DNA Upgrade problem?

[nickj]

Hi,

I'm new to the forum, and quite new to the world of scooters. My son recently bought a 2005 Gilera DNA 50cc and I'm helping him with the mechanicing side of things. First we removed the washer in the variator, which brought the top speed up from 46km/h to 65km/h. Then yesterday we fitted a LeoVince TT exhaust, which boosted top speed to about 85km/h, and more importantly it increased speed up a large bridge from 40 to 65! We haven't fitted the variator rollers that came with the exhaust yet.

Something I did wonder about... From the original exhaust theres a pipe coming off that goes up to a strange device screwed onto the side, looks to be around the air filter? I've absolutely no idea what this may be, but the LeoVince had no such fitting, so it's just sitting there for now.

One problem that surfaced after fitting the exhaust is that it will be happily going at full speed when suddenly it's as if some restriction kicks in and it will only do 30-40 km/h. After a bit it's back to full speed.

I've been variously advised about changing the main jet, some say it needs a 60 jet, others say it doesn't need changing. Could this be the problem? I need to find some proper info about this scooter, so I know where the various parts are, my normal field is old english cars.

Any tips very welcome. I have to order everything by mail-order (we live above the arctic circle in Norway), but will be in the UK next week, where things appear more available.

Cheers,

Nick

[nickj]

Well, we fitted the clutch springs and variator bobbins that came with the Leo Vince TT exhaust today. Had lots of problems getting it to start and run afterwards, but finally it ran. Did a 3 km test run without incident. Does 85 km/h on the flat, no problem. Power comes in at 7k with a noticeable punch.

I did notice it heated up a lot (the temp display was flashing), so it's probably running lean. I've tried to find info on how to adjust the Dellorto carb, with no luck. Can anyone tell me which screw is which, and turning which way does what?

Cheers,

Nick

[chopper18]

Originally Posted by nickj

Well, we fitted the clutch springs and variator bobbins that came with the Leo Vince TT exhaust today. Had lots of problems getting it to start and run afterwards, but finally it ran. Did a 3 km test run without incident. Does 85 km/h on the flat, no problem. Power comes in at 7k with a noticeable punch.

I did notice it heated up a lot (the temp display was flashing), so it's probably running lean. I've tried to find info on how to adjust the Dellorto carb, with no luck. Can anyone tell me which screw is which, and turning which way does what?

Cheers,

Nick

hi there it should be a gold screw which takes a flat headed screw driver and has a spring behind it. If the bike is running lean which my friends did i would try adding a performance sponge into your standard airbox as this will allow more air into the bike keeping the bike cooler

[butch-182]

As you have fitted a new exhaust you will need to increase the jet accordingally, Now depending on many variables (atmospheric pressure, heat etc) Its usually about 10 more, so if your standard is a 65 jet, increase the main jet to 75. This is located by removing the float boal, if in doubt do a search as there is many threads showing you this procedure. As for fitting a performance air filter this would only add more problems to the situation as you would be allowing more air to pass with a lesser fuel mix, therefore making the bike run leaner (which can damage your engine) This is where the heat issue will come from.

Hope this helps your problem.