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Discussion Starter · #1 ·
Hi everyone, now that my battery issue is fixed, I'm working on another improvement.

I had a sticky throttle issue last year that I thought was related to my throttle adjustments. I read somewhere that when the bleed screw on cylinder no1 is opened too much, it makes for a jumpy throttle.

So, I adjusted the screw to basically closed and balanced the 2 other TBs.

From that moment on, my bike had issues idling when it was colder outside. Wasn't as bad as a badly adjusted carburator but still.

So, after fixing my battery issue this weekend, I re-adjusted the screw a bit and tried balancing my TBs. They eventually balanced fine but my idle is now around 1500rpm and I feel like the throttle response is jumpy, erratic.

I can clearly see the bleed screw in the tiny hole when I adjust it on cylinder no 1 (the one to the left when sitting on the bike). Where should that screw rest when it's adjusted properly ? If someone can give me that answer, I can then balance 2 to 1 and the 3 to 2...

When I'm done, should I do an ISC and idle calibration ?

Maybe do a reset adaptations as well ?

thanks in advance !
 

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2018 Kawasaki H2 SX SE, '73 Yamaha RD350, '74 Kawasaki H1E 500
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Where should that screw rest when it's adjusted properly ?
There is no specific setting for the air bleed screws. Fully in or too far out might cause problems so start around 1¾ turns out from fully-seated and adjust until all three TBs are balanced. Generally a good idea to reset adaptions and let the bike run a bit to establish new trims any time you make adjustments.

Correct idle speed should be maintained automatically by the engine management system. If it was OK before then my first guess is maybe you backed out the air bleed screws too much when balancing the TBs to the point that even when the ISC closes the throttles completely it's not enough to compensate.

Other possible causes could be insufficient slack in the throttle cables, a poorly adjusted ISC or an air leak.

Refer to this thread for info on checking ISC & TPS adjustment.
 

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Discussion Starter · #3 ·
What a great community.. thanks for that answer, it's exactly what I was looking for.

Now, If I wanted to do the ISC, TPS, reset adaptation and TB calibrations. In what order should I do them ?

Thanks !
 

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2018 Kawasaki H2 SX SE, '73 Yamaha RD350, '74 Kawasaki H1E 500
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Now, If I wanted to do the ISC, TPS, reset adaptation and TB calibrations. In what order should I do them ?
Reset adaptions would be the last one. For the other tasks it doesn't really matter what order but I'd check the TPS/ISC first.

Although I gave a link to the TPS/ISC thread, be aware that this isn't a regular maintenance item. You can check the settings using TuneECU by hooking up to the diagnostic port without having to remove anything other than the stowage box cover. Removing the tank, airbox, etc. only becomes necessary if you need to make adjustment.

You may have already discovered that TB balance requires some patience. When you adjust an air bleed screw it will affect idle speed slightly. The ISC will then adjust throttle opening to maintain correct idle. That, in turn, changes all the manifold pressure readings - including the one you're trying to match! The secret is to let idle speed settle after each adjustment.
 

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I would said 1 1/2 turn from fully closed but 1 3/4 doesn't make much difference.

I personally use tuneECU on the GT (as opposed to the 955) as the vacuum gauge as included allows that kind of adjustment w/o external vacuum measurement device.

Champ is right about the adjustment (obviously). Needed only when a part is replaced.

What do you exactly mean by sticky throttle?

Fred
 

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Discussion Starter · #6 ·
Allright, I have done the ISC adjustment last night. It's not at 0.61v and 0.76v.

I have also done the throttle adjustment. I started at 1.5 turn from fully closed on the 3 of them and then only required like 1/8 of a turn on no2 and no3 to perfectly stabilize at around 540. Gave it throttle, let it settle, so on so forth, purrfect.

Now, I still have that surge or hesitation when cruising and the rpm sits right between 4300 and 4500rpm. Whatever gear I'm in, if I hold that rpm steadily, it misses or so it seems. No problem whatsoever when accelerating. I seem to feel it when decelerating, it's weird.

Here's what I played with in the past 2 weeks.

- Changed the battery (for a second time)
- Replaced the two grounding wires and the red power wire with 4gauge and used soldered on type connections on big flexible noodle 4 gauge amp wiring.
- Removed air box, air filter
- Adjusted throttle bodies
- Checked ISCV adjustment, reset adaptation
- The plugs were changed last year
- I've had 2 different tanks of fuel from two different suppliers

I now remember that initially when I had the air box completely out and did the first TB adjustment, I plugged my MAP or MAF sensor in the wrong connector. I plugged it in the connector that remains empty right below the TBs. The bike would not start. I realised my error, plugged it back in the right location and everything seemed fine. Could I have killed it ?

I have no check engins when the surging happens... and nothing stored either.

Any ideas ?
 

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A faulty sensor would be detected by the ECU I guess. Whatever TuneECU would show wrong indications for this sensor.

Could it be the TPS? Well regarding the fact you experience the symptom at the same rpm whatever the gear, that implies at different loads so different TPS positions. It's not likely that the tps is faulty at multiple spots.

I don't recall whether you did the 12 minutes auto calibration.

BTW there's a manifold absolute pressure sensor but no mass air flow sensor.

Fred
 
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