distance on two stroke bike?

Question

I've just bought a 1981 model Yamaha DT 125 MX and it's in good shape having been mostly rebuilt.
I was wondering how many miles you would be able to travel on one at about 50mph before needing to stop to let the engine cool down and make sure nothing is melting, and also how long you should stop for.

thanks!

Answer 1

Traveling at 50 for an extended period is about the Kindest,Gentlest duty that type of bike usually ever sees.

Picture how most of them spend their lives.
Low speed,,
wound out,
packed with mud,
churning thru the gears
incessantly under load,,,pulling accelerating

"NORMAL" use for those bikes is the hottest,harshest operating conditions.
10~15 ~30 mph in 1st~2nd~3rd gear is MURDER on them .

No Airflow across the engine to cool it due to low road speeds.
And Then engine is usually "insulated" with mud and dirt

Compare that to "road trip" type conditions.
*Engine stays clean
*Air flow remains High and Consistent
*It runs at steady,part-throttle
*Very lightly loaded,,,,except for mountain /hill country driving.
*few gear changes
*few clutch engagement cycles

Fuel capacity becomes the limitation.
You've gotta stop every couple hours to refuel anyway

Extended running at hi-speed is No Prob for engine/gearbox.

But it IS harder on Chain &Tires & Wheel bearings.
Keep chain well-lubed with a good lube.

You didn't say what sort of conditions you had in mind,,,
but if you're planning a "road trip" of a few 100 miles or more,,
there's several small things you can do easy & cheap that make for a better ride.

Good luck.

***Oh,, far as,,,"How long to shut down for Cool Off"....
That really does not apply.
Nothing is gained below normal operating temp.
And when Stopped,,,,Cooling is ZERO

Answer 2

If the Mikuni carburetor hasn't been changed. It may be a better idea to keep varying your speeds between 30 - 50 for the first two hundred miles. Use Yamaha's best two stroke oil and a minimum of 89 octane gas. The higher the octane the cooler the engine runs. Check with a Yamaha dealer concerning stopping to let your motor cool. I really see no need to stop because the thin cooling fins around the barrel of the sleeve keeps the cylinder cool.

Answer 3

Two different answers here!

1. if the bike is in good working order, you , should be able to ride all day!

BUT!

2. a good rule of thumb. you legs will let you know when the bike is getting warm. when you start to fell heat coming thought your pant legs, you are getting pretty warm! so you will probably need a cool down.

the cool down time, when you can put your hand on the head! not a cold head but but just to were its bearable to touch!

Answer 4

it should not over heat if the oil mix is right