top end bogging prairie 360 4x4

[mudseeker]

hey again? well my bikes are running great but my main bike is bogging at top end!!! i dont understand valves are adjusted,my front diff has all new bearings and seals,new plug,carb is clean and adjusted,changed air filter, and i change the oil every other ride????could it be the 1.5inch snorkle kit? or maybe the fact that the brillow pad looking stuff in the exaust came out??please help hunting season is here?thanks again!!!

[RCW]

If you are bogging only at the top end it is your main jet.

I really do not know if it is rich or lean, because I have no idea of how much air the snorkel kit will flow, but if it restricts your air flow you will be rich. As a rule of thumb for every inch you add in distance on an air intake you should add a quarter inch of diameter to the pipe to avoid restriction from air friction in the extended intake plenum. So, if you added a 1.5 inch snorkel and used the same size pipe as the air inlet, you are likely running rich and will need to reduce the main jet accordingly.

I am not sure of what sort of packing came out of the muffler, that generally is usually only sound deadening along the sides of the can and will not reduce back pressure. But if some of the baffles have been removed or are rusted out, then you may have reduced back pressure and created a lean condition with the carburetor main jet and need a larger jet size.

A lean bog generally will generally create a bit of a surge as the engine hits full power while running with a load and tries to rev then drops back and then tries to rev again, etc. A rich bog will generally simply run you out of power then tends to darken the spark plug insulator. A lean bog will hurt engine with overheating and piston damage, and a rich bog will generally only just eat spark plugs, dirty the oil quickly, and cause excessive fuel consumption.

[mudseeker]

thanks it does sound like a lean bog because it dies and comes right back. can i possibly adjust something or do i have to buy a jet kit? and if i am not misstaken it did it before i put the snorkel kit.

[RCW]

You may find the main jet is partially plugged with gum or dirt, if that is the case they are reasonably easy to clean. Go to kawasaki.com and follow the user links to the parts diagrams and take a look at the construction of the carburetor.

If the 360 Prairie engine runs good to a quarter throttle, then bogs and only recovers at full throttle you can sometimes solve that problem by raising the needle so it rides higher and richer. The needle rides in a needle jet, and the needle is tapered so it makes a richer mixture at higher throttle settings, but at wide open the needle is fully retracted and that will not solve a full throttle bog, as that is main jet only as long as your ignition is functioning properly.

If it starts bogging at quarter throttle all the way through full throttle then the needle could be failing to raise. That is generally where someone has installed the spring and needle retainer incorrectly and the needle is not pulling up when it should. Another cause for quarter through full throttle bogging can be a cracked needle valve diaphragm in the carburetor.

Similarly, a low carburetor float level can cause the same sort of symptoms.

Full throttle bogging can be ignition coil or igniter failure, but you will notice that quickly in the smell and color of the exhaust, as it will turn excessively rich from unburned gasoline. You will also see the impact on electrodes and insulator of the spark plug.

Same is true of an old or failing spark plug, but again you will see it when you pull and inspect the plug right immediately when you shut it down after it starts bogging. Do not let it idle and clean up the plug, but get right when the problem occurs.

So, the short answer is no. If you are bogging at full throttle and have none of the ignition symptoms, you need to disassemble the carburetor and check the main jet. It is either too small or plugged.

The 360 Prarie is like the 400 and pretty much the best of the ATV's that Kawasaki ever built. So, if you have not done so pick up a service and repair manual, it will walk you through the diagnostics and steps to repair. The sponsor of this site sells that manual to members for a discount.