TBS - high idle

[mattster31]

Now that the bike is running I thought I would do a TBS. As I was doing it, the idle kept creeping up (over 1500). I had to shut cyl 1&2 and make the adjustment to 3&4 to balance in order to keep the idle down to 1200. but that's the lowest I could get it. I checked for leaks....etc......any suggestions?? Prior to this...the idle was fine, but it ran rather rough which is why I did the TBS. It is smoother now, it's just the high idle.

 

[03HiYoSilver]

Mattster,

Perhaps you can do your sync at 4k RPM ...that is where I fine tune mine.

Unless you have a leaking Throttle Body Boot which will give you this erratice RPM.

Another thing, make sure your #3 Air Screw is about 1 -1 1/2 turns out from the bottom. Sometimes a bottomed out #3 will do the same erratic behavior.

Hope this helps...

 

[mattster31]

I tried that after the idle crept up to above 1500. This actually made the problem worse and the idle went up to just under 2K. (behaving like a vaccum leak).

I thought I would see what it does with all the caps off (and no manometer tubes on).....the idle jumps around between 3500 and 4K....very irratic.

Then I closed all the screws and the idle smoothed out down slightly at 1K.....but out of balance on the manometer. Balancing required adjustment to cylinders 3 and 4 only of about 1/2 turn at most (1&2 left closed). Idle is quite smooth at about 1200, and quick twists of the throttle are crisp with no hesitation......but I am at the bottom of the idle screw adjustment so I can't reduce it any further. The throttle cables are not tight or binding, I sprayed brake cleaner around the boots and TB (I've used this method before when checking for leaks) and nothing. Could air be leaking around the screws?? I am at a loss......

 

[escapefjrtist]

Sounds like you may have the common idle adjustment too high.

Try backing it way off to reduce the idle to say...below 1K and then open up the air screws. Begin with #3 at 1-1/2 turns out from lightly bottomed and then match the remaining cylinders to it. Assuming you don't have a vacuum leak (as you've tested) this should fix you up.

Have fun.

--G

 

[RaYzerman19]

I have been concerned with my idle adjust as it may be starting to stick.... maybe you want to check this out?

https://www.fjrforum.com/forum//index.php?showtopic=122016&st=0&p=643206entry643206

 

[mattster31]

Sounds like you may have the common idle adjustment too high.

Try backing it way off to reduce the idle to say...below 1K and then open up the air screws. Begin with #3 at 1-1/2 turns out from lightly bottomed and then match the remaining cylinders to it. Assuming you don't have a vacuum leak (as you've tested) this should fix you up.

Have fun.

--G

My common idle screw is backed off all the way already....there is no more adjustment.

 

[mattster31]

I have been concerned with my idle adjust as it may be starting to stick.... maybe you want to check this out?

https://www.fjrforum.com/forum//index.php?showtopic=122016&st=0&p=643206entry643206

That's an interesting thread. I had the damn TB in my hand cleaning them and I didn't even think to check the fast idle....i will admit I wasn't sure how it worked so thanks Radiohowie! Anyhow, the idle was fine before I did the initial TBS......should have left well enough alone....but Cylinder 3 was way beyond the rest and it was a bit rough....figured I was doing something good. it's about 1200 now so I think I'll just leave it to see if it miraculously cures itself, or I'll just have to bite the bullet and pull the TB's again....I've done it enough times I think I could do it with my eyes closed.

and I don't think I have seen TB's that dirty before (Radiohowies).

 

[03HiYoSilver]

Then your Common Idle Adjustment Screw may have Disengaged and has to be re-attached.

You may want to give it a 1 oz per Gallon of SeaFoam Fuel treatment and see if this will clean things up.

 

[mattster31]

Then your Common Idle Adjustment Screw may have Disengaged and has to be re-attached.

Nope............I can increase it no problem, and I can then back it off to the point where the butterfly valves hit the "stops". Yes I realize if I kept going it would disengage, but that is not the case.

 

[mattster31]

You may want to give it a 1 oz per Gallon of SeaFoam Fuel treatment and see if this will clean things up.

Missed that line.........yes, I am going to run some fuel treatment through it once I put the front end back on (waiting on a tapered bearing kit). I am hoping that will improve the idle situation.

 

[03HiYoSilver]

Glad your Idle Screw is fine... it is tough to get back attached again.

SeaFoam treatment has cured my Hot (NO)Start Flooding problem a few weeks ago after sitting for about a month.

Hope it all works out for you!

 

[Queensland Ken]

Hi,

Just a quick question.

Did you happen to flush the radiator or drain it ??.

It was RadioHowie's post that helped me fix my idle probs after I checked the valves.

I suspect I had air in the small radiator water lines to the "Wax Fuse".

Cheers

Ken

 

[03HiYoSilver]

Mattster,

One more BIG thing that will do this is the Connector Prob:

https://www.fjrforum.com/forum//index.php?s=&showtopic=22734&view=findpost&p=268059

Check this out and things will most likely smoooooth out.

 

[RaYzerman19]

Hi,

Just a quick question.

Did you happen to flush the radiator or drain it ??.

It was RadioHowie's post that helped me fix my idle probs after I checked the valves.

I suspect I had air in the small radiator water lines to the "Wax Fuse".

Cheers

Ken

Now that's an interesting point, and isn't that a bleed screw on top of the thermostat housing (see fische for Water Pump, item 33)?

 

[mattster31]

Hi,

Just a quick question.

Did you happen to flush the radiator or drain it ??.

It was RadioHowie's post that helped me fix my idle probs after I checked the valves.

I suspect I had air in the small radiator water lines to the "Wax Fuse".

Cheers

Ken

Good point but I've changed the coolant 4 times since I've owned the bike and I have never needed to open the bleed screw. Once the temp creeps up and opens the thermostat it pushes the air bubbles with it IMO.....but I could be wrong. Perhaps i'll try.

 

[mattster31]

Mattster,

One more BIG thing that will do this is the Connector Prob:

https://www.fjrforum.com/forum//index.php?s=&showtopic=22734&view=findpost&p=268059

Check this out and things will most likely smoooooth out.

I remember that thread from a few years back. I think I did that at the time as I was having surging issues at around 3-4K when cruising. Upon rebuilding the machine over the past few weeks, I have gone over every single electrical connection with spray cleaner, a fine wire brush to gently clean away any debris, compressed air, and finally using dielectric grease.

That said, there was only one or two connectors that had a bit of crud, but those I had never touched with the DE grease before. I might try the high idle mechanism, although I'm not happy about having to rip it down again......but if I gotta, I gotta....

 

[03HiYoSilver]

Mattster,

One more BIG thing that will do this is the Connector Prob:

https://www.fjrforum.com/forum//index.php?s=&showtopic=22734&view=findpost&p=268059

Check this out and things will most likely smoooooth out.

I have gone over every single electrical connection with spray cleaner, a fine wire brush to gently clean away any debris, compressed air, and finally using dielectric grease.

Mattster,

This was the MAIN problem that caused my Erratic Idle Problems along with the Surging. This is the appx 4" Wide Main Connector just forward of the TripleTree.

Since these Aluminum Contacts are easily Corroded/Dirty.. it does not take much to return to its Evil Ways after a bit of time.

 

[mattster31]

Mattster,

One more BIG thing that will do this is the Connector Prob:

https://www.fjrforum.com/forum//index.php?s=&showtopic=22734&view=findpost&p=268059

Check this out and things will most likely smoooooth out.

I have gone over every single electrical connection with spray cleaner, a fine wire brush to gently clean away any debris, compressed air, and finally using dielectric grease.

Mattster,

This was the MAIN problem that caused my Erratic Idle Problems along with the Surging. This is the appx 4" Wide Main Connector just forward of the TripleTree.

Since these Aluminum Contacts are easily Corroded/Dirty.. it does not take much to return to its Evil Ways after a bit of time.

HiYo,

I know the connectors you are referring too, and trust me, they are clean and shiny

I did experience erratic idle/surging a few years ago, and both of those connectors must have been the culprit because it all disappeared after cleaning. I am getting the sinking feeling I need to pull the TB's off, but I am going to give it a few hundred K's with some fuel treatment before I go down that road. However, with the foot of snow that just dumped today, I won't be doing that any time soon. Ah heck, I have nothing better to do now, so I might as well go for it. I'll keep you posted and thanks for the help everyone. This forum rocks!!

 

[JamesK]

Mattster,

Perhaps you can do your sync at 4k RPM ...that is where I fine tune mine.

Unless you have a leaking Throttle Body Boot which will give you this erratice RPM.

Another thing, make sure your #3 Air Screw is about 1 -1 1/2 turns out from the bottom. Sometimes a bottomed out #3 will do the same erratic behavior.

Hope this helps...

I only do my TBS at around 4k RPM, it maybe unorthodox but really makes a difference in the smoothness of the bike. In fact just a few weeks ago when I was doing a TBS I decided to just try syncing the TBs at the FSM recommended idle and after only a few hundred miles of running I remembered again why I've been running the bike with the TBS set at 4k RPM, the buzziness and general feel of the engine was much more noticeable when the TBS was done at idle. Needless to say I was back under the tank re-doing the TBS at around 4K RPM the next day and will always run it that way.