[sinks88]

So with the season going away for us northerners, there is a bit of a question about my ironhead that is kind of getting to me:

its a 77xlt, The "lurching" is a problem when im off the throttle, basically whenever I let off the gas regaurldless of what gear im in, Im getting a lurching/jerking from the bike. It makes "coasting" (without pulling the clutch) near impossible.

the biggest problem is approaching corners at low speed without ingaging the clutch, when I do this the bike will kind of fall all over its self and makes it all but impossible to go thru a corner or a straight line for that matter without the jerking/lurching to an exaturated extent. to the point I will HAVE to pull in the clutch or gas all the way through (which I cant do when Im coming to a stop) I've been basically having to find nutral (way early) or ride the clutch whenever Im doing non throttle activities.

I know that the Ironheads have a bit of that by nature, but not to this extent (I dont believe). Otherwise the bike runs great, and it doesnt stall or quit, and has great throttle recognition.

Soooo....Is this my life with this Ironhead or am I missing something here?

 

[dhallilama]

how is the bike setup? what carb, what pipes?

experience with the ironheads i've had or have ridden:
-Keihin butterfly carb & drag pipes w/o baffles, poorly tuned = lurching and lunging
-Mikuni carb & drag pipes w/o baffles, well tuned = quite smooth
-CV carb & twisty fancy pipes w/o baffles, tuned for top end (my bike) = pretty smooth, mild flat spot mid rpm
-same as above with lollipops in the pipes = very smooth. no lurching. no jerking. no flat spot.

 

[16ouncePBR]

How is the adjustment on your chains (Primary and Final)? Symptoms seem like one or both might be too loose.

 

[sinks88]

how is the bike setup? what carb, what pipes?

experience with the ironheads i've had or have ridden:
-Keihin butterfly carb & drag pipes w/o baffles, poorly tuned = lurching and lunging
-Mikuni carb & drag pipes w/o baffles, well tuned = quite smooth
-CV carb & twisty fancy pipes w/o baffles, tuned for top end (my bike) = pretty smooth, mild flat spot mid rpm
-same as above with lollipops in the pipes = very smooth. no lurching. no jerking. no flat spot.

So since Im running the bolded....it seems to be tuned alright with exception to the above....what Im I looking at to fix it?

Come to think of it, it did it also before I put on new chain, aircleaner, pipes. (pretty much the same as now)

 

[Dr. Benway]

Sounds like it could be NOT transitioning across the carb circuits smoothly?
What do your spark plugs look like?

 

[sinks88]

I have:
Keihin-Drag Pipes-No bafflles-custom Air Cleaner-

the primary Chain is "within spec" and I havnt inspected the chain since I put on a new one to specs.

Also, its seems worse the more I ride, and smoother the less I ride (or beginning of ride)

 

[sinks88]

Sounds like it could be NOT transitioning across the carb circuits smoothly?
What do your spark plugs look like?

Plugs were just changed, Id have to pull them again and look.

 

[threeston]

you need a larger pilot jet. right now you probably have the 0.75mm. If you have to turn the air screw out more than like 1.5 turns its too much (the pilot jet is too small). and it causes that really shitty keihin cough. I ended up with a 1mm in mine.

jp # 402-232

does the throttle seem to not respond until you open it up way too far? keihin put way small jets in cause they are stupid emissions idiots.

if you check the jet its the one under the rubber plug. it should say the size on it. get the next 2 sizes up (at least) to tune it. also check the rubber plug isnt covering the port into the main jet area.

It really works. youll find you can probably even back off the main jet a size too. the keihins for ironheads seem to find themselves with too large a main jet with too small a pilot. (from people who think that since they put drag pipes on they better increase the gas amount, due to the now crappy throttle response from not fixing the pilot circuit).