Downtown issues

[Yengski]

Hi Guys. I just want to ask if anybody are having issues with their downtown. I purchased mine brand new last June 2010. First 5 months was an awesome ride until one day, the engine stalled on my way to the office. Restarted the engine a few times and it worked. However, ever since that incident, the engine stalls at least 3x a week. One time battery almost run out after a few times of restarting the engine. Brought it to the local dealer twice and they did some tuning but up till now im still having the same problem. Scoot is well taken care of. Changed oil at 500km, 2k and 4k. Changed spark plug 2x. It has now 5K on the odo.

Dont get me wrong, I still love this scoot... Appreciate any help you can provide!

[axy]

This is why I hate too much electronics in simple machines like scoots.

I would propose 10 things to check, but you cannot do any of them on your own because you have injection and not carburetor.

I doubt you will get any help here, you are left to mechanics...

[Whisper]

  Yengski - You can try resetting the TPS (Throttle Position Sensor) for starters.

  I'll have to check, but as I remember the procedure is:

1. Put scoot on centerstand, sidestand up
2. Pin the throttle wide open and hold
3. Turn the key to on
4. Hold the throttle open for 8 seconds
5. Let the throttle go

  My idle was wandering a bit to much for my tastes +/- 200 vs +/- 100rpm.  And this seemed to help.

  Look up the service manual on scribd - The D300 lets you access a ton of information when set to service mode.  Unfortunately, if none of the idiot lights are on, it generally means every thing is nominal.

  I've stalled the D300 once so far.  I tried throttling while holding the back brake (>.< )  D'oh!

  The last thing to watch out for is overfilling the tank!!!  Do not do it!!!  Never fill it to the brim.  Just like the Vespa, it has some crazy emissions charcoal canister - If you overfill the tank, the gas expands during the day and flows into that thing.  From then on it is a ton of headaches.  Stick the pump nozzle all the way in there, and when it clicks, just stop.

  Can you test the battery voltage as well?  Is the battery holding a charge well?  Is the scoot idling when it stalls, or are you moving?  When is it hard to start?  Did whatever the mechanics do help for a period of time?  Are you seeing any warning lights?  The more info, the more the forums can help!

  Lastly, you should still be under warrenty - Get that sorted before it runs out!  Squaky wheel gets the greasing!

  

[Yengski]

Axy: same here. it used to be so simple.

Whisper: I brought the bike to the shop yesterday and told me that they fixed the problem and only did some "minor: adjustments. On the way home from the shop, it happened again. I will try your TPS suggestion this weekend and will let you know what happens.

My normal idling is about 1500 and sometimes comes up to 1900 or down to 1000 for unknown reasons.

I'm guilty about that overfilling of fuel tank but thanks for the hint. Wont do it again.

Battery voltage and charging is normal per the last check up. When the scoot stalls, the engine totally shuts off and rpm goes back to zero. Sometimes i it starts back quickly but sometimes it will take a heck of time (and im hating it specially in a slow traffic). No warning lights whatsoever.

[Whisper]

  I miss the simplicity of mechanical components.  But then I think of all the time I spent, rejetting, cleaning, synchonizing carbs.  Cold natured engines, reading plugs.  Rejetting for elevation.  Bleh.  I'll learn to work with the new stuff. 

  Did you ask what adjustments they made?  According to the service manual, there really are no service adjustments to make on the throttle body.  Hrmmmm.  Did they check the fuel pump pressure?  Though if that were a problem, I'd expect drivability to suffer.  Does it run well when you are driving?

  Does the Engine light ever come on when riding?  If so, we can pull codes from it.

  However, the TPS reset ALSO sets the ISC (idle air bypass valve).  Definitely can't hurt.

  I reread the procedure from the service manual - It had 2 extra bits:
- Make sure the kill switch is set so the engine would run
- After you let the throttle go, turn the key off, then turn it on normally again.
If the procedure fails, you can try it again.

Please let us know if this makes a difference!

BTW - The engine also has an anti-flood mode.  If you are trying to start the engine a couple times and no luck, try this:

1. Turn key to on
2. Open throttle all the way - Hold it there
3. Push starter and hold for 3 more than seconds

Worth a try.  Hope this helps!!!

[TechGuy]

If he filled the cannister, it may take some time for the fuel to clear from the cannister.  I don't know where it's located or where it vents but in the Vespas I read about, it can be several days for to clear up.  Even longer when the weather is cold. Based on my reading of forums like this one, it's commonplace for many Vespa owners to disable the cannister or remove it completely. Are you in the USA?

[Yengski]

 Yengski - You can try resetting the TPS (Throttle Position Sensor) for starters.

  I'll have to check, but as I remember the procedure is:

1. Put scoot on centerstand, sidestand up
2. Pin the throttle wide open and hold
3. Turn the key to on
4. Hold the throttle open for 8 seconds
5. Let the throttle go

  My idle was wandering a bit to much for my tastes +/- 200 vs +/- 100rpm.  And this seemed to help.

  Look up the service manual on scribd - The D300 lets you access a ton of information when set to service mode.  Unfortunately, if none of the idiot lights are on, it generally means every thing is nominal.

  I've stalled the D300 once so far.  I tried throttling while holding the back brake (>.< )  D'oh!

  The last thing to watch out for is overfilling the tank!!!  Do not do it!!!  Never fill it to the brim.  Just like the Vespa, it has some crazy emissions charcoal canister - If you overfill the tank, the gas expands during the day and flows into that thing.  From then on it is a ton of headaches.  Stick the pump nozzle all the way in there, and when it clicks, just stop.

  Can you test the battery voltage as well?  Is the battery holding a charge well?  Is the scoot idling when it stalls, or are you moving?  When is it hard to start?  Did whatever the mechanics do help for a period of time?  Are you seeing any warning lights?  The more info, the more the forums can help!

  Lastly, you should still be under warrenty - Get that sorted before it runs out!  Squaky wheel gets the greasing!

  

Whisper i tried resetting TPS last Friday night and it seems to be working. I'm keeping my fingers crossed. Thanks a lot!

[Hoolander2]

Fingers crossed here for ya too. 

[Whisper]

  Yengski - While poking around on my DT300, I did notice that my battery was reading 12.85 volts the day after a good, 50 minute ride.  Hrm... 

  Going to check the voltage when running this weekend.  See if there is a voltage leak or if the charging system is just weak.  Could be that the battery was simply undercharged from the factory, I guess.

  In the short term, I added a pigtail for a Battery Tender - Fully charged now!!!  Makes a HUGE difference when starting, BTW.  Best 15USD evar.

  I just ordered some white LED bulbs.  I'm going to try to replace the non-functional turn signal bulbs (US only - sad) with them.  Then install a switch to turn off the headlights and use the LEDs as Daytime running lights.  That should help take a load off the electricals.  Or just look cool.  I'm good with either.  HA!

[axy]

  Yengski - While poking around on my DT300, I did notice that my battery was reading 12.85 volts the day after a good, 50 minute ride.  Hrm... 

Quite normal.

[Yengski]

Hi Whisper,

So far, the recommendation you gave me is still going strong and no issues for now. When I first bought the scoot I was thinking of changing to a good quality battery but hesitated.  I hope I had spare to time to do all these things that you are doing but sadly I have to reply to the dealer's mechanics for everything.

Might try out some mods later on.

Yeng

[Whisper]

  Axy - I am a big ol' n00b when it comes to electricals.  Maybe you can help me out - What is a good voltage range for a scooter battery at rest?  I wish I had a load tester...  I wish I knew how to read the load tester I don't have.  HA!

  Yeng - No problems!  I'm a bit of a grease-monkey, and getting to work on a scaled down Fuel Injection system is fascinating to me.  Much less intimidating than a car for some reason.  I am dissapointed that your dealer couldn't help you more.  They are supposed to have all the manuals and crazy tools/computers. 

 

[axy]

  Axy - I am a big ol' n00b when it comes to electricals.  Maybe you can help me out - What is a good voltage range for a scooter battery at rest?  I wish I had a load tester...  I wish I knew how to read the load tester I don't have.  HA!

Hi, take a look at http://www.totalmotorcycle.com/maintenance/battery.htm .

[streetdown]

Can you explain the anti-flood mode again? I just dont get it. I do have a problem starting at times.

[Whisper]

I've actually used that and it works.  I think.

When I drive to work, it is COLD - Like 55F.  Then at the end of the day it is warm 80F.  I think the gas left over in the lines expands and dumps the excess in the cylinder, sometimes requiring some cranking to get it to start.  This NEVER happens at home, when it is in the garage.  Or if it is sitting for an hour or 3.  It comes to life immediately.

The technique is this:

1. Turn the key to on
2. Twist the throttle to WIDE OPEN
3. Hit the starter and hold it for a good 3 seconds

That is supposed to close the injectors and cycle the excess out.  Last time I tried it, it started immediately on the next try.  I also popped the gas cap in case there was excess pressure.  I'll try to isolate the winning procedure over the next few weeks.