Agility City 125 Stops accelerating under full throttle above 50 -SOLVED AT LAST

[arc1979]

Please help, I am new to these bikes, I bought an Agility 125 City and it's ok except that if I ride on full throttle and above 50mph after about a minute of riding fine... it cuts acceleration, taking the throttle off and back on puts it back on but then it cuts again, and again, and again until going about 30mph! It's driving me crackers! It has only done 1500km from new, anyone any idea please? I've spent hours looking for an answer to this online, to no avail.

[eamartin]

Open/remove the gas cap, go for a ride and report back.

[Mr. Paul]

Open/remove the gas cap, go for a ride and report back.

Thats what I was thinking also.

[arc1979]

As simple as that? OK, will do, thank you!!! I read about the venting/vacuum issue but assumed not on mind as I have a tiny hole in the cap.

Off out on it today so will try that when the tank isn't so full!

Thanks for replies!!!

[arc1979]

Sadly this didn't work. It seems worse on long hills and seems to only happen under full throttle. It's so frustrating. The power comes back on a bit if I release the throttle and put it back on again but then goes off quicker and quicker until the bike is going slowly. Leave it without throttle for a little while and it will pick up for a bit further. Grrrr.

Anyone?

[Mr. Paul]

 Chances are at 1500 km your air filter should still be good but it would not hurt to check it. The next thing I would do is to pull and clean the carburetor, particularly the jets. Its a process of elimination and those two things are a good place to start, and they cost practically nothing. Oh, and check the spark plug. Be very, very, careful putting it back in. The aluminum on that head is thin and soft and the threads are very easy to strip.

[knowitall77]

Chances are at 1500 km your air filter should still be good but it would not hurt to check it. The next thing I would do is to pull and clean the carburetor, particularly the jets. Its a process of elimination and those two things are a good place to start, and they cost practically nothing. Oh, and check the spark plug. Be very, very, careful putting it back in. The aluminum on that head is thin and soft and the threads are very easy to strip.

Agree. If all else fails the main jet might need cleaning

Sent from my XT1575 using Tapatalk

[jeeves]

It seems odd that you would have a clogged  jet after only 1500km. Was the scoot left with old gas inside for a long time? Tried putting in some kinda of carb cleaner?
All vacuum tubes ok, no cracks? Fuel and air filter ok? Nothing lose?


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[Mr. Paul]

Low miles is one of the things that point to a possible clogged jet. Scooter probably sat more than it was ridden at some point and the carb got a little gunked up. In any event, it never hurts to clean the carb, as it is practically free.

[arc1979]

Thank you again guys.

I'm currently running it on a strong concentration of Redex fuel system cleaner. It seems to be ok with it in the tank, weirdly. I haven't done the standard test of up the steep dual carriageway yet though... kind of living in hope and ignorance

I'll let this run through and keep speed down for a while... then do high speed full throttle; if that fails i'll check air filter, replace plug (thank you for heads up on ally head) and clean jet. Yes it has been stood, 3 years and only 1400km. I'm surprised that petrol would gunk up in that time but my other bike is an XR400 which had been stood for a few years and I had to strip the petrol tap and filter from it because it had gone jelly like, so not that surprised. Oh and I'm running this on the 97 ron super unleaded with supposed cleaning additives too.

Many Thanks!!
Hopefully if it all works out someone else will benefit from this too.

[Mr. Paul]

Best of luck Ark. I would be surprised if the fuel additive does the trick. The problem is the holes in the jets are so tiny, they clog easily. I'm talking the width of a guitar g or b string.

[mckayprod]

Check the vacuum diaphragm for cracks or other leaks.  It's a quick thing to check and cheap to replace.

[arc1979]

Thank you to everyone for suggestions. I thought I would post the result in case anyone else ever has similar troubles.


After months of troubleshooting... the solution for me was to bypass the "fuel tap"... the vacum powered fuel switch thing under the fuel tank. It appears that this was somehow restricting the fuel supply under heavy load.

Does anyone know any way to get a bit more poower out of these bikes? Any EGR type things that can be removed? Is there a cat in the exhaust? I do have a weird screw in the midle of the exhaust heatshield that when removed makes it blow but it has no affect on speed or power, any idea what this is for? I'm happy for it to be running properley, it was getting tedious. But I know you guys are experts so any ideas welcome!

[CROSSBOLT]

No EGR. Fuel valve is vacuum activated, full throttle reduces vacuum to near atmospheric so valve closes with the spring. Many on here have converted to manual fuel valve. Yes, there is a catalytic converter and aftermarket exhaust is the answer. That mystery screw is the sampling port for exhaust analyzer used in adjusting mixture and inspections.

Karl

[Plamenen]

Thank you to everyone for suggestions. I thought I would post the result in case anyone else ever has similar troubles.


After months of troubleshooting... the solution for me was to bypass the "fuel tap"... the vacum powered fuel switch thing under the fuel tank. It appears that this was somehow restricting the fuel supply under heavy load.

...

I have same problem with my Kymco. It's accelerates up to 80km/h and that's it.
Could you give me a picture how you bypassed this "fuel tap" or any video in net.
Thanks in advance