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Offline Notsoaverageguy

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DIY snatchy Throttle cure?
on: November 21, 2019, 08:39:02 AM
Sorry this is going to go long. But if you suffer from what you think is a snatchy throttle (i dont, 2018 Cafe California) you might want to read this. First I will give my background so you can discern it is my pie hole I am talking out of. I was a Ford tech from before FI existed in production automobile, and was there for the learning curves, both Techs and the factory. They had same drivability issues as some of you are experiencing. I mean the exact same!!! meaning some customers complained and some didnt (most) on the exact same cars. Which got me to thinking why do some say they have it and some say they dont? And it dawned on me, maybe its the same problem as before. FIRST let me clarify I do NOT know this is the problem but got a pretty good idea and will explain why I think so.
1) EFI systems are all the same in the fact that they all run on sensors and processors that have perimeters. And yes re-flashing a computer  will sometimes cure it but its only really masking the cause. We had MASSIVE problems with TPS (throttle possition sensor) and throttle plate settings that drove everybody bonkers. They would set a perimeter in the processor and for safty and idle purposes it had to be a tight tolerance, that didnt always match the MAP and would piss off the computer which retaliated in lousy drivability.
Recently experienced this on my 06 ZX10R and immediately recognized the problem, and on THAT bike fixed it very quickly.
2) These problems are from idle stop onward. Maybe you dont recognize it as being that but I am willing to bet, that it is between the gears and when you are on and off the throttle. I again havnt ridden a RS with the problem so this is the big "IF"
 
Here is what is going on. The MAP says when the throttle plate is closed (fully warmed up and not using secondary butterflies or ABV (air bypass valve) the TPS should read ;example/ .45 volts. Great in the imaginary world of the engineers. Problem is (and I did have to adjust my idle screw because of occasional stalling) all the idle stop screws and TPS dont match up exactly. I am not going to go into why they dont, its cost related, nuff said. So when the computer sees the throttle plate closed and the TPS where it is not supposed to be it gets pissed off and runs its own map! The fix is easy TRUST ME.
By the book you would hook up a DVOM to the sensor lead + and ground the negative, find out what those engineers had in mind and adjust it to match (provided you idle was already set) and off you go. A much easier method on our RS is (the sensor is right there on the left side easy access. Loosen the 2 screws I think its marked in it present location, and move it one way or the other (make a note) just a touch. Go and ride. You can do this on the rode.  NO you cant hurt anything. Adjust till you make the computer happy. Again I had the exact same problem on my ZX10R. Much harder to get to the screws but it was solved.
Anyone can do this if you know how to run a screw driver (hand held no gun please) I am away fro home now so dont have access to Mona or I would get the DVOM readings for you. So if you do this and are successful please pass it on to the rest.
Just saying.   
Things should be made as simple as possible, but no simpler!
(Albert Einstein)

Offline Dirty Dave

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Re: DIY snatchy Throttle cure?
Reply #1 on: November 21, 2019, 11:59:25 AM
Wow! Why so long to suggest this? Great news and also an explanation as to why some have the problem
while others think we're nuts.

 :138:
Last Edit: November 21, 2019, 12:17:51 PM by Dirty Dave
18 Z900RS Jaffa
97 Honda Valkyrie
79 Honda GoldWing

Online Otown

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Re: DIY snatchy Throttle cure?
Reply #2 on: November 21, 2019, 01:20:45 PM
*Originally Posted by Dirty Dave [+]
Wow! Why so long to suggest this? Great news and also an explanation as to why some have the problem
while others think we're nuts.

 :138:

Some of us still think you're nuts, just that your bike may have been snatchy as well.

Offline Killer_01

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Re: DIY snatchy Throttle cure?
Reply #3 on: November 21, 2019, 01:30:42 PM
You're talking about that sensor being the TPS right? When someone says right or left about a vehicle I tend to see it from sitting position, that made confused about your "left side" meaning.
Happy Zed Café commuter..

Offline Notsoaverageguy

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Re: DIY snatchy Throttle cure?
Reply #4 on: November 21, 2019, 01:58:39 PM
Ok OK 1) I hadn't said anything because has I said my bike didn't do it. And a lot of others didn't as well. What keyed me in was the newbie (Martin) stating the new bike (he feels still did it). I originally thought Kawasaki would have just fixed it problem solved, but now see maybe not. Thus I felt the need to share.
2) Yeah it is the right side, I guess I had my wife's Z1000 on my mind, as I stated I am not at home, or I would have double checked it. Thanks for pointing it out.
Carry on then!
Things should be made as simple as possible, but no simpler!
(Albert Einstein)

Offline Dirty Dave

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Re: DIY snatchy Throttle cure?
Reply #5 on: November 21, 2019, 02:06:04 PM
*Originally Posted by Otown [+]
Some of us still think you're nuts, just that your bike may have been snatchy as well.

Now, now......
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Offline Feelooz

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Re: DIY snatchy Throttle cure?
Reply #6 on: November 21, 2019, 05:29:19 PM
Thank you for this technical explanation Notsoaverageguy. The TPS setting may vary from one machine to another and explains the differences on its own. Nothing psychological or personal feeling in it.
Kawasaki Z 900 RS - Suzuki 1200 GSX - Triumph Bonneville T -100 - Kawasaki Vulcan 900 - Triumph Speed Triple 955 I - Triumph Sprint ST 955i - Triumph 900 Legend - Yamaha 1200 XJR - Norton 850 Commando MK2 - Kawasaki 1100 Zephyr - Yamaha 750 FZX - Yamaha 1100 XS - Kawasaki 1000 ST - Suzuki 600 DR - Honda CB 750 F2 - Kawasaki Z 650 B1- Triumph Bonneville T120 (1972) - Yamaha 650 XS 1H1 - Honda CB 350 K4 - Jawa 350 Californian - Jawa 250

Offline Notsoaverageguy

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Re: DIY snatchy Throttle cure?
Reply #7 on: November 21, 2019, 07:37:55 PM
Oh so now I looked at the illustration and noticed the pointer is pointing at the SECONDARY butterflies. I need to clarify. That is NOT the potentiometer  to adjust. It is the one below it that is on the throttle plates. It looks the same its just bellow that one.
Hope this didn't confuse anybody.
Just saying.
Things should be made as simple as possible, but no simpler!
(Albert Einstein)

Offline hell-wart

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Re: DIY snatchy Throttle cure?
Reply #8 on: November 22, 2019, 12:28:16 AM
Many thanks Notsoaverageguy,

I checked the service manual and it says:
Don´t touch the sensor.
If the sensor is out of range, change the throttle body assy  :007:

But they offer a tool to make the measurement very easy.
It´s about 20 $ for this pn: 57001-1538 - Sensor Adapter
And of course you can use it for the adjustment.

What we need now are some data/ values to find the best setting.
Manual says 1.02 V - 1.04 V at idle  => section 3-47 to 3-50

I found a lot of information in a Suzuki forum as they have the same issue.
An adjustment of 0,1 V made a huge difference

As soon as the renovation of my garage is finished, I´ll gonna check my sensor values

@Ivan:  I know.. 
That´s why mine has been flashed and it is way better. Cannot be wrong to check the correct setting of the sensor

My bike history:  Yamaha TY50, Suzuki GT250, Honda CB 650, Kawasaki Z 650, Kawasaki Zephyr 550 + Yamaha XS 400, Harley Sportster 1986 + Kawasaki Zephyr 750 D,
Today: Kawasaki Z900 RS + Harley Sportster 1986

Offline Notsoaverageguy

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Re: DIY snatchy Throttle cure?
Reply #9 on: November 22, 2019, 05:09:33 AM
Yes when I get home I am going to check my sensor readings and post the results. If anybody else does the same thing maybe we can get a graph and see if the correlation matches feelings from other people. If nothing else it will be fun and interesting. Won’t be home till mid December   :006: Man I miss my bike.
Things should be made as simple as possible, but no simpler!
(Albert Einstein)