Xciting 500 arbitrarily slow, doesn't rev up normally

[sissy mary]

It sounds as if he raised the needle jet by one notch? Or used a washer to lift it? Just have him put it back to stock settings. 

[guile]

I would have to travel quite a bit to have him do that. I think I would have to put it downwards one notch then?

[sissy mary]

He might have played with the air jet and not the needle? Who knows? That's why I said to have him set it back to stock, you don't know what he's done.

[guile]

Have you replaced the diaphram before?  No. It is the diapharam.  I don't care how many miles it is still a 7 year old rubber component.  They wear out.  It is your issue.  Your gas mileage was great, right? On the flat no problem any hill even a small one like rolling a boulder uphill and no power.  It is the diapharam.

Replace it and go back to the original setting on the air fuel.  These machines are finnikey when you screw with the air fuel mixture.  Too lean burn the piston crown, too rich foul the plugs.  Clean or replace the air filter as well.

BigOrange, your assessment was spot on! I installed a new diaphram and I can jump and bounce around in traffic again like never before!
Thanks very much.

Regards from the Netherlands,
Gijs

[BigOrange]

  I am happy to help.  The forum has been a great help to me.  I am lucky and have a great local dealer that is honest.

It is way more fun with a working scoot. Safe travels!

[guile]

Have you replaced the diaphram before?  No. It is the diapharam.  I don't care how many miles it is still a 7 year old rubber component.  They wear out.  It is your issue.  Your gas mileage was great, right? On the flat no problem any hill even a small one like rolling a boulder uphill and no power.  It is the diapharam.

Replace it and go back to the original setting on the air fuel.  These machines are finnikey when you screw with the air fuel mixture.  Too lean burn the piston crown, too rich foul the plugs.  Clean or replace the air filter as well.

Unfortunately, I have to re-open this thread. After having replaced the diaprahm the scoot was very responsive again, but lately I'm experiencing exactly the same problems as described above 
Could the diaphram be worn already?
Please advice.

[guile]

Please guys, I need help.
I'm never sure if it will rev up to the normal maximum (7000 - 8000 rpm). Sometimes I'm stuck at 50-60 mph!

[BettinANDlosing]

Have you had your belt and rollers checked out?

[guile]

No. Belt should be fine, second one installed about 10.000 miles ago.

[BettinANDlosing]

No. Belt should be fine, second one installed about 10.000 miles ago.

I was more thinking about flat spots on the rollers.

[ce]

Check all your vacuum lines and fittings for wear and cracks. It sounds like you're leaking air somewhere. You have an electric fuel pump, so check the connections as well.

[guile]

I opened the carburetor up and checked the diaphragm. Didn't seem anything wrong with it. I polished the  piston. Putting the diaphragm back was a real pita. The diaphragm gets bigger in time (gas?) and won't fit the groove. So I put the diaphragm in the freezer to shrink it a little and it fit after some cursing.
But what's more important is that it runs fine now. I accelerates normally and revs up to 8000 rpm 
I hope this solved the problem permanently

[sissy mary]

Next time put grease down inside the carb groove that the diaphragm seats into. That will hold it in long enough for you to put the carb top/lid back on. You may have gotten a bad diaphragm, or the mechanic may have torn it when installing? The rubber is pretty thin!