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2009 Vulcan 900 Classic LT Fast IDLE

94K views 88 replies 48 participants last post by  slickman 
#1 ·
Is there a way to eliminate or reduce the fast idle. Just got the bike a month ago and noticed the fast idle after start up. Today it is 99 out, had taken a couple short trips ( less than a mile ) and it will still be on fast idle when I take off. Is there a adjustment for this. I know there is idle adjustment but this is injector controlled ( I think ) It starts out at a normal idle but as soon as you give it throttle it stays up for couple minutes.
 
#4 ·
Check your battery voltage. The hot fast idle is for battery voltage, short trips will drain the battery and cause the fast idle to set up due to low voltage. I solved the problem with a SHORIA Litium Iron Phospate Battery.:cool:

How long do most of you let them warm up before riding? It would seem like a waste to let it warm up for 3+5 min. for a 2+3 min. ride to post office.
Do people really do that.:confused: I just start, and off I go. The engine will warm up anyway.:rolleyes:
 
#5 · (Edited)
I had a fast idle once and all I did was turn the adjustment knob. It's a 1/2" black knurled plastic knob located in the middle [front?] of the pistons on the engine's right side. [Sorry my bike is downstairs]. I have the same bike as u basically.

Post-adjustmt-- It sounded more like a cruiser and not a sportbike. My guess? 900 to 1000 rpm, repeat --my guess.
 
#9 ·
The fast idle circuit is controlled by a small "egg" shaped piece of metal on the right side (as looking at it) of the throttle body. It is visible if you remove the air filter housing and backing piece. You can (I have) remove that piece and get rid of the fast idle circuit, however, the bike will idle very low until warmed up at that point causing a very easy stalling situation. You can also modify the shape of the piece to modify the speed of the fast idle circuit.
 
#13 ·
the fast idle circuit is controlled by a small "egg" shaped piece of metal on the right side (as looking at it) of the throttle body. It is visible if you remove the air filter housing and backing piece. You can (i have) remove that piece and get rid of the fast idle circuit, however, the bike will idle very low until warmed up at that point causing a very easy stalling situation. You can also modify the shape of the piece to modify the speed of the fast idle circuit.
+1
___________
 
#10 ·
Start up idle it´s high rpm for default to pre warm the machine and fluids, it´s only for that, the real warming of the 900's ocurs normally after ride for 30 mins, that´s a real warm for this bike.

Your battery will drain power if you only do short trips during day, so it´s highly recommended that you almost every 8 or 15 days ride about 1 hour on higher rpm's to recharge battery fully.......that´s a trick for all bikes.

Let the start up idle alone, that´s only 2 mins, then the bike automatically goes down to the recomended factory settings (950~1050 rpms at idle)
 
#11 ·
Let the start up idle alone, that´s only 2 mins, then the bike automatically goes down to the recomended factory settings (950~1050 rpms at idle)
This ^

The initial fast idle is there for a purpose - to get the oil flowing & warm up the bike. It only last a little while. After a period when the bike is well & truly warmed up you should check that the idle is at around 1000rpm. Some like to adjust the idle speed down to sound more hardcore but I've read that it is not good for the engine (oil pressure or something).
 
#12 ·
Kawi's explanation is that it ensures a flawless consistant idle....similar to a choke.

Now, I've researched this extensively, as I've fought with this annoyance for 3 years.

1. Start bike, put gear on, ride.
2. All 900's do "it". Fat idle lasts for perhaps two minutes on a cold morning, substantially less when the bike is hot.
3. There are "fixes". discussed extensively in the search function.
4. If your bike doesn't do "it"...and your not the original owner, bike has been modded.
5. Some, have eliminated it by removing the small cam (egg shaped device) discussed earlier.
6. Some gently "file down" the cam, enabling it to come off fast idle quicker.
7. I don't recommend you ride away until bike has come down off fast idle. It's been know to stall, surge etc....if you "start and go".
8. After the bike comes down off fast idle, then, AND ONLY THEN, can you adjust the idle with the black knob discussed earlier.
I hope this answers a few questions....basically, I've learned to live with it.....putting my gear on while the bike "warms up".
 
#14 ·
I`ve been meaning to comment on this issue for a while now. As a master mechanic, I always thought that the cold idle, and even the initial restart idle after a hot soak, was rediculously high on my 9 custom. After reading multiple posts on here about the issue and how to fix it, I came across everything from holding the throttle backward really hard, to disconnecting the solenoid and finally, filing down or even removing the fast idle cam. Now, knowing full well that a higher idle is needed for many reasons, especially when cold, it most certainly didn`t need to be that damn high......., so I decided to dive in and see why this thing screamed bloody murder every time I fired it up. I tore my way down to the throttle body and figured out how Kaw set everthing up and Viola!..., there it was, a fast idle adjusting screw. Most, if not all of us that looked into this issue, overlooked this damn thing because of where it`s positioned. If you rotate the throttle to WOT position and look at the bellcrank (part the cables attatch to), you`ll see a phillips head adjusting screw with a small spring beneath it facing downward. Heres the deal....the bellcrank is actually 2 pieces, and turning that screw changes the position of the 2 pieces in relation to each other. If you turn the screw in (compress the spring), you will lower the high idle, if you turn it out...raise it. I turned mine to the point of just seating the spring, purrrrrrfect!!.....Starts, idles up slightly, settles down...no drama!
 
#15 · (Edited)
If this is indeed the case..(and I have no reason to doubt your word)...you've figured out one of the most frustrating things about the 9.....AND it would warrant "sticky" status IMHO.

PACO, Can I nominate you for a second opinion on this?
No disrespect to the OP!
 
#18 ·
I am a little "under the weather"...but, I am eagerly awaiting results. This could be an earth shattering fix for our 9's that are plagued by the foolish and excessive fast idle.
 
#20 ·
orangepeel You are truly a MASTER Mechanic

Read your post, jumped up and ran to the garage. The screw is just where you said it was. Never saw that before. Turned the screw in and saw the high idle roller move very slightly. Started the bike and no screaming at all.

Thank you for the info you have made a lot of people very happy.
 
#21 ·
Glad I could help. I`d be lying if I said I found it immediatly. Fact is, the first time I looked, I saw the screw and dismissed it for something else, what I don`t know. So I just checked to make sure the solenoid was not sticking and made sure the cam and roller were smooth/lubed and said oh well, it is what it is! Again, knowing what I know, I had a hard time accepting that for an answer. The throttle and electronics on these bikes being simple compared to what I see all day, I was convinced there had to be an adjustment....so back in I went! Stared at long enough......"I`ll be damned!!". Sorry I didn`t post this sooner guys, hope it brings a smile when ya hit the fire button........
 
#22 ·
My 9 has just started this; or I should say it has been revving a little higher for a little longer than it has in the past.
I wonder if the vibes can 'back' the adjustment out?
If mine gets worse, I will definitely need this thread.

Thanks!

Scott
 
#23 · (Edited)
By the way, I only made the master mechanic reference to make my thought process known. I hope I didn`t sound like "that guy"......! That being said, I have also done a few other simple things to address the other things that drove me bananas about our bikes. I need to post some pics and explain them in detail at a later date.....for now I`ll leave ya hanging!! lol Shawn
 
#25 ·
I meant the remark with humble reverence. In six years you are the only person to notice that screw, not referenced any where, even in the parts manuals or the service manual, barley found a picture with it in it but no reference to what it did.

You have solved my last peeve with bike.
I will adjust when it gets cold, about December, some fast idle is needed for the colder rides.

Please post any fix or Idea you may have.

. I suspect people complaining about the fast idle do have an actual problem as my fast idle is not annoying at all - it's just a bit faster than normal. From descriptions i read maybe some people's fast isle is a LOT greater than 1000rpm?
Mine has jumped up to 2000 on cold starts and 1500 on 90 degree starts.
People at a gas station ran one day, sounded like it was going to explode.:eek:
 
#24 ·
Interesting. I had a look in the service manual & couldn't see a reference to this screw. I suspect people complaining about the fast idle do have an actual problem as my fast idle is not annoying at all - it's just a bit faster than normal. From descriptions i read maybe some people's fast isle is a LOT greater than 1000rpm?
 
#29 ·
The bike always idles at 1000...or 950 optimally....we are talking about the fast idle at start-up....before it quiets down to 1000.....mine idles at about 2000, clicks...then 1500...clicks again, then at 1000. This entire episode takes upwards of two minutes....has done it since new. When I was at the dealer the other day....a fella came up to me and noticed I had de-baffled. He asked me if I could start it up so he could listen as he had read about the mod...he loved it.....second question? Could anything be done about the fast idle at start-up.....lol. Now I could have told him!!!!(He had a BRAND NEW CUSTOM)...LOVED THE BIKE...but was already frustrated waiting for two minutes till the bike quieted down....
 
#28 ·
In my opinion u have reached super "sticky" status!
Thanks for verification Bytehead!
Repeating the results means cold fusion IS a reality!!!!lol.
Man....with my cigar fingers....I did not want to file down that miniscule cam lobe.....
I'll do this as soon as I can!!!!
We've been kicking around for a fix for YEARS!
 
#31 · (Edited)
Remember this is throttle body injection, not true 'fuel injection', it's a set of injectors mounted inside the throttle body. It's a halfway point between carbs and fuel injection (what cars in the 80's had).

And, like those cars in the 80's, start up isn't as easy and smooth as TRUE fuel injection, so while those other reasons are true (fluid warmup, voltage, etc.), it's also needed to help it start smoother and not stall. Think of it like an automatic half-choke, because, essentially, that's what it is. The throttle remains in the same position, but it runs extra rich at start up.

Also, there is some virtue in letting any vehicle you have warm up for a minute before you take off. Not up to operating temperature or anything, but maybe hit the starter button before you fiddle with your helmet and gloves or whatever, give it a good 30-60 seconds. The reason is, that will get the oil pressure up, get oil circulated to the top, etc. Your engine can be 'starved' of oil in it's first few seconds of running, and if you immediately go from start up to a couple thousand RPMs + a load, it can, over time, wear out faster than if you had warmed it up. I don't think you're going to blow the engine up instantly doing it, but it's probably going to last you longer if you just give it a few seconds before start up.

Edit: Stickied, thanks to that great info on the idle set screw.

If anyone would like to do a write up on that, maybe tear down their own TB and take pics, let me know and send me a PM, and I'll replace this thread with whatever you write up (giving credit, of course, where credit is due to Mister Orangepeel for the discovery)
 
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#32 ·
I agree completley. I will stress again the necessity of a cold/high idle on these engines for all the reasons stated previous, which is why I was against removing the fast idle cam. Now, considering that Kaw considers 900-1000 rpm base idle to be loveliness for voltage and most importantly..oil press, I think a realistic high idle target rpm should be around 1500 rpm at max. For all witout a tach, like myself, just have a reponsible ear/feel for the revs....then enjoy!
 
#37 ·
With all due respect fellas, I think we`re making a mountain out of a mole hill. This system is pretty simple, in that it really does hold the throttle open slightly to raise the idle (screw?), and the ecu might fatten up the mixture a bit upon cold start (air temp sensor?). Cold engines without all the bells and whistles of modern automotive type EFI (o2 sensors, mass airflow sensors,ect..) tend to run a little dirty/rough upon cold start. A slightly fatter mix and a faster idle speed has always been the default remedy for this, and thats exactly what our 9s do....just to the point of absurd from the factory!

Turn it down to reality and enjoy the sweet pipe music guys, ya dig?
 
#38 ·
That is what I am saying Orangepeel. The fast idle is a mechanical 'cam lobe' that PHYSICALLY holds what I will call the 'secondary throttle' open. Yes, the mixture is richened or fattened up, but the 'fat' mixture does not cause the idle to be high.

I have found that when my bike is hot; to avoid what seems like an unnecessary high idle, I do this: switch the key on and wait until the fuel pump stops, then crank it. Most of the time when I do this it doesn't do the 'hot' fast idle thing.
 
#39 ·
fast cold idle

I have a 2010 900 cl and I am(was) extremely annoyed with the fast idle and even asked my dealer how it could be changed. He said it couldnt!!!! So I dug into it one day and I did file .032 off the cam. I did not see the screw but the next time I do maintenance I will take note of the screw. My fast idle is 200 roughly above warm idle so I am happy with it now but may want to adjust when it gets colder. It is a mechanical fast idle as a few stated. My original fast idle was rediculously high. Next we need to figure a way to quiet the noisy fuel injectors. Nice thread
 
#41 ·
Not the same issue. The fast idle cam overrides the warm idle adjuster (black knob) during start up. In some cases the engine screams when it's just started. This is adjusted by means of the screw on the primary throttle shaft which is only accessable when the throttle is opened fully.
 
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