Top 20 2008 KTM 250 SX Questions & Answers


i would remove the clutch assy and check all parts including rear bearings ! something is failing !

2008 KTM 250 SX | 227 views | 0 helpful votes


The KTM SX is a 2 stroke,the SX-F is 4 stroke.

2008 KTM 250 SX | 315 views | 0 helpful votes


dont recomend it if piston liner is going to fail as it could trash the crank and make you cry ! P...

2008 KTM 250 SX | 64 views | 0 helpful votes


The arrow should point to the front of the bike.

2008 KTM 250 SX | 803 views | 2 helpful votes


Sounds like the main jet is clogged, or you have water in the bowl..
First try draining the bowl on the carb, drain into a glass so you can see if there is any water dirt etc... If there is water, it should be fine after that. If its the main jet you are going to have to remove the carb and clean it.

One other thing it may be. If it has a CV carb (constant velocity) the boot may be ripped on the slide causing it not to lift during acceleration.

2008 KTM 250 SX | 214 views | 0 helpful votes


Check the compression, I dont know what the manufacture calls for the gas oil mixture ,but that sounds too lean..

2008 KTM 250 SX | 390 views | 0 helpful votes


Hi and welcome to FixYa,

Offhand, the only factor to be checked that could foul a sparkplug for your bike would be the 2T oil injector/pump. There is too much 2T oil going to the combustion chamber. Either the injector would require restricting or for some reason, there is also 2T oil in the fuel tank (pre-mix).

Good luck and Thank you for using FixYa. Happy Holidays.

2008 KTM 250 SX | 819 views | 0 helpful votes


Take the engine apart and you will find out.
Quite possibly will need new piston kit and a thorough cleaning and you'll be fine.
If you're unlucky, main bearings, and cylinder coating repair.

KTM 250 SX... | 172 views | 0 helpful votes


Mervin, I'm not a motorcycle mechanic, but just knowing engines as I do, I would say drain the fuel tank and replace with new fuel and either a water remover additive or a more complete fuel treatment (Lucas makes some great products for that); pull the plug(s) and check them for any corrosion or buildup, replace if necessary; change the oil and filter; check the air cleaner; and check tensioning on any belts. I'd also suggest either replacing the battery straight away or just putting it on a charger for a while so you know it has a full charge when you go to start it - if you need to replace it, that will eventually become evident, but you should at least be able to get the engine started and see what else -if anything- needs doing.

KTM 250 SX... | 39 views | 0 helpful votes


The starter pinion attached to the kick pedal has an ratchet pin that engages in the engine shaft - the role of the pin is to allow the engine to turn freely once started. This pin is pressed on the shaft with a simple spring that in your case either broke or went out of position.
You will need to open that side of the transmission, access the starter mechanism and refit or replace the pin and its spring - it's a delicate job, work very carefully or you can do a lot of damage if you try to start the engine with the parts misplaced.

KTM 250 SX... | 23 views | 0 helpful votes


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

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KTM Motorcycles | 83 views | 0 helpful votes


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.

KTM Motorcycles | 115 views | 0 helpful votes


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

KTM Motorcycles | 77 views | 0 helpful votes

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