Intro and a fueling problem

[Thirsty]

Hi guys. I'm an XS650 owner from Oz with a lovely mostly original 1979 XS650 Special. It's not restored but is in very nice condition.

It runs well overall but there is a small niggling problem I'd love to solve.

My bike runs a couple of teeth less on the rear sprocket to enable better higher speed cruising. Now to the problem - if I run around town in top gear at 60kph (about 37mph) the engine is doing less than 3000 revs. After a while (about 5 or 10mins) the bike will start spluttering and seems to be having fueling issues. It surges and splutters on acceleration. If I give it a good thrashing for a few minutes it comes good again.

If I ride around at the same speeds in 4th gear ie keeping the revs above 3000 then it's fine. Possibly unrelated is a problem where the bike will stall while idling at the lights. Only happens sometimes and I can catch it with the throttle if I'm quick.

The previous owner put a carb kit through or so he says.

If anyone can offer any advice I would appreciate it,

Thanks

Tony

 

[gggGary]

You might consider checking to see if the charging system is weak. Sounds like it could be erratic ignition due to low voltage.

 

[Thirsty]

I should have said Gary that the bike has the MikesXS electronic ignition in it. Would that make a difference?

 

[gggGary]

Low voltage will take down any ignition even an electronic one. I usually start by watching headlight brightness. or even a voltmeter to see how the charging is going. The battery is known good?

 

[jayel]

less than 3000 in top gear you're lugging the engine, roller bearing lower ends hate that

 

[XSLeo]

If your running the pamco ignition, it will work down to around 6 volts. I might check the idle circuits in the carb. As jayel said, stay above 3000 rpm in high gear. At 37 mph 3rd gear would be better.