Help with the The Really, Definitely Completely Un-Authorized TBS

[Chiefblueman]

Okay, now I'm getting worried. Two SOS's in a row.

Buttoning everything up after many farkles and maintenance items such as: AVCC installation, CCT replacement, valve adjust, LED lighting - LR4's, Skene controller, USB port, Powerlet, Datel, Jack's harness, etc. Gonna check that TBS before all the plastic goes back on.

Starts up and idles fine (after I realize kill switch is off

). No leaks, everything works, Datel shows 14.3v with all 4 LED's on high, yay. I grab my new Carbtune and plug 'er in.

TB's 3-4 are in almost perfect synch. 1 and 4 are low. Close air screws, adjust TP's to achieve balance, 3-4 remain good, 1 is out a bit, 4 a bit less. Once I synch up, idle speed raises and won't drop below 13-1400 with idle adjuster. Check throttle cable slack, good. TP tangs are resting on the stops, those allen headed screws with lock nuts. Still won't get to 1100.

I can get good balance at idle and at partially open throttle, won't adjust down. If I twist the grip forward speed will decrease a little. Checked for vacuum leaks, none found. No hanging throttle, throttle response is quite snappy. 1300 rpm idle is smooth as is higher rpm. I guess I could accept this higher idle, but there is no adjustment, me no likey. I could probably put it back to the unbalanced state it was in but it's still close to the bottom of adjustment. Me no likey that either.

This is with air bleeds screwed in, seated lightly, opening them only increases speed.

This bike had a previous owner and I had the problem of slightly high idle, adjuster ineffective. Was able to re-reference with air screws when I bought it.

Found many references on getting adjuster back in range because the adjuster wouldn't go high enough, my problem is the opposite.

I really hope I don't have to mess with those locknutted set screws. Hoping it's something simple that will make me feel really dumb. Once this is taken care of I promise I'll just leave the damn thing alone and just ride it!!

 

[Fred W]

This is very curious. I would not want to mess with those lock-nutted throttle stops either. Those are your known reference. And at proper idle the tangs on the linkage should be off the stops by a visible amount.

Based on everything that you've said there must be a vacuum leak somewhere that is admitting air around the throttle plates. When they are on the stops they are completely closed for all intents. Re-check all of the vacuum lines and fittings and then inspect the devices that are vacuum operated (like the fuel pressure regulator) for leaks. Something is letting extra air into that intake.

Good luck

 

[bhendron]

What type of manometer are you using? Does it require calibration? If so, did you do that first?

TB's 3-4 are in almost perfect synch. 1 and 4 are low. Close air screws, adjust TP's to achieve balance, 3-4 remain good, 1 is out a bit, 4 a bit less. Once I synch up, idle speed raises and won't drop below 13-1400 with idle adjuster. Check throttle cable slack, good. TP tangs are resting on the stops, those allen headed screws with lock nuts. Still won't get to 1100

I find this bit confusing. Here's my nutshell version of the sync. (after warming engine to normal operating temp (fan comes on)) 1. close all the air bypass screws. 2. start engine and, if need be, hold the throttle open slightly to maintain ~1100 rpm. 3. balance 2 and 3 TB's first. 4. balance 1 to 2 and 4 to 3. 5. open all airs screws ~1 turn. 6. balance all tb's at idle or adjust as necessary to achieve 1100 rpm idle . 7. done.

 

[RossKean]

I don't know about the Gen I, but on the Gen II idle speed adjustment range will depend upon your starting point for the air screws. If your "reference" screw is out (or in) too far, you may be able to balance all of the cylinders but the idle adjust may not have sufficient range to get you where you want to be. I had this issue and ended out closing all of the air screws all the way and then used one turn out as a starting point. As I said, I don't know how this works for a Gen I since the idle speed adjustment doesn't work the same way. Something to consider (or ignore if I am off-base with respect to the earlier bikes).

 

[Chiefblueman]

Fred, I will double check everything. Good idea on the fpr.

B-H, using Morgan Carbtune Pro, no calibration required. Since 2 and 3 are in sync, 3 being the reference, by syncing 1 to 2 and 4 to 3 all should be good. I may have misspoke earlier, I meant 2 and 3 were good.

With air screws lightly seated, idle is too low. Any turns out raises idle speed.

 

[RaYzerman19]

+1 on the 1 turn out. Double check (or actually slacken and readjust) the throttle cable free play. Adjusted too tight can prevent the throttle bodies from returning fully to idle position.

 

[Chiefblueman]

Ross, Rayzer,thanks, I'll try it again. Problem is, at 1 turn out with vacuum levels balanced can't adjust idle below 1300.Turning air screws in drops idle speed. With adjuster backed all the way down and air screws seated still can't get to below 1300. Rayzer, throttle cable has slack, throttle plates are resting on the stops.

Sorry for poor typing, dumb man with smart phone. It

 

[bhendron]

Have you touched the idle adjustment KNOB?

 

[Chiefblueman]

Have you touched the idle adjustment KNOB?

Yessir, this is what I'm calling the"adjuster". Very familiar with it, knob, flexible shaft, threads below the bellcrank on throttle shaft, contacts the same tang the CC cable is attached to. Is currently not in contact with the tang, throttle plates are resting on the set screw stops. Should be able to achieve idle speed of < 1100 rpm without contacting these stops. Will be searching for possible vacuum leak when I get home from work.

Thanks for your responses, keep 'em coming. This could be something simple that I'm not seeing - I hope. #3 TB as reference should be closed all the way at idle, with vacuums balanced to #3 and air screws seated the engine should idle very slowly or die unless throttle is opened, either by twist grip or turning adjuster knob clockwise.

Tonight I will start over by opening air screws 1 turn and balancing at idle, whatever speed I can get, forget about the higher rpm adjustments, and see if I can achieve proper idle speed.

 

[ionbeam]

...Tonight I will start over by opening air screws 1 turn AND SET THE IDLE TO 1100 THEN and balancing at idle, whatever speed I can get, AND WHILE SYNCHRONIZING WILL KEEP THE IDLE ADJUSTED TO 1100 AS NECESSARY AND forget about the higher rpm adjustments, and see if VERIFY THAT I can achieve proper idle speed.

 

[Fred W]

If he can't get it below 1300 rpm with the air screws fully CW, that ain't gonna work.

 

[Constant Mesh]

Maybe the cold, fast idle gizmo is letting in some additional air -- not closing off the air valves completely when the coolant is warm. Maybe the previous owner turned the adjustment screw on the fast idle gizmo allowing a small amount of additional air into the throttle bodies at all times.

Both the installation of an AVCC and valve clearance adjustments could affect the engine idle.

If you affected the timing somehow with your work on the valve clearances and chain tensioner you might experience idling issues.

 

[Fred W]

Maybe the cold, fast idle gizmo is letting in some additional air -- not closing off the air valves completely when the coolant is warm. Maybe the previous owner turned the adjustment screw on the fast idle gizmo allowing a small amount of additional air into the throttle bodies at all times.

Oh!! This is a good one, CM. I'll bet that this is it.

I'm just pissed that I had not considered it.

 

[Chiefblueman]

Maybe the cold, fast idle gizmo is letting in some additional air -- not closing off the air valves completely when the coolant is warm. Maybe the previous owner turned the adjustment screw on the fast idle gizmo allowing a small amount of additional air into the throttle bodies at all times.

Oh!! This is a good one, CM. I'll bet that this is it.

I'm just pissed that I had not considered it.

Tip o' the cap to you, sir. Wish I'd considered it. Will be checking this out. AVCC cable is slack to avoid idle adjust issues, final AVCC adjustment will be done after idle issue resolved. Valve adjustment consisted of removing material from intake shims, 3 - 4 thou to bring clearance to middle of spec.Shims measured with micrometer in several spots, reinstalled, clearances checked,(achieved goal), engine rolled a couple rotations, rechecked, spot on. All intakes are within a thou, same with exhaust, all near middle of spec. Timing rotor was removed to expose small timing gear, stiff closed cell foam wedged around chain and gear, teeth and chain links marked and ty-rapped on cam gears. Cam laid to side for adjust, no need to remove cam entirely. No teeth skipped, engine rolled through 3 or 4 revs, cam gear marks line up perfectly withtop of head. Upon first start after all this work, started quickly, high idle at about 2400, backed down to 1100 at 1bar. Smooth throttle response, but the outer cyl's show low vac.Runs fine, just like it did prior to work. Runs a little quieter with the new cct. I can bring the idle down by unbalancing 1&4 with butterfly adjusters, but that's not right.

Mr. Ionbeam, what Fred said. Throttle blades on the stops, idle adjuster knob disengaged, air screws seated, shouldn't idle.

Thanks, guys!

 

[Chiefblueman]

YAHHHFOOKINHOOOOO!!!!!!!!!!!

I knew you guys and this great forum would save me from myself!!! I'm one happy boy right now. Problem discovered and solved!!!! No need to toss this beast on the scrap heap. A life has been saved by all who posted here and many who didn't. Bike idles like a dream, smooth all the way down to 750rpm, like buttah! Vacuum balance perfect and easily accomplished. I'm very grateful, this forum is THE BEST repository of FJR knowledge on the web. Once again - THANKS++++

oh, you want to know what it was????

Constant Mesh, I owe you a cold one. Got me thinking about the cold start system, did some searching and found this https://www.fjrforum.com/forum/index.php?showtopic=122016

Great post from years back by Radio Howie. I love ya, man (but not in that Bustanut kinda way

. Great detailed photos of TB bank and cold start mechanism.

In my wiring adventures I had inadvertently pulled the little rubber boot off the cold start air valve on TB 1 (left side facing forward). the boot was bunched up and wouldn't allow the valve to close completely. Very carefully put it back on, made sure no wiring interfered with valve and linkage, fired it up and warm up and VOILA!! Joy has returned to the Chiefblueman homestead.

Thanks again.

 

[Fred W]

I love a happy ending.

 

[Constant Mesh]

I assume that the '13 & 14 FJR's don't have this "stone age" fast idle system. With the servo controlled throttle valves maybe the engine idle is totally controlled by the engine computer.

Has your cold idle dropped back down to 2K or so?

I assume there's no user adjustment on the '13 & 14 idle speed. I wonder if the idle is smoother and less erratic on these units?

Getting rid of the wax motor, the coolant hoses, and all the paraphernalia on the throttle bodies had to be a good thing.

I believe there's good info to be had by hooking up your syncing tool before the engine is warm. The fast idle air valves are open at a cold start so you'll see lower vacuums at the beginning and then the vacuums gradually increase as the air valves slowly close. If an air valve is misbehaving relative to the others you'll notice it immediately. I believe you would have spotted this problem with your syncing tool and a cold start.

 

[Queensland Ken]

The Gen 3 is different as you said.

No idle adjustment knob, all done via the ecu.

I did a TBS on the new girl and all was perfect up to 5.5K rpm.

The air bypass screws are rather awkward to get into, luckily I didn't have to adjust anything.

One service item in the manual states, that if you have trouble syncing the TB's, clean the throttle bodies.

It the gives you a procedure on removing and cleaning them.

 

[Chiefblueman]

I assume that the '13 & 14 FJR's don't have this "stone age" fast idle system. With the servo controlled throttle valves maybe the engine idle is totally controlled by the engine computer.
Has your cold idle dropped back down to 2K or so?

I assume there's no user adjustment on the '13 & 14 idle speed. I wonder if the idle is smoother and less erratic on these units?

Getting rid of the wax motor, the coolant hoses, and all the paraphernalia on the throttle bodies had to be a good thing.

I believe there's good info to be had by hooking up your syncing tool before the engine is warm. The fast idle air valves are open at a cold start so you'll see lower vacuums at the beginning and then the vacuums gradually increase as the air valves slowly close. If an air valve is misbehaving relative to the others you'll notice it immediately. I believe you would have spotted this problem with your syncing tool and a cold start.

You can consider this system stone age, but if a hamfisted caveman hadn't been rooting around in there the little boot would have remained in place and all would have been well. Cold idle speed ~ 22-2300. Since you mentioned it, I did start the engine this AM with Carbtune attached and watched vac levels. The li'l boot didn't affect operation until the very last step down to warm idle. It wouldn't allow the air valve to seat that last little bit on TB #1.That little leak throws a monkey wrench at the whole process. Once remedied, the whole TBS procedure took about 10 minutes.

I did a synch in '12 when I purchased the bike. I used a homemade comparative manometer which is still hanging on the wall. Using that tool allowed me to readjust the air bleeds and regain use of the idle adjust knob. The Carbtune makes the procedure much easier.

Thanks for pointing me in the right direction. I had nasty visions of having to remove the TB's and trying to clean the individual air valves but I knew it had to be something simple. The bike ran quite well before I tore it apart so I thought I may have had something to do with it. Thank goodness I didn't start twisting throttle plate stops trying to fix this.

Now it's time to wrestle some plastic into place and ride it.