90's/vintage restoration project in Phoenix

… moving my restoration project to this thread…

I am trying to restore a few engines and karts from 90s and early 2000s.

Yamaha kt100
Rotax DSC Formula A
Parilla Leopard TAG

Roller frames:
Top Kart (small tubing)
Top Kart (larger tubing)

I raced for several years but never got to fully learn how to work on the engines and carburetors. My engine builder passed away and I want to honor him by restoring these karts (maybe even race in a vintage class if they do it here in Phoenix)

I’m a noob in terms of working on the engines so thank you in advance for your patience and help!

Question about the KT100 disassembly:

I have a long crank (for a wet clutch previously). I run direct drive so I think they put some spacer on the shaft. I have a gear puller but it isn’t long enough to reach the gear. Any suggestions on how to remove it?

I already removed the starter nut but can’t remove the spacer or the gear.

Try using a torch to heat the ring and gear to expand the metal enough to break free of the shaft and slide off. Don’t over do it or you may scorch the seals.

It’s going to take a puller of some sort. Drops mic

Thanks everyone, I picked up a gear puller set and got it off. It was just stuck on there well. Interestingly, the gear is friction fit only with no key.

Not sure what the gear was from originally.

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Please bear with me as I’m just a bit paranoid of breaking something along the way…

On the Rotax, do I just need to use a piston stopper and wrench off the rotor?

I am going to go out on a limb here and so, NO! Rotors are usually keyed to keep the timing correct with the shaft. Try using the puller tool again.

Thanks Greg. I did try again tonight with the gear puller but it wouldn’t budge and the puller kept slipping off.

I started removing the rest of the crankcase bolts so maybe I can at least take a look at the rod and crank after splitting it open.

Here is the rod and crank for the Yamaha. I think it looks ok but let me know if anyone thinks otherwise.

I’d avoid using a stopper and try an impact with the puller. Sometimes the rotor is keyed, sometimes they are just run on the taper.

The latter if done right (lapping compound) can be more reliable in a direct drive than relying on the woodruff key to hold the rotor.