to plug-s resulting in a cyl misfiring or not firing at all at times causing perf/pwr loss,bad coil can do that when up to norm op temp too.

So since the stock original plug wire-s are 16+yrs old with almost 60k miles on them i'd replace them because its not only easy & very cheap to do but could save you from chasing your tail with this intermittent pwr loss issue your trying to track down.

Scott

 

I agree I am planning on getting plugs wires and filter this week and I am also planning on pulling injectors and checking them for debris. I am learning a lot about my bike. thanks for the replies.