Hi Mike
Firstly hello and welcome. I'm a newbie in the uk too
Er, yeah, the downpipes on the GPZ500S do rot rather quick and they are quite expensive. I seem to remember about £100 each. I don't know how yours have gone, it may be possible to get them welded up.
My post
http://www.kawasakimotorcycle.org/forum/viewtopic.php?t=402 is probably quite relevant. The Nexus exhaust is quite common, partucularly on the older GPZ500S A series bikes sold second hand. You can probably find pics on biketrader.co.uk, or ebay.co.uk. Actually you can on ebay.
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=2456772032&category=9807 is a nexus pipe.
For parts I have found in the UK
M and P (
http://www.mandp.co.uk)
MPS (
http://www.thefastone.co.uk)
http://www.gear4bikes.com
are all pretty good. gear4bikers were very good on the phone, guy seemed to really know his stuff and it all arrived next day. Busters were about 50p cheaper on the brakedisks but mine was on its way from gear4bikers before they had given me a quote.
MPS appear to my to be the same company as M&P but their prices differ. MPS give a 10% discount on your first order so if you are ordering an exhaust system
M&P/MPS are about half the price for oil filters (genuine Kawasaki ones are cheaper than their copies).
Right on to exhausts.
Motad (
http://www.motad.co.uk) do the Nexxus which appears to the be the cheapest and most common. I'm guessing they will send you a catalogue if you want one. I know several people who have had motad exhausts on other bikes and they do seem to work fine and last well.
Looking about laser do a downpipe kit, don't know if you can fit it with the Kawasaki cans or not but I'm sure they would be happy to help you. The suggestion is that the JAMA Originals should be compatible with the factory parts.
http://www.laserexhausts.com/MotorPDF/954021.pdf
They also do a 2 into 1 with EU approval (road legal).
http://www.laserexhausts.com/MotorPDF/99401315.pdf
Or go to
www.laserexhausts.com and say you have a GPZ500S.
The Website lists it as for a EX500A but the M&P and MPS catalogues show the 2 into 1 for all GPZ500Ss.
You will need Adobe acrobat reader if you can't view the PDF files
http://www.adobe.com
Micron do a 2 into 1 performance exhaust (listed in M&P's catalogue)
http://www.micronexhausts.com/ is flash but doesn't actually have the information you require yet.
That should be enough to get you thinking. Your other option would be to see about second hand parts (you may get lucky and find a new GPZ thats being broken).
Barton Motors
http://www.usedkawasaki.co.uk
01225 427906 (+44 1225 427906) are worth a call.
Also worth mentioning is that a new (different) exhaust is something you will probably need to tell your insurance company about. If its road legal and not performance enhancing then it should not put your insurance up much, but many companies do class it as a modification :-(
