Odd Idle and TB Sync observation

[Greenham]

I'm one of the FNG on this board, but been riding and participating in many boards over the last 20 yrs. So I know this is how real problems are solved. You Gurus's helping the FNG's So thank you upfront

I have an 05 w/ ABS that only had 14k miles.. The guy bought it brand new.. The guy had $$$ so the dealer did all the maint on it. He only put 1,000 miles a year on it.

Got it home did some familiarization and have been trying to get the numb thumb problem resolved. One of the many suggestions was the TB sync. I came from a Valkyrie some years ago with 6 carbs to sync so I had the tools. Using the # 3 cyl as the reference 1,2 and 3 were almost identical.4 was only 2mm out but as an anal guy I wanted it to match. I could a just it up one way but the screw bottomed out and was still the same 2mm out.

The bike has a ever slight uneven idle, even after warm up.

The thing that bothers me the most is the "Stumble, Bog or a hesitation" at just off idle to about 2400 RPM. This is most problematic when making a low speed turn when the bike stumbles through that RPM range then kind of takes off.... A bit un-nerving...

I had this problem with an old Concours I could NEVER get sorted out....and happily got rid of.

Does anyone have any ideas? My only no mechanical thought was perhaps some gumming up from so little use over 10 yrs... So some Seafoam through the fuel system..... After that I'm not sure what else to do. So I am open to any and all ideas.

 

[HotRodZilla]

I'm thinking vacuum leak from a rubber cap. '05s in general are pretty smooth off idle. FredW will be along soon with his Unauthorized TBS. Probably a good thing to try. Inspect the caps while your at it.

 

[JamesK]

Having used a G2 Throttle Tamer for a while now, I can tell you that it's worth it's weight in gold, it will make any bike function/behave 10x better.

SKU: 4y-142

https://www.g2ergo.com/store/g2-street-tamer-throttle-tube/

 

[RaYzerman19]

Sounds like your air screws are turned too far in..... set them all at 3/4 to 1 turn out and redo your TBS.

 

[bluesdog]

Unauthorized TBS and seafoam the s**t out of it.

As HRZ said, there could be a vacuum leak. Check for intake vacuum leaks using a spray can of starter fluid.

Since the bike has not been ridden enough, there's a possibility of fuel related gunk at the injectors, so seafoam or equivalent may help clean it out.

 

[Fred W]

@Greenham - First off, welcome to the forum, and congrats on finding such a fine bike. Let me tell you a few things about your bike that may help you on your journey.

First off, the idle of FJRs is generally a bit lumpy for an inline 4 cylinder, with what appears to be stumbling or surging at idle and just above. I believe that this comes from the relatively advanced (and fixed) valve timing, but may be made worse by the government mandated lean fuel ratios.

Here's a link to a video of a 2nd Gen FJR at idle. That is about the "normal" amount of idle stumbling for an FJR if you have the idle speed set up at 1200 rpm. You may be able to make it a bit smoother by dropping the hot idle speed down to 1100-1000 rpm, but some of the same stumble will always be there.

As for you numb right hand, that is probably more of a function of how tightly you are gripping the handlebars, how much weight you have on your wrists, and what your handle bar angle is to your arm, than the amount of vibration. You may want to experiment with ways to alleviate some of those things to reduce hand numbing.

Loosening your grip on the throttle can be achieved by unwinding the throttle return spring 1 turn, if that has not already been done (probably not based on your description of the PO). This is a very common mod for first and second Gen FJR owners.

You can also buy a "Throttle Rocker" or "Wrist Rest" which allows you to hold the throttle open with no grip pressure at all. Many people can't get comfortable with having the flap there and claim it causes them to hit the throttle at times the do not want to, but after many years of having one on all of my bikes (including bikes I ride off-road) it has become second nature and I have never had such an issue.

Bar risers, set backs, or adapters that allow a change in bar angle can also help reduce hand numbing by having you put less weight on your hands.

Or, better yet and less expensively, you can look up the MYRP (Master Yoda Riding Position) which has you support your torso with your legs rather than your arms.

Many folks also use all manner of throttle lock to allow resting the throttle hand grip when maintaining a steady speed (on the highway, etc.)

Now, on to your TBS questions:

Although the FSM (Factory Service Manual) says to use the #3 cylinder as the "reference", that is really not important at all. The primary goal of a standard TBS is to make the vacuum equal on all 4 cylinders, which means that the power pulses should be equal. This will smooth out the idle somewhat, but as mentioned above you'll still have some of that surge in the video. As long as you can still adjust your idle speed to spec (1000-1100 rpm) then you can open or close any of the air screws that you want to achieve the best balance

Can you describe further how that #4 air screw behaves? It sounds like when you adjust it the vacuum of the #4 cylinder doesn't change at all? If so, you may have a clogged air bypass passage. Not a stretch considering how little use the bike has had over the years. If that is the case you can carefully remove that air screw and spring and shoot some carb cleaner in the port and hopefully get that cleared.

Because the amount of air passing through the air screw adjustable bypass ports is so small, it will have a rapidly decreasing effect on the synchronization of the cylinders as the throttle is opened. In other words, the air screws really only adjust the balance at idle. But they should all affect the vacuum for their respective cylinders at idle.

If you want to adjust the vacuum balance (to help reduce vibration) at higher rpms, you'll need to adjust the linkages that connect the four throttle butterflies. I developed a procedure to do that quite simply that has worked for many FJR owners. I call it the Really, Definitely, Completely UnAuthorized TBS (RDCUATBS) to distinguish it from other UnAuthorized TBS procedures.

You can get a copy of my procedure here, or click the little NERD in my signature line to get to it along with some of my other procedures and posts that I have made in the past.

Good Luck!

 

[ionbeam]

The G2 throttle tube that JamesK suggests is for an early Gen II that has an eccentric throttle pulley on the throttle bodies which causes a non-linear throttle response. The G2 has a profile that is the exact negative of the throttle pulley to cancel out the throttle body pulley and create a linear throttle response. The Gen I don't be this way and doesn't need a G2. But, if one were to put a G2 throttle tube on a Gen I it would slow down the rate that the engine would respond to throttle inputs for the first ~25% of the throttle travel and you would have to twist the throttle further to get the engine to speed up.

 

[Barn Boy]

I had the same problem with my low mileage 2005 about a month ago. I would put my $ on a dying TPS. PM sent.

 

[Greenham]

Well I checked and you guys were right. This bike is associated with the recall. According to the NHTSA site it says RECALL INCOMPLETE. Head to the dealer for that fix and see if things get better. Thanks again ALL.

The power of the people... Thanks again

 

[Greenham]

Well so much for that.... Turns out Yamaha did the recall in 10'. For whatever reason the Yamaha database doesn't talk to the Gov't database. To double check I reached out to the previous owner who confirmed the recall was done...

So gonna do some cable and throttle tube cleaning and lubing then I am just gonna ride it, get used to it and figure it out as I go....

 

[Fred W]

Don't completely rule out a TPS as the culprit just because the recall was done. The TPS they put in was an improved part, but they are still prone to failure. TPS failures are actually fairly common on any (fuel injected) bikes that have one (or more).

TPS symptoms tend to come on with higher heat, like after you have run the engine hard for a while, not when the engine is cold. And they tend to be rather significant, not subtle at all.

 

[dudeckp]

An additional $.02....

Recently did a TBS & PAIR removal (go WynPro!) and soon felt a mild hesitation, uncomfortable vibration, and noticeably lower MPG.

After checking airbox for winter nesters, I found threads like this one on spark plug wires. Sure enough, #4 wire was a few turns short of tight (please, no suggestions that I might also have a wire or screw loose.)

Vibration & hesitation near idle disappeared, and it's back to getting 250+ miles out of a tank.

YMMV,

Peter

 

[Greenham]

Fred, Dudeckp

I went through the diag process looking for the 1-1-1-1 drop outs. It never showed any of the drop outs as described. Could it still be a TPS?

I will check the plug wires next time I'm under the tank

I am currently running Seafoam through it,

Got a cable luber and lube so I will pull the throttle tube, clean it up, clean and lube the cables

Fred, I have read and study Yoda's write up.... very in depth and seems based in strong science and consensus. I am still working on using his method. As a life long cruiser rider who could make ANY bike comfortable, this one has been a real challenge to get that long distance comfort. Seems when I solve one problem (numb Thumb), another pops up (Sore lower back) I have been surprised how differently you really have to ride a ST vs a cruiser.

I do appreciate the responses from all you long time FJR riders

 

[Fred W]

Not sure what you mean by 1-1-1-1 dropouts. The only Diag I am aware of is to display the TPS sensor's digitized value in the diag screen while you slowly rotate the throttle tube. The TPS itself is an analog device, really just a giant potentiometer attached to the end of the throttle shaft. The value displayed is the digitized value of the analog voltage from the TPS. The number displayed should smoothly increment and decrement as you rotate the throttle open and closed.

All of that said, I think bad TPS problems are often intermittent in nature and do not show up using that diag. They generally do not start acting up until they've been heat soaked, like after a half hour or more of highway speeds. And you would have to run the diag test while it is in the "failure mode" to catch it with the test.