QUAD QUESTION! 1998 yamaha warrior 350 bogging down

Could be a weak fuel pump - top end is where you would notice the pump dying out.

First.. check the compression..>120PSI...
Why did you replace the carb..???? that was unnecessary.. carburetors don't "just go bad"..
Stop playing mechanic.. take this ATV to a QUALIFIED professional!!

hello, you probably need to have your stator checked out, sometimes the pickup coil in the stator will go out, also you can try ign coil, the one spark plug wire is hooked to,warriors are bad about cdi going out, mine would idle, would not rev up, would bog down, source coil in stator probably needs to be checked also..

hello, get piston up on tdc, hold finger on spark plug hole turn engine untill finger blows off,that should be compression stroke. take screwdriver in hole make sure piston is all the way up, take timing cover off top gear, there is a v mark inside the motor , make sure gear marks and timing chain is all aligned upp, timing chaing should have a different colored link, aligned this with mark on gear-chain and the mark on the motor, it looks like a v or a point, you have to remone the top gear cover to see this, once they are all aligned it should be in time, piston has to be up all the way on compression stroke, really its pretty simple....

Clutch switch behind clutch lever. Parking brake cable is attached to it. It cuts the revs if the parking brake is engaged to stop it from being reved when stoped.

I had a problem somewhat the same.

Make sure the air-intake boot has no holes in it.

Try checking the switch for your parking brake. It is the top wire in the clutch handle boot. This wire connects to your CDI box, and restricts the RPM's while the parking brake is engauged. To find out for sure, trace the wire down to the plug under the headlight assembly and disconnect it. Now try starting you machine and give it some throttle!

check the parking brake on the handle bars. un hook all of the wiring and see if it runs better. this is a common problem.

Float and or float valve stuck, flooding Carb. If it just can out of storage, it will need to have the carb cleaned.

Have you changed the spark plugs? If your plugs aren't firing correctly, this can cause the problem. If you have dirty carbs, this can also cause the problem as you will put too much air in and not enough gas.