How-To: KTM 250 350 380 SX MXC EXC Top & Bottom Engine Rebuild 2003-2015

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Here are two new videos for you 2 stroke guys out there. The top end video covers piston & ring replacement, power valve maintenance, and runs 1 hour 10 minutes long! Bottom end video runs 2 hours 50 minutes long and covers crankshaft and transmission disassembly and reassembly.

Don’t pay a shop $80+/hr when this is a job you can totally handle yourself. I’ll walk you through the process step by step in this easy to follow video tutorial. Have a question? I’m here for email support every step of the way.


Service Manual

I found a cool website that has several KTM service manuals available for free. Please help support this site by hitting the donate link at the top.

KTM Service Manuals




Tool List

Here is a complete list of special tools. Most can be bought from Amazon.

Motion Pro 08-0008 Clutch Holding Tool – Holds the clutch basket while loosening/tightening the nut.

Motion Pro 08-0427 Gear Jammer Tool – Jams the gears allowing certain fasteners to be removed/installed. Super helpful since it has a magnet to keep it in place.

Motion Pro 08-0026 Flywheel Puller M27X1.0 L.H External Thread – You will need this puller to remove the flywheel.

Tusk Crankcase Splitter – This tool was not needed to split the cases. However, it does serve a way to press crank out from RH side.

BOA BO13010 Constrictor Aluminum Strap Wrench – This tool is awesome for holding pretty much anything. It’s aluminum body and rubber “grippy” strap makes it a solid tool.

Lisle 56750 Seal Puller – Nice tool to remove seals.

Impact driver – I have the Vessel 2500 which has been discontinued. Click here for the Vessel page, they have a newer version and sell JIS bits.

IR Temp Gun – Great tool for measuring case temperature.

Assembly Lube – Lube it up!

Moly Grease – Some areas call for Moly.

Three Bond Liquid Gasket – I used Hondabond. This Three Bond is pretty much that same stuff.


Part List

If you have an OEM crank, it would be best to send it out for a rebuild. Since the stock crank was long gone in this bike, we are replacing the Hot Rod crank with a new one. Hot Rod costs a fraction of what the OEM goes for.

Hot Rod Bottom End Kit CBK0006

Vertex 23375B Replica Piston Kit



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