20 Most Recent 2004 Yamaha YZ 125 - Page 4 Questions & Answers

Hi there! What kind of oil are you using? You are supposed to use oil of similar grade to the engine oil. Is the filter still in good shape? If all these check ok, that might not be dust, but small deposits from carb blowback which can be considered perfectly normal.
Hope this helps and let me know if you discover any thing more on this subject! My regards, Sergio

either the float is stuck in the down position or the float needle cannot close properly due to debris in the float valve or a worn float valve assembly.

Hi,
The weigh is 87 kilos.
Alex

take the case off and be careful not to drop any gears out the back of the case. Then snap the spring loose and then pull the kick axle gear out. The key is putting it back in. Carefuly line up the clip and square on the back of the kick axle with the holes in the back of the transmision then be sure to push on the gear to see if it popps into place. then bring the spring clockwise to fit into the hole. Besure the spring is pushed all the way back. Now carfully put the case back on.

I was not aware you could! Please let us all know when you have found a free site, Thanks.

Not to be the devils advocate but if there is absolutely no compression while using a compression tester, you may want to check the top end was correctly installed. Even then, you should have some compression. Your only real other issue would be lower main seals. these are the seals thatseal the crank to the case. if they are bad, you will see oil protrude through them when you remove the side covers and turn over the engine. And again, if the top was done correctly or evan has a piston and rings it will still read something. if your merelyh going by feel of kick, be sure to get a compression tester at yout local autozone

http://www.bikebandit.com/houseofmotorcycles/2000-yamaha-motorcycle-yz125m/o/m8835#sch111222


Please see this schematic.

The oil level is determined through the level indicator at the bottom end of the plug. You will see oil in it. The oil level must be in the safe level.

A screw in plug by kick starter or sight glass on engine too on some.

Noises coming from the inside of an engine are not good. Someone needs to pull the right side engine cover and look at the clutch, crankshaft drive gear and kick gear. It sounds like something has come loose.

check your sparkplug if it is good and check your woodruff key inside the flywheel maybe it is damage

They build up carbon in the exhaust port, if you take the exhaust off you will probably see the carbon has build up leaving only a small hole.

Scrape the carbon out and give it a start with the exhaust off for a few seconds.
Buy some stainless bolt or nuts to bolt the exhaust back on, as this will need doing again. Try some different 2 stroke oils, the more expensive are not necessarily the best, as they might need higher temps to completely burn.
They can also build up a bit in the exhaust outlet.
I used to own 50 hire mopeds and worked on a few hundred of the competitors bikes and this was the most common problem.
The yamahas used to get to about 55km

That is like a vent hole, but the seals for your water pump should be replaced. Also, check the shaft for wear from the seal, as they can "cut" into the shaft. Then the shaft is bad also.

You can get a schmatic from BikeBandit.com but they don't give you any directions with it. Also try You Tube. Alot of people put bike rebuilding on there. I hope this helps!!

reed valve, or reeds, yes.

650cc

no.
you would, change the jag out. You can hone the jag if you are put in new rings if they STD.

reach down with your left hand by the carburetor and its the little black pull switch right on the carb.

20w40 motorcycle oil,(the same as four strokes use) car oils have friction modifiers in them that will make the clutch slip

If you cant see it leaking anywhere, the engine oil seal may need replacing, as it can s uck oil from the gearbox through the seal, and this will burn through the engine, especially if you notice it is smokier than it should be