'97 Runner 50 slow revs on start

[Runner]

Hi folks, so I've got a '97 Gilera Runner I'm trying to get back into decent shape after a long time being left outside and not moving.

Overall it seems ok, however I have an issue with what to me feels like responsiveness in terms of gas/revs. A lot of the time it'll take a couple of seconds on the same (low) revs to get going and then shoot up to full revs. When moving and letting go of the throttle, then applying again, it does almost the same thing; low revs for a little and in a split second boom right up to full revs. Also; this issue is not to do with the fact it had been left for a long time, it had this issue before.

I'm operating under the impression that if a scooter is in healthy condition, as long as you've got the gas open fully you should hear full revs the whole time right?!

I've been tidying the bike up a bit; cleaned the carb, new intake manifold, cleaned air box, calibrated oil pump (was a bit off), cleaned crankcase, new rollers, all new fluids/oils.

Now is it combustion or transmission related??

If you could give me your insight it would be greatly appreciated.
Thanks in advance

[Deleted]

yjrydjru6u 6 57 u  6

[Runner]

Yep everything is completely standard. New rollers standard too.

[humanshield]

I'd open the CVT and have a look in there.

Could be the clutch bearings are rusted, belts gone bad or something.
The CVT plays a major role in the RPM's

I cant see a CVT being happy sitting that long outdoors. (could have aggrevated an existing problem?)

I dont hear "Full" revs all the time.  Mainly at takeoff, then it drops.

[90GTVert]

Make sure the belt meets original spec. If there's much slack in the belt the contra spring could be worn, assuming the belt is correct.

If it's carb related I'd expect that you could get it to take off at say 1/2 throttle or by changing how you roll on the throttle. A CVT issue would make it sluggish at times no matter what throttle application you're using.

[birdman]

[Runner]

Mar 11, 2015 20:57:36 GMT -5 humanshield said:

I'd open the CVT and have a look in there.

Could be the clutch bearings are rusted, belts gone bad or something.
The CVT plays a major role in the RPM's

I cant see a CVT being happy sitting that long outdoors. (could have aggrevated an existing problem?)

I dont hear "Full" revs all the time.  Mainly at takeoff, then it drops.

Yeah I'll have to remove and check out the rear clutch and the springs. I was thinking to replace it anyway for the sake of maintenance/improvement. Maybe the pads on the clutch are destroyed...

[Runner]

Mar 11, 2015 22:43:56 GMT -5 90GTVert said:

Make sure the belt meets original spec. If there's much slack in the belt the contra spring could be worn, assuming the belt is correct.

If it's carb related I'd expect that you could get it to take off at say 1/2 throttle or by changing how you roll on the throttle. A CVT issue would make it sluggish at times no matter what throttle application you're using.

Noted.

I know that the belt is original spec for sure and there's no slack whatsoever. Its in pretty good condition too, so it couldn't be slipping or anything like that right?

[Runner]

Oh and thank you all for welcoming me!!!

[90GTVert]

A good belt can slip if there are other problems. Belt slip usually results in higher than normal RPM and may be accompanied by black marks on pulley faces and signs of overheating like belt glazing, discolored parts, melted plastic bits.

[Runner]

Figured it out. Transmission not the issue. Faulty airbox taking in air through cracks and needed to adjust air mix screw on carb. Thanks for the input anyway guys