O/T but need help:ZR550 - loss of power at highways speed ..

[OzJavelin]

Apologies for the O/T subject, but I'm at my wits end and you guys seem very switched on!

My Kawasaki ZR550 has developed a very annoying, but regularly intemittant(?!) problem of losing power when running at about 100km/h (64mph) in 6th. It's like you are heading into a severly strong headwind; I can power through or drop back to 5th and punch the revs up, but at 6th in cruise mode on the highway is't not happy. I've had this problem before just after it went for a sleep on its side one day; and this started again after the same thing (fell over in the garage). I've cleaned the heck out of the carbs - at least four times I've stripped them. I've cleaned the tank, lines and replaced the inline filter (which was working fine beforehand).

I'm wondering what I should be focusing on when I strip the carbs AGAIN!! I've pulled all the jets cleaned with carb cleaner, blown air thorugh everything, and pulled the vacuum diagphrams and checked them all for leaks, etc. Checked the carb boots both engine and airbox side .. and replaced the spark plugs .. no help

I'm at my wits end .. seriously just thinking of selling the damn thing for scrap and buying something else!!

BTW: Will a carb sync help? My understanding was this is done at idle so I'm assuming it will have no impact on high-speed running?

Help?

[BassCliff]

Hi,

I'm sure there may be other causes but I have noticed this behavior when the carb vent hoses were not properly routed and are susceptible to air turbulence. Do your carbs have vent hoses?

Have you checked the float height on your carbs?

It's possible that it's electrical, intermittent coils, leaky spark plug wires, etc.

Hopefully this will at least get bumped up so that someone smarter will respond.


Thank you for your indulgence,

BassCliff

[OzJavelin]

Hi,

I'm sure there may be other causes but I have noticed this behavior when the carb vent hoses were not properly routed and are susceptible to air turbulence. Do your carbs have vent hoses?

Have you checked the float height on your carbs?

It's possible that it's electrical, intermittent coils, leaky spark plug wires, etc.

Hopefully this will at least get bumped up so that someone smarter will respond.


Thank you for your indulgence,

BassCliff

The carbs do have vent hoses .. I could try re-routing them (easy to do)
I have checked the float height everytime I've had the carbs apart
Could be electrical, but doesn't appear to be "breaking down", just slowing down .. an I can power though the problem .. just can't stay on "cruise" ..

[almarconi]

You could try removing the inline filter. Does it feel like it is starved for fuel?

I have also experienced surging if the vent tubes are left to hang in the wind.

Also check to make sure you don't have any intake leaks and that your airbox is sealed.

[OzJavelin]

Hi,

I'm sure there may be other causes but I have noticed this behavior when the carb vent hoses were not properly routed and are susceptible to air turbulence. Do your carbs have vent hoses?

I think you nailed it. I re-routed the hoses up under the seat and it's been fine since. Thanks!