4 Stroke 05 250sx-f motor build...

Mihylo33 · Apr 10, 2011

Long story short... My buddy blew up his 05' 250f today racing super moto.

I just need to know what the hottest and best parts are so I can rebuild this motor into a fire breathing dragon. He wants all the best parts so where do I start?...
I don't mind doing the work, it comes easy, I'm just not familiar with KTMs at all...
thanks,
M33 :hail:

Travace · Apr 10, 2011

http://www.rockymountainatvmc.com/oem/id/2.3

i went with mostly all OEM parts on my 525... just looking there might be a good place to start.

MikeinFresno · Apr 11, 2011

Look at Thumper racing and Dave Hopkins for info on rebuilds, head flow work, etc.

Mihylo33 · Apr 11, 2011

Thanks fellas

bajataxi · Apr 11, 2011

and turn it into a 280 while you're at it?
Parts are going to be listed as an '06 (I had the '05 1/2, the first year out).

Mihylo33 · Apr 11, 2011

bajataxi:
and turn it into a 280 while you're at it?
Parts are going to be listed as an '06 (I had the '05 1/2, the first year out).

Thats good info... thanks.

I'm trying to convice him to have PR2 technologies build the motor for him.

http://www.pr2racing.com/index.asp

jackson409 · Apr 11, 2011

I would sneak smoker motor in there when he aint looking :smirk:

Mihylo33 · Apr 12, 2011

jackson409:
I would sneak smoker motor in there when he aint looking

Tell me about it. He had a MINT 04 125sx he sold to buy this POS.... now its gonna cost him 2K just to get it running again. 3k for a worked to the tits motor... He thought the thumper would make him faster in supermotard... it just made him more broke.

He actually said he was struggleing to keep up with the other guys...

timoyz · Apr 12, 2011

I don't know if I'd do the big bore, or not. I've heard too many negatives to ever do that my own bike, but if it was a buddies, that you could see first hand without wasting your own squish... :devil:

I would think some bigger lobes on those cams, and a high compression piston, with a newly rebuilt head, the bike should scream. :ride:

snowflake · Apr 12, 2011

Mihylo33:
Tell me about it. He had a MINT 04 125sx he sold to buy this POS.... now its gonna cost him 2K just to get it running again. 3k for a worked to the tits motor... He thought the thumper would make him faster in supermotard... it just made him more broke.

He actually said he was struggleing to keep up with the other guys...

what the hell did he do? rev it 15k so that all 4 valves dropped?

josmoloco · Apr 12, 2011

Mihylo33:
Tell me about it. He had a MINT 04 125sx he sold to buy this POS.... now its gonna cost him 2K just to get it running again. 3k for a worked to the tits motor... He thought the thumper would make him faster in supermotard... it just made him more broke.

He actually said he was struggleing to keep up with the other guys...

Why did he want such a small bike for SM?

Mihylo33 · Apr 12, 2011

josmoloco:
Why did he want such a small bike for SM?

he's a small guy... 5'4 and a 140"lbs.. He also wanted it small enough to run on the TTR/ fiddy track we have.