Hello all. Trying to help my brother work out some issues with an XS650 that has turned into a little bit of a nightmare. Its a 1980 special I believe. He bought it off craigslist as "running perfect", he got it home and immediately the starter motor ceases to function and there was always hesitation during acceleration which he attributed to the carburetors. So I got the carburetors to clean for him which I did, 3 times with the hesitation and a break-up remaining, hence the repeated cleaning attempts. Cleaning involved complete disassembly of all needles and jets and soaks in a heated ultrasonic cleaner. I replaced the seat O-rings, needles, and bowl gaskets, reset the float levels (someone dropped them to ~23mm, probably using the plastic float spec) and essentially cleaned the things to the point that i'm thoroughly convinced they're not the problem. When i say these things are near spotless I mean it. Today he came by so I got to hear and toy with it for myself and from what he tells me its actually been running progressively worse since he got it.
Symptoms are as follows. Wont accelerate past 4000 RPM at WOT. Lots of break-up during acceleration. Exhaust backfiring. Smokes a little when you max the RPMs at ~4k. Idle performance seems to be not bad though it does backfire/pop a little bit. I checked for vacuum leaks and found none.
After coming to the conclusion that the carburetors weren't at fault, at least in my opinion, because its running that bad, im leaning towards the ignition system and tell him as much. He hops on it to go home and its hard to start, gets it going and goes to give it throttle and it just dies out. Doesn't re-start, even with persuasion from starter fluid (engine is now very warm from running for quite some time-yes it had plenty of fresh gas in it). This has all the symptoms of an ignition system that's completely took a dump to me but wanted to see what you fine folk thought and if anyone has any advice as to where to go from here if you've dealt with any similar issues. The bike wasn't exactly cheap to begin with and if possible i'd like to diagnose and replace individual components rather than throwing a $200-$300 ignition kit into it.
Thanks in advance for any guidance.
Symptoms are as follows. Wont accelerate past 4000 RPM at WOT. Lots of break-up during acceleration. Exhaust backfiring. Smokes a little when you max the RPMs at ~4k. Idle performance seems to be not bad though it does backfire/pop a little bit. I checked for vacuum leaks and found none.
After coming to the conclusion that the carburetors weren't at fault, at least in my opinion, because its running that bad, im leaning towards the ignition system and tell him as much. He hops on it to go home and its hard to start, gets it going and goes to give it throttle and it just dies out. Doesn't re-start, even with persuasion from starter fluid (engine is now very warm from running for quite some time-yes it had plenty of fresh gas in it). This has all the symptoms of an ignition system that's completely took a dump to me but wanted to see what you fine folk thought and if anyone has any advice as to where to go from here if you've dealt with any similar issues. The bike wasn't exactly cheap to begin with and if possible i'd like to diagnose and replace individual components rather than throwing a $200-$300 ignition kit into it.
Thanks in advance for any guidance.