Old Dog back in the Game.

[ScomanKTM250exc]

Greetings all, I've been away from the sport for some time now but recently felt the urge to return....

Thought I'd kick it off by buying an inexpensive older machine in order to find out if I still had it in me........Turns out I've got mud in my veins as I'm bloody well loving every minute of it.

Few problems with the bike though and I'm wondering if you guy's could lend me a hand.

Bike: 1994 KTM250EXC
Problem: Terrible Misfire at high Rev's.
Fails to start by kicking over from cold. Need to run start it every time. Once warmed up able to kick over no problem.

Now just before everyone goes down the re-jet path I believe the bike has been recently re-jetted, besides at this stage I think she's running rich anyway.

Some thoughts I've had,
I've noticed a large crack in the expansion chamber, may be some debris floating inside causing exhaust blocking, yet to check. Heard this can sometimes cause starting and high rev problems.

Silencer seems to be useless may need to be repacked. I've read this can create excessive turbulence which may result in high rev issues.

Anyone have any thoughts about these theories or another one to add? I'd like to begin checking possible causes off the list and work via a process of elimination....

Any help would be great.

[bajadog]

Welcome.

I haven't had a two smoker in a while, but I would pull the reed valves out
and inspect them. At least eliminate the easy things first.

Is the choke not working?

[ScomanKTM250exc]

Thanks Bajadog,

I'll keep it in mind but at this stage I'm not in a mad hurry to pull the engine apart as it's not long been rebuilt and I'm assuming reed valves would have been replaced with the rebuild. (One would hope)

If I'm not successful finding another cause I'll definitely check it out though...

As for the choke it seems to be working fine......Still puzzles me why I cant start it by kicking from cold. Although if it's been started within a 24 hr period prior to kicking it over I can usually get it started by the 4th or 5th kick from cold.

If it hasn't been started for a few day's, forget it.....Run start only.

Anyone else have any thoughts?