There may be a problem with your internet conection, as some people in tonight's match noted that the game became less laggy after you got disconnected.

Don't blame Nintendo if your wireless connection sucks.

It's not the nintendo servers. Check to see how good your wireless signal is at your Wii. Also, most people leave their wireless router on the default channel 6, this will cause random 'disconnections' and interference, as everybody in your neighborhood is probably using channel 6. Change it to a clear channel and all should be well.

If this doesn't work, you may have an old 802.11b wireless router, these SUCK. You also may just have interference in your area causing dropped packets on the wireless. You could also try the USB LAN connector and go wired.

In about 100 races online that I have done I have been disconnected twice only

I use the Wi-fi USB thingy that first was available for the NDS

You can do a simple test to see if your connection is laggy.

Run this command:

ping -t www.nintendo.co.uk 

Let it run for a minute or so, and then paste the result here.

 Also possible that somebody set up a nother WiFi Router near you, and yours and his is using the same "Band", because they don't see each other (but your wii see's both, dues it is in the middle of both) in that case it should get really really laggy.  Is your PC connected through your Wifi? If so, do the following: Hit start->run (ausführen in german) enter cmd. Enter in the black box apearing "ping heise.de" and post the results.

If you have a laptop with wifi please go as near as possible to the wii and search for networks, maybe you see more than one. If so, reconfigurer your router to another wifi band. 

Don't know what any of it means but I got the message:

 Packets: sent=4 received=4 lost=0

Approximate Round trip Times in milli seconds

Minimum=34ms; Maximum=37ms Average=34ms

ok thats not perfect, but that doesn't explain the disfunction.

Are there other WiFi accesspoints nearby? (Neighbors etc?)

Did you try striker charged? 

I can see about 8 other wireless access points when I search on my laptop.

 Tried Pro Evolution and got disconnected with message saying Incident Code 85010 so I guess must be something with my broadband or interference from all the access points in the area.

Just change your wireless router to an unused channel.