Clutch set up ktm 50sx

You need to go to ktmtalk.com. There is an entire section dedicated to the minis and much discussion of the clutch.

How big are you? My son has one, he is 10. I really don't think these bikes are good for full grown adults, mostly due to the auto clutch mechanism. You can set the clutch up to hook sooner but you are really straining the hell out of the whole system if you are more than 80 pounds or so. Also, if you haven't done it yet...immediately drain the clutch fluid and replace it with 250ml of your preferred fluid. The manual calls for 150ml and this is not nearly enough. When it slips, it puts enormous heat into the engine and the bike will boil over. I use B&M Trick Shift in my son's bike with an additive called 2TwoCool. Both of these were recommended on KTMTalk. When I went up to 250cc the clutch immediately started to slip less and the bike stayed cooler.

The clutch is probably the biggest tuning item on the bike. It is almost like black magic with all of these different suggested washer stacks. I have not delved into it myself as my son does not race the bike yet, he just plays with it in the dirt. It looks pretty daunting to me, actually. I am already planning the move up to a bike with a traditional transmission for him, instead of going crazy trying to learn all of the ins and outs of the centrifugal system.

Mike

We have been racing the KTM 50's for a little over 4 years now (with about 2 years yet to go with my little one). The clutch adjustment is not very difficult, but it must be done often to keep the bike running at a top level.

In addition to the advice on oil capacity, here are a few pointers:
KTMTalk is a great resource.
The clutch springs are actually cone shaped washers. These washers can be stacked in different directions to achieve the desired engagement RPM. There are a few prefered stacks, but you will find one that your riders likes with a little testing. The main thing to pay attention to when stacking the washers is the overall stack height (should be about 0.630" to 0.650"). The stacks will look something like this (())(())(())((|| where each ( is a cone washer and each | is a flat shim washer. You can change the direction of the washers to change your engagement RPM and how hard it engages. The stack I show above is the one we have always used with an overall height of 0.650".

The individual washers should measure at least 0.047". If they are below this throw them away.

Don't buy the washers from your KTM dealer unless you want to pay $0.68 each. You can buy bags of 100 for about $15 from 50cc parts or C&C racing. They also have stainless steel washers available for a little more, but they last longer.

The more often you change the clutch oil the better. If you disassemble the clutch and clean the washers they will also last longer. They quickly get caked with the clutch friction material which causes the clutch to slip. You will be able to hear a difference when it starts slipping. I usually change or clean the washers about every hour of engine run time.

Ok, so here is the most important part of it. Listen carefully.....






If you have the money, buy a Dominator clutch from D&D. Almost no maintenance, just change the oil often. We have been using one of these in the race bike for about 3 years now, and it works great!

Good luck. It's not as hard as you think it is right now. Once you go through the clutch one time you will be a pro. Remember do not torque the clutch nut more than 25 ft-lbs or you can break off the end of the crank.

Ok, I'm tired. If you still have questions, post them up and I'll try to answer.

The shock is buildable. There is a rebound adjusting colar at the bottom of the shock. If adjusting that doesn't make a difference, then you should rebuild it or have someone rebuilt it. There are also aftermarket shocks available.

One fork leg controls the compression damping and the other controls the rebound damping.

On my clutch cover I used some yamabond adhesive, and glued the gasket to the cover. It has never leaked, and I have had it on and off well over 100 times. Just don't over torque the bolts, and you should not have any issues. The oil drain plugs are commonly stripped out so be careful there. If you continue to use the stock clutch, you will never use the drain plug anyways, just pull the clutch cover and tilt the bike over a little to drain it.

As soon as your kid gets used to this bike, he won't want to ride the XR again.

I don't recall the fork oil level off the top of my head. I would have to dig through my notes to tell you the effect of the oil volume and what we use.

Paolli makes an aftermarket shock as well as Curnutt. I think they are fairly pricey. I'm not sure if Ohlins makes one small enough for the 50, but that is who I would check first. If it were mine, I'd have the shock serviced and revalved.

There are free online manuals at www.munnracing.com. Go to shop online and look in the lower left hand corner. You can get the owners manual and parts manual. These are very helpful.

50cc parts and C&C racing specialize in aftermarket parts. For OEM stuff, I go to Chip at Munn Racing. Same link as above. He has most everyting and is fast to ship. I have a KTM dealer 10 miles from here, but I buy from Chip. Service and part availability are important in this business. Chip is great at both.