[Hombre]

Picked up my new to me Wee strom, and rode it for an hour. It starts and runs fine, but after a while it develops a splutter that slowly gets worse while cruising.

At first it feel like a small hiccup, then after a while it feels very jittery and is not firing correctly. If I wind on the throttle it has a hesitation before picking up it's skirt and blasting off. And if I let off the throttle it gives a little buck as if it ran better for just a fraction of a second.

When I pull the clutch in it stalls.

When I let it sit off for a a few minutes, all the syptoms disappear.

I am 90% sure it's a blocked air vent, but the fact it can still deliver good performance when you wind on the throttle has me that 10% unsure.

 

[greywolf]

See if you get a pressure equalization sound when you pop the fuel tank cap open. The vent has a one way flap valve in the cap. Australia doesn't have the tank top vent tube into a charcoal canister AFAIK.

 

[Hombre]

Yeah it does. Where do I go from here? I am confident with tools, and have worked on my old bike, but I've never come across a blocked vent before.

 

[greywolf]

You can take the cap off and take it apart.

 

[enumclaw]

This may help with the gas cap disassembly.

http://www.stromtrooper.com/maintenance-how/63893-gas-caps-vented-non-vented-how-change-tumblers.html

 

[greywolf]

Good job. I was looking for that.

 

[Biggirafe]

I know this is an old thread but I have the same symptoms, was the vent the problem and did cleaning this fix the issue

 

[Rolex]

Ride the bike with the cap open and see if your symptoms persist.

 

[NVDucati]

Ride the bike with the cap open and see if your symptoms persist.

That is good advice. Also, you don't mention if you have a tankbag. I have seen multiple times when a fully loaded tank bag can seal off the air to the gas cap. (sometimes just enough to make it only run badly)

 

[Biggirafe]

That is good advice. Also, you don't mention if you have a tankbag. I have seen multiple times when a fully loaded tank bag can seal off the air to the gas cap. (sometimes just enough to make it only run badly)

No tank bag, good point tbough

 

[Biggirafe]

Ride the bike with the cap open and see if your symptoms persist.

Good idea although it's only a problem after 20miles or so cruising on mway, I actually stopped and opened cap and could hear the air equalise like. An airlock, back to dealer who are stripping and cleaning cap under warranty