maraakate
XS650 Member
Hello,
I am working on an 81 XS650H for a friend. For a bit of backstory, it originally had pod filters and bad float needles. So, we found the original airbox, looks to be in good shape and new OEM filters and new OEM float needle assemblies (the entire assembly including the o-ring, not just the needle). Installed all of this, reset the float height according to the book and then checked again with the clear tube method. The bike also had some electrical issues, particularly for the charging circuit. On closer inspection the connector for the regulator (pretty sure it was for the regulator, but I don't recall off-hand) was corroded. Installed new connectors and the charging circuit works properly. Installed a new battery since it had a beat AGM in it. New battery is standard fill-type. Valves, cam chain tension, and carb sync has been done. I verified the timing at one point with a timing light and seems in spec. Clutch, rear brake, and drive chain were also adjusted. I also installed new OEM float bowl gaskets, new OEM carb sync rubber stoppers (unsure the proper term) and new OEM clamps for that. There are no air leaks. Verified from top to bottom with PB blaster at the intake, the linkages and airbox boots. The bike had some half-assed soldering and some crappy harbor freight style fusebox (with wrong fuse values!) that I converted to use the nice waterproof Littlefuse micro-fuse holders.
Anyways, the bike runs pretty good for the most part. The only 'gotcha' that I need to revisit is that the right side is a bit lean on idle with some occasional backfires which is probably from a slightly plugged pilot jet. I have not removed the pilot jet yet to verify this. However, I did put new OEM slow jet plugs (forget the actual term for this part). The bike has proper power, pulls good through all the ranges and throttle positions. But, my friend has taken it on some longer 1hr-2hr rides and noticed that sometimes while cruising it appears the bike loses half of it's power and bogs; almost as if it is running on one cylinder but it's hard for him to explain it to me. I drove the bike for an hour the other day and it was running just fine for me. I had him check and notice if it was when he was going up-hill/down-hill (indicating some sort of float height issue) and he said it doesn't matter the incline and that it's happened on flats as well. I told him to try and pull over when it happens and feel the amount of air pressure coming out of the exhaust; but he's unable to do so because usually when he downshifts then upshifts again the problem goes away. When he went to stop he said when applied the front brake the problem went away. I tried cleaning the terminals on the coil and cleaning up the grounds for the coil, but this hasn't changed the issue.
My guess is that the coil may have some internal resistance and the value is changing when it gets good and hot on a long ride. Or the TCI box may be intermittently bad (possibly a component drifting out of spec when exposed to enough temp) or an intermittent connection from the TCI box.
I haven't measured the coils or done a compression check yet, but will do so over the next few days. I will recheck the valve spacing as maybe it has drifted, but we haven't put much miles on it yet so I doubt it is that. Maybe about 300 miles total since it has been ran.
I am out of ideas at this point and do not want to blindly throw parts at it or switch it over to a Pamco Ignition system unless absolutely necessary. Curious on what everyone's thoughts here are. Maybe there is some known issues with the ignition system that are common to this bike that I am unaware of. I normally work on Honda CB/CM stuff so I am unfamiliar with the particular quirks of these bikes.
I am working on an 81 XS650H for a friend. For a bit of backstory, it originally had pod filters and bad float needles. So, we found the original airbox, looks to be in good shape and new OEM filters and new OEM float needle assemblies (the entire assembly including the o-ring, not just the needle). Installed all of this, reset the float height according to the book and then checked again with the clear tube method. The bike also had some electrical issues, particularly for the charging circuit. On closer inspection the connector for the regulator (pretty sure it was for the regulator, but I don't recall off-hand) was corroded. Installed new connectors and the charging circuit works properly. Installed a new battery since it had a beat AGM in it. New battery is standard fill-type. Valves, cam chain tension, and carb sync has been done. I verified the timing at one point with a timing light and seems in spec. Clutch, rear brake, and drive chain were also adjusted. I also installed new OEM float bowl gaskets, new OEM carb sync rubber stoppers (unsure the proper term) and new OEM clamps for that. There are no air leaks. Verified from top to bottom with PB blaster at the intake, the linkages and airbox boots. The bike had some half-assed soldering and some crappy harbor freight style fusebox (with wrong fuse values!) that I converted to use the nice waterproof Littlefuse micro-fuse holders.
Anyways, the bike runs pretty good for the most part. The only 'gotcha' that I need to revisit is that the right side is a bit lean on idle with some occasional backfires which is probably from a slightly plugged pilot jet. I have not removed the pilot jet yet to verify this. However, I did put new OEM slow jet plugs (forget the actual term for this part). The bike has proper power, pulls good through all the ranges and throttle positions. But, my friend has taken it on some longer 1hr-2hr rides and noticed that sometimes while cruising it appears the bike loses half of it's power and bogs; almost as if it is running on one cylinder but it's hard for him to explain it to me. I drove the bike for an hour the other day and it was running just fine for me. I had him check and notice if it was when he was going up-hill/down-hill (indicating some sort of float height issue) and he said it doesn't matter the incline and that it's happened on flats as well. I told him to try and pull over when it happens and feel the amount of air pressure coming out of the exhaust; but he's unable to do so because usually when he downshifts then upshifts again the problem goes away. When he went to stop he said when applied the front brake the problem went away. I tried cleaning the terminals on the coil and cleaning up the grounds for the coil, but this hasn't changed the issue.
My guess is that the coil may have some internal resistance and the value is changing when it gets good and hot on a long ride. Or the TCI box may be intermittently bad (possibly a component drifting out of spec when exposed to enough temp) or an intermittent connection from the TCI box.
I haven't measured the coils or done a compression check yet, but will do so over the next few days. I will recheck the valve spacing as maybe it has drifted, but we haven't put much miles on it yet so I doubt it is that. Maybe about 300 miles total since it has been ran.
I am out of ideas at this point and do not want to blindly throw parts at it or switch it over to a Pamco Ignition system unless absolutely necessary. Curious on what everyone's thoughts here are. Maybe there is some known issues with the ignition system that are common to this bike that I am unaware of. I normally work on Honda CB/CM stuff so I am unfamiliar with the particular quirks of these bikes.
