Idle Adjustment Range

I put my new Carbtune Pro to the test this morning on my 2009 FJR1300A and was rewarded with a perfectly synched set of throttle bodies--just as advertised. This product makes a wrench-in-training like myself feel really good about going under the tank. Anyway, as part of the process I adjusted my idle speed from around 900 to 1100, and the combination of perfectly synched TBs and increased idle speed makes it perfect (need I say more).

I noticed that the idle speed adjustment knob seemed to be at the end of its effective range (to change RPM) when I reached 1100. I would have thought there would be more range of adjustability in the idle speed by using the adjustment knob, but I guess not on my bike. I did notice the knob seemed a little a little loose in the hanger(?), but that shouldn't make a difference as long as the adjustment cable is turning (and it was).

What has been your experience in idle adjustment range from using the knob? Is there a way to increase the range should I need to make further adjustments in the future. Thanks for your help.

learnin4life said:

I noticed that the idle speed adjustment knob seemed to be at the end of its effective range (to change RPM) when I reached 1100. I would have thought there would be more range of adjustability in the idle speed by using the adjustment knob, but I guess not on my bike. I did notice the knob seemed a little a little loose in the hanger(?), but that shouldn't make a difference as long as the adjustment cable is turning (and it was).

What has been your experience in idle adjustment range from using the knob? Is there a way to increase the range should I need to make further adjustments in the future. Thanks for your help.

Click to expand...

Yup. Just open each of the 4 air screws up an extra 1/4 - 1/2 turn (equally, whatever you decide on) and then re-sync from there.

The added bypass air introduced by that adjustment will allow you to crank down on the idle speed adjustment and it will be more towards the middle of its range.

Fred W said:

learnin4life said:

I noticed that the idle speed adjustment knob seemed to be at the end of its effective range (to change RPM) when I reached 1100. I would have thought there would be more range of adjustability in the idle speed by using the adjustment knob, but I guess not on my bike. I did notice the knob seemed a little a little loose in the hanger(?), but that shouldn't make a difference as long as the adjustment cable is turning (and it was).

What has been your experience in idle adjustment range from using the knob? Is there a way to increase the range should I need to make further adjustments in the future. Thanks for your help.

Click to expand...

Yup. Just open each of the 4 air screws up an extra 1/4 - 1/2 turn (equally, whatever you decide on) and then re-sync from there.

The added bypass air introduced by that adjustment will allow you to crank down on the idle speed adjustment and it will be more towards the middle of its range.

Click to expand...

Excellent! Appreciate the help. I'll follow up tomorrow.

I used #3 throttle body as a baseline for the others as specified in the service manual. Therefore, I'll start by turning down #3, then adjust others to match. Then I'll check idle speed which I'm assuming will increase as a result of more air). After this I'll dial back the idle speed adjustment knob to get to the 1,000 to 1,100 RPM recommended. This will be an iterative process so I may need to go through the sequence more than once to get the idle speed adjuster in the middle of its range.

I would appreciate confirmation that this is how you would proceed.

Penultimate process question. Should I replace the small rubber cap retaining clip that disappeared into the nether regions of the outside of the engine? :dribble: I even had a small wire wrapped around one of the clips and it still went bye-bye. :huh: If you think the caps may be shoved up and off, I was thinking of just putting an 18 gauge wire around the rubber caps and twisting it tight as opposed to ordering exact replacements.

Last question. For the throttle body synch do you guys remove the tank, or just hold it up with a rope as suggested by Warchild? The reason I ask is because I had a dickens of a time lining up the holes to reattach the tank to the frame after doing this. It was like it was sprung just a bit from being levered up and back by the rope. I may have gotten carried away when cinching up the rope.

By "turning down", can I assume that you mean turn the screw CCW which will cause the vacuum to drop? If so, then yes, that is a good way to proceed. But I'd just crank them all open (CCW) the same amount, adjust the idle speed down, and then do the balance. You'll save time (and iterations) in the long run.

Clips. I throw them away first time I touch them. They are not needed. I've never heard of a FI system backfiring enough to blow the vacuum caps off the ports. Heck, they are pretty hard to get offa there (without giving em a twist) even without the clips.

I don't remove the tank (ever). Jack it up, and use a tie-down strap to hold it back to the luggage rack. And for things where you need to get in elbow deep (like valve adjusts) just disconnect the electrical and fuel lines from the bottom of the tank, but still leave it on the rear pivot bolt. Less chance of dropping the $$$ thing and dinging up the pretty paint, IMO. I've never felt it was in my way.

Others will undoubtedly disagree, but we did... what? 4 or 5 Totally UnAuthorized TBSes at NERDS tech day in about 3 hours. If I had to pull all those tanks it wouldn't have gone nearly as fast.

YMMV.

Yes, CCW or open. As a wrench-in-training I use the wrong terms sometime, but try to learn quickly. Great advice about starting wide open. Thank you for sharing your experience!

learnin4life said:

Last question. For the throttle body synch do you guys remove the tank, or just hold it up with a rope as suggested by Warchild? The reason I ask is because I had a dickens of a time lining up the holes to reattach the tank to the frame after doing this. It was like it was sprung just a bit from being levered up and back by the rope. I may have gotten carried away when cinching up the rope.

Click to expand...

Depending on what I'm doing under the "hood" dictates if the tank comes off. Valve checks / adjustments, definitely, I need all the room I can get.

Regarding lining up the front tank bolts, you DID loosen the rear mount, right? If not, that 'splains the alignment challenge.

--G

learnin4life said:

... I did notice the knob seemed a little a little loose in the hanger(?),...

Click to expand...

The cable for the idle adjustment screw is supported by a slotted bracket. It will pop out quite easily and the cable will disappear into the engine area. Can be a right nuisance.

(click on image for larger view)

escapefjrtist said:

...

Regarding lining up the front tank bolts, you DID loosen the rear mount, right? If not, that 'splains the alignment challenge.

--G

Click to expand...

mcatrophy said:

learnin4life said:

... I did notice the knob seemed a little a little loose in the hanger(?),...

Click to expand...

The cable for the idle adjustment screw is supported by a slotted bracket. It will pop out quite easily and the cable will disappear into the engine area. Can be a right nuisance.

Click to expand...

Speaking from experience there? :lol:

Regarding lining up the front tank bolts, you DID loosen the rear mount, right? If not, that 'splains the alignment challenge.

Click to expand...

Ughhh.....no. I'll try doing that today. I can see how that would make the tank more mobile. Thanks for the feedback.

RadioHowie said:

mcatrophy said:

learnin4life said:

... I did notice the knob seemed a little a little loose in the hanger(?),...

Click to expand...

The cable for the idle adjustment screw is supported by a slotted bracket. It will pop out quite easily and the cable will disappear into the engine area. Can be a right nuisance.

Click to expand...

Speaking from experience there? :lol:

Click to expand...

Oh, yes.

[edit]

Note the marks made by pliers where I squeezed the slotted bits together to reduce the chances of re-occurring.

(Click on image for larger view)



[/edit]

2 things for me whenever I do a TBS:

- have extra rubber caps on hand. I always find 1 or 2 are starting to crack a little. 5/32", O'Reilly's Auto Parts.

- don't be so strict on the idle setting, each bike is a little different. Mine likes 1150-1175 better so play with it a little and find what yours likes best.

Good idea about the rubber caps. There is an unwritten law that small parts in a confined space seek out dark places when dropped.

Interesting idea about varying idle speed. Now that I have a lot wider range of adjustment with the idle adjustment knob (thanks to the advice already received on this thread) , I can experiment much easier. I've always been a manual nerd as far as recommended settings, so this will be something new for me. I'll probably give the 1,100 rpm setting a good test now that it is up from 900 to see if the bike is in its happy place.