Dax KTM 50cc clone build

I'm working on a new build, using a KTMC 49cc motor. This is going into a very old Elgin 26" frame. It is a tight fit.

The motor mounts consist of two holes at the back of the aluminum case and one at the front. The holes appear to be tapered inside. I drilled them out with a 3/8" drill bit. Then, for the back mounts, I heated and bent a long 3/8" threaded rod to a 90 degree angle, then heated it again for the second bend, quickly pulled it through the hole and bent it again while it was hot. Hard to describe, but that made pretty good motor mounts.

I purchased an extra wide pedal crank on ebay from someone calling it a "Whizzer" crank, but I rather doubt it has anything to do with the original Whizzer company. This crank still doesn't fully clear the motor, but seems OK with the motor mounted high.

Getting a working muffler is a major engineering challenge. I purchased a pipe from Dax, chopped it up into sections and welded it back together in a way that would fit the bike. This is difficult and I am a lousy welder. It still has some tiny leaks, but I'm out of acetylene so it has been clamped in place. The exhaust is kind of a fiasco, but I'll make it work eventually.

The motor (engine) ships with an NGK plug, but the reach is obviously too short for the head. The plug is also too long. I got a shorty lawn mower plug that just barely fits.

The front sprocket is made for a 420 chain, but the rear sprocket is made for a 1/8" chain... So I ground down the front sprocket and put a 3/16" KMC 415 chain on there. Grinding it down took a while.

I purchased a rear rack gas tank (with rack) from Bikeberry. The tank is supposed to go beneath the rack, but it obviously won't fit my bike that way. I had to put the tank on top of the rack and then bend the rack mounting arms in several places to make it sit at a somewhat normal angle. The petcock is all the way in the back.

I am putting Sturmey Archer hubs on there with big internal brakes and using 13 gauge spokes. I managed to put a 5 speed rear hub on the bike and have cut the rear sprocket out to go around it. Looks like it will work..

I may be at this for a while.

It's just one of those little E3 plugs from Autozone. This plug doesn't have a long enough reach either, but at least it fits in the frame. Now I'm waiting for some handlebars in the mail; the old ones didn't quite accommodate the throttle and brake levers. Then I should have all of the parts - knock on wood. The chain tensioner pulley is a little close to the exhaust so I'm thinking it's going to melt and I'll need the metal one.
- say, Bill, what did you do for an exhaust?

"too lazy to look in the book" <-- sounds familiar. They said they didn't stock any such plug, but could order one if I could give them a cross reference or a part number.

Mine's just about ready for a shakedown cruise. Need to know how much ATF...

http://www.ktm.com/dealer-service/service/manuals-documents.html ...
.. looks like a mini adventure... 0.15 Liters .... ok, now to drain and measure.

ATF level should be good now. Thanks, Bill!
I discovered that the standard throttle cable is actually too short for the clone carb, but that's fixed now too by screwing a shorter tube on top of the carb where the cable attaches.
The motor starts and runs. Low vibration; sounds nice; quick throttle response.

The clutch hardly seems to engage. It just barely pulls when revving it medium-high. Maybe it is fouled, out of adjustment or just needing to warm up an break in...

Clutch woes...
I got a spring set for a mini adventure and put them on this morning.
First I had to make a puller... I used a short piece of bar stock and drilled 2 holes, 28mm apart, and big enough to put a pair of metric #5 bolts through them. Then drilled and tapped a center hole for a 5/16" bolt to drive the clutch loose. That worked. The clutch still didn't work after putting in the spring set, which was a little tricky itself. The key was to put a nut in the socket so it didn't go down much past the bolt head.
It still doesn't grab. I rev it up to an exceedingly high rpm while pedaling along, but nothing. It just doesn't grab. Neighbors probably love me.
there is a relatively large gap between the clutch surface and the surrounding ring. That looks wrong to me. The parts may be mis-matched or maybe the bolts holding the shoes are too short. It's frustrating. I am considering getting a complete set, clutch and ring, but that seems expensive and wasteful...

The springs are apparently too stiff, and the shoes need to be shimmed out closer to the basket. I suppose it won't hurt to jack around with it for a while. Thanks for telling me about the Tomar. That is a lot of $$$, but better than some of the prices I've seen on a genuine KTM setup.

I looked through some of your posts, but didn't find the "setup." Could you post a link or suggest a washer stack? Maybe it is worth another try or two before I get the Tomar, which frankly looks likely.

That's a nice looking exhaust, by the way. What holds the exhaust to the head? Is that a clamp of some sort?

This clutch is not going to cut it. The shoulder bolts appear too short and the whole washer thing is nuts. I ordered a Tomar. It is a beautiful looking looking thing. Apparently you must get the installation kit because it is wider and the case must be widened with a special spacer. I hope the crank for the pedals will still fit.