Flat spot/hesitancy/surging at 4500/5500 rpm

[mnpugdog]

Ok I found 3 ways to fix this issue, I have it too.

1. make sure the outdoor temp is around 75F and dewpoint is mid 50's or lower.
2. Go WOT then you past it really quick.
3. Go BOT (barely open throttle)then you don't notice it cause you're going to slow to notice it.

Hope this helps.

[Stig / Major Tom]

De dee...
How much shop time would it take to have dealer replace the steering head bearings?
Seems like a serious issue...and perhaps some DT owners would not be comfortable attempting this repair.
I guess one could call the dealer for a price....
Stig

[de dee]

De dee...
How much shop time would it take to have dealer replace the steering head bearings?
Seems like a serious issue...and perhaps some DT owners would not be comfortable attempting this repair.

  just a guess,   2 hours to open it up and 2 hours to finish  I am 83 years old that is the time I took,  A good Mech.,, might take 3 hours ,. 

[DiscoPotato]

steering bearings ,.  very easy to do just takes time, buy your bearing first,  I listed them a few weeks ago ,. with the size,.  or if you want just rotate the outer races and grease them well, and re install,.  they wear in one spot,.

I will be ordering new upper and lower steering head bearings soon. I found brand new genuine Kymco head bearings for the DT300i on ebay for $55 USD each. Are these OK to use if I use a synthetic grease on them? ( I'm assuming the problem with the OEM bearing is the grease that they use and not the bearings themselves, or am I wrong?)

[de dee]

YA. USE FULL SYN. GREASE,.   and press the grease in to the bearings, and cover the races with grease,
  the factory puts just a little grease in there,. 

[ioioio]

Hallo, I have the same issue with the injection and as stated moving the MAP sensor changes it a bit but never really fixes it. Anything else we can try?
About the TPS sensor, in the manual it says it should be 3,5k to 6,5k, but is that an average resistance of the potentiometer (and why should it vary?) or is it the resistance between throttle open/close? I measured the TPS and to me it gives 4,5k overall and it spans from 1,5k to 4,5k.
tx
Simone

[DiscoPotato]

Hallo, I have the same issue with the injection and as stated moving the MAP sensor changes it a bit but never really fixes it. Anything else we can try?
About the TPS sensor, in the manual it says it should be 3,5k to 6,5k, but is that an average resistance of the potentiometer (and why should it vary?) or is it the resistance between throttle open/close? I measured the TPS and to me it gives 4,5k overall and it spans from 1,5k to 4,5k.
tx
Simone

Hey Simone, I still have not found a solution to the flat spot/hesitation issue. I just learned to live with it lol. I think I read somewhere that someone installed an iridium spark plug which lessened the hesitation between 4500-5000 rpm...not sure if it will work or not for me but it's worth a try when the time comes to change my spark plug. As far as the resistance for the TPS goes I'm not entirely sure, I don't have the manual in front of me, but if it lists 3.5k ohms - 6.5k ohms of resistance I would assume the resistances would signify the range from closed throttle to wide open throttle. If you're getting 1.5k ohms - 4.5k ohms you still have a range of 3000 ohms from closed throttle to open throttle which is the same range you have given me from the manual so I assume it is fine?