surging

[Tibo]

Hey guys,

I'm having a problem with my '80 xs11, it has to top end, it maxs out at about 65mph. To get it there I need to have the throttle wide open, and then it's like it gets little surges of power and continuously jumps forward.

Anyone have any advice?
Thanks.

[Ken Talbot]

My first guess is that you've got a broken pick-up coil wire, so it is only running on 2 cylinders. Besides that, the carbs are probably not synchronized, and you may be having fuel supply problems from debris in the carbs. Have you just got this bike and this is how it came, or did this just start to happen after running okay?

[Tibo]

I have spark on all 4 cylinders, and I just bought the bike off of a buddy who had it in storage for years (with gas in it unfortunately). I drained the gas and ran some carb cleaner through and now its doing this. I rode it before it went into storage and it was fine.

[TopCatGr58]

Need More Input?

Hey there TIBO,

Sure, we have lots of advice, but it could be mostly wrong without more info about your machine! I see by your profile that it's a 80SG, that could be helpful?!

But we need to know how long have you had it or if you just got it, what mods you've done to it, like pipes, intake, filters? Also, what if anything have you already tried, or what changes have you recently made to it. Have you ever been able to run up to redline? Is this a new symptom?

Have you pulled the plugs and checked their condition, any of them black/sooty, or bleach white? Have you checked your fuel lines to ensure you're getting fuel to all four carbs? Do you still have the octopus vacuum valve? Also, have you checked to see if you're getting spark to all four plugs? Have you checked your vacuum advance hose for cracks. Have you checked your intake manifolds for air leaks? Have you checked your brakes to make sure they are not locking up??

Lots of things can cause poor performance, do some checking, and then report back, and don't feel bad about how long your post is, we like to read!!
T.C.

[TopCatGr58]

Okay, slow typing, I now see more info!

Okay,

Storage is BAD. Carb cleaner in tank is probably not enough. You probably need to pull the carbs and do a thorough cleaning. THis means taking each one almost completely apart, pulling the bowls, the tops, the vacuum slides out, all of the jets, the central emulsion tube, the pilot jet, and the pilot SCREWS, and spritzing carb cleaner thru it. Careful pulling the floats, then the needle seats, check and clean the filter under the seats, and you'll need to replace the O-ring around the seat, and possibly the rubber tipped valve as well! ALso, check the petcocks and Octopus, fuel could have gummed it up as well. Switching to PRIME will bypass Octopus and send fuel directly to carbs, IF it runs better, then the Octy is suspect!
T.C.

[Tibo]

Thanks for the tips guys, the octopus valve seems to be sticking, and the plug from cylinder 4 is bleach white, cylinder 2s plug is also fairly white but not near as bad as cylinder 4's.