Top 20
2004 Yamaha YZ 125 Questions & Answers
Small pinholes in the reed valves
Yes mate... It is hard to say without seeing the reed valve but I guaranty a dodgy reed valve will make running and tuning the bike a nightmare. Your reeds need to seal perfectly and open and close about 2-3 times a second so if any cracks, holes or damage to them then they will never seal correctly which will allow blow back through the carbi and incorrect air and fuel mix to be sucked into the motor. best solution buy a V force reed kit it replaces the entire cage and reeds just bolts in (4 bolts) I sell them for about $160 delivered, or if your know what you are doing then you can just replace the reed petals with new... About $60 ish
www.motoxpartsonline.com
I have an 04 yz 125 that won't shift into 2nd but
2nd gear is at the bottom of the shafts if the tranny is stacked in the mag side case. So it is controlled by the bottom fork. You should be able to shift it thru all the gears by turning the shift drum. Make sure as you shift the shafts stay all the way in the output shaft and idler shaft bearings. As you shift it, look for full mesh between the wheels(shaft that goes to the clutch) and the gears across on the output shaft.
If that all looks good, the shifter cluster(on the end of the shift drum, with the 2 dogs that engage the notched wheel on the end of the drum) may not be lined up properly. If the gears and shift drum are new, I'm thinking I'd look there first. Good luck!
I have a 1993 yz
Check that the arrow on the top of the piston is facing the exhaust. Sounds to me like you have it in backwards.
What is the correct spark plug for a 2005 yz125?
hope this information helps these are Denso Plugs
YAMAHA
YZ125
YEAR
2004-1999
ENGINE
125 cc
APPLICATION INFORMATION
STANDARD STK#
4049
STANDARD PLUG#
W27ESR-V
IRIDIUM POWER STK#
5317
IRIDIUM POWER PLUG#
IW27
IRIDIUM RACING STK#
5714
IRIDIUM RACING PLUG#
IW01-27
GAP
0.024
Gas flowing out of the
The float is stuck open by some trash at the float needle OR the float is bad and literally does not float any more. Remove the float bowl and clean the carb using spray carb cleaner. Gently lift the float and the flow of gas should stop. Lower the float and the flow should start again. Please rate my answer. Thanks.
Im 16, and ive never ridden a 2 stroke in my life
I would suggest a 250 2-stroke or a 4-stroke. Lots of power, lots of pull and the motor would likely last you for years. I've raced both the 125 and the 250 2-stroke at the pro-am level (A-class) and the difference in engine life is tremendous. I would re-ring a 125 every week (running 26:1), while with a 250 I could go for 2-3 months or more without doing the top end while running 32:1.
A YZ 125 will definately be a bit of maintenance - primarily because it has a single ring and the ring doesn't last long. A pro or semi-pro racer would re-ring every race (when the 2-stroke was popular) - some races I would re-ring in between motos. I know you won't be racing, but I would still imagine you would want to freshen up the top end at least every other month at the most. Granted - you can re-ring a 125 in about 45 minutes for a cost of about $18 if you know how and it costs a LOT more for a 4-stroke and is more of a job.
Other than the ring, the rest of the maintenance will be about the same between a 2-stroke and a 4-stroke. You'll still have to do your air filter every ride and your engine oil (tranny oil in a 2-stroke) every other ride. Tires, spokes, sprockets, clutches, chains, brakes - all pretty equal maintenance between the two. Lots of variables, of course.
The difference will be keeping the motor fresh and for that, the 4-stroke will beat the 125 2-stroke. Not the 250 2-stroke, though - these motors last as long or longer than the 4-stroke and are a LOT cheaper to maintain/rebuild.
This is MY experience and my opinion. Your mileage may vary.
Scott
2004 yamaha yz 125,All stock,wont
sounds to me like the carb needs sorting, either the float height needs setting or the needle valve is leaking. to test if it is either of them try turning the fuel off and start it, if it runs a lot better then thats your prob.
T
The fuel is leaking from
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.
I need to know how much and how to determine how
you really need your manual for this. you can get a manual on cd-rom for your computer for $4.00 on ebay. also check out this video, it will be the same for your bike. you would need to measure down from the top of the tub when it is fully compressed....should be about 135mm from the top (5 inches) but i would find a manual to get the exact height....but check out this video.
http://www.youtube.com/embed/Y43k1qFVGW4" frameborder="0" allowfullscreen>
Hi i have a yz125
Was it sitting around all winter? Try cleaning the carbs- usually means replacing o-rings and gaskets, possible even jets if really clogged.
I'm replacing the front stock
The steering stem bearings and mounts should be okay as is. Before you buy, be sure the new forks are the same diameter as the old forks. Also check the overall length of the forks. The length should be the same on both sets of forks.
Hi my yz 85 is a 2007 and i came of it and the
possibly the shifter came loose on the shaft that it is bolted on, there with a spline it could be slipping there and not changing the gear. also could have jammed the shift fork but would have to take off the clutch side case to get to fix that.
How do i download a
I was not aware you could! Please let us all know when you have found a free site, Thanks.
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