Recent content by Fingerscrossed

Hello, reviving this thread. I'm curious about the 'standby use' and 'cyclical use' on the smaller batteries. I'm in Aus and there's a cheap 1.3ah 12V battery that states: - standby 13.50V-13.80V - cyclical 14.4V - 15V Am I right that the stock XS charging system (charging at 14.5V) will cook...

I've been busy with work but have an update: I charged the battery this week, but on 1.5A it only took about 45 mins for the battery to fully charge. So it seems like it wasn't dying from the battery losing charge. I kind of think it's just a wire somewhere that has a bad connection, there are...

Ok I see, I'll give that a go! So just to clarify, so the battery is slowly discharging which = a weaker and weaker spark. Changing the spark plugs helped this at first because the other ones were sooty (probably from a weak spark?), so improved the spark. But when I changed them after running...

Yes, this makes sense. Wouldn't my battery die though at some point? I'm not charging it except when riding the bike, and it seems to be ok when I let it sit for a bit. Thinking about it, I did charge it up before the longer ride I did and that's when it was running fine for the longest...

Ok, I replaced the regulator/rectifier, no difference. I was losing 1V at the ignition switch, so I replaced that and now get the same voltage (about 13.1) at both ends. I'm now getting 14.1 at the battery when I'm revving, which is on the right track, but it's still not sounding right. I'll...

Made it back with no issues, about a 15-minute ride. For reference here are the spark plugs after the engine died. I have a spare all-in-one regulator-rectifier which I might try. I'll have a look for threads on that as I'm not sure where to mount it on the '75. Also, the reason I think it's...

Hello, back again. I was waiting on some parts and had other bike issues so only just got back around to testing this again. I took the bike out this morning and it was fine for the first 20 mins or so, just some popping from the left on decel. I tested the charging system with the...

Sorry, embarrassing but simple fix. Didn't put the alternator in right...

Hello all, I've had a few posts here, there seems to be something new popping up each time I fix something else, have to love it :) So my '75 was running great but the plugs weren't getting hot enough. I went through the charging system and got that looking right. This meant taking off and...

Ok great, I'll get those brushes on the way. I'll check the ignition switch too. I think I'm also going to order a new regulator/rectifier while I'm at it. Thanks for the help!! I'll see how it all goes.

Ok good advice, I'll keep going through everything. The brushes are about 4mm. At 200 ohms on the multimeter, the rotor measures 06.3 between the slip rings and nothing between a slip ring and a ground.

Ok thanks! I’ll do some more testing and check the stator. Would the charging system be what’s fouling the plugs though?

Ok, so I did some measuring but didn't get very far as I suspect something is wrong with the charging system. I have one cap rated at 9k and one at 5k. With the ignition on, I measured 12.55 at the battery and 10.4 at the brushes. 'The Yamaha XS650 Engine' book says anything under a .5v drop...

and for reference, here are the plugs I took out when it started cutting out yesterday. I haven't touched the mix screw on the right side since but was playing with the left due to the popping. Any idea why it would go from tan to black without adjustment?

Ok! Some more info... It's reading around 13.2V at idle and going up to 13.8 when revving (not sure on rpm, don't have tacho with me). I pulled the new plugs and as seen in the photo, they are bad. They look a little wet? I think it must be something fouling the plugs, which is probably not...