pike2112

have been doing some further research into this and don't belive the 650 top end conversion will work or indeed be worthwhile. I think the main problem is the bore stroke calculation. the current 400 is a 68 x 55mm Bore/stroke. adding a 650 piston will not (I believe) change the stroke eg 650 bore 81mm with same stroke 55mm at best will give me a cubic capacity of around 550cc. I guess will equate to a few extra horsepower? So I'll try to tune with perhaps a k&N filter and re jet. I guess fitting a 650 motor complete is an optionbut they are very few and far between...don't go wrong much! Cheers all

so much for going easy on me eh Yes I am an enthusiast with many years of mc and amatuer mechanics running my own rides, a ducati monster and hack cb250rsa (if you're lucky enough to remember one) and yes my son and i do travel around the country lots but unfortunately he's restricted to a 33BHP bike. The reason i want to do this is because the rest of the bike is in excellent condition with plenty of history and has been running without missing a beat. So back to my original questions...is this possible or are the 650/400 top end engine parts not interchangeable? thank you and look forward to some advice

Hi All, Just joined this forum so please be gentle with me! I want to convert my sons 1999 xvs400 dragstar Classic to a 650. I understand that the two engines are the same except that the 400 is a sleeved down version of the 650? Can i simply fit a set of 650 pistons and barrels to the 400 bottom end and fit the original 400 head to the new barrells? I believe the carbs are the same for both models Mikuni BDS28 x 2. i'm guessing I will have to re jet (Main and Pilot)? Also, will the 400 exhuasts fit to the new 650 parts or will I have to invest in a 650 system? finally, if the top end conversion isn't an option, will a 650 engine just bolt in as a replacement with obviously a carb set up to suit new engine size? Any advice would be greatly received cheers pike