Downtown 200i cutting out at idle - but only after cold start.

[richardhoward]

Hello!

I have a DowntownT 200i and have a problem that occurs only in the morning. I live in Singapore so the morning's are not cold, maybe 23-25 degrees.

I start bike for first time.  Starts perfectly and sets into normal idle, no issues.  I ride it out on my condo basement car park and towards the condo gantry, max maybe 70-100m. So just accelerating briefly up to maybe 5000rpm. All good.  When approaching the gantry I slow and coast getting ready to stop at which point the engine would normally go back to it's 1500rpm idle whilst I am coasting.  However it doesn't, it goes down to 1000rpm and struggles for a few seconds, often cutting out as the idle cannot sustain at that level.  Restarting the bike is the difficult cranking for 3-5 seconds to get it going, sometimes blipping the throttle to help it.  I ride on but the problem never happens again.

(so I assume the engine warmed up ever so slightly resolving it??).

My bike is 2015 DT200i.  Only 19400km on  clock.  Well serviced.  I just replaced air filter, oil filter, oil, spark plug, transmission oil, and that has not solved anything.  I tried the TPS reset procedure many times, doesn't work.  I wonder if it is a sensor given that it only happens when 'cold' (this is singapore cold) and after a very brief period it never happens again (so warmed up).  Even after work the issue doesn't occur, the ambient temperature is closer to 30+. 

I've read about possible sensor issues, and I've also been advised to check throttle body (clean) and tappets.  I don't; think it is tappets as the engine runs fine.  Throttle body I can try asking workshop to clean, but then why does this issue happen only in the morning when the bike is at it's coldest all day?

Can anyone help me with the topic of sensors and how they might effect the bike? 

Thanks

[CROSSBOLT]

I harp on stuff once it seems to work: next time it happens try opening the gas cap. Really neat way to do this on a DT is to use your second key! If this test fixes the problem then either replace the vacuum vent valve or vent the gas cap. Gas cap easiest.

[PaulF]

My Kymco LIKE 125 had the same problem and I thought it may have been the autochoke but one day I just raised the idle a fraction and that solved the problem, never cut out again. 

[richardhoward]

I harp on stuff once it seems to work: next time it happens try opening the gas cap. Really neat way to do this on a DT is to use your second key! If this test fixes the problem then either replace the vacuum vent valve or vent the gas cap. Gas cap easiest.

Thanks.  But can you comment why this issue does not happen again after the engine stitter and cuts out?  For instance.  This morning same issue happened.  I drove a litte after starting engine and the revs struggled and cut out.  Struggled to restart but it started.  Everything was fine again after that.  No issue. 

If gas cap is the problem why does it not happen all the time? 

I will try, but it won’t be easy as the engine stops pretty quickly...

[richardhoward]

My Kymco LIKE 125 had the same problem and I thought it may have been the autochoke but one day I just raised the idle a fraction and that solved the problem, never cut out again.

Thanks.  The weird thing is the idle speed when starting is fine.  And after the first time engine struggles the idle speed is again fine. 1500rpm.  I also get the inpression the engine idle is better/soujds better after the engine has warmed up a little after driving, which really doesn’t take long at all.

The annoying thing is this is only happening in the morning (so far)... so i am getting frustrated to having only one chance in the morning to figure out what is going on.

Surely others must have had this issue? 

Thanks so much for the comments and suggestions.  Really appreciate

[CROSSBOLT]

The theory, Rich, is the stuck vent valve gets unstuck! I have had two DT300I scoots and both would get a surging idle as first indication of any trouble. Initializing seemed to temporarily fix the symptom but it would recur unpredictably. Venting the gas cap removed the problem PERMANENTLY! Now it serves to try the cap trick as the first, easiest thing to either find the cause or rule out one possible cause.  This paticular cause would NEVER show on the Kymco analyzer! By the way, my wife's Buddy 150 had the same problem, fixed the same way and the folks on the Buddy Forum called it the "Stall of Shame!"

[richardhoward]

The theory, Rich, is the stuck vent valve gets unstuck! I have had two DT300I scoots and both would get a surging idle as first indication of any trouble. Initializing seemed to temporarily fix the symptom but it would recur unpredictably. Venting the gas cap removed the problem PERMANENTLY! Now it serves to try the cap trick as the first, easiest thing to either find the cause or rule out one possible cause.  This paticular cause would NEVER show on the Kymco analyzer! By the way, my wife's Buddy 150 had the same problem, fixed the same way and the folks on the Buddy Forum called it the "Stall of Shame!"

Thanks for the continued help. Unfortunately didn’t work.  The stall issue i am baving happened ahain this morning and now seems every morning.  I ride a little (20m) stop, fine, ride a little (20m) stop idel starts robstruggle, ride a little more (20m), stop, engine cuts out.  When this was happening and before the engine cut out i opened the fuel cap.  Engine still cut out.

I do not experience a surge in revs.  The initiatlisation of tps never solved the issue.  Clearly i want to find the cause.  It is almost like the engine is starved of fuel for a while.  The weird thing is that when the engine warms slightly everything is perfect..... so if the fuel cap is the issue how come this is the case? 

Scratching my head.  I plan to go to wrokshop but on monday bu these guys are mot kmyco compnay, even so they sell their bikes. So not sure.

Any more ideas guys?  Thanks again

[CROSSBOLT]

You may have to pull the fuel pump/fuel quantity to inspect the inlet filter.