Just purchased a SW and it pulls and runs great up to about 60mph, then feels like a speed govenor kicks in and doesn't even try to go any faster. Engine RPM is about 5500, and doesn't act like it is trying at all. It kind of goes in cruise mode. It has normal slack in the throttle cable. Any ideas?

Are you by any chance in Europe?
Apparently over there they can fit a throttle limiter on their motorcycles and scooters as part of a graduated licensing system.

Indeed that is so in the UK.
A restrictor is inserted to reduce the horsepower to below 33BHP to enable those who take the Restricted Test (A2) to ride bigger-engined bikes.

Apparently, the Burger 400 just comes under the limit but 250ccs is the rule-of-thumb measurement.

The restriction lasts for 2 years, after which the rider can ride bigger bikes without taking another test - it's what I did.

The unrestricted licence (A1) requires 4 or 5 days' solid training culminating in the Test and is very expensive.

Mike, was there no grandfathering in the UK, or did you get your A2 licence more recently?

I was lucky in the fact that I took my original motorcycle road test in 1967. I hadn't had any riding from 1974-2009. Getting back into the game in 2009 required nothing on my part, as our motorcycle endorsements are self renewing every time our regular 4 wheel licences are renewed.

If I had to retake written and road tests I don't think I would have bothered. The whole testing procedure is over 2 years, costs about $350, is graduated for the first 8 months (no passenger and no night riding), but displacement is unlimited, which is crazy.

I took my m/c test in 2003, Terry, and had to do the written part as well as the Hazard Perception bit although I've had a car licence since 1966.

A couple of years after I retired I decided to buy a 50cc scooter as an economy measure - I could ride it on my car licence - but thought I should do the non (for me) Compulsory Basic Training as I'd not been on two wheels for ages.
I was bitten by the bug, had a day's training with a riding school, took and passed my test.
In some ways I wish I'd done it before but it gave me a great new interest.

I am actually in the United States (Florida). It seems like the throttle is not opening all the way. It does have a 'cruise control' device that you push down on to lock the twist grip in place. Going to remove it to see if it is the problem. Will advise. Thanks, Jasper

Jasper
What part of Florida do you live? Perhaps someone hear is close enough to you to give it a look.

Live in Destin. I just took the slack out of the cable and it helped some. This is the first variator trans I have ridden since I was a kid (long ago) so possibly I am expecting something different... Just seems like the engine never wants to get within 2000 rpm of redline. It gets to the 5500 - 6000 rpm kind of fast and then seems to lazily move from there up. Above 60 mph, accelleration is slow.

That is definitely a problem, not a stock Silverwing Trait.

I wonder if you are having a spark problem or another issue...

What does your bike sound like? is it a PUTT PUTT PUTT or do they sound pretty close to each other when it is idling?

Are you putting out any smoke or smelling any gas fumes?
If you do go from 0-60, how long does it take you to get up to 60?
Do you hear any backfiring when you decel or release the throttle?

I would suggest finding another silverwing owner nearby and comparing the two.
Start with just comparing the sound of the Swing's....