Top 10 2003 Yamaha YZ 125 Questions & Answers

www.denniskirk.com-1-800-969-7504orwww.j&pcycle.com-1-800-318-6847. they should have it.

The clutch and gearbox share the same oil. The oil for the motor is 10w40. Stick with the major brands; Pennzoil, Quaker State, Mobil, Yamalube or Shell.

I have a dennis kirk book, the correct spark plug is a --BR9ES--(NGK)

i always used SAE 10w-30 oil on all my dirtbikes,
no transmission fluid

for the chain you should move the back tire back until the chain is at a snug tension

a yamaha warrior isnt a 2 stroke. they make a street bike nad a four stroke quad. Check your carburator. check your spark plug and check your stator. it may be very minor considering it was running fine then just went out. no noise or anything. you would have heard something if you broke something internal.

The two seals in the diagram below are separated by the casing they fit into. The impeller is threaded to screw onto the impeller shaft. I think you already knew that by your "holding the tire" note. The center casing does not get split. The right casing does remove then a wrench is used on the shaft as the impeller unscrews counter clockwise. It is risky to "Lock the wheel" because the gear on the impeller is very thin and can break.

A “very helpful” rating on this answer? Thanks!

Hi Leewy....Ok...Turn the crankshaft counterclockwise until the " I " mark on the rotor is aligned with the stationary pointer on the crancase cover.Fit the timing chain onto both camshaft sprockets and install the camshafts on the cylinder head.The camshafts should be installed onto the cylinder head so that the exaust cam sprocket punch mark " E " and the intake cam sprocket punch mark " I " align with the surface of the cylinder head,both marks facing out of course towards their prospective ports.thats about it Lee.Please leave some feedback if this has helped in anyway. from tilleydog at Moto Headquarters.

G'day i am a . YZ 125 j ...lets see now! You could perform these tests yourself.Check your plug CAP,if in doubt replace it with a new one. Take the below ohm figures and see if they match up. Pulse coil: white/blue and white/red= 310 ohms. low speed coil: Green/white and Black/red= 900 ohms. high speed coil: Green/blue and black= 55 ohms. hope this has helped in some way to helping you solve your problem.If it has please leave feed back.Ride hard , see ya,Tabbycat

I would be more concerned with the stuck gear than the clutch, but we will start with the clutch.

The push cam may be bent or deformed and the push shaft may be bent. Assuming the ball bearing is in place, the cam and rod are all that can really go wrong. The rod slides out of the left center case. You will need to loosen the springs to get the left side cover back in place. Roll the rod on a flat surface to see if it is bent. I fear a bent shift fork is causing the gearbox to be stuck in third. Fix the clutch and then post a comment to get back to me.

check that reed valves not sticking and check the pilot jet its prob. half blocked. have to stick a very thin wire through it.

Service manual says oil capacity is 19.4 oz. per leg which is 573.726 ml per leg. Be sure that you have drained all the old fork oil out first.