KA100 rebuild DIY

How ambitious would it be to try this kind of work yourself? If the top end needed to be rebuilt could you in theory buy the piston and cylinder assembly (amongst other things) and do a refresh yourself? Other than likely being more expensive, is this possible? Has anyone gone this route? What am I missing here? I’d really like to get more familiar with these engines.

No need to buy a cylinder, a piston, rings, wrist pin and wrist pin bearing will do the trick along with a proper hone to clearance on the cylinder.

It boils down to how much to do yourself, for a top end, it would be easy to send out the cylinder to a shop to buy a piston and have them do the hone, and then assemble back at home. Otherwise you’d need a rigid hone, torque plates, dial bore gauge to perform the hone. The rest is relatively standard stuff, torque wrench, dial indicators, etc.

I would advise you read through this, decide how much you feel confident doing yourself, and go from there.

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This manual just explained to me why people get confused with the original reedjet from 1998 and the KA 100.

IAME kept the Reedjet name as part of the KA100 engine. However the KA100 has different ignition system, smaller bore, longer stroke, longer rod, different port timing, larger crankpin and of course a clutch and electric start.

Well, what’s your plan for replacing the piston if you seize the engine on track? You should have the next piston size up and a little bottle of hydrochloric acid if nothing else.

I’ve done a top end rebuild on a Mini Swift myself once, which is a just a smaller KA. I just measured and got the correct piston, and honed the cylinder some. It ran strong and was setting track records afterwards.

For a top-end rebuild, I think it’s definitely a good way to learn your engine but if you are unsure of some things you could do, consult an expert and do it along with them to ensure the next time you do it you could be confident in what has to be done. A full or bottom-end rebuild, it’s more complicated when having to balance and rebuild the crankshaft. Also, I don’t know your capabilities, maybe someone else could do it and figure it out and maybe you can’t, I don’t know you. What is easy for others may not be easy for you. tbh it is a complicated question since it depends on the person working on it and what help and tools you have. Is it possible yes, but is it also possible to do it wrong yes. It’s all up to you and your capabilities and what you learn from your research in how to do it at the end of the day.

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