Swing seems to be a bit rougher during acceleration

While the bike is still up for sale, I've been riding it regularly, most of the time to and from work. I've noticed within the last few weeks that it seems a bit rougher when rolling on the throttle going from maybe 10 up to 40 or 50 MPH. Bike has about 8700 miles on it and is a 2009. Nothing has been changed on the variator and the belt is original. I'm wondering if maybe the belt is flopping around a bit more or one of the motor mounts could be a bit loose? Anybody else ever run into this?

I wonder if you could be a bit more descriptive of the word rougher. Does it feel like engine trouble or is it the drive train? Are you getting belt squeal? My SW creates a fair bit of vibration below 4000rpm and feels like it's lagging but above that it is much smoother and quicker. This could be perceived as engine timing or carburettor trouble but I'm convinced it's natural wear and tear on the pulleys and final drive etc. Does hard acceleration improve things?

I've noticed a 'roughness' a couple of times but changing the plugs and air filter has always improved things. Just some thoughts.....

As an after thought, I replaced my clutch drum bell a little while ago (it was badly scored from worn clutch shoes) and since then I've had no belt squeal at all and very little belt slap.

I had a similar thing with a previous SW I had. I cleaned off the pulley faces and it seemed to get better. The one I have now does that a bit at 12,000 miles. I notice that it seems to lessen when after I take a ride on the freeway for a few miles.

One thing that seems to help reduce the effect is to accelerate briskly a bit faster than you're going to be traveling and then slow down a bit to the speed you want. The CVT ratio isn't exactly the same each time one is traveling at a given speed.

There's a bit of hysteresis effect involved. If you come up to speed slowly and go at a chosen speed the CVT pulley ratio will be slightly different than if you go above the chosen speed and arrive at the chosen speed by slowing a bit. That means you might be running at an RPM that develops some harmonics evinced as vibrations that might not be present at a slightly different pulley ration. I've noticed it in all three SWs I've had. One had pretty high mileage on the belt and one had brand new belt that I installed on it. Pretty much the same thing. I suspect it might be endemic to the CVT system on the SW. I didn't notice it on my BMW C650GT but it's CVT works a bit differently.

On my SW ther's a definite 'sweet spot' around 60mph. It runs very smoothly at that speed. Most of the motorcycles I've owned seem to have a 'sweet spot' speed. It's something to do with harmonic vibration between the engine, bike frame, suspension and other vibration inputs. It's pretty obvious if one looks for it at different speeds. There will be a speed that the bike just seems to be running with no vibrations at all.

My first SilverWing was ruff on the take from the first days---FIX=run the engine up against the brake for 5-10 seconds, now and then. Kept thing smooth for me. Second SilverWing never had this problem. Both were ridden about 50,000 miles, Belts changed at 15,000 mile intervals with OEM belts---I never bothered to take clutch apart or worried about grooves worn in pulley, just rode.

Thanks for the replies. Only way I can describe it is that it just doesnt feel as smooth as it did a month or two ago. My first instinct is something with the belt wasnt the same, maybe some more vibration, sorta sounds a bit like a growl. Since I got the BMW. I dont do that much highway travel with the Swing, mostly side roads, stop and go.

I might try Johns suggestion and or a run on the highway for a few miles and see if that changes things.

I recently purchased my '08 with 12,000 miles on it. At first it had a belt squawk when opening the throttle after slowing down. It also had some vibration coming from the drive system. I just rode it and rode it pretty hard for a week and all became nice and quiet. Not more belt vibes and squawks now.

I suspect the lady who owned the bike before I bought it rode it pretty timidly. Mostly low speed, very gentle on the throttle. Once in a while it's good to ride the bike like you mean it. Tends to keep the pulleys clean and the bike running smoothly.

A good fast run on the freeway is helpful to keep the engine in shape and clean, a lot of short, slow runs without bringing everything up to full temperature isn't good for any vehicle.

It was always a glazed clutch drum/shoes on my old Burgman 200 that made take-off rough. When my Buddy 125 did the rough take-off I lost a end bearing on the crank! On my Helix it was the rear drive shaft seal leaking inside the transmission, that obviously made everything slip. If you pull the trans cover and take a look and suspect the belt, I have a new factory Honda belt in the black hole, aka the garage, your welcome to try it if you want.

Way back in the '50s I managed to glaze the centrifugal clutch on my Cushman scooter. It was relatively easy to take it apart and sand the friction surface to get rid of the 'glassy' surface. At the time my dad told me it was like riding the brakes on a car (drum brakes back then) they'd get a glazed surface. He said I needed to hit the throttle hard enough to lock up the clutch quickly and not ride the clutch. He was right, I never had a problem with that scooter clutch after that.

I haven't had any problems or excessive wear on any of the Silverwings or snowmobiles, which used to have a similar drive system, by opening the throttle quickly to engage the centrifugal clutch instead of controlling acceleration by easing into motion. Give it a good goose to get going then back off the throttle as you approach the desired speed. It's not the locking up that wears a centrifugal clutch it's the slipping of on that has a load on it but not enough centrifugal (centripetal) force to solidly lock it up.

Took the bike for a decent ride today, about 80 miles. I was pretty hard on the throttle and got it up past 70 for some miles. Seems a bit smoother now, so I think it has something to do with how the belt rides on the sides of the pulleys. I'll probably take it to work tomorrow, will see how it does on that fairly short run.

there is a bike directive Mr. Spock´s ET I heard in the USA.
RIDE IT LIKE YOU STOLE IT!
It served me well for my time with 3 different bikes there.
I never be caught.

It your age does not permit that, try my crazy CTV mod.
You do not need to ride WOT  But you are in a higher RPM band in certain situation
it can be really gentle it is still enough to keep your bike happy.
Just for a quick trial you only have to install the aluminum cover with the 3 big screws and the 4 small  (I do not know if the cyclope eyes has the same setup as as the modern 2 eyes)
I always do my 30 min test drive that way.
If I am happy I close the rest, if it needs some more tinkering I let it cool and try something else.

- no more squealing from the  belt
- no more flapping from the belt
- belt last (proven) longer
- no more glazed  clutch pads
- no more blue clutch bell
- spark plugs look like new longer
- not more money at the pump with your identical riding style
- a happy bike and a happy owner (proven for 55.000 km with the Piaggio 460cc engine and also for 1500 km on the siwi 400)

I once had a CB 125F that had a clutch that was acting up. It was glazed and made for a choppy start. Rubbing the plates on a smooth concrete sidewalk was the cure. Just clean them good before reinstalling. Anyways roughing them up works if they are glazed.