2003 Yamaha YZ 125 - Page 6 - Answered Questions & Fixed issues

may have bad fuel.... has bike or fuel been sitting for a long time. drain tank and the carb bowls. try New Fresh fuel ... What do you mean by taking water??

What is the compression after putting the piston in? seems like carb problem, was it cleaned out when you changed piston?

Once you have to bolts loosened from the caliper, I usually use a painters spatulla or a screw driver flat head, but with the screw driver be very very very carefull not to bend or score your brake disk.

take a match book cover and use it should fire on about anything .03 to.05

So you've tested a spare spark plug sitting outside grounded to cylinder and you defintely have good spark?
If so....is it getting fuel? Is the enricher (choke) working?l

When your bikes cold take your rad cap off and see if your antifreeze is being pumped through

2qts

Tell me.Are you losing gear oil out of the gearbox???
Reason I ask is there is no connection between the gearbox and the combustion chamber.
The g/box is a sealed unit.It's a 2 stroke motor,not a 4 stroke.
Come back to me on this and I hope I can help

I'm assuming you mean gas comes out the spark plug hole with the plug removed??? You probably have a gummed up carburator, due to old gas or dirt. Make sure your air filter is clean first, and then get your carburator thoroughly cleaned. If your float is sticking, or the float needle is dirty or worn out, it will keep dumping fuel to the engine.

hey there i,m not sure what your asking but if you need parts for it those 2 # are the ones you need to get parts

Check the fuel level in the bowl of the carb, if it's set too low when the engine revs the bowl empties and the engine cuts out. Also check the fuel lines and the filter, if they are partially clogged the fuel flow to the carb is too low, the bowl empties and, again, the engine cuts out.

WHATEVER OIL YOU RUN MAKE SURE IT IS MOTORCYCLE OIL BECAUSE THERE ARE ADDITIVES IN IT TO SAVE YOUR CLUTCHES FROM ABUSE ,CHEAPEST WOULD BE YAMALUBE 1040 OR 2050 DEPENDING ON TEMP.OUTSIDE.EASIEST AND QUICKIEST REPAIR IS TO GET A MOOSE CARB REPAIR KIT FROM YOUR DEALER AND INSTALL IT THEY ARE ONLY 20 BUCKS OR CHEAPER AND IT COMES WITH JETS GASKETS AND EVERYTHING BASICALLY INSIDE THE CARB.BECAUSE EVEN IF YOUR PILOT JET IS CLOGGED AND YOU WOULD NEED A NEW 1 THEY ARE OVER TEN THRU YAMAHA,WHY NOT GET ALL OF THEM IN 1 KIT ANDINSTALL AND BE POSSITIVE EVERYTHING IS WORKING CLEAN,ITS A WISE INVESTMENT AND EASY TO INSTALL.BECAUSE YOU HAVE THE PARTS THERE TO LOOK AT

The head light often runs straight from the coil and doesnt matter about the battery, I would be checking the bulb, wiring and switch block

You will need a special puller. The tool is about $20 to $30 after market or $70 at the dealers parts department. Call around to find one. It will last a lifetime and will work on nearly all bikes, Honda, Yamaha, etc.. You just thread the tool into the magneto threads then turn the puller bolt very tight to put pressure on the end of the crankshaft then smack the puller bolt with a hammer. BINGO, the mag is free. Please rate my answer.

I am presuming you are giving the gear lever a positive shifting motion when changing gears.
If the gear lever is completely tight on the gear shift shaft and the toe of the lever does not touch the engine sidecover when changing up, you may have a worn roller shift lever or loose screws holding this mechanism in place. See the exploded view diagrams of the SHIFT CAM and SHIFT FORK with all part names and numbers on the link below.
Cheers!

http://www.cmsnl.com/yamaha-yz125m1-2000_model10887/partslist/

Hi, did you remove the float and needle, you may have some muck or varnish on the float needle preventing it from closing, poss worn needle the end of the needle is rubber this may have gone hard, remove it and clean the seat aswell

Suspension Oil "01" as per Yamaha manual

Well - you will first have to buy an earlier model to get into 6th gear. The 2003 YZ 125 is a 5 speed transmission. There's nothing wrong with your bike.

You are saying that with the clutch lever pulled in the bike still wants to go forward. Generally that is caused by dirty, gritty oil in the gearbox. Go ahead and change the oil. 10w40 motor oil is what you want. I think that will fix the problem assuming the clutch plates were installed properly. The first plate installed and the last plate installed should be a fiber friction plate, 8 plates total. A metal pressure plate goes between each fiber plate, 7 plates total.

Be sure the lever assembly arm is installed so that it gets full movement of the clutch cable. If the full range of movement is not present then full disengagement of the clutch is not going to happen.

cape cod bob did you a good service in the manual referral. Be sure to say thanks.

there is a small bolt 8mm on clutch cover on the side next to the water pump