1971 cl100

Been working on this bike this week before classes start up again. I swapped the crank over to the 125 unit, and I looked over the transmission and replaced one shift fork. Other than that, nothing else really looked too bad. Someday I would like to build this engine from the ground up, I’d love to see just how far I can take it on original cases, but today is not that day haha. I think I’ll place a big order with David Silver in the next week or so here and get the piston and some other misc stuff.
For anyone else messing with these engines, I did find that swapping the cam cover and cdi unit from an atc200 or trx200 (looks like that spare engine is gonna come in real handy after all, thanks ken!) is possible and there doesn’t seem to be any issue with fitment on the one piece heads, albeit some slight overhang on the cam cover. Only difference I can find is the “snout” on the earlier cams seem to be shorter, so it doesn’t extend all the way through the pickup rotor. I plan to either just use a longer bolt here, or swap the 200 cam over altogether. I believe the cams should be direct swap, though I’m not 100% sure yet. But I figure this would net some performance and help make sure everything fits just right.
There will definitely be some wiring and electrical guesswork to get this converted to CDI, but I think it’d be worth it in the end

If anyone has any pointers or experience with doing a CDI conversion and cares to share some knowledge it would be much appreciated!

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Crank is in, cases are back together, just need to get the piston and get it to a machine shop. I also will be doing the exhaust valve as it’s a mess, as well as the rocker and rocker pivot pin on the exhaust side, as they’re pretty bad. This engine is is worse shape than I’d hoped, I could easily dump a lot of money into it but I’m hoping replacing the worn parts and keeping up with maintenance will get me some good miles before I stick something else in this frame someday.

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What's the valve seat look like? And the rest of the inside of the head..
What's the valve seat look like? And the rest of the inside of the head..

Believe it or not, perfectly fine. The seat actually looks really nice, and the rest of the head/combustion chamber and piston crown too. It almost looks like corrosion to me

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Finally ordered the piston and new valve for this. Will be taking the cylinder and piston over to the machine shop soon hopefully, and then I can start reassembly. While I’m waiting I tore the bike down to the bare frame and rattle canned it. It’s not perfect, but far better than it was. I tried to find SEM paint but I couldn’t get it locally, but the krylon fusion actually came out much nicer than I expected it to. Worth the extra couple bucks.

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