20 Most Recent 2005 KTM 125 SX Questions & Answers

go to this link might help you... how do you test the magneto Google Search

Where is the oil leaking from ie front of motor ,left side so on how did it start where you ridding the bike ,just started it , just shut it down after a long ride as this will help in finding what is wrong

check no damage to liner and piston rings , head gasket could be leaking , check measurements of piston and liner and see if gap isnt too big ! what compression do you have ?

this is not the vin vin is 17 digit once u find it on the fork tube i can search it for u

try turning the gas off and take the fuel line off and clean it out or mayb put a screw driver in though it to clean it and then take the carb apart and clean the pilot jet and the main jet then check the carb bowl for any signs of dirt and clean it out. then put the carb back together and put the gas line back on and turn on the gas. let on for about 30 seconds to a minute then take carb apart toe c if gas is in the carb or just lay the bike on its side to see if gas comes out. and if gas does come out try kicking it about 10-15 times or mayb more (no more the 25 times.)and it should start. hope this helps

That would be like riding a fixed wheel bike.Think about how you will stop and start. Only hydraulic fluid will leak. Bad idea!

Question edited for clarity. That sounds like it is just a bad connection somewhere or possibly a bad switch. Remove the battery leads and clean the lead contacts and battery posts with a wire brush. Smear with Vaseline and reconnect. Remove the starter leads and do the same. Then it could be the Starter Relay https://www.google.com/search?q=ktm+450+sx-f+starter+relay+location Or Starter Button https://www.google.com/search?q=ktm+450+sx-f+starter+button+replacement ..

personnaly I would replace cylinder with new OEM

All dirt bikes have a VIN. It is on the steering neck. https://www.google.com/search?q=vin+on+my+ktm+300 ..

Have you checked battery connections. Run switch in the correct position? Checked spark plug for debris? Just thinking out loud..

Drain oil. Use degreaser to clean area. Use JB Weld & allow to set up properly before adding oil.

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Hi, try to see this link and looking for the manual that you need. https://www.pdfmotomanual.com/manuales/ktm/eng I hope to give you an help. Luca

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Hi, most likely your cdi unit or ignition coil needs replacing.

took me a min or two of WTF-ing to see pic and realize you meant a 2-stroke motorcycle..

try replace spark plugs

It's a bad seal of the head gasket. You need a new head gasket and to scrape every particle of debris from the cylinder head and cylinder surfaces that mate with the head gasket. Use the factory specified gasket sealing compound and do a clean job - no blobs or pools of the stuff. The head gasket should lay flat on the surface of the top of the cylinder, and you have to make this surface free of grit, leftover sealant and any other foreign matter before you put the head in place and torque it down. Start with the head bolts just finger tight and then go by the manufacturer's specs for the pattern and amount of torque to be applied. Usually it is recommended that you get to the specified torque amount in stages, going around several times and repeating the torque pattern until you get that maximum rated amount. This will prevent the seal from shifting or warping and should make the gasket seal perfectly. This is the old school method of doing this job. and I have never seen this fail to produce good results. Take your time, be clean, and you will have the results you want.

Check the clutch, adjust, clean, or replace

over full sump fuel getting into sump badly worn rings allowing excessive blow by

Worn out shift dogs.