drummingpariah
XS650 Member
I purchased a non-running xs650 last year for $500 when I realized the PO broke the electric starter. A few kicks and some starter fluid and it kicked to life right away, and I thought I was in good shape. I bought it just before winter, and took it out for a few cold rides to find that it wouldn't idle consistently and didn't like to run after warmed up. I added some gas treatment to the tank, tossed the battery on the tender, and covered it up.
Fast-forward through the winter, where it didn't get much attention at all. I rolled it out this spring, and couldn't get it to run or idle at all. I pulled the carbs, and found that a diaphragm had torn, and decided to take it to a shop that had parts in stock where they replaced the slides/diaphragms and sync'd the throttle plates. They also replaced the coil and wires, since the wires were really old and crusty. It was running when I showed up to pick it up, so I decided to ride it home. After it warmed up, the idle started to climb, then climbed some more, then wouldn't stay below 4k rpm unless it was in gear.
That sounded like a lean condition to me, so I pulled the carbs down again, cleaned all the passages and jets carefully (cleared passages with a guitar string to be on the safe side), replaced the boots, adjusted the floats as per the Clymer's manual, and threw in a float rebuild from MikesXS as well. After reassembly, I fired it up and have a whole new problem. Here are the symptoms, in broad strokes:
Here's how the plugs look after around warming up at idle (it doesn't run well enough to be able to ride it):
I'm no plug-reading expert, but that looks extremely rich to me. I'm open to ANY feedback, even if you're suggesting that I go over something again. I just ordered new orings for the idle mixture screws, since that could theoretically cause some of the idle issues I'm running into. I'm also open to any suggestions regarding ignition tuning; I haven't dug into that at all yet.
Thanks in advance, and I hate to miss out on this season because I can't sort out some basic tuning settings for my bike.
Fast-forward through the winter, where it didn't get much attention at all. I rolled it out this spring, and couldn't get it to run or idle at all. I pulled the carbs, and found that a diaphragm had torn, and decided to take it to a shop that had parts in stock where they replaced the slides/diaphragms and sync'd the throttle plates. They also replaced the coil and wires, since the wires were really old and crusty. It was running when I showed up to pick it up, so I decided to ride it home. After it warmed up, the idle started to climb, then climbed some more, then wouldn't stay below 4k rpm unless it was in gear.
That sounded like a lean condition to me, so I pulled the carbs down again, cleaned all the passages and jets carefully (cleared passages with a guitar string to be on the safe side), replaced the boots, adjusted the floats as per the Clymer's manual, and threw in a float rebuild from MikesXS as well. After reassembly, I fired it up and have a whole new problem. Here are the symptoms, in broad strokes:
- The choke MUST be pulled out one stop or two to start
- If one stop out, the idle sputters and is very low
- If two stops out, the idle hangs at 3500
- If no stops out, it will not start when kicked
- The choke is EXTREMELY sensitive, moving it a couple mm will change the idle rpm by ~2k
- There are no external vacuum leaks, not at the throttle plate, not at the boots, not at the caps or anywhere else.
- The air filters look like the Green Giant's 3-year-old socks
- Jetting is stock, exhaust is stock, airbox is stock
- I've tried setting the idle mixture screws from 1 rotation out to 3.5 rotations out with no discernable difference
- I have pod filters that I could install, but do not have larger jets on-hand, and have not tried them
- I cannot run a compression test, as the electric starter doesn't work
- I cannot run a leakdown test, I don't have a compressor
- I believe (and have to continue believing) the bike has good compression, the exhaust pulse on both sides is strong
- Spraying starter fluid into the RIGHT cylinder's airbox causes the idle to rise as expected
- Spraying starter fluid into the LEFT cylinder's airbox ... just ... empties the can. No effect on the idle rpm.
- This is my first xs650, and I've done my best to go through due diligence and problem-solve it on my own, but I'm at the point where I'm asking "Can this even be fixed?"
Here's how the plugs look after around warming up at idle (it doesn't run well enough to be able to ride it):
I'm no plug-reading expert, but that looks extremely rich to me. I'm open to ANY feedback, even if you're suggesting that I go over something again. I just ordered new orings for the idle mixture screws, since that could theoretically cause some of the idle issues I'm running into. I'm also open to any suggestions regarding ignition tuning; I haven't dug into that at all yet.
Thanks in advance, and I hate to miss out on this season because I can't sort out some basic tuning settings for my bike.
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