01-01-13, 12:33 PM
I wouldn't go the Sandy Spares route, personally ... you'd be swapping one flat spot for another because those headers are designed to work correctly with the 5-valve Yamaha head. Yes, I know the ad says no rejetting required etc, but I have a dyno chart showing otherwise.
Look out for a replacement valve (or headers with valve) on ebay, UK and USA. Consider Euro ebay search, too. Save the search and get e-mail notifications of all new listings as soon as they hit the site.
Early model R1 valve components are identical. The headers aren't, though. You need the 4XV/5JJ version. I also recall reading somewhere that Thunderace EXUPs are the same as ours.
Look out for a replacement valve (or headers with valve) on ebay, UK and USA. Consider Euro ebay search, too. Save the search and get e-mail notifications of all new listings as soon as they hit the site.
Early model R1 valve components are identical. The headers aren't, though. You need the 4XV/5JJ version. I also recall reading somewhere that Thunderace EXUPs are the same as ours.