Well I find most of what I'm looking for I find on ebay, they are getting harder to find and you may have more luck on the us ebay, seca 400 is the dohc xs400 over there and most parts should fit your I do have a spare untested wiring loom which you could have for free but I think the postage would be steep. never found my 400 to be slow or unreliable and have owned one of them from new. The only real problem is the CDI which is mounted behind the left side panel & is prone to getting wet,well it is the the uk anyway would imagine one would be really hard to find for the 250 always good to have a spare if pos as they do tend to fail after about 30 years, engine is petty bullet proof most of the wear & tear parts are available on ebay german ebay seems to have more parts which is were I get a lot of bits from over their its known as the xs400 12e good luck with your project, look forward to seeing it finished