DT125R Engine Problem

 

Has anyone experienced problems with big end or main bearing wear on a
DT125? I have just taken the cylinder bore off and found what I would
describe as gunge around the crank with metalic fragments, the engine has
been lying outside (in the bike) for two year without the exhaust on it (did
have a rag poked inside the exhaust port) I am going to strip it down but
some pointers as to what I might find (and the solution would be helpful)
TIA
Andrew

 



on an unknown, i would split the cases and get out the
mikes. replace anything not spec and off you go.
barnyard engines aren't worth taking chances on.
rebuild it right or buy a good used motor.
you may find anything...up to a rats nest, that's why i
suggest a teardown and mike up.
let us know what you find.

i spenty the day on my $300 78 sr500. i found a good front
master cylinder and did the inspection of pads. install
bleed and test. then i had to swith the brake light switch
out and test it.
then i took off the no baffle pisspot muffler some idiot
welded to the stock header, (moron made a lod, lousy running
bike) and stuck on a supertrapp with 10 plates.....sounds
like a thumper should.
lastly i started the dread electrics. the bike runs well,
but has no lights. it was wired up to have no battery, so i
thought it would be easy. well, there is no capacitor, just
a hot lead that disappears into the harness and no ground
wire. how the hell does it start?

 


Andrew Dix wrote:

Check to see if the metallic stuff is magnetic. The needle bearings in
the big end of the connecting rod are very prone to wear out in a
high-revving 125cc 2-stroke.

Two-stroke connecting rods will normally rock from side to side, if you
grab the small end and try to move it, but you shouldn't get any
perceptible movement radially on the rod pin. A repair manual will tell
you how much rocking is acceptable.

 

Thanks for that, have decided to try and split the casings and have a look,
there is a fair bit of side play on the con rod and a little up and down
movement not sure how much is acceptable and I don't have a manual for it.
Don't want to spend money on it if it's not worth fixing!
The parts are metallic they stick well to my pick up tool!

 

Hey do you have the contact breaker gap because i need to replace mine
and i dont know the gap thanks