List of causes for high idle?

[WilliamGLX81]

CV I think. Mikuni BS32SS... Yep, wikipedia says they're CV.

PS I was just thinking about it - the air filter was not particularly oily (read - it felt almost dry to the touch). Should I oil it now or after I figure out the carb synch?

[tom203]

A good bench sync should have left carbs close enough so you could get a stabil 1200 idle (set with idle stop screw) to proceed with vac sync.If you still got too high an idle, too much air (likely leaky boots,clamps between carbs and engine) is to blame. You did put new o-rings on the idle/air mixture screws?

[bomber737]

I had the same problem but mine was erratic idle. up and down it went. I finally resolved myself to spending the cash on all new intake boots and o-rings. Even when I put them on bench synced the idle was a problem until I synced them with my manometer. I also had to set my idle mixture screws at 2 3/4 turns out. Now for the first time in the 3 years I have had the bike it finally idles like a dream and runs smoother than it ever has

[tfb]

Now for the first time in the 3 years I have had the bike it finally idles like a dream and runs smoother than it ever has

I hear ya... and that's the way it always seems to be, hey. We chip away at these problems bit by bit, until one day we can say that "finally" things are sorted! Few things are more satisfying than resolving a long term tuning problem.

[Steve]

You have had a BUNCH of hints and a few outright requests to check a few things in this thread, you keep shooting them down with one excuse or another. I believe tfb hit the nail on the head with the right idea, even though it was the wrong carbs.

Even with a "good" bench sync, I have seen one carb that was still open far enough to hold the idle speed higher than it should be. A vacuum sync will get them all adjusted properly and you will then understand what we are talking about.


Now, if you don't mind, give me some details on your "homemade carb sync tool". You admit that it needs restrictors, but give us some details on how it's made, there might be a flaw in the design that will prevent proper readings, which will only keep you wondering.

.

[WilliamGLX81]

Sure thing.

The balancer tool I'm trying to use is simple. I could make it more complex, but I don't think that would necessarily help.

It's made of 4 pieces of equal length clear vinyl tubing (about 40", which I'm going to add to and get closer to 80"). They are all linked at the bottom - each pair of long lines are connected to the "top bar" of a barbed T-fitting, and the | has a short piece connecting the two loops. The lines are filled with ATF about halfway.
With no restrictors in the lines, the atf moves far too quickly from one line to another and towards the intakes. I don't have time to make any adjustments before I have to kill the engine.
I saw plans for the same basic synch tool for twins, basically made two and linked them together.

I could probably modify this design using 4 sealed containers and having an air gap, but that would be harder to seal.

I also think I set up the butterflies backwards when I did the bench synch. The inside should have lower vacuum than the outside, but I set the inside more closed than the outside. Oops.


I'm convinced I don't have any intake leaks because of the absolute lack of response from the soapy water and starting fluid.

Do the CV carbs have any other adjustments besides the mixture screw? Those are all set to 2 full turns out from gently seated.

My #1 exhaust pipe was less hot than the others before I did the synch. Don't know if that's relevant. It wasn't cool, but it was less hot. Not sure if that's relevant.

[Steve]

Good luck with your carb sync tool. After many hours of frustrated attempts, you will finally see that the $100 or so for a Carbtune is well worth it.

The only adjustment on your carbs is the mixture screw. Start with it THREE full turns out for better results. They might end up in the 2 to 2 1/2 turn range, so starting at 2 turns is too lean for a reliable starting point.

Your #1 might have simply been closed too far (a sync job will take care of that), it might be running too lean to fire (a mixture screw adjustment will take care of that) or it might not have good connection in the plug wires and plug caps.

.

[WilliamGLX81]

Ah, I'm pretty obstinate, creative, and resourceful. I'll find a way to make it work.

I checked the plug contacts, and they're good. Didn't remember to check the temps of the exhaust tubes though.

I'm not sure how to do the mixture adjustment yet (highest idle method, I'm guessing?), but the 2 turns came from basscliff's CV rebuild guide.

This is a few tweaks from my end result: (Mind the foul language towards the end)

http://www.youtube.com/watch?v=3qfVwyWJZK0

And here is someone else using the same sort of setup on an R1.

http://www.youtube.com/watch?v=E2J_N4VVGGo

It sounds MUCH better. Can't wait to take it for a test ride. The vacuum restriction orifices really made the difference.

I'll post photos of the fittings I made for the carb vacuum ports between now and the end of the weekend for anyone who is curious.

[tfb]

Ah, I'm pretty obstinate, creative, and resourceful. I'll find a way to make it work.

That's the spirit!

I'm not sure how to do the mixture adjustment yet

Essentially you're looking for the engine's response when you 'blip' the throttle from idle. If the revs 'hang', then the mixture is too lean, so you need to wind the mixture screws OUT. If the revs 'dip' below the set idle speed after you blip the throttle, then the mixture is too rich, and you need to wind the screws IN.

[koolaid_kid]

For the mixture adjustment, many have found the answer using the method from the link in my signature.
Best of luck.

[Nessism]

I'm not sure how to do the mixture adjustment yet (highest idle method, I'm guessing?), but the 2 turns came from basscliff's CV rebuild guide.

Better go back and read basscliff's CV rebuild guide, because pretty sure there is no reference to "2 turns" there.
Also, your video of the sync process seems to show the bike at idle. You are not supposed to sync at idle and doing so may lead to inaccurate adjustment.

[WilliamGLX81]

Oh, it was the doc linked in koolaid kid's profile. "Turn all the screws to the same setting, usually 2 - 2½ turns counter-clockwise from being lightly seated."
But that's for initial setup before tuning. Whups. I expected to do another go-round with the synch because I hadn't set the mix screws.

It was at 1750, though it did drop and I had to raise the idle with the knob once or twice during the procedure.

Cheers!

[koolaid_kid]

Oops. Seldom would you end up at the start. That is to say, 2-2 1/2 turns will get the engine running, but you are far from done. And yes, I would be greatly surprised if you do not have to adjust the idle screw during the procedure. Don't forget the test ride as well; many times I have had to tweek the mixture screws a bit after the garage adjustments.