Bike is sick today....

[bosco659]

Tried to go for a ride this evening and pulled the XS out of the garage. Suited up and attempted to start the bike. No electric start. Battery voltage ok. Flipped kill switch and ignition switch several times and still no starter. Also noticed the horn wouldn’t work. Started it with the kick starter and it fired up. Warmed it up for a few minutes and rode off. Seemed to be running ok but had a slight misfire which I attributed to it being cold.

Rode several blocks and the misfire persisted. Even stalled at one light but go figure the electric starter worked. Pulled into a parking lot and checked fuses - all ok. Starter and horn still working intermittently. Wiggled the wiring harness from the ignition switch and found if I moved it the right way, the starter and horn would work. No biggie, I’ll check the switch and inside the headlight tomorrow to find the gremlin. Noticed after being parked, one of the carbs was leaking from the overflow. Don’t know which one though.

Fired the bike back up and got on the highway. Accelerated ok but may have been a bit sluggish. Rode at about 65 mph and the bike started to lose power within 1/2 mile. Eventually it was only running on the right cylinder. Limped it off the highway, pulled into a parking lot. Checked plugs and switched them from side to side. Started the bike up and seemed ok. Adjusted mixture screws. Went for another highway run with petcocks on reserve and gas cap cracked open to eliminate a possible venting issue. Left cylinder died again.

Limped it home at slow speed and occasionally the left cylinder would kick back in but not for long. By the time I got home (several miles), if I kept the revs up it felt like both cylinders were firing again. Even on acceleration it seemed pretty good.

Got it home in the garage. Will have a look tomorrow. Any ideas what I should check first? I’m thinking carbs have to come off for sure.

 

[jetmechmarty]

Do you have points ignition on that lovely piece of machinery? It’s very common for carburetors to have electrical problems. Unless you believe floats are stuck, I would chase spark before fuel.

 

[bosco659]

Do you have points ignition on that lovely piece of machinery? It’s very common for carburetors to have electrical problems. Unless you believe floats are stuck, I would chase spark before fuel.

No it has a Pamco ignition. Maybe tomorrow I’ll switch the spark plug wires from side to side to see if the problem follows the wires. Maybe a bad plug cap?
The only thing I messed with prior to this occurring was the seal replacement on the gas cap. That’s why I tested it with the cap open in case it wasn’t venting properly.

 

[Jim]

Wiggled the wiring harness from the ignition switch and found if I moved it the right way, the starter and horn would work. No biggie, I’ll check the switch and inside the headlight tomorrow to find the gremlin.

Starter button and horn button share a common ground. It's the black wire coming out of the left bar switch, going into the headlight bucket.

 

[bosco659]

Starter button and horn button share a common ground. It's the black wire coming out of the left bar switch, going into the headlight bucket.


View attachment 192017

Does that ground have anything to do with the the ignition switch Jim? Maybe my wiggling the ignition switch wiring harness is just affecting that ground connection in the headlight bucket? Thx it will help me with the troubleshooting tomorrow.

 

[Jim]

Does that ground have anything to do with the the ignition switch Jim? Maybe my wiggling the ignition switch wiring harness is just affecting that ground connection in the headlight bucket? Thx it will help me with the troubleshooting tomorrow.

No, it doesn't. Trying to think if anything in the bucket would cause one cyl only problems. Nothing come to mind.
Yeah... I suspect wiggling the iggy wiring also moved that ground wire around inside the bucket.

 

[grizld1]

You have more than one problem to deal with: defects in the electrics and/or tank seal won't make a carburetor puke fuel from the vent, and a defective carbie can kill one cylinder. If it's puking fuel that carbie can also cause a fuel scoured cylinder, which is one of the many reasons to think about heading for the barn at the first sign of trouble instead of trying to "ride through" engine trouble. Take things one step at a time, troubleshooting is a process of elimination. Be sure to check your oil for fuel contamination. Be patient; the gremlins can hide, but they can't run. You'll catch the little varmints.

 

[bosco659]

You have more than one problem to deal with: defects in the electrics and/or tank seal won't make a carburetor puke fuel from the vent, and a defective carbie can kill one cylinder. If it's puking fuel that carbie can also cause a fuel scoured cylinder, which is one of the many reasons to think about heading for the barn at the first sign of trouble instead of trying to "ride through" engine trouble. Take things one step at a time, troubleshooting is a process of elimination. Be sure to check your oil for fuel contamination. Be patient; the gremlins can hide, but they can't run. You'll catch the little varmints.

Thanks, will get the electrical issue fixed up first. I think Jim’s post has me pointed in the right direction. I’ll get the bike on the lift and start checking the fuel system. Good idea to check the oil. When I pulled the plugs the “dead” cylinder plug was dry so I’m thinking it wasn’t getting too much fuel but needs to be investigated anyway. Getting good at pulling the carbs off anyway

 

[member28833]

Getting good at pulling the carbs off anyway

Wouldn't get too anxious about that yet. Maybe you could drain them for now and look for sediments.
Once the electrical issue is found, The BS38'S will be much easier to test for symptoms..
WFO !
One day at a time

 

[bosco659]

Well I got the scary stuff out of the way first. Cold compression test 160 psi both sides Whew! Decided to attack the fuel issue first. Removed bowl drain screws and turned petcocks on. Right side lots of flow, left side just s dribble. Even though I knew the carbs need to come off I dropped the left bowl cover. Gave the float a poke and sure enough it was sticking. Off came the carbs.

With both bowls removed, I checked the float action. Right side moved freely but the left side was sticking intermittently. Couldn’t see anything real obvious but kept looking, got the vernier out and started measuring one float to the other. Still no obvious issues. I thought I’d just bite the bullet and order all new components but assembled everything one last time then I found my problem. The fuel needle valve seat had become loose, not to the baked eye and when the tip of the hex was just in the right position it would ever do slightly interfere with the part of the float that the pin rides in. I tightened it down good reassembled everything checking float height and all went back together again.

Quick test ride and the bike is running well again. Didn’t do a highway run but am confident it will be fine.

Now look for the electrical gremlin. Well after an hours searching the gremlin was nowhere to be found. No amount of pulling, pushing or wiggling could reproduce my loss of horn and starter. Tightened up a few connections and did some minor cleanup of wiring and put it back together.

All that’s left to do is ride it!

 

[jetmechmarty]

All that’s left to do is ride it!

Good plan!

 

[member28833]

Bosco dang it! now you have me wondering if I actually tightened the seats on the BS38'S I just jetted and buttoned up !
Spose I'll have to take the bowls back off just to check that now lol

 

[grizld1]

Re. hunting electrical grief, the meter is your friend. Check voltage into device vs. battery voltage, and if you find a significant drop, check voltage out at each switch and connector till you find the culprit. Unplug coil and Pamco system while you're doing this. Forgot to mention this, but it's important. When you grab a gremlin, use long needle nose pliers; the bite is painful and toxic.

 

[Team Junk]

Damn that thing is shiny. I love all the little details.

 

[bosco659]

Re. hunting electrical grief, the meter is your friend. Check voltage into device vs. battery voltage, and if you find a significant drop, check voltage out at each switch and connector till you find the culprit. Unplug coil and Pamco system while you're doing this. Forgot to mention this, but it's important. When you grab a gremlin, use long needle nose pliers; the bite is painful and toxic.

Thx. I do disconnect the coil and Pamco but is it sufficient to put the kill switch in the off position.

 

[GLJ]

Thx. I do disconnect the coil and Pamco but is it sufficient to put the kill switch in the off

If it kills power to the coil yes.

 

[bosco659]

Bosco dang it! now you have me wondering if I actually tightened the seats on the BS38'S I just jetted and buttoned up !
Spose I'll have to take the bowls back off just to check that now lol
View attachment 192059

Don’t know what happened to mine. I’d really be surprised if I forgot to tighten them. For now I’ll blame it on vibration lol.

 

[member28833]

Bosco Thanky for that seat tightness reminder. Re checked mine and found too loose for comfort today
Might have just saved me a day.
-R

 

[bosco659]

Bosco Thanky for that seat tightness reminder. Re checked mine and found too loose for comfort today
Might have just saved me a day.
-R

Glad you had an opportunity to check them before they were installed. I’m going to check mine after a few hundred miles to see it they loosened off at all. I’m thinking it may be the fibre washer under the seat may be contributing to the loosening. Perhaps an aluminum or copper washer would be better. I’ll post my findings next month.