Never done this before 79 GS1000L

[Rodman]

Rode 16 mile then 4 hours later another 2 miles. Took 30 minutes and got back on. Didn't fire up immediately (not normal) but noticed a different sound, another 100m and on the road. There was no power but still ran, Exaust note sounded funny, like not all 4 were working. Started to dread my 16 mile commute home, almost at my destination 2 miles later it surged and we were back on. A couple of spins outside the office and all was well and experience was written off as a "fluke". The ride home went well for the for the first 8 miles then it did it again but after a few surges all was normal. My experience with mechanics is that issues will either get better or worse, most likely worse. No smoke, backfire, or weird emissions. So far I have been successful at doing maintenance and some electrical diagnosis but this one has me beat, it could be anything and my experience at troubleshooting other mechanicals is nil, why I come here. Any ideas?

[chucksuki]

dirty gas?

[Rodman]

I thought this one as its obviously low hanging fruit but my filter is 3 months old and the see through type, looks great, so I'm giving this one thumbs down but thanks for the feedback.

[Gonzo]

What's your baseline look like? What basic maintenance has been done and how long ago?

[Rodman]

Gonzo,

Not sure what you mean by baseline?

Recent engine maintenance has been new plugs and oil change. I replaced stator, r/r in March and went to Dyna ingnition in April.

[Guest]

points / condensers if you have original ignition

ask me how I know.

[Guest]

"Never done this before " Thats what the farmer said when the horse died .
No really check your fuel petcock, and your tank vent make sure that they are working properly

[BassCliff]

Hi,

"Baseline" = all of the maintenance tasks in the "mega-welcome". Have you taken any shortcuts on the maintenance?


Thank you for your indulgence,

BassCliff

[G. Bruns]

It sounds like a fuel system problem. You mentioned you have a fuel filter. I'd suggest taking it out of the equation and seeing if your symptoms improve.

[Guest]

You're either dropping a coil or having fuel starvation.

[1_v8_merc]

check for loose connections to coil
check for loose spark plug caps

if it's not either of those, it's likely Fuel Related

[Rodman]

Hey guys,

Been too busy to work on this issue but had some time last weekend read the replies, many thanks, and right off found the vacuum hose between 1&2 carbs disconnected??? I hooked it back up and have run 2 tanks through and the issue is no more. This does raise some questions though and I see many posts about bad petcocks. I assume this petcock is the original. Over the couple of years i've had this bike I have had it in all positions in all driving conditions and it runs the same. Maybe this is okay? If this needs service which is best, new one OEM at $100+ or rebuild at 1/3 the cost. I don't cut corners and if a $70 decision is what puts me on this side of the road versus done and forget about, for me its a no brainer, please advise.

Thanks

[tom203]

Thanks for follow up. You can keep testing your old petcock to be sure or just opt to replace it and forget about it for 20 years.

[Steve]

... found the vacuum hose between 1&2 carbs disconnected???

Confusing, as there is no "vacuum" hose between 1&2.

There is a VENT hose and a FUEL TUBE, but the only vacuum hose in the entire set goes from #3 to the petcock.

Having a loose VENT hose should not show the symptoms you described.

.

[Rodman]

Steve,

This is not good news for me, here I thought I was done with this. I guess as with all mechanicals, it will get worse over time. I'll wait it out and see what happens.

Thanks