Why won't my Honda Silver wing scooter "shift" when cold?

by Cyndi
(Durham, NC)

I have a 2003 fuel-injected Honda SilverWing scooter with over 41,000 miles on it. I replaced the stock variator with a J Costa about 2 years ago and the stock clutch was replaced with a Malossi.

It also has a K&N air filter on it, fairly new belt, new iridium spark plugs and recent engine and final drive oil changes.

The bike has no problems starting, warm or cold, but when I try to drive it after it has been sitting for several hours, the transmission will not "shift" (these engines have a three-stage transmission that autoshifts).

The engine will over rev to nearly redline if I try to drive normally and it will only go 35mph. The bike will buck and scream when it does this. The engine can be at operating temp at this point with no effect.

After a few miles it seems to "loosen up" and will start to shift normally until it reaches normal RPMs. It will continue to run fine after that.

I can stop the bike for lunch or a gas stop and it will still run fine afterward. Only if I let it sit for several hours or overnight it will act up. The colder the weather, the worse the problem, and the longer I let it go before taking it to the shop, the worse it gets until it won't shift at all.

I have had 2 different shops dismantle the transmission, inspect, clean and lube everything, replace variator pins, belts, spark plugs, fluids...and the bike runs fine for a couple of months.

But soon it starts doing it again. No one seems to know what is causing the problem. Any ideas?