lemur

Sight unseen it sounds like your engine is running lean, check the position of the cir-clip on the main jet needle, that setting is easy to alter and makes a significant difference to how rich or lean the carburetor operates, one screw adjusts the low speed fuel circuit and the two adjustments together might need attention, idle adjustment screw is in addition to the 2 fuel/air ratio adjustments and all it does is push the throttle slide open slightly. Carburetor cleaning particularly in the emulsion tube which is located in close proximity to the main jet needle is critical, or that can also make the machine will run lean. Reed valve is another service item that can cause your machine to sound different than one that is operating correctly, make sure the reed valves are closing sufficiently to be light tight when you inspect them. ... remove and hold the reed cage assembly up to sunlight and if you see light shine past the reeds you found a problem.

Seeing as you already have MX boots, I'd be looking at it the other way, Trials boot is equally multi-purpose, I even like them for hiking and operating a chainsaw. Trials boots as daily wear do wear out fast, that's a down-side.

I find short levers moved far in on the bars and finger right at the end near the ball gives better leverage and greater friction range, might work for you too 👍 shorty levers go on all my bikes right from new.

I like the Galfer red ones, what pads are you running now? If my brakes act up I often find it is the wheel bearings that are the source of problems, make sure it's not just that 👍 How you have your levers setup can make a huge difference. ... and how many fingers are you using now, should be 1 or you will always grab way too much front brake. ... and is that the brake pad model with no mounting hole in it?

Don't use solvents on the big connector attached to the throttle body it can dissolve the blue silicon sealant looking stuff, but if the bike ever acts up and it's not a bad spark plug check that connector for water.

Ticking sound is not a symptom, the clearances tighten with wear. There is a tiny decompressor on the exhaust valve to aid in starting but you would never hear it, it's way too small. I own trials bikes in pairs so trouble-shooting is always easy. One of the nicest 4-stroke engines ever. You should do a compression check on the engine when it is still new and record that as a baseline for future reference.

Had to do it with every 4RT I owned, usually needs adjustment within 3 to 5 years of use, first symptom will be hard to start. It gets easy after the first time but you have to be very precise with your adjustment and verify the feeler gauge with a micrometer. The head of a red Robertson screw is the same size as the adjuster so you can improvise a tool out of a screw stuck in the end of a wood stick. You need to remove the engine or at the very least lower the front part of the engine from the frame to access the adjusters easy.

All the fools gave the same recommendation, replace the clutch pack with new stock parts and be done with it 👍

Dump the old oil into a clear glass container and you might even see all the problems before venturing inside, watch for water, bits of slide bushings and the amount of grey aluminum discolouration in the oil which came from wear in your lower fork leg.

Ask the TRS dealers in B.C. I already had a TRS battery pack exchange serviced by the dealer out your way.

Surflex plates will look like normal organic clutch plates, I really wonder if he has a mismatch of parts now, I can't imagine the original plates have cross hatch spaces like that. Are we even looking at carbon fibre discs and is that why they are so black? Cork or paper discs should clean up to be cork colour like in the pictures of new ones and nothing in a 2-stroke transmission should make the oil and pads stain black unless it is from burning.

My rule of thumb is: Light oil yields lively suspension, heavy oil retards suspension, do I want my suspension to act lively or retarded. It's the springs that carry the weight, if you need to carry more weight you adjust the spring rate.

Found this: The steel ring in the photo with printing on it appears to be a spacer to make the clutch pack thicker and the fibre plates are not black they are the colour of organic friction plates. These look a lot like your clutch, if your clutch pack is undersized it could be you are missing that spacer. Oil should never be as black as those plates or the oil has been burning in there for a while. Personally for the cost involved I would replace the clutch pack with stock parts and be done with it. add: There are only 3 friction plates in this set because it is for a newer model GasGas, so no I am not suggesting this is the right part for your bike, I am suggesting a previous owner exchanged the originals with something that apparently does not work.

Not sure what the original clutch plates on your bike look like, but the plates in the photos look like S3 aftermarket plates. Thickness of the clutch pack should be taken from the service manual. The transmission oil I use in all my bikes is the same oil they use in a farm tractor or excavator so it is relatively inexpensive and very easy available from any heavy equipment store. The oil will be called UDT (Universal Drive Train) or all season hydraulic excavator oil and is well suited to wet clutch and wet brake applications. The brand I am currently using is sold by Kubota but I have used similar spec oils from other manufacturers with equal success. Oil level should be no higher then the plug where a sight level window would be if so equipped, just like the Jim Snell video they linked you in your other thread.

If the spaces between the friction pads become clogged with friction pad material or if the oil level is way too high oil pressure can happen that pushes against the springs. It is one of the scenarios that can make a motorcycle clutch slip. Yes to the groves needing to be clear so that oil can pass through, some times it is very obvious on inspection where the groves have become plugged with fibre material.

Imagine if you could build something that held all the little round cells in stacks so you could replace just one bad one at a time, sort of like in a 100 year old flashlight. I bet they make them like that some day.

I was not questioning the friction pads being intact, the other guy was, it's the spaces between the pads I had question with and I asked if the clutch pack looked swamped. If oil can not evacuate from inside the clutch pack then hydraulic action can keep the clutch from engaging.

Can't tell from here but if the clutch basket is swamped the oil level is too high. Another thing to inspect and clean is the spaces between the clutch pad friction pads, if oil can not evacuate from inside the clutch pack then hydraulic action can keep the clutch from engaging.

Have to ask because you didn't specify; any chance you over-filled the transmission oil capacity?

Then call it a rotor. We know it has one of those because yours has a crack in it and if you search for 'KTM 50SX rotor' you come up with something that looks very similar to your broken part.

Unlikely but to know for sure you would need another same model bike that is working.

I'd pull it off to determine exactly why it split, see if the crack can be reduced back to zero and hit all the cracks with superglue to reinstall and see if it splits open again.

Owned 5 4RT models from 2005 to 2017, 250, 260 and 300RR, owned 3 at the same time and swapped parts between each to trouble-shoot. Model makes almost no difference because the 4RT didn't change much to the point where most parts from one will fit right onto the next and work just dandy. I have the header pipe with the Cat converter and the O2 sensor from my 2014 260 4RT sitting in my spare parts box. That was my only 4RT that came in the crate straight from Spain unopened.

You're right, sometimes it's better to direct the question to the source of an answer and let the reader figure it out from there 👍 https://www.nature.com/articles/s41598-023-43695-6

When I installed the race kit on mine and removed all the street stuff the only thing I had to alter was the idle screw after letting it come up to operating temperature. It came with the catalytic header plus the straight header plus heat shields for both, ECU seemed to know how to deal with either way or with restrictors in or removed. PGM-Fi works brilliantly, only way I could make one run rich was if the air filter was plugged.