Scooter runs fine then loses power??

[strikethebox]

Hey guys,
I'm new to this forum and scooting in general. I bought a cheap Chinese scooter and have been putting lots of new parts into it but this latest issue has got me stumped. In the early morning on my way to work I usually don't have any issues. But on my way home it starts to go south. After riding for a while (15mins) it will begin to suddenly lose power and come to a stop without any response from the throttle. It will begin to back fire before it shuts off completely. Then it takes a while to start again. Once it starts, It'll ride fine for a few minutes and then start the process all over again! So far I've replaced the plug, ignition coil (twice), clutch, belt, tires, fuel filter and a few other odds and ends. It does have a small oil leak around the valve cover which is very difficult to get to because of the plastic housing around it. Haven't gotten to that one yet though. Any thoughts you guys can offer are much appreciated!

Thanks
Rich

[snugglebunny]

i am TERRIBLE at diagnosing probs,
once im told what it is , i can fix about anything,
but diagnosing, i suck

it sorta sounds like you are running either to lean or to rich
prob to lean. maybe to lean
see i suck at this
but my guess is one of the 2

[richardthescooter1]

strikethebox, First tell us a little about your scoot, make model, year, how many mile on it. Let me ask you this, Do you live somewhere that the whether is getting cold? If yes, (back firing is a sign your running too lean, these scoot need to be richer in these temps) when your scoot begins to act up, is it sputtering before it shuts off?

[strikethebox]

Richard,
I guess I should have told you the details. Its an '08 Tank touring 150dhe with 5500 miles on it. I live in south west Fla. so I don't think it's too cold. Not to mention it's been doing this off and on for some time. Each time it does it I replace something and it seems to get better then after a week or so, the problem comes back.

When I'm riding it (50-55mph), it will begin to lose power drastically. As it starts to slow down I notice I have no throttle response. When I get on the throttle it will back fire a few times and then shut off. I then pull over, wait a sec, and fire it back up. It takes a few seconds to fire back up as though it's being choked out then it's fine for a few minutes. Then, after I get up to speed again, it starts all over again.

Hope this helps in your diagnosis! :-)

Thanks, again!
Rich

[scootnwinn]

I know mine will do something similar if I hold it wide open for long. Though it never shuts off. What's the throttle position when it does this? I read something about the vacuum fuel pump being unable to keep up at higher rpms and with a WOT... It's on my list of things to look at if someone decides to use the thing regularly

[richardthescooter1]

I think you have a vacuum leak somewhere or you need to adjust your carb, check all the vacuum lines and intake clamps, make sure they are tight

[50cc]

Mine did the same just before my first engine seized (R.I.P. 2006-2012). Any weird noises from the crank area? Are you sure you're not running it too lean? Did you try to adjust your carb float?

[prodigit]

Temperature could do something to performance;
In the mornings sounds like it's cold, and in the afternoon warm.
Only explanation I can give why your scoot won't work in the afternoon vs morning.

[bhinch]

Another thing to check is your valves....need to be adjusted...probably....which engine do you have....some more info would help....enjoy the ride...

[richardthescooter1]

That's what I was thinking bhinch, he said there is 5,500 miles on that scoot.

[jazzman]

Check your Flange that is the part that bolts up to the motor(exhaust port). You could have lost a stud or nut and blew the gasket out. That will cause some nasty backfires and you want to find the problem quick because backfires will damage your exhaust valve.

But yes it is running really lean and is locking up on you. So with 5500 miles on it FIRST adjust your valves .004 each or .004 intake and .005 exhaust. Then check for leaks, cracked intake manifold, cracks in the air tubeing, loose carb clamps, leaking manifold where it attachs to the motor, the Flange where you pipe attaches to the motor etc..