help with my bike

[lossinlife]

hello i am rather recent to the sport and thought id try to learn by fixing up an old bike, i bought a 250 yamaha enduro off a guy, but thats all i know, no papers or anything, the vin is 450-024518, i know i can tell the year off that but i dont know how, i know its 70's from the pictures, also how do i tell if its oil injected i was told it is but i see no line to the carb from the oil tank, any help would be appreciated

 

[pryor]

You have a 74 DT 250, the oil injection line runs from the tank to the pump in the right side of the motor. The DT 250 is a good bike and they made a billion of them so parts are easy to get, the first money you spend on it should be a manual it's well worth the 20 bucks, have fun and good luck. :cool:

 

[480 mike]

probally somone eliminated the oil injection because it screwed up if the colour of the gas is blu-ish in the tank then the oil pump is toast.

 

[Rotorranch]

FWIW...I've NEVER seen a Mikuni oil injection pump fail.

We did often remove them back in the day...supposedly you would get .002 more horsepower if you removed it. :coocoo:

Also, the general concenses was the fact that if you forgot to fill the oil tank, you could seize the engine. With pre-mix, if you had gas, you had oil, too!

My Yammie 175's have the oil injection intact.

Rotor

 

[lossinlife]

thanks everyone for the help, as far as i can tell the oil injection is still intact, the bike does start every once in a while but not easily, i'm thinking my gas and air screws are off, any suggestions would be awesome

 

[chiro972]

Make SURE the oil injection is intact and working. If it isn't you WILL seize the engine. I never liked the things. I like to pre-mix my fuel.

 

[pryor]

Check to see if your oil pump is working if it isn't pre mix your fuel 32to1 you don't want to end up with both or neither. If you have fresh fuel and a new plug and it still wont start easy pull the carb apart and clean it real good you may have a pluged pilot jet, also worn reed valves will make it hard to start, check them while you have the carb off new ones are cheap and easy to find, boysen makes cool two stage reeds for it. If you are going to ride it on the street keep the oil injection as Rotorranch said they are real dependable as long as you keep it full of oil and the lines are good, the only problems I have had is with the cable that controls the pump and that was just bad maintenance.

 

[lossinlife]

what would be the best way to make sure the oil pump is working

 

[pryor]

If it was mine I would remove the oil tank and clean it out, then check the line going to the pump and the line from the pump to the intake, also you want to make sure the throttle cable going to the pump is hooked up and working. If every thing checks out refill the tank, bleed the air out at the pump by opening the bleeder screw, its next to the supply line, turn the wheel at the bottom of the pump until all the air is gone. then start the bike (I would use a little pre mix just in case) and see if you have oil at the banjo fitting going into the side of the intake. A good manual will show you how to adjust it properly.

 

[lossinlife]

thanks pryor, the manual is on order