KTM 50 SXR COMPRESSION QUESTION

[Chris Vecchione]

My son has a 1996 ktm 50 sxr that was purchased used.the bike seems to
be loosing power,so i did a compression check and the best reading i
could get was 50 psi. what should the compression be on this engine?
also does anyone know what the cylinder bore is stock? and the
tolerences? thanks in advance, chris

[PRCTNY]

1998 Pro Junior +-40 hours, 145 psi with cold motor.

Hint: Don't practice wheelies on driveway. Kid complains about scratches on
bike.

[TSMaxel]

In article <8982-37B...@newsd-152.iap.bryant.webtv.net>,
chris...@webtv.net (Chris Vecchione) writes:

Sorry, I don't know what the cyl bore is stock... I always bought the pistons
and took them in with the cyl to be bored. You can buy a s"stock" piston and
it will be stamped with an A B or C on the top. If I remember correctly, the A
is a slightly larger bore than the B or C (or the opposite).

As for the compression, you are low. Our KTMs were around 170 psi... Except
for our 50SXPro. The head was milled .080 and cyl bored .050 and ran at 190 to
210 psi. It was a pain to start, but she ripped!

TMax
'94 RM 250
Currently, 80less... :-(
'99 PW 50