Stretched Belt??

[edoggdoremus]

Could a stretched belt lead to a weaker takeoff? While getting the variator nut off, my strap wrench system was tugging on the belt a bit, and ever since I have noticed a weak takeoff compared to before. I don't know how hard it is to stretch a belt accidentally (or if it's even possible), but just wondering if this could happen and be the culprit of my sudden loss of takeoff. The belt's width checked out fine.

[Clivester]

I would think the belt would just sit lower in the clutch pulley rather than stretch, unless it was being excessively tugged to the point you would know its not good.

Why did you break into the variator? Did you change the weights? That could have something to do with it too. May be possible that a weight is sticking due to incorrect assembly.

[Wheelman-111]

Greetings:

The only to "stretch" a belt more than .01mm is to break it. What Clive said. If the Variator isn't held tight all the way to the shoulder of the crank, one of the rollers can flop across and jam the vario in a partly-engaged position. This would explain sluggish, "second-gear" takeoff. It's not as easy as it looks to reinstall the variator unless you're like Wheelman and have an extra thumb on your right hand.

[edoggdoremus]

I installed a new Keli Variator, double checked many times and am pretty certain it is installed well.

Before installing the new variator, on takeoff from a dead stop the scooter would hesitate for a second, then kind of all of a sudden grab and takeoff quick (enough to do a very quick little peel out on gravel or wet pavement). Since the new variator was installed however, that problem is gone but i am stuck with the second gear lug up until about 3-4 mph then nice accleration after. From what I have read slow takeoff isn't common with a new "high speed variator", so I will probably just start at replacing the belt and while i am in there take another look at the variator. In the end i may just clean up the old variator and reinstall that with the greaseless rollers that came with the Keli Variator and see where that gets me.

[Wheelman-111]

Greetings:

Thanks for the clarification. I can think of two belt-related reasons for your symptoms:

1. It could be a case of the variator trying to act like a clutch. If the pulley boss was replaced or the new Vario's dimensions are thinner than stock, the belt isn't quite tight between the front pulley sheaves. The clutch engages like before, but the belt begins to slip 'twixt the front pulleys when it encounters resistance. When RPM reaches the point where the variator begins to "shift", the belt grabs and firm thrust is re-established.

This situation occurs if the pulley spacing is the slightest bit wide, and worsens when the belt wears down below the 15.5 stock spec. The solution is an in-spec belt, or carefully to address the pulley boss length, taking away 0.5mm or so until you're sure the belt is firmly grasped between the front pulleys.

2. Is sort of the reverse of the first situation. Here the clutch engagement point is high, or at least higher than the shift point in the variator. The engine spools up some RPM, and before the clutch can engage, the Variator has already "shifted" into "2nd gear". When the clutch does engage, the belt ratio is no longer the 2.4:1 prescribed by Honda-san, but something less than that.

Decreasing the grab spring strength (or lessening the preload on the coils for an adjustable clutch) will ensure the clutch engages before the Vario shift point. Another solution would be to lighten the roller weights, delaying the Vario shift point to higher on the RPM scale. This might not be optimal for performance at the top-end, however. Another solution is to install a ramp plate with steeper angles, which also has the net effect of delaying Variator shift until the clutch completely engages.

Cosider the possibility of an engine power "flat-spot" that was there all along, but only becoming apparent as the clutch/variator engagement matches the off-idle RPM where it occurs. If you swapped filters, jets or pipe lately this is more likely.

[edoggdoremus]

thanks for your help, i'll check everything out when i open 'er back up.