Kawasaki 1100 STX lacks top end speed

[greatsmiledoc]

I have a 1997 Kawasaki 1100 STX with 165 hours on it. It is a little hard to start when cold but otherwise has run well. Carburetors were rebuilt and reed valves replaced a couple years ago. I close fuel valve and run fuel out when finished riding. Have run two or three tanks of fuel through it last weekend Top speed has been 52 or 53 mph. While out on the lake last weekend after riding for an hour or so it would die when throttle applied. It will come from a stop on to a plane if throttle is applied and released over and over(pumping fuel with acclerator pump ?) And now top speed is 45 or 46 mph. It seems to run smooth on the top end.

What should I check other than the fuel filter(which looks clean). If I can blow through the fuel filter is it OK. Any suggestions much appreciated.

 

[studlymandingo]

Re: Kawasaki 1100 STX lacks top end speed

Just a suggestion... Pull the carbs, pull the diaphragms, check to see that everything is in order with the needle valves and the screws that hold the plate in place. Apparently these suckers vibrate to he!! and back and minute adjustments work themselves loose inside the carbs.​

 

[adrenilinpwrsports]

Re: Kawasaki 1100 STX lacks top end speed

greatsmiledoc,A few tips if I may..I recommend a compression test right off the bat to rule out needing a top end rebuild at those hours....If your mechanically inclined and have access to a guage I can walk you through the RIGHT WAY to do it...First, you running it out of fuel is not a good thing for 2 reasons.First,you are taking all of the fuel/oils out of the cases which lubricate the lower internals and your leaving the bare metals exposed (Bearings,Crankshaft,Cylinders) open for moisture corrosion..We All Know How Rust Loves Bare Metal!!!! Second,Its causing your cold hard start issue..You are having to pump fuel back through the carbs fill all the bowls and into the cases to get it started. If that doesnt kill your engine it will most definitly wipe out your battery after time. I personally own this same machine and I recommend after your use for the day do the complete opposite..Pull the choke and fill the cases with fuel/oil..Let it idle,pull the choke and push the stop button after a second or two and then close the fuel valve...When you go to start it the next time it will fire right up...Check the fuel filter/water seperator you may have some contaminates floating around in there due to sucking up water,sludge,dirt off the bottom of the tank..If the tank has never been cleaned out, I dont recommend using reserve as you surely will suck up gunk if this has never been done....

 

[greatsmiledoc]

Re: Kawasaki 1100 STX lacks top end speed

Thanks for the tips. I do have a compression gauge but am not sure how to do the check the right way. Is 165 hours on this engine alot? It smokes a bit but isnt that why they are called two smokes. Typically,when do they need a top end? As for not running gas out of the carbs, that makes sense. How long can you leave gas in these things before it turns to gum. What about at the end of the season? Fogging oil? I really appreciate the help. Thanks much.

 

[Jeff Walkowiak]

Re: Kawasaki 1100 STX lacks top end speed

your symptoms indicate a lack of fuel , maybe you have an issue with the fuel valve selector or you are pulling in air from a loose clamp on the suction side of the fuel system.

 

[greatsmiledoc]

Re: Kawasaki 1100 STX lacks top end speed

Lack of fuel sounds most likely. Will check selector valve and clamps, hoses etc. Thanks much. What oil should I try to cut down on smoking. Am using Kawasaki's jet ski oil.

 

[Jeff Walkowiak]

Re: Kawasaki 1100 STX lacks top end speed

I'm probably wrong but every kawasaki I have ever owned smoked a lot at low speed,, never could get them to stop,, maybe use synthetic oil but not sure if it will do any good

 

[JUSTINTIME]

Re: Kawasaki 1100 STX lacks top end speed

yep all about the oil

 

[greatsmiledoc]

Re: Kawasaki 1100 STX lacks top end speed

Changed the fuel filter and it runs fine. Thing is, the old filter looked clean and barely had any resistance to blowing through it. Any suggestions on brands of oil to try to reduce low speed smoking. Also, does anybody use fogging oil at the end of the season. Thanks again.

 

[studlymandingo]

Re: Kawasaki 1100 STX lacks top end speed

Also, does anybody use fogging oil at the end of the season.

What is this "end of season" thing you are talking about?

The fuel filters are small micron filters to keep very tiny particles out of your carb. Not something that will generally look dirty... If it ever looks really dirty, you have real problems.​