20 Most Recent 2001 KTM SX 125 - Page 3 Questions & Answers

I dont know of any bearings in the basket. The clutch consists of the basket(drum), clutch shoes(3 of) on a centre hub and disc-spring stacks(one stack to each shoe) consisting of disc springs(that look like washers) and a bolt. All of which can be replaced seperately.
To remove undo the centre lock nut.Get the drum assembly off the crank(you'll need a puller for this). Take the shoe assembly out of the drum. Mearure the inner diametre of the drum and the outer diammetre of the shoe assembly. The difference between the 2 measurements should be between 1.50mm an 2.00 mm. If the difference is bigger you can insert a shim between the center hub and shoes up yo a maximum of 1mm shim, then you'll need to replace the shoe. Clean the disc springs and check for wear. Replace if needed.
The quickest way to mess up your clutch is to run on old oil. Change the transmission oil after a maximum of 5 hours riding. It needs about a cup full(250ml) so it is really not expensive considering a set of clutch shoes will set you back $60. Dont neglect this.

You dont normally need to set them, just leave at original mark

You have an internal problem with the shift mechanism.You will need to remove the clutch cover to identify what is broken.It is rare that you can't fix a problem such as this from behind the clutch cover.(ie no need to split the crankcase).pull of the clutch cover & look to see if when you try to select gears if the selector drum turns. It should then be apperent what has gone wrong.(circlip fallen off,selector drum actuator or spring broken)
If you find something broken you need to find all broken pieces before it goes back together so it/they don't find there way into the gearbox or BANG your gearbox will go.
Hope this helps
Regards Andrew porrelli

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.

Make sure cables are working . Follow it down to clutch and make sure clutch lever is actually moving. It is does then pull clutch in and pushbike backwards. Should release If not , plates are probably frozen through excessive heat. Replace them. If lever does not move when clutch handle pulled, then adjust or broken cable. hope that' it, easier and cheaper!

Make sure the wires on the other side of the relay box are holding when you push the relay in.