Bluestreak06
XS650 Member
Hey guys, Im at my wits end with this bike a little background on myself since Im new....had an 81 xs650 in high school that I tore down to the frame and rebuilt, and rode for 4-5 years before moving on to sports bikes...currently ride a Hayabusa.
A friend of mine has this '80 650 that has been sitting for awhile....purchased new by her dad, and only has 12000 miles on it. It hadnt run in awhile, so we rebuilt the carbs and put a new battery in it and everything seemed great. Sat for awhile again, and started having issues. It needed a new chain/sprockets anyways, so I said Id do it all and get the bike back to her after. Replaced the chain/sprockets, throttle cable, cleaned up the carbs, and adjusted the clutch cable. Now the bike feels sluggish down low (I think, Its been awhile since I rode one and Im used to the power of the Busa), and once you get up into 4th/5th it wont get above 3k RPMs and tops out at 50mph.
Ive since pulled the carbs back apart, inspected and cleaned everything, made sure the slides were clean and no holes in the diaphragms, adjusted the floats to spec per the carb guide on here, made sure they were adjusted (sync'd), replaced the spark plugs, HT leads, and coil, air filters, etc. Ive got the mixture screws out 3 turns from bottom on both sides......
I know this is long, but please bear with me....one cylinder appears to be running warmer than the other (you can physical feel a temperature difference in the exhaust gas)...that spark plug looks normal. The left side the plug almost looks wet when you pull it. That being said, the bike idles great, and once you get moving it revs fine until you get into 4th, where it seems to fall on its face. I dont know what else to try and check; it was running fine 8 months ago so it has to be something I caused. The only things I havent tried yet is adjusting the valves, or checking the cam chain...there is no tapping from the valves, and the cam chain isnt making any noise either (I remember from my 81 that it is very loud when its out of adjustment). Any thoughts on why it wont go over 50mph? Or why it tops out at 3k RPM in 4th/5th? It just stops pulling....
A friend of mine has this '80 650 that has been sitting for awhile....purchased new by her dad, and only has 12000 miles on it. It hadnt run in awhile, so we rebuilt the carbs and put a new battery in it and everything seemed great. Sat for awhile again, and started having issues. It needed a new chain/sprockets anyways, so I said Id do it all and get the bike back to her after. Replaced the chain/sprockets, throttle cable, cleaned up the carbs, and adjusted the clutch cable. Now the bike feels sluggish down low (I think, Its been awhile since I rode one and Im used to the power of the Busa), and once you get up into 4th/5th it wont get above 3k RPMs and tops out at 50mph.
Ive since pulled the carbs back apart, inspected and cleaned everything, made sure the slides were clean and no holes in the diaphragms, adjusted the floats to spec per the carb guide on here, made sure they were adjusted (sync'd), replaced the spark plugs, HT leads, and coil, air filters, etc. Ive got the mixture screws out 3 turns from bottom on both sides......
I know this is long, but please bear with me....one cylinder appears to be running warmer than the other (you can physical feel a temperature difference in the exhaust gas)...that spark plug looks normal. The left side the plug almost looks wet when you pull it. That being said, the bike idles great, and once you get moving it revs fine until you get into 4th, where it seems to fall on its face. I dont know what else to try and check; it was running fine 8 months ago so it has to be something I caused. The only things I havent tried yet is adjusting the valves, or checking the cam chain...there is no tapping from the valves, and the cam chain isnt making any noise either (I remember from my 81 that it is very loud when its out of adjustment). Any thoughts on why it wont go over 50mph? Or why it tops out at 3k RPM in 4th/5th? It just stops pulling....