2005 Yamaha DT 125 X - Answered Questions & Fixed issues

Two cycle engine injection oil - any quality two cycle injection oil.Crankcase oil - Quality 10-w30.A DT2 is a 250cc enduro - on/off road.

1. Why do you think you need a "racing" cdi? What circumstances present themselves to require you have a "racing" cdi?

hi,most two strokes run a gear oil in the gearbox,unless specified by the manufacturer dont use engine oil as it is not heavy enough,i use a 75w gear oil in my nsr 250 and it works fine..cheers

10w40 is what you want for the gear box. Yamalube two stroke engine oil is what you want for the small oil resevoir side cover

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Do a Vin number search and you will find out what you have, the frames are identical as i have done complete builds of both the 125 and DT175MX and every part fits each bike here in the UK

your clutch disc might be bad.

Not familiar with that bike...is the oil tank higher than the carb? I have seen 2 strokes weep past the injection pump into the carb if the tank was high. a simple fix to that is to get a longer line and put a loop in it. I have also seen vents on the oil tank get clogged with dirt, then expansion of the oil in the tank forces it into the carb...check to make sure the tank is venting. If it is venting...then I would loop the oil feed line,,,don't even really have to loop it...just at some point the line needs to be lower than the carb, how much lower is trial and error, but oil generally doesn't weep upwards very easily.

If is violently loosing coolant from overflow then best case you need new radiator cap worst case head gasket needs replacing.If it squirts a little when hot now and again or when you turn motor off squirts or drips a little then this is probably normal. just releasing pressureI am guessing its leaking alot or you wouldn't have posted here.www.motoxpartsonline.com

if it seems to be running fine, its probably about as good as its gonna get. the 125 just isn't a power house. you might be able to gain a little bit of extra power through add ons like exhaust, rejetting the carb, etc.

32 to 1 is the proper fuel mix > 4 ounces of two stroke engine oil per gallon of gas. Advance the timing a couple of degrees for more rpm. The power wil come with the revs. Boring the cylinder and installing a larger piston will help. Also, consider installing fresh crank seals. Rejet the carb one or two steps larger and move the jet needle clip downward one or two notches.

Hi,,,put a bigger sprocket on the front and or smaller gear on the back wheel.

more teeth on front less teeth on rear

usuaully rule of thumb .002"piston to cylinder wall clearence,anything more than .004"is about do for next size piston and bore.

Hi,
A new one costs about 3990.00 euros
and a used one from 1000 to 1800 euros, here in italy.
Regards,
Alex
PS-Dont't forget to vote me, thank you !

If you don't put pre-mixed fuel in your tank then the tank in the back is probably a fuel mix oil tank. You'd use an injector oil to fill that so it has something to mix into your fuel. Engine crankcase oil is a different thickness and wouldn't work for that application.

2 stroke poop! A certain amount of this is normal due to the oil/gas mixture you're burning. However, type of 2stroke oil used, amount used, and jetting of the bike can all affect the amount. If it's coming all the way out the back, it's time to repack the muffler. If this is the case, you'll probably notice your bike is a little louder and raspier than before. This also impacts performance negatively and, eventually, the inside of your muffler can start smouldering.

use a strong light and look under the seat and behind the side covers or follow the wires back to their source. also try the web and look up your bike and see if a manual is posted on line with this info. also going to a dealer is a good idea as the parts counter will usually gladly look this up for you. good luck

Yes , time to top up the oil, Yamaha just want to give you plenty of notice, cause nothing will destroy the engine quicker than running out. I would be topping it up as soon as you see a bubble in the window.

Yes instrument lights at least should come on.
Power goes from the battery to the ignition switch via the main fuse, & then splits to ignition & lights (via auxiliary fuses if present) which are separate circuits.
The problem could be an auxiliary fuse (if fitted) then contacts inside the ignition switch or wiring/connections from the ignition switch out to the ignition circuit
That is presuming the cluster light bulbs work!

Hope this helps ( if so please mark as very helpful)
Ride Safe
Bike-Doc

it wouldn't be the thermostat unless you have it installed backwards. you can gain a **** load more power by putting in a performance camshaft and a full pipe.

Check you float needle is not stuck ,and is not shutting of the fuel