EFI stumbling LIKE200i

[Stig / Major Tom]

My fuel injected LIKE 200i has developed an issue.
At steady 20 to 38 mph speeds the engine seems to lose fuel or spark....for a split second....resulting in a stutter or surge. Speed has to be steady to get this - at idle and heavy acceleration the engine performs perfectly.
Plug, airfilter, valves, brakes, grounding wiring etc. all check out fine.
There are NO CELP codes showing, nor vacuum issue with tank venting. Replaced overflow one-way valve on tank vent..(I've seen other people mis identify that valve as a fuel filter - there is no fuel in those lines unless you've serioulsy over-filled your tank. Then that valve is fouled and would need cleaning or replacing.)
I questioned the gas, added sea foam and am running second tank of different gas....
Surging at these lower steadily held speeds still seems to be there.
Runs great at 40>61 MPH.
@7000 miles
Ideas?
Thanks, Stig

[mnpugdog]

Same thing happens with the DT. Using non ethanol gas helps but it's still there.

[zombie]

I have just developed the SAME issue. It started a few days before I left for VaCa.

I have two suspicions... One is a flooding issue, maybe or a worn timing chain/worn tensioner.

I'm gonna pull the carb, and replace the auto choke/rebuild the carb, and see if that has any effect. I'll let you know. Even tho you are FI it could still be a flooding issue.  If that does not get it I will inspect the timing chain, and see if that is it.

The bike runs like a top at load but is cutting in/out at any cruise speeds or if I slowly roll off the throttle.

[Stig / Major Tom]

Same thing happens with the DT. Using non ethanol gas helps but it's still there.

DT has a carb?
You probably have tried to clean the carb?
I will not put up with this poor driveability. If I can't find a cure (new injector?) I'll unload it and look at another scooter or a Honda bike. I dumped my old VW because it was no longer reliable - this scoot starts that behavior after only a year & 7K miles- it'll be history, too.
At my age I will not put up with poorly operating machines.
And the only nonethanol gas 'round here in on the shelf in walmart at like $9 a pint. I like my scoot, but not that much. I'd buy the Honda CBR300R-ABS - would be cheaper than the Walmart gas-in-a-can.
Stig

[zombie]

DarkSide meetings Tues/Thurs. Crawfordville Ramada.

New guy buys the treats.

[ophelia]

Is your exhaust header and muffler secure? My motorcycle has a bit of an exhaust leak lately.

[Stig / Major Tom]

Is your exhaust header and muffler secure? My motorcycle has a bit of an exhaust leak lately.

Thanks, I'll check that.
New plug today pn my lunch hour, also refreshed the plug wire with a quarter inch cut....and kept checking for loose wires. Might be on my own...dealer has no rentals, no loaners. Will try to get to it in a week or two, then another week or so if it needs parts.
Price of car rentals makes it feasible to start replacing a few parts.
Just looking for some expert advice ....which parts should I start replacing first.
Stig

[zombie]

I wouldn't go that route with this problem. There are TOOOOOOO many possibilities. Could be a simple wiring issue or a bad coil/ECU/timing chain/cracked magnet in the flywheel/pick up coil/loose stator/weak intake valve spring... Too many maybes.

[mrbios]

At steady 20 to 38 mph speeds the engine seems to lose fuel or spark....for a split second....resulting in a stutter or surge. Speed has to be steady to get this - at idle and heavy acceleration the engine performs perfectly.
...
Thanks, Stig

I cordially welcome you to the world of fuel injection.  There is nothing to check or change.  The condition you describe plages many fuel injected cars.  At a very light load and throttle position especially on the highway where the motor runs the most lean - insufficient fuel and or incorrect timing advance results in this condition.  This commonly happens with carburetor that has either a vacuum leak and or clogged pilot aka slow jet.   If the problem started after your scoot was worked on you inspect the boot and all vacuum lines.  Other than that just ignore it the way I have with my fuel injected car that I bough new 18 years ago.  If you really wanted to go to the effort you could purchase an after-market fuel re-map chip / box from a company like power commander and make custom adjustments to the range & conditions where the problem happens and save those particual settings under a custom fuel map "profile" and resolve it that way but I don't think it is worth the effort. 

[Stig / Major Tom]

I cordially welcome you to the world of fuel injection.  There is nothing to check or change.  The condition you describe plages many fuel injected cars.  At a very light load and throttle position especially on the highway where the motor runs the most lean - insufficient fuel and or incorrect timing advance results in this condition.  This commonly happens with carburetor that has either a vacuum leak and or clogged pilot aka slow jet.   If the problem started after your scoot was worked on you inspect the boot and all vacuum lines.  Other than that just ignore it the way I have with my fuel injected car that I bough new 18 years ago.  If you really wanted to go to the effort you could purchase an after-market fuel re-map chip / box from a company like power commander and make custom adjustments to the range & conditions where the problem happens and save those particual settings under a custom fuel map "profile" and resolve it that way but I don't think it is worth the effort. 

Sorry ,can't go with you on this one.
Have had 45yrs of cars with efi....all ran great (most were german with a couple japanese)
All my vw,audi mechanics said the same thing about bosch efi.....very easy to sort the problems. 7000 miles of trouble free on this scoot...it is not a condition to live with, but rather an issue to put right.
Or I'm getting a HONDA if I'm proven wrong on this Kymco.
Last resort will be the dealer.
Stig

[Stig / Major Tom]

I cordially welcome you to the world of fuel injection.  There is nothing to check or change.  The condition you describe plages many fuel injected cars.  At a very light load and throttle position especially on the highway where the motor runs the most lean - insufficient fuel and or incorrect timing advance results in this condition.  This commonly happens with carburetor that has either a vacuum leak and or clogged pilot aka slow jet.   If the problem started after your scoot was worked on you inspect the boot and all vacuum lines.  Other than that just ignore it the way I have with my fuel injected car that I bough new 18 years ago.  If you really wanted to go to the effort you could purchase an after-market fuel re-map chip / box from a company like power commander and make custom adjustments to the range & conditions where the problem happens and save those particual settings under a custom fuel map "profile" and resolve it that way but I don't think it is worth the effort. 

Looking for a fix involving Kymco products.....
Suggestions?
Stig

[mrbios]

Looking for a fix involving Kymco products.....
Suggestions?
Stig

My point is that EFI is the same on a car, scooter, motorcycle, dirt bike.  They all use the same basic technologies.  The problem you are describing and the conditions under which it happens are identical to many fuel injects cars....

[Stig / Major Tom]

Let put this another way.  You are so focused on yourself and wining about a minor problem that you forgot the most basic rule of etiquette. 
Of your 2000+ posts how many are a direct solution to someone else's problem?  If your so smart solve the problem yourself and stop wasting the forums time.

A scooter running with an intermittant stumble in traffic is an issue for that rider.
Nevertheless, as an utter novice I am not smart enough to try remapping my EFI w/an aftermarket appliance, and I doubt that I have ever contributed much more than the occasional laugh to this forum.
Point taken, I will stop wasting the forum's time with my whining and unhelpful posts.
Tom

[zombie]

STIG!!! I never figured you for a pouter!

MrBois, Stig didn't get the point across to you. This is a NEW issue w/ his bike, and a bit more severe than you may think it is.
I have a COMPLETELY different bike/engine/fuel system but I understand his post because I have developed the SAME symptoms.

The only other difference is I am living w/ it till I have time to figure it out. Stig needs his bike on high speed roads, and longer commutes. I just run it in town. What I suspect is the timing chain or tensioner. Pull off the valve cover, and see if there is any slack by turning th crank forward, and back. The cam should follow exactly. There should be no movement of one without the other. If there is pull out the tensioner, and see if it is all the way extended. Then you can put a thin bladed screw driver into the tensioner hole, and push down on the chain guide. Repeat the above test...

Try to install the tensioner without collapsing it. If it installs all the way the chain has stretched. If it does not install test the tensioner for free movement or replace it.

Don't pout or you get the strap!

[vespbretta]

Obviously a lot of weird issues also occur due to bad ground contacts (-) as well. These are the green wires at Kymco Models.
Framemetal to Enginemetal (0 - 0,5 Ohms)
Framemetal to Battery Minus Pole (0 - 0,5 Ohms)
Enginemetal to Batterie Minus Pole (0 - 0,5 Ohms)


In case of higher resistance than above:

Clean and remount those contacts with adequate contact grease (Copperpaste/Battery Grease).
Ev. add another/more  green Groundwires if resistance is still to high.
Clean and grease all wiring harness plugs and contacts with saltresistant grease/acidfree roller bearing grease - but no MoS2-Grease (-> boatshop?). Especially when riding often in humid rainy conditions or in winter.
Use only spare spark plug caps with 5 Kilo Ohms +/- 0,5 Kilo Ohms (-> 4500 Ohms - 5500 Ohms) and interference suppressed. This is important for your CDI/ECU funcionality.