Suddenly Suckage!

[jordanepp]

I need help, BAD! Not two days from the greatest bike trip I've ever had the opportunity to go on (not saying much, but) the old 650 decides she's gonna run like garbage. I've got no power, it's as though she's starved for fuel, but I pulled the fuel lines and drained some fuel from the petcocks and all seems fine.

Please! I have one night to fix the problem otherwise the bike trip is off, again, and here in Saskatchewan Canada there's not too many warms ones left. I need this ride.

So where do I start?

[projectcrawler]

Need more info. Check the basics. What do plugs look like. What is battery voltage and voltage while off idle(like at 3 grand). Make sure carbs didn't pop out of boots and clamps are tight. What is the rest off the condition of bike. cam chain adjusted, valve clearnce checked, timing checked? Have you done any mods recently?

[pamcopete]

jordanepp

1. Plugged fuel filter? (Replace)
2. Sticky advance rod? (Remove and service)
3. Bad gas? (drain tank, get fresh gas)
4. Throttle cable not opening throttle? (Check for WOT)
5. Does it seem to affect both cylinders? (Pull vacuum barbs one at a time)
6. Is it only bad under load? (Binding brake?)
7. Any recent work done? (First thing to check, is recent work)
8. Plugged air filter? (Remove both filters to test)
9. Enricher stuck in on position? (Check linkage. Make sure both plungers are in)
10. Fouled plug(s) (Replace)

For a lot of these possibilities, just replace the part rather than spend all night troubleshooting.

1. Drain tank and fill with new gas
2. Replace spark plugs.
3. Replace fuel filter. If you don't have a replacement, just remove it.

[jordanepp]

pamcopete

Things I know:
Plugs look good tanned and greyish.
Throttle cable working fine. Bike revs fine, but slugs when riding.
Only recent work is pulling the headpipes to take pics for another posting "valvey, poppy, noise".
Enricher plungers look to be down.
Bike starts up on the first kick and idles and revs fine, just slugs out when running.

Things I'll check at noon:
check voltage
swap gas
pull air filters (but they are new)

thanks for the quick response. I'll update this post as soon as I have more info, but most of my trouble shooting will have to wait until this evening.

If anyone is around to keep checking for new posts I'd be ever grateful.

[5twins]

I would drop the float bowls and check for debris if nothing else shows up. You could have clogged main jets. That would allow the bike to start and idle, maybe even rev under no load, but it wouldn't perform well under load going down the road.

[pamcopete]

jordanepp

Well, again, jack up the front wheel and check for front brake caliper piston binding. Check the rear brake on the center stand too.

Bad ignition advance might only show up under load as well, so strobe the timing and check smooth operation to max advance.

Wild card: Screwed up or loose shifter claw. You might be in a higher gear when starting out that you think you are. Compare MPH to expected RPM's.

[jordanepp]

Noon hour update:

pulled the air filters, no change.

checked voltage, no different than usual. Although admittedly the charging system on this bike is on my ever expanding "to do" list. The battery itself meters at about 13, idling and revved to 3000, 11.7. changed the alt. brushed, but no change. I usually get about a couple weeks riding before I need to apply the old trickle charger.

didn't have time to do any fuel fiddling so I'll get to that after work.

thanks for all the great suggestions so far this is a great trouble shooting list. I think I'm going to attack the main jets and float bowls first after freshening up the fuel.

[jordanepp]

Well I'm officially impressed! If anyone ever doubted the power of a good wrenching community let them forever hold there tongue. In the end... right carb was caked with some foreign substance yet to be recognized.

There must be some kind of record won though for speedy replies. Thanks for all your help with the trouble shooting lists. You've saved my trip.

I'll post some pics here when we get back.

[jordanepp]

Did I mention it was a short trip. I'm back and pleased to say that for a bike that came to me earlier this summer on a trailer and in two cardboard boxes, she ran remarkably well. Only one minor incident involving a dead battery. Nothing an hour and a half in Christopher lake couldn't cure. We needed lunch anyway, right?

So here's some pics of the trip to Waskesiu in northern Saskatchewan Canada. If any of you XS'ers are ever in my neck of the woods you should definitely take a ride among the many northern lakes.