STIG- new parts SOLVED~!

[TLRam1]

Stig,

You put the shop guy on the back while YOU drive and replicate the issue, than you know he knows. Does this have nothing to do with your cdi box, throttle sensors, etc? Some electrical part in the initial stages of failure.

[BettinANDlosing]

I'm surprised they charged you to test ride...... Then say well it's fine. You should email kymcousa a long detailed message with forum links once you do nail it down for at least slight reimbursement. I have a vantage point from scooter rider to test riding customer bikes and there has been times I have not felt claimed stumble/stalling/ect and it sucks because a dealer especially small like us can only test ride for so long. It does not sound like you're dealer was TRYING to find a problem.

[2wheelfun]

Stig if this were a car the symptons you describe are exactly what a bad tps would do. Throttle position sensor. If you have a DVOM you can test it. Voltage sweep should be precise from say .5 to 5 volts, no stumbles or eratic readings along the way. Just an idea that won't cost you anything to check besides a $3 dvom from HF. Not exactly sure what the low/high voltage is on a scoot but the principle is the same. At 20/30 mph is where your issue is, so in the middle of that sweep you should find some stumbling......dunno if this has been covered already but this is where my thoughts are.

[Stig / Major Tom]

Stig if this were a car the symptons you describe are exactly what a bad tps would do. Throttle position sensor. If you have a DVOM you can test it. Voltage sweep should be precise from say .5 to 5 volts, no stumbles or eratic readings along the way. Just an idea that won't cost you anything to check besides a $3 dvom from HF. Not exactly sure what the low/high voltage is on a scoot but the principle is the same. At 20/30 mph is where your issue is, so in the middle of that sweep you should find some stumbling......dunno if this has been covered already but this is where my thoughts are.

2Wheel,
This is the 2nd or 3rd time I've been advised to do this check...problem is I cannot figure where I do the touching and testing. The TPS is in the ECU....not a place I'd want to mess up!
My cyclepedia on-line maual says this fault is found using the Kymco diagnostic tool. ( I have a fellow offering to let me borrow one ) but is there another way to test the TPS...manual says it is in the ECU and to use the Kymco diagnostic tool to test it.
I'm a lousy mechanic - but these remarks about the TPS having a fail section in it is making more  & more sense to me. I spent a LOT of time cruising the state parks at that speed ...a lot of time - and was doing so when it first stumbled.
 I have the meter. (never used it but can figure it out using youtube)

So, I guess I turn the key on and advance the throttle slowly and read the meter - but where do I hook up the meter?
Thanks a bunch,
Stuig

[2wheelfun]

TPS sensor is a simple creature, think of a gas guage in the tank same principle. One wire is the feed, should be 5v [if its the same as alot of cars]. There should be 1 or 2 other wires for output. The one going to the ecm is where the voltage should vary as the throttle moves. Wiring diagram would be beneficial. At idle the voltage will read either.5v or the full 5v, then as the throttle is moved the v will sweep. Can't remember if v at idle is full 5v or .5v. Either way doesn't matter it's the sweep that counts. Might be easier with 2 people, one to turn the throttle while testing. No need to disconnect anything, just use the pointed probe to probe the wire connecters from the outside of the connecter.

[vespbretta]

Out of a workshop manual for Synerject Systems:
TPS Voltage should be 5Volts measured with key on going from ECU to Sensor. Measured at the TPS Connector and the wire 18 purple/red against ground or wire 16 (which is also ground coming from the ECU).
Furthermore check wire 7 purple/black and wire 16 purple/green for passage to the ECU.  And then check (probably after key off!...?) with disconnected wireplug the resistance of the sensor. -> 5Kilo Ohms+/-30%.

Idle 0° ~0.23V+/-0.05V
Full Throttle 90° and over ~3.27V and over

Do not disconnect or connect the ECU Connector while Key on or Scooter is running!


Keihin Systems:
Wire 13 grey/purple voltage measured against ground.  -> 5Volts+/-0,25 Volts.
Passage measurement of wires from sensor  to connection 5 green/black, 13 grey/purple and 24 green/grey of the ECU Connector.
Resistance measurement between the contacts of the sensor. At 20°C it should be 5 Kilo Ohms+/-30%. Between the green/black and the grey/purple wire.


Take care! This is kind of heart surgery... Doing these measurements the wrong way with short circuits might/will destroy your electronic parts, ecu etc.

[CROSSBOLT]

Stig, I have another bright idea: there are two ways to pursue this idea: 1. dyno and 2. street. There is a really good independent tech in Nashville with a dyno. This would require you to get the scoot to Nashville and commission him to find/fix the problem. His number is 615 200 7337 name is Junior Padilla and his shop is Dimelo Motor Works. There might be someone similar nearer to you. You are a good camera guy so you could strap(duct tape) a camera to shoot into the timing hole while the timing light you also taped to shoot in the hole strobes while you ride in the "stumble speed" range. I know both sound a little far fetched but I am suspecting you have something that vibrates at those speeds and the only way you are gonna find it is to "catch it in the act." This all may give you a flash to something else that may be a bit more practical.

Karl

[big blue]

Stig-  One more brainstorm idea that may go nowhere. Is the tach that you installed still connected? Have you tried disabling it and then testing the scoot?

 ...Len

[Stig / Major Tom]

Stig-  One more brainstorm idea that may go nowhere. Is the tach that you installed still connected? Have you tried disabling it and then testing the scoot?

 ...Len

Hey Len,
Yes, I've had it off a couple of times when fitting one of the 3 ignition coils...makes "n o   d i f f e r e n c e" (use a French accent)
My family of course harbors this (usually, but not always) unspoken idea that because I was always tinkering with it, that I broke it.
It does no good to plead my case that all I've done is:
Bleed the brakes
Change the belt and rollers
Change the plug
Install a Bestem box w/lights
Change the gear and engine oil
Change the plug, coil, plug wire and cap (3 times - no help)
Change the injector
I am about ready to change out the fuel pump with a new Yamaha EFI, 30mm, 12V, intank pump

Have I checked over my work to see if anything I did is causing the stumble at 25MPH cruise --You bet! This thing runs so good at all other speeds it is pathetic! !
It could not run any better....I hammer it and cannot replicate that problem at any other time.
Back off to a slow cruise ...and she stumbles - not every time but most of the time.
Stig

[Stig / Major Tom]

Stig, I have another bright idea: there are two ways to pursue this idea: 1. dyno and 2. street. There is a really good independent tech in Nashville with a dyno. This would require you to get the scoot to Nashville and commission him to find/fix the problem. His number is 615 200 7337 name is Junior Padilla and his shop is Dimelo Motor Works. There might be someone similar nearer to you. You are a good camera guy so you could strap(duct tape) a camera to shoot into the timing hole while the timing light you also taped to shoot in the hole strobes while you ride in the "stumble speed" range. I know both sound a little far fetched but I am suspecting you have something that vibrates at those speeds and the only way you are gonna find it is to "catch it in the act." This all may give you a flash to something else that may be a bit more practical.

Karl

Hello Karl,
I'm listening here....
Duct tape, timing strobe, vibrations, Grand Ole Opry, cats.
OK - I sent my daughter down to the hardware store for more rolls of duct tape.
Here's the  plan:
My sis-in-law collects cats. She has about 25 or so.
I know a single cat will probably top out at say 18 mph - in a steady cruise.
But, say 12 cats duct taped together - end to end - can probably cruise at the required 25 MPH.
So, I duct tape my cell phone -set for video- to the lead cat and climb on my LIKE200i LX. We find some clear road and start the "Scooter Repair With Cats", and post the whole thing on youtube.

I think this is one of my better solutions to my scooter issue.


I've discarded the idea that something is vibrating & causing a problem.
There is no evidence of that during my dozens of test rides.
I think it is ....the Throttle Position Sensor.
Or a cat issue; one....
Stig

[big blue]

Rats!

[200i]

Stig, I want to be present for the cat duct taping...or at least have a family member record it:)   I have a feeling it would be a great utube hit...viral indeed!!

[CROSSBOLT]

'Scooter repair with cats," Stig, you are potty in the head! What a video!

Karl

[Stig / Major Tom]

Exploring the possibility of a failed Throttle Postion Sensor in my scoot's illness.
A senior member -  r e a l  old guy, I guess - is lending me his Kymco Diagnostic Tool so I can check a few things, namely the TPS.


From The Biker's Garage:
The components of motorcycle fuel injection systems are reliable, but parts can wear out, or even fail prematurely.  When a failure happens the process for diagnosis and repair can seem daunting, but in most cases it’s only a loose wire, or failed sensor.

The most common sensor to fail is the Throttle Position Sensor, or TPS for short.   The TPS tells the ECM (Engine Control Module) where the intake butterflies are in their travel from fully closed to wide open.  That information, combined with data from other sensors, allows the ECM to correctly meter the fuel being sprayed from the injectors.  The primary reason for TPS failure is simply wear, since it moves every time you twist the throttle, eventually it wears out.  Typically it will be in one specific place on the throttle, this comes from operating on that point repeatedly.

I did like to cruise at just about 25mph through the State Parks around here....less damage if I nail a deer. I did this every w/e and some week days. Also, this is what I was doing the morning the first set of stumbles occured.
As I tried to explain to the dealer - the scoot runs great at all engine speeds except at a 20-something cruise.
Interesting.
We will see.....
Stig

[bluesin]

Rats!

The cats should take care of those !