Heya, I've been messing with these for a minute and I know some of you guys have too, just wanted to kinda share some thoughts and see if you guys have any revelations I haven't found yet. I know a lot of this info is on some of the KTM mini forums but those guys aren't as cool.
All I've messed with are the cheapy eBay/Amazon ones. Some of them are better than others. I usually buy a few at a time, and then disassemble all of them and check the bolt length. I've had them vary by several mm before, and getting them all the same length so each shoe has the same preload is important. The latest batch I got had nicer hardware that was all the same length, so that was cool. Previously I've gotten them where a good amount of the washers they come setup with are cracked.
Same thing with the shoes. They're usually right around 40-41g or so but I tryn pair them in their sets of three that are the closest in weight. Another thing is to make sure each shoe slides easily in and out of the hub, I've had it where some shoes like to bind up instead of being able to move freely to engage and return.
The spring bellvile washers suck. I've tried a buncha different washer stack combos and never was satisfied with how they worked. It was either no engagement and revving the shit out of it with nothing, or grabbing too low. The washers I was using were the shitty ones that came with it, sometime I might mess with some of the stainless washers or some higher quality ones and see if I can find a setup I like. If anyone has had good luck with a washer setup what's your secret?
Replacing the washers with the spring kits is what's up in my experience. They usually are listed as like KTM mini adventure kit or something like that. The ones Ive been rocking I got from a buddy so I dont know their source but they've been working well for me. I used a couple of hardened m8 washers and one of the nicer cone washers they come with to preload the spring to get it to stall happily. I've got a couple different thicknesses of springs. One of them was supposedly passed on from paz and are custom wound thick duders. I couldn't get those to engage, even with no preload washers. Ive seen a few different ones online, I haven't ordered those but if I were to guess I'd bet the ones I like are stainless steel medium? Idk lol
Another thing I think is important is a needle bearing bell. My first KTM setup was a v1 bell with regular e50 gear on it. I wasn't super satisfied with it so it chilled on the shelf after a little bit. Eventually I got some more of the clutches to experiment with, got the bell bored for needle bearing. Idk if it got a little bit out of wack or what but the bell kept eating it's circlip and trying to escape. Back on the shelf again.
I got a set of straight cuts offa treats, which are super nice quality. They come with a bushing tho which is dumb. They solved the problem I had with the clutch bell circlip, but I seized like three bushings to the crank which was a giant pain in the ass to get off before getting it bored and a needle bearing pressed in. Getting the bell welded to the gear well is important too, I've had the gear walk out on the straight cuts before getting a buddy to Tig weld it real nice. On the regular e50 bells I've broken the welds on them a couple times.
The setup I got this on is a polini with the dio vforce and big oko, hpi inner rotor, simonini. Prior to all the KTM bullshit I was having issues with the crank walking, like you could see the flywheel moving in and out with throttle. So I did the dual snap ring mod thing to run dual 6203nr, that seems to have helped that. I imagine the KTM would've exacerbated this problem had I not done that before.
With the KTM ya gotta be rocking the pull start, I've seen a few dudes on here mod them for kickstart cases tho which is rad. I've just got Allen head bolts in the puller holes on the hpi flywheel, the cheap cast pull start and space it out on a stock flywheel cover. I like to rewrap the pullstarts with Kevlar Paracord, the nylon they come with is shitty. If your carb is setup right it starts fine, if it's a pain you aren't dialed in.
Opening it up pretty regularly to inspect is nice, but I've usually been waiting until something feels off. I've had it happen a few times where it won't stall like it's supposed to, open it up and it looks alright, but on closer inspection the clutch hub had a hairline crack thru one side of it. That's been the most common failure I've had so far with them, lol. Another time a bolt broke but I feel like that's just wear
I feel like a lot of this is obvious if you've gone deep enough down the KTM e50 hole, but I bet there's things I've missed and you've missed before
But yea, I like how it works. Throttle response is off the chain, it revs up real quick and takes a second from off the line but then it starts pulling like a motherfucker, pardon my language
Sorry about the book, hope that makes sense (edited)