Two Stroke Motocross

Two Stroke Motocross Forum => Vintage Two Strokes => Topic started by: jamez-0001 on June 07, 2013, 09:57:08 PM

Title: KTM 495 MX query.
Post by: jamez-0001 on June 07, 2013, 09:57:08 PM

Hello All,

I have a question about my KTM. It's a 1984 495 MX. However, going by the engine number and the appearance of the lower barrel fins, it is a 1983 engine with a low compression head. I am wondering if putting a high compression head on would make much difference. Thing is, I am running the bike without a head gasket, as I can't find one for it. Would this take the compression up by much? There's one more thing - it looks like a 1984 expansion pipe and aluminium tailpipe that's on it. Not sure if the pipes are much different or not?

Thanks.

Title: KTM 495 MX query.
Post by: evo550 on June 08, 2013, 09:20:34 AM

A low comp head is a blessing in disguise,  softer power deliver, runs better on low octane fuel, doesn't get as hot.
Did those old KTMs have a head gasket, I thought they had a recess thingy in the cylinder that the head sat in to seal?
Get the suspension and brakes...I used that term loosely, sorted..and hang on.

Title: KTM 495 MX query.
Post by: jamez-0001 on June 08, 2013, 02:57:04 PM

Well, part of me thinks it's best to leave it alone. It's just curiosity as to how insane this monster can get. I did crash it into a birch tree not that long ago after giving her a handful of throttle, which caused the back end to start snaking side to side then... well it all happened kinda quick!

I didn't think of that - maybe it doesn't originally have a head gasket. It does have a recessed head right enough.

Got brakes working OK. WP USD forks seem a bit firm. Put new front tire on and that made a heck of a difference. The old one seemed like it was made of steel - probably the old rubber hardening up.

It would be interesting to see how it stacks up against a newer 500 or a 450 thumper in pure power. Certainly, in a grass field where there is plenty of grip, it really snaps my arms out straight when it comes into the mid-range!

Title: KTM 495 MX query.
Post by: SachsGS on June 08, 2013, 04:03:04 PM

I almost bought a used 495 once, the ignition failed in the dealership parking lot. I would think the high compression head would yield more torque and one of TSM's members has owned a couple of these KTM's, he should discover this thread soon enough. Evo's right, early WP suspension is very harsh and that front disc brake (Grimeca I think) isn't much of an improvement over the drum it replaced. However, the KTM 495 is well built, tough, and would still be a pleasure to ride (properly setup) in wide open spaces.