Top 20 2001 Yamaha YZ 426 F Questions & Answers

On this model you measure oil height with the fork compressed and spring removed. Pour 5 weightfork oil in until itis 90 mm from the top. lift and lower the damper rod inside the tube a couple times and recheck your oil level.

2 1/2 quarts

Time for a valve adjustment. You have done the right thing by replacing the spark plug and cleaning the carb. Check your valve cleareance and make sure is up to specs.

Hi there,Have you checked your accelerator pump daiphram ? Could be old and needs replacing or dirty.

Some 426's have a decompression lever and some don't if there is been a cam job done.

clean plug .. although new plug if old fuel or unbalanced carb it may quickly foul. if this works you may need help to work out whats causing plug to foul.

minha yz426f quando vou de terceira marcha devagar mas quando eu acelero a fundo ela engasga , mas ? so de terceira marcha de rewsto nao faz isso

2 to 3 clicks. Make sure you fire the bike up a couple of times to make sure is running good.

It is not normal, The oil is coming from the engine lubrication system and it sounds as if you have not renewed the rocker cover gasket when the engine was rebuilt. Check the torque settings on the head bolts and that no oil is getting into the coolant.

If it starts but won,t idle I would adjust low speed jet on carborator.

I would think head gasket due to the piston pushing compression out to your coolnat system.
Do a compression test

Right hand side right next to the water pump in between the big clutch cover and the water pump cover you will see a small cap about 6- 8cm has 3 bolts they will be 8ml bolts or maybe allen bolts on the older YZ
Tip drain all your sump oil first before opening and lean bike over to the left as much as you can to save big mess of oil coming out when you open this cover. Don't forget to smear some clean oil on the rubber on the end of new filter before installing it will help seal it and keeps in place a bit so you can install cap back on easier...

Things to check 1st. If it overheats after riding for a while, check the air filter. If the filter is not sealed properly, air will get in between the seal and the airbox causing the bike to overheat. Other possibilities on a bike that old would be clogged radiator tubes(replace), bad water pump(replace impeller)
Please comment

Either you got air in you cooling system or, you have wrong combination of air and gas in your motor. Good luck :P

did you just get it?....do you have a manual for the bike....on the waterpump their is a coolant drain bolt....their should be 3 bolts, it is the bottom bolt, put a big drain pan under it remove the bottom bolt, then take off the radiator cap.and it should all come out.out.. i would use a 10w40 semi synthetic. also get a manual for that bike, you can get one on CD-ROM on ebay for about 4 bucks or if you google it you can download a pdf manual right on line for about 6 bucks...ya need to know how much oil your bike takes. i think it takes 1.2 liters, but i would make sure. hope this helps

Well bad news is yes to replace shaft you do need to split motor
But I have seen a few solutions that are a bit back yard mechanic jobs but they work !
you could tap and thread a small bolt into the the gear lever 90 degree's to the shaft then it has something to tighten down on the shaft
I have even seen guys put a spot or two of weld on the end so you can reach it to grind off if you need the lever off again at any stage
Some gasket glues can work also if you still get could tight grasp from just tightening the lever on the shaft then some good old gasket glue can be enough to increase diameter of the shaft to get even better grasp from the lock nut and when it sets also helps with securing the lever to the shaft and unlike glue it never sets rock hard so you can always get it off again if you need to

I am speaking from my Yamaha XS1100, with 4 carburetors.It is a 1980 model, but the carburetors are always gunking up, especially if it sits over winter with gasoline in the tank. This also happens more frequently with the alcohol laced fuel that you have to buy now days. The alcohol causes it to absorb water that mixes with the gasoline and alcohol to form a sticky gunk that blocks up the orifices in the carburetors. The first thing that you can try is to get some Seafoam additive, or maybe Textron. Pour out all of the gasoline in your tank and change the inline filters if possible. Fill the tank with fresh gasoline and add the Seafoam in a generous amount. Allow the bike to sit over night and try to start it. You may get lucky and get the bike to fire up. If it runs rough and doesn't smooth out, you may have to clean your carburetor. See: http://www.bikebandit.com/houseofmotorcycles/2002-yamaha-yz426fp/o/m8901#sch252680

For a breakdown of your carb.

There is no problem, that's how it works when the engine is not hot.

In the UK climate, I would use a 5W 40W semi synthetic. That will cover you if there was synthetic oil or Rock oil in the engine and allow you to upgrade to fully synthetic in the future, if you want to.

if its the one by the choke it is the "Hot start", if you have trouble starting in warm weather it should help the bike start....i am no mechanic but that is my understanding.