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Discussion Starter #1
So I have had this issue once when the bike was stock, and it went away on its own.

4 months later, it's not stock now for a few months and it's back again.

So, it won't idle properly when it's warmed up, keeps dropping off and then picking up again just before it stalls, and when cruising along at low throttle it does the same to the point I stop going towards until I wack the throttle open.
Which in low traffic speeds makes me kangaroo, and isn't safe or fun.

I have reset the ECU and TPS but no difference.
The spark is fine, cleaned the airfilter and checked there is no air leaks.
Exhaust is fine too, did the valves about 1000km ago.
Oil was the same time too.

I have fitted new exhaust, air intake system, Efie device a couple of months ago and it's has been running fine until last week.

Spark plug is a good light tea colour.

I'm at a loss as to what this is?

Oh and I'm not going back to the dealer, as every time I have it comes back in a worse state, even had it back once and it was covered in oil and leakin,and the bolts for the top fork brace were missing.
 

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Check your charging system to make sure it is charging your battery at 12.6-13.2dcv, make sure your battery cables are snug and secure to the frame and the battery.

Check and remove the A/F adjustment screw, make sure there is no carbon build up or junk on the crew tip.

check and make sure your spark plug is torque down correctly and the spark plug cable is secure.

Drain gas, and add new gas possible contaminated fuel or try a different brand of fuel, here in California I find that Union 76 91 octane gas works the best for my Grom and I also add VPRacing octane mix, but I'm running a 181-4v BBK kit.

Good luck and ride it like you stole it
 

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Discussion Starter #4
My idle has sorted itself out now, it's bogging while cruising at half or less throttle still though.

I will try without the Efie later after school.
Plugs look good though, and no idea why it's just randomly started.
86079
86080
 

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Discussion Starter #6
What's up with the exterior of your spark plug. Are you riding under the ocean?
It's -20'c here and has been since October.
So lots of road salt, the whole monkey is rusty everywhere after only owning it for 5 months from new
I even wash it once a week too
 

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Discussion Starter #7
What's up with the exterior of your spark plug. Are you riding under the ocean?
86087


That's from 5 months of just normal use here.
Gets cleaned regularly too, it's the same for the mudguards, petrol tank, mirror stems, rear brake light housing, exhaust, coil etc
 

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View attachment 86087

That's from 5 months of just normal use here.
Gets cleaned regularly too, it's the same for the mudguards, petrol tank, mirror stems, rear brake light housing, exhaust, coil etc
I use a desalinization product called Salt Away to good effect. Spray the bike down after every exposure and you let it drain/cascade of the bike with no rinsing after. It leaves corrosion inhibitors behind.

 

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Discussion Starter #10
I use a desalinization product called Salt Away to good effect. Spray the bike down after every exposure and you let it drain/cascade of the bike with no rinsing after. It leaves corrosion inhibitors behind.

Yeah I've looked for such things here, bit can't find any.
 

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Discussion Starter #11
Well I used the bike without the efie, and reset the air mix screw.
Seemed better.
Idled fine, and little to no hesitation or bogging cruising at 1/8-1/4 throttle.
Bit very lean at the top end.
Put the efie back on, lower setting of 0.150.

Ran awesome uptop again, but once warm starts bogging at the above throttle use again.
Think I will try the air screw turned out more, see of it leans up that first bit of throttle.
 

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Discussion Starter #12
Well now it's doing even worse!

It's back to stock ECU, and still doing the bogging at low throttle to the point it tries to die unless I wack the throttle open, and now when I got to college it started acceleration on its own, even in neutral it just kept revving higher.

Throttle was closed, could even hear the tap it makes when the throttle valve closes, but made no difference to the revs.

Starting to get a bit pissed the amount of problems this bike has been since new
 

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Have you reset the ECU and the TPS after your recent changes?

EDIT - I see in your first post that you have reset...


Yeah I've looked for such things here, bit can't find any.
There are international distributors in the Netherlands and the UK - maybe try contacting them to see if they can suggest options for Finland?

 

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Try turning the black plastic phillips head idle air screw all the way in and then backing it out 2 turns. This is the initial factory setting and a good place to start. Did you mess with the butterfly opening adjustment? I hope not. I have never touched mine in 7,500 miles since my Grom was brand new.

I highly recommend getting a Yuminashi stand alone self tuning ECU. There's no adjusting, no resetting, no tpi, no programming, no downloading, no mapping.

Simply install it and ride. :)
 

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Discussion Starter #15
Try turning the black plastic phillips head idle air screw all the way in and then backing it out 2 turns. This is the initial factory setting and a good place to start. Did you mess with the butterfly opening adjustment? I hope not. I have never touched mine in 7,500 miles since my Grom was brand new.

I highly recommend getting a Yuminashi stand alone self tuning ECU. There's no adjusting, no resetting, no tpi, no programming, no downloading, no mapping.

Simply install it and ride. :)
Yeah I haven't adjusted the idle screw on the butterfly valve, and I have reset the air mix screw too.

Reason I went with the efie device (and has been working perfectly for 4000km) was I can't afford anything expensive like yuminashi, PCV etc

Only thing I can think of is a sensor is not reading properly or something is blocked the air inside the TB, so I will open the whole thing and clean it tomorrow and then reset everything and see how it goes.

It's odd that it's suddenly running richer for no reason, nothing has been changed in about 1000-1500km
 

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Mine was pretty cheap... just $87 shipped. It's for an OG so you move 4 wires in the plug for an SF. I've been running it for thousands of miles and made lots of changes and never touched it. Starts easy, idles steady, and runs great. :)

 

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I'm not sure Old1 will like it not having the cold start function. Might be fine in California, I'm having a very hard time at 10*c (so much it took it off). -20*c in Finland is something else altogether!
OP I think a reflash retaining the cold start function will serve you better.
 

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I'm not sure Old1 will like it not having the cold start function. Might be fine in California, I'm having a very hard time at 10*c (so much it took it off). -20*c in Finland is something else altogether!
OP I think a reflash retaining the cold start function will serve you better.
My Grom is always parked outside under a carport and it freezes overnight here in Winter because we live up in the hills. Mine starts right up without touching the throttle with just a tap of the button. It always idles slow and rich without stalling. Sometimes there are other mods which are affecting startability.
 

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I wonder if you have an intake vacuum leak? Check manifold bolts and vacuum hoses?

Also this reminds me a little of a head gasket leak. At high throttle the leak doesn't matter but of course has an effect at low speed.
 

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I wonder if you have an intake vacuum leak? Check manifold bolts and vacuum hoses?

Also this reminds me a little of a head gasket leak. At high throttle the leak doesn't matter but of course has an effect at low speed.
I believe you're onto something there.
 
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