250SXF prone to seize?

[Rotorranch]

Are the 250 SXF's prone to seize?

The '07 parts bike we bought is totally seized. The piston stuck real good, and the crank is locked up too. But the rod is free.

Now, the '06 we got seized too! Got it running, and The Kid rode it down the driveway for about 45 seconds before it locked up. :

I'm not real happy right now. :

Rotor

[Rotorranch]

I guess not. I guess I'm the only guy with 2 seized up KTM 250 thumpers.

Rotor

[KKXR400R]

WOW.....Thats crazy. I have not heard anything bad about theses bikes whatsoever. Have you tried KTMtalk to see if there's something going on? good luck and keep us posted.

-Kevin-

[crfjedi393]

The main issue the Duncan crew has with KTM's is the carb.
You say the piston is stuck and the crank is locked up but the rod is free. So I guess it's not a wrist pin or a rod bearing that is the problem.

[Rotorranch]

I haven't posted on KTMtalk yet. I figured I'd try y'all first, since I don't lurk too much here.

I've been lurking there a couple of months while researching the KTM's, but haven't seen anything about seized motors.

Maybe I'm jinxed.

Rotor

[Rotorranch]

Originally Posted by crfjedi393

The main issue the Duncan crew has with KTM's is the carb.
You say the piston is stuck and the crank is locked up but the rod is free. So I guess it's not a wrist pin or a rod bearing that is the problem.

Got no problem with the carb. It didn't run long enough.

On the '07, the rod is free on both ends. No radial movement. The rod didn't seize. The crank is locked up, and the piston definitely seized. Pretty big time. I've not torn down the bottom end to see what locked the crank up. I should get on it tomorrow.

I don't have any idea yet what seized on the '06. It kick started, warmed up, then seized.

I'll get pics of the '07 tomorrow, the '06 when I get it torn down.

So from what I'm hearing, there really isn't or is a precedent for the thing seizing?

And just to add, there IS oil in both bikes.

Rotor

[crfjedi393]

Originally Posted by Rotorranch

So from what I'm hearing, there really isn't or is a precedent for the thing seizing?

Not that I've heard anything about.

[Rotorranch]

Got the '06 torn down...the big end rod bearing seized. Piston, cylinder, and head all look good. The mains are free.

Wondering why the rod seized.

At least The Kid still has the KXF250 to ride. His crossover to "the darkside" has been postponed.

Rotor

[Rotorranch]

Here's some pics of the '06 partially torn down. We have to go deeper.


The piston looks good, but we will probably replace it while we're at it.



View of the front side of the piston and crank.



The bore looks good.







Looks like they ran cheap gas.



We got work to do, and money to spend, unfortunately.

Rotor

[Rotorranch]

Pics of the '07. Seized crank and piston. The rod moves, but I think it's damaged too, upon further inspection.

This is what we got of the '07, plus a rear wheel that's now on the '06.




The pic is a little dark, but you might see what looks like the big end of the rod got hot. But it's not seized.



The piston definitely seized!



The front side of the piston looks good, though.



Rotor

[char393]

Man Rotor...looks like you've got quite a project on your hands.

The pics of the '07 make me bank account hurt.

[Rotorranch]

Originally Posted by char393

Man Rotor...looks like you've got quite a project on your hands.

The pics of the '07 make me bank account hurt.

Yeah, it makes my wallet hurt!

We got the '07 for a parts bike, since my buddy and The Kid both have '06's. Figured the wheels were worth almost what we paid for it. Plus the foroks, shock, etc made it worthwhile.

The '06 was bought for The Kid to ride, but it blew up about 3 minutes after we got it home and got it started.

Really want to figure out what caused both failures.

Rotor

[pjg351]

Bad news Roto! A mate of mine who is mad on KTM'S has 06 and a 07 250's, has had the same results as you. His son does a lot of racing and he has some dealership support, but he is on his 3rd engine on the 06 and 2nd on the 07. He said one time for sure the motor got dusted because the way those air filters are to be put in right. Another time the rubber mount that joins the carby and the head split. He also said they are notorious for breaking the top engine mounts, he was going to strengthen them up, but was told not to by KTM as there was a chance of braking out the whole side of the head where they connect. 35 hours is about all he can get out of a engine before it blows, they unfortunatley don't seem to have the reliability.

[Aus_Rider_22]

This is the first I've heard of repeated engine failures on these bikes.

Even on KTMtalk.com I haven't noticed recurring engine problems. There must be a problem somewhere along the line. Maybe some of the engine guys can offer you advice based on the pics.

I am assuming you bought the 06 second hand as you mention the previous owner using bad fuel. What fuel and jetting specs you running? As well as oil? Just trying to get familiar with what you are running

[Rotorranch]

Originally Posted by Aus_Rider_22

This is the first I've heard of repeated engine failures on these bikes.

Even on KTMtalk.com I haven't noticed recurring engine problems. There must be a problem somewhere along the line. Maybe some of the engine guys can offer you advice based on the pics.

I am assuming you bought the 06 second hand as you mention the previous owner using bad fuel. What fuel and jetting specs you running? As well as oil? Just trying to get familiar with what you are running

Not much help here...we had just got the bike. Took the valve cover off to check the valve clearance, changed the oil with Valvoline 20-50 petroleum oil, cleaned the carb, fresh gas, and started it. Warmed it up, then The Kid eased down the driveway about 200 yards, and the rod seized.

Rotor

[Florida 393]

This is a new one to me. I'd go ahead and post up at KTMTalk they are super people there. I imagine KTM USA would be interested to know what is going on with 2 250 SXF having crank and piston seizures. Please keep us posted on what happens with them.

Bill

[jim_513]

My 06 250sxf rod siezed. This is the 3rd ktm in my area to do the exact same thing. Some one on KTMTalk said something aboud the oil passage around the clutch cover area, but you have to take off the whole side case to get to it( which I have to do anyway). I think I can smell pre-mix in the near future