thecurryman
XS650 New Member
Hey yall new to the forum and I've got a few questions. Not sure if xs400 talk is allowed here, I'm not really interested in talking about the engine as much as I am in talking about the bs34 carbs. Seeing as how the xs650 uses the same one I figured I'd ask.
Bought the bike a few months ago, PO claims running the bike pretty hard with no filters on carb, sucked something in there and some bits made it to the head. Instead of looking for valves he bought another head with camshaft and installed that. Literally just put it back together and did nothing else to it.
When I got it, I did valve timing and ignition timing. Fresh battery and some ether got it to turn over. Idle all over the place and some hanging idles so figured vacuum leak. Carbs off cleaned, new throttle shaft seals, diaphragms look good, new carb boots and gaskets. Broken mix screw tip in one of the carbs, got that removed very carefully, replaced with oem screws. Float bowl height set to 26mm from gasket surface. Bench synced the carbs and put them back on. Scored an H pipe and original airboxes off of ebay along with some emgo filters. Put all that on, cranked it up and set the idle as well as sync with manometer. Went for a ride and couldn't get it past 3k on the tach so I figured some tuning was needed. What follows is the log of combinations I tried. Carbs came with a 145 main and 42 pilot so already up a couple sizes.
Started, 145 main and 42 pilot, raised needle one clip position boggy and too rich ro run well. This also put the needle in the last clip position.
Returned needle to previous position, 147.5 main and 45 pilot, same thing too rich to run.
Swapped pilot out for 42 and left the larger main, runs but won't make it past 3k.
Did some plug chops and noticed that the lean condition was coming back to more stoic.
Some things I noticed while I had the carbs off, left side carb needle is bent. Must have been from whatever got sucked into the carbs from the PO. Cant find one to save my life, not sure how much performance will be affected but I know it will wear eventually and that will cause issues. Thought maybe the auto advancer for the ignition timing was sticking so I looked into that and it moves freely and returns fine. Even advanced the timing to see if that would help but it didn't. Also of note, riding it when you start to crack the throttle in 1st its not firing evenly and smoothly and it's a little sluggish till it hits 2k and then it pulls pretty hard. Also when you are pushing at 3k, you can feel it pull a little and then stop, pull a little and then stop.
I've got the jets and needle to go bone stock if I have to but I dont think that needle is gonna work.
Truly scratching my head on this one and im at the point to where if you point at a rock and say look under that I will. Thanks in advance for any help you can send my way and also sorry for the long post.
Bought the bike a few months ago, PO claims running the bike pretty hard with no filters on carb, sucked something in there and some bits made it to the head. Instead of looking for valves he bought another head with camshaft and installed that. Literally just put it back together and did nothing else to it.
When I got it, I did valve timing and ignition timing. Fresh battery and some ether got it to turn over. Idle all over the place and some hanging idles so figured vacuum leak. Carbs off cleaned, new throttle shaft seals, diaphragms look good, new carb boots and gaskets. Broken mix screw tip in one of the carbs, got that removed very carefully, replaced with oem screws. Float bowl height set to 26mm from gasket surface. Bench synced the carbs and put them back on. Scored an H pipe and original airboxes off of ebay along with some emgo filters. Put all that on, cranked it up and set the idle as well as sync with manometer. Went for a ride and couldn't get it past 3k on the tach so I figured some tuning was needed. What follows is the log of combinations I tried. Carbs came with a 145 main and 42 pilot so already up a couple sizes.
Started, 145 main and 42 pilot, raised needle one clip position boggy and too rich ro run well. This also put the needle in the last clip position.
Returned needle to previous position, 147.5 main and 45 pilot, same thing too rich to run.
Swapped pilot out for 42 and left the larger main, runs but won't make it past 3k.
Did some plug chops and noticed that the lean condition was coming back to more stoic.
Some things I noticed while I had the carbs off, left side carb needle is bent. Must have been from whatever got sucked into the carbs from the PO. Cant find one to save my life, not sure how much performance will be affected but I know it will wear eventually and that will cause issues. Thought maybe the auto advancer for the ignition timing was sticking so I looked into that and it moves freely and returns fine. Even advanced the timing to see if that would help but it didn't. Also of note, riding it when you start to crack the throttle in 1st its not firing evenly and smoothly and it's a little sluggish till it hits 2k and then it pulls pretty hard. Also when you are pushing at 3k, you can feel it pull a little and then stop, pull a little and then stop.
I've got the jets and needle to go bone stock if I have to but I dont think that needle is gonna work.
Truly scratching my head on this one and im at the point to where if you point at a rock and say look under that I will. Thanks in advance for any help you can send my way and also sorry for the long post.
