I think I have the solution...but I wanted to bounce this off some experts to make sure I am looking in the right place before I waste money on parts.

I recently acquired an 883 Sportster, 2009 registered ... so it's a fuel injected model not carb.

It needed a few things doing, but is basically low miles ( less than 7000 ) and most of the jobs are ones I am fully capable of handling. The clutch was poorly adjusted, with the cable having too much slack. Done. Helped gearshifting..
The primary chain sounds noisy, especially on the over-run and at certain revs...will check and adjust as necessary this weekend to get around the half-inch of play at the tightest spot. Would have done it sooner if I had the right spanner for the big adjuster bolt....
The gear change is tricky....and I thought it was just me, getting used to it, and 'they all do that' .... but the last issue is also really not helping.

Rev the engine up, with a quick blip of throttle, and it is slow to return to idle. When it does drop to idle, the idle is spot on, shakes and all, but it doesn't drop like it should. It drops slowly back. This really isn't helping with gearshifts either.

Initially, the 'pull' cable on the throttle was slack. Very slack. Adjusting this helped, and now I have correct free play, and not 30 degrees of slack before the engine responds. When released, the throttle shuts and there is a nice 'clack' of the throttle hitting the stop

The return cable also seems to have a bit of play in it...about 1/8 inch at the handlebar end, but it appears to be jammed on the adjuster and while I can slacken off the lock nut, I can't turn the actual cable adjuster to pull in the slack. Have soaked some penetrating fluid so maybe that will fix it...but I suspect the cable may be at end of life. It has a different shaped adjuster on it...so at least one of them have been swapped...but not as a pair.

So...my question....

What is doing this? Is the cable sticky...and while I hear the 'click' of the twist-grip return the return cable isn't pulling the throttle butterfly closed.
What is the best way to check?
What else could be causing this. Its fuel injected...so no 'choke' as such....but could that be an issue?

My head is still tuned to Japanese thinking, and I am not trusting my instincts yet with the Sporty

 

If you can't adjust the cable you need to fix that first. Second you need to know how to adjust the cables. Taking out the slack is not the correct way to do it!

1. Loosen throttle friction screw.
2. Slide rubber boot off each control cable adjuster.
3. Loosen jam nut on each cable adjuster.
4. Turn cable adjusters in direction which will shorten cable
housings to minimum length.
5. Point front wheel straight ahead. With engine OFF, gently
turn throttle control grip to fully open position (fully
counter clockwise) and hold in position.
6. Gently turn adjuster on throttle control cable counter clockwise
until throttle cam touches throttle cam
stop. Release throttle control grip and turn adjuster
counter clockwise an additional 1/2-1 turn. Tighten jam nut
on throttle control cable adjuster.
7. Turn handlebars fully to right. Turn adjuster on idle
control cable, lengthening sleeve until end of cable
housing just touches spring within cable guide.
8. Check adjustment. With throttle friction screw loosened,
twist and release throttle control grip two or three times.
Induction module throttle wheel must return to idle position
each time throttle grip is released. If throttle does not return
to idle, turn idle adjuster, shortening sleeve until correct
adjustment is reached. Tighten jam nut.
9. Slide rubber boot over each cable adjuster.

Once you have that sorted out then you can see if you still have the problem. You might need to get new cables. The 2008 I have here both cables had seized adjusters.

The gear change should not be tricky at all. It might go with an almighty clunk/thump into first gear when stationary but after that it should go up and down the box smoothly and effortlessly.

 

Thanks for that

I'll run through that this weekend.

Gearshifting into first will always clunk...but...the other shifts need the revs right. It's not right every time. I really don't blame the gearbox....as it's not always clunky on shifts...but if you don;t match revs and roadspeed, she tells you. But when the throttle isn;t responding the way it should, I got no chance.

I had to take a chunk of slack out of the pull cable though....I could rock it back and forwards a lot with no effect on revs. Couldn;t ride it as it was....but I like to do things properly...so I will do it again, the right way this time!

I am guessing, from what you have outlined there, that with the filter off....I will also be able to get a much better idea of what is happening with the cable and whether things are returning smoothly.

One thing I do know, as I have all the MOT test certificates for the bike to confirm it's annual mileages over the last few years, this thing sat in a garage for most of the last year or two. Last year it did 6 miles in total. I suspect this never got it's 5K service properly, and some things might be a little gummed up and in need of attention.

Now I just need some decent weather this weekend to work on the old girl!

 

Don't forget to lube your cables, Dri-Slide works well. That idle return cable is a POS on my bike, going to ditch it sometime and just go single cable.

John

 

Just be aware I am not suggesting this is the actual problem with your engine not returning to idle but fixing each problem as you find them is a good bet to success.

With the OEM cables I put a little silicone grease on the adjusters before sliding the boot back into place.