Help with 77 dt 250

[dt502001]

You missed answering 1 important ? is it using gear box oil?

Have you checked the level to see if it's droping or getting thinner.

The cranks seal on the right side if worn would cause this to happen.

[flyday58]

You missed answering 1 important ? is it using gear box oil?

Have you checked the level to see if it's droping or getting thinner.

The cranks seal on the right side if worn would cause this to happen.

Agreed. From experience.

[77 dt 250]

I havent noticed it using any. i just changed the oil when i re-adjusted the clutch and it hadnt been that long since id changed it the first time but the oil looked good when i changed it last

[77 dt 250]

Like i said im new to all of this. i just find it wierd that it only does it at higher speeds in higher gears

[77 dt 250]

I have been riding it and keeping an eye on the oil. i havent noticed it burning any or it changing color.

[77 dt 250]

What causes an engin to overheat and score a piston. Ive had a bit of a mishap. and is there any hope in salvaging the old one?

[dt502001]

Ignition timming,too lean a fuel mix,leaking crank seals. as far a saving the old pistion not a good idea.

How did it seize ie; wot top gear ,cruseing???

[77 dt 250]

Yeah i was crusing on the highway and it died going up a hill so i pushed to a parking lot and it seemed like everything was fine. i cleaned the carb and plug and messed with it a while and got it running. I started heasing back towards the house on back roads and had to stop at a stop sign and it died. when i went to kick start it i could tell something was wrong. It turned over but with alot of resistance. so i stopped and got a lift back to the house.

I took the jug off and it was scored some on the side where the exhast is.

Could it be possible that my oil put got clogged and caused it to runn without oil for a min?

[blackhat250]

Thats a heat seidure" and exaust side is the hottest part, your oil" are u pre- mixing ? or oil tank, ,, I think its more likely to be lean mixture,[ air/ fuel] up the main jet a size,

how bad is it scored, [ jug] is it just alloy that can be rubbed out with sand paper, .. or deep grooves,?

[77 dt 250]

I was using the oil tank. The only reason I say It may be lack of oil is that when i pulled the oil line off the carb i didnt see any in it. I took the tank off and cleaned it out yesterday after my mishap. The jug has very little aloy on it and is fine. the piston isnt to bad. Where would i find a jet at?

[77 dt 250]

After looking in my book i remembered there is a jet needle adjustment. it may be set too lean

[blackhat250]

Yeh you can lift the needle a clip, but when at Wide,OpenThrottle , the main jet size will regulate the volume of fuel, and after a mishap [ patial seize] i would go up 1 /or 2 Sizes,,, whats in her a 150 ? you may need magnifiying glass to read , if so do a 170.

there on ebay ,,,cost nickles "

[77 dt 250]

Yeah book says 150. Ill check it though. Thanks alot. Im new to all of this and that really helps

[Airhead]

1: you need to bleed your oil pump!

To do this, undo the small philips head screw at the top of the pump, when it stops blowing bubbles and a steady stream of oil flows replace the screw

2: you need to prime the oil line!

To do this (when you get the bike running again) Start the engine and pull up the cable to the oil pump (Gently) until it comes to a stop, this will open up the pump pulley and allow the pump to stroke fully so the line to the carb or intake will be quickly filled with oil, if you have a clear tube you will see it

[77 dt 250]

Thank you will do