2013 KYMCO Downtown 300i hesitation while throttling issue

[scootermaven]

I have recently gotten a 2013 KYMCO Downtown 300i w/about 6,000 miles on it that has some concerning hesitation most noticeable between approximately 25-45 mph.
I can power through the hesitation and it seems to run fine.  Have any of you other Downtown 300i owners ever experienced this particular issue?  If so,
any recommendations on what to check and/or what might be a solution to restore consistent, smooth acceleration?  Thanks in advance for any help.

[john grinsel]

Check valve adjustment.

[scootermaven]

Check valve adjustment.

Thanks, John!  Doing that tomorrow actually... setting intake and exhaust valve clearance to 0.10mm (approx. 4 thousandths).

[scootermaven]

Check valve adjustment.

Checked and adjusted the valves back to spec, John.  Unfortunately, that apparently wasn't causing the running issue, which is hesitation during acceleration.  I am going to investigate the map sensor next, which according to a post I read on here, could be an issue.  If you have any other suggestions, please advise.  Thanks, John!

[john grinsel]

Take is to Dealer.

[CROSSBOLT]

Most dealers have no idea how to trouble shoot these things. There are good exceptions to that. Maybe you have one. Is the plug wire on the plug correctly? Do you see any flashing of the CELP symbol on the panel after the selftest is finished? The TPS sensor is more likely to cause this problem than MAP sensor. It could be caused by a loose connector or a corroded or dirty one. More on that after the questions above answered.

[john grinsel]

Since bike is 2013 with only 6,000 miles---which means it spent a lot of time sitting---I would check gas tank,(clean it)  fuel lines and clean  injector---before getting into computer junk, even gas tank vent/cap needs checking.

[scootermaven]

Most dealers have no idea how to trouble shoot these things. There are good exceptions to that. Maybe you have one. Is the plug wire on the plug correctly? Do you see any flashing of the CELP symbol on the panel after the selftest is finished? The TPS sensor is more likely to cause this problem than MAP sensor. It could be caused by a loose connector or a corroded or dirty one. More on that after the questions above answered.

Plug wire is on securely.  No flashing on the instrument panel.  I have moved the MAP sensor around from the factory position of 1 o'clock.  It seemed to run best after consistent/consecutive road tests at the 12 o'clock position.  However, not long afterwards, it became hard to start and didn't run so good.  By the way, I did reset the TPS/ISC using the throttle grip and ignition switch method according to the service manual.

Thanks so much for your help!

[scootermaven]

Since bike is 2013 with only 6,000 miles---which means it spent a lot of time sitting---I would check gas tank,(clean it)  fuel lines and clean  injector---before getting into computer junk, even gas tank vent/cap needs checking.

Thanks, John!  All good ideas.  How do you recommend checking the vented gas cap?

[john grinsel]

If cap is vented, hole should be clear.

[scootermaven]

If cap is vented, hole should be clear.

Thanks, John.  The only HOLES (3) I see are along the top edge of the cap, just below the black plastic ring on the top of the cap (see attached).  How do I check those holes or vents...to see if they are clear?

[CROSSBOLT]

The standard cap is not vented. That vent is SUPPOSED to be vented by a vacuum valve scheme but that cheapo valve sticks sooner or later on ALL brands and models. I have a post way back how I vented mine but the pictures are gone. I am willing to take mine apart and post new pictures if you want, if that is your problem.

[scootermaven]

The standard cap is not vented. That vent is SUPPOSED to be vented by a vacuum valve scheme but that cheapo valve sticks sooner or later on ALL brands and models. I have a post way back how I vented mine but the pictures are gone. I am willing to take mine apart and post new pictures if you want, if that is your problem.

I can't specifically say that is the problem, Crossbolt.  It was just suggested I check the gas cap by John Grinsel.  I wish I knew what the problem is, but at this point, I'm still troubleshooting.  Do you have the same gas cap I have, except that you vented yours?  Thanks!

[CROSSBOLT]

Same machine, same year. I just wanted to make sure you understood the cap is NOT vented. Your symptoms could be related to a stuck vent valve but may be something entirely different. That's why it would be good to take your second key and stick it in the cap. When it malfunctions just reach down and pop the cap loose. The symptom will stop if is a venting problem.

[scootermaven]

Same machine, same year. I just wanted to make sure you understood the cap is NOT vented. Your symptoms could be related to a stuck vent valve but may be something entirely different. That's why it would be good to take your second key and stick it in the cap. When it malfunctions just reach down and pop the cap loose. The symptom will stop if is a venting problem.

Thanks so much, Karl.  Do you know where the vent valve is, just in case?  I'll try the popping the cap loose when it does it again.