Join Date: May 2019
Location: Newcastle CA USA
2008 KTM 50 sx engine/clutch HELP NEEDED PLEASE
Ok, so I bought my son a 08 ktm50 sx. When I purchased it the guy told me that the person before him put in a ďbeginner clutch". I though nothing of it because honestly my knowledge is limited on these bikes....
Well we got it home and the bike ripped, it was great. It shredded up our steep hill on the track easily and my son loved it.
I changed the fluid in it, the guy gave me a bottle of asmiol ATF fluid so I just stuck with that since it worked so well. I added 225cc even though I only got out 175cc. Fast forward to it running good riding every day for about 1 week the bike starting struggling to make it up our steep hill, it felt like it was overheating so I adjusted the air fuel mixture screw on the carb.... that helped with it a little but you could tell it was slipping big time up the hill so I had him pull it in for the night. That weekend we went to our local track that is flat and the bike ran great, no issues for about 3 hours damn near of straight riding. After that I got home and started researching stuff about the clutches because I want my son to be able to ride my full track at home..... the guy I got it from gave me a bunch of the beveled washers and a clutch puller a bunch of other crap so my dumb a** thought hey ill pull this thing apart real quick to fix it so he can ride the full track a few days before he has to go home to mom.
so I drained the oil, I only got 110cc out of the motor even though about 6 rides (probably 4-5 hours run time) ago I had put 225cc in it. Now my son is 4.5 years old.... his killing it but he does have at least 2-3 tip overs every ride but from what I could tell there isnít anywhere for the clutch oil to come out other than possibly the crank seal????
The bike does have a little smoke coming from the exhaust (doesnít seem excessive for 2 stroke), but it does have oil running down the back of the muffler. There isnít any restrictors or anything in the exhaust it does have a spark arrestor installed.
Iím running at 50:1 because I was told thatís what the bike always been at....
So I pulled the clutch found out that it actually had the mini adventure clutch springs installed instead of the beveled washers.... I found the stock configuration and ran that. OD of the clutch was 81.58mm, my stacks of washers was .5815 for all three. The bike needed damn near half throttle to engage but boy did that thing take off when it did engage. The bike was squirrelly everywhere shredding and tearing the track up. The rear wheel was breaking loose with a brand new tire on good dirt. So I though ok cool he will get used to it and gain control. Well the thing shut off while he was hauling butt on our track..... I took it back in, defiantly have a little scoring on the piston... so know Iím looking up top ends.... the bike had 30 psi first kick on the compression gauge but then I couldnít get it to go past 110psi after multiple kicks.
It still starts and actually seems like it runs fine so I decided to continue to play with the clutch. From what I was reading it was saying that if you want the clutch to engage faster (at lower RPM's) to remove a .5mm flat washer.... and if you donít have any .5 mm shims in it to remove a set of double washers..... I converted the bike from HH (()) (()) (()) () B and went to HH (()) (()) () () B. Now you canít even start the bike without the wheel moving. Was I supposed to replace the removed bevel washers with flat washers???
Everyone Iíve talked to said these bikes are a constant struggle but after they are dialed they are great for at least a bit. My son came off a PW50 since heís jumping now and his suspension was shot of his pw. I figured this was the best route to go since heís really into racing and loves it/wants to do it but now I feel like a POS because he canít even ride. Every "Moto Dad" just says I feel your struggle and a few old times said F that bike just by a crf50 itíll run for ever and you donít have to do anything to it....
Any help with the bike would be appreciated tremendously.....
Thanks for reading my novel.