My 1980 XS650 Runs!!

[JonW]

Back in the fall of 2018, I picked up this 1980 SG Special. It was not running, and the carbs that came with it were completely apart and in terrible shape. I ended up buying another set and rebuilt them, encountering a few snags along the way, as documented in another thread here https://www.xs650.com/threads/bs34-idle-mix-screw-issue-ideas-wanted.54337/page-4#post-883150. As can be seen in the video, the throttle cable is not attached. It was too short, so I raided my stash and found one that works.

However, as can be heard in the videos, there is a popping/knocking sound in the exhaust. I realize the carbs have to be synchronized. I wonder if it's just the carbs needing synchronization or possibly something else?

Regardless, I am super happy to hear it run!!

 

[JonW]

In the meantime, I was able to take it for a ride in the neighborhood!!

 

[JonW]

But wait, there's more.

 

[JonW]

And more!!

 

[Wingedwheel]

Sounds like you need to lean it out a touch.

 

[Jim]

Have you adjusted the valves and cam chain yet, Jon?

 

[JonW]

Have you adjusted the valves and cam chain yet, Jon?

No, not yet, but will do!

 

[Jan_P]

I would recheck ignition timing first with a strobe light -- it can be a little to advanced.
Can be carbs also but timing is simpler and quicker to check -- to start with

 

[JonW]

Sounds like you need to lean it out a touch.

Do you mean with the idle adjustment screws?

 

[JonW]

I would recheck ignition timing first with a strobe light -- it can be a little to advanced.
Can be carbs also but timing is simpler and quicker to check -- to start with

Not a problem as I do have a strobe light, but being a 1980 model, as I understand it, the timing isn't adjustable unless the factory bits are removed.

 

[Jan_P]

Not a problem as I do have a strobe light, but being a 1980 model, as I understand it, the timing isn't adjustable unless the factory bits are removed.

Aee ... hh forgot about that .I have a 1980 here in Europe stock with points
Still I would do a quick check.

 

[JonW]

Aee ... hh forgot about that .I have a 1980 here in Europe stock with points
Still I would do a quick check.

Will do, thank you.

 

[Wingedwheel]

Do you mean with the idle adjustment screws?

Yes, should help with that popping at idle.

 

[JonW]

Yes, should help with that popping at idle.

Will do, thank you!

 

[JonW]

Have you adjusted the valves and cam chain yet, Jon?

I got as far as the cam chain adjustment today after having to go and buy a 27mm socket . After the cam chain adjustment, it now starts instantaneously with the push of the button. Tomorrow I will check the valve lash and ignition timing.

 

[JonW]

Unfortunately, I was not able to devote any more time to the bike, as I will be out of the loop for the next few weeks with work related matters. I will update as soon as I return.

 

[JonW]

Back to it, and trying to make some progress. Cam chain adjusted, valves adjusted ( Exhaust .006" and Intake .0024").

Using a remote fuel bottle and vacuum gauges. However, the left side carburetor started pissing fuel, so I dropped the float bowl, and I found these crystallized chunks of who knows what, and it was everywhere. It was also in the float needle galley and on the needle itself, obviously causing the float to stick open. I can't imagine this came from anywhere else but most likely residue that was in the passageways that found its way out after putting the carbs back into operation. Has anyone else seen something similar and have a different take?

 

[Jan_P]

Can be a lot of things .. From Hoses ..Coming with the pump at the gas station Something poured into the tank as fex carb cleaner.Oil
Modern fuels with other additives have solved something in the line from the tank and fuel lines ethanol.is not Good in there.
Some sticking float valve is common at start up .I have it more or less every spring.
Some tapping on the outside of float bowls with a screwdriver handle and poor running first 2 tanks.

 

[JonW]

I think I have it running a lot better, now!!

 

[5twins]

Yes, that sounds much better (no more ticking), but your idle speed is still a little high. Turn it down to 1100-1200.