Downtown cuts out when warm

[philcol76]

I went out for the first commute of the year last Friday and the DownTown started first time, idled and ran perfectly until it was warm (Showed one extra segment in the temp screen). It then cut out and was a 'mare to restart and keep running. To get it home I had to hold the throttle at 2000ish revs otherwise it would cut out. I dread to think what I have done to the belt!!!

Once home, I started it again on the Saturday morning on the centre stand and it again fired up faultlessly. I left it running and revved it every now and then until it warmed up and again it started to cut out as soon as it warmed up. Left to cool for 1+ hours and it again started with no issue.

Does anyone have any ideas? Battery has been on a tender all winter and is fully charged. Spark plug has been checked and appears ok. Fresh fuel was put in on the Friday. I have checked the ISC after reading other posts here, not sure if its ok as there doesn't appear to be much movement in it! I have tried the TPS reset but it hasn't made any difference.

TIA

PhilCol76

[CROSSBOLT]

Next time it quits like you described, open gas cap and report the sucking noise/instant starting! I am betting your fuel vent valve is sticking.

[philcol76]

Hi Crossbolt, I have tried your suggestion but it never made any difference. Started and ran fine from cold and then cut out when warm. I removed the gas cap but didn't hear any audible noise and getting it restarted took a whilst but would only stay running with me holding the throttle open a bit. Its just typical of this bike, the weather its the best its been in the UK for Feb and cannot enjoy it 

[philcol76]

Is there a fuel filter on these bikes?

[CROSSBOLT]

OK, good! We now know what it is not. Next, try initialize. Also severely consider checking the valve clearances. Do valves, then initialize with minimal riding/running in between. Check coolant level in radiator, not just overflow bottle. Like I said, that system is consistent regardless of temperature. I suspect with your increased temp indication you have one or more exhaust valves not closing when it warms up. Allowing it to run will burn a valve and cost a bunch to fix.

[CROSSBOLT]

Is there a fuel filter on these bikes?

Yes. It is on the intake to the fuel pump which is in the tank.

[philcol76]

Thanks again Crossbolt. I will check the valve clearances on the weekend, weather depending as it gets dark to early after work. Just to be clear, I'm not seeing an excessive rise in temperature only as soon as the second segment appears on the display is when it plays up and won't idle. I've never had a scooter before where the filter is built into the pump, doesn't make checking or cleaning any easier. When you mention initialise are you referring to the TPS\ICS reset? I've tried that a number of times but it doesn't appear to make any differance.

[CROSSBOLT]

OK, that's great! Now we know it is neither vent nor initialize! If it gets cranky with the second bar of the temp gage, which is normal temp, then valves is the highest suspect, particularly exhaust valves. There are only three bars on that temp gage, I am quite sure so it is not overheating. Hurry up! Check those valves! I'm dyin' here to see what it is causing problems! Weekend? I gonna pas out!

[scooterfan]

Check if there is any spark at the spark plug when the engine does’nt start.

The battery might be on a charger all winter, it migh be fully charged,  but that does’nt mean the battery is not faulty. A faulty, fully charged battery does not have “holding” power.
So you actually need to get a proper load test done on the battery.

So if you don’t see a proper spark at the spark plug:
1. Battery might be on it’s way out. (Symtom applicable on all scooters with DC CDI’s).
2. CDI might be on it’s way out. (Symtom appliccable on all scooters with DC CDI’s).
3. Bad spark plug, wire connections, wires, switches, spark plug, ignition coil, or corroded connections.