78 400 crankshaft

Would anybody know what cranks I could swap out with my stock one. I have this 78 400 c model and the crank is shot. I can't find any info on it. I found this kz440 motor that looks almost identical to mine only difference is the cam chain tensioner. And I was told the crank is still good in it.

The KZ400 and KZ440 cranks are different part numbers. Ed

So I just have toto find one wih the same part number!? Correct?

Sometimes you can interchange parts between models but swapping a crank is not typically that simple. Hopefully there are some twin experts that can chime in but I think you would be better off looking for a 400 crank or a new engine.

Edit: just checked ebay and there are quite a few KZ400 cranks for sale for cheap.

If you find one with the same part number it will be a direct swap. I don't know why the KZ440 crank has a different part number than the KZ400, but it may be that the ends of the cranks are different. The image below shows a comparison of photos I found on the internet. I don't know how accurate they are, but it looks like the crank ends may differ. Ed

Note: from the diagrams at Partzilla there appear to be at least 2 different crankshaft part numbers for the KZ400, Their cross-reference isn't 100% accurate so be sure to double-check the diagrams for each model.

There's the deal breaker.
Steve

The '78/79 KZ400 is a hybrid engine. It still has a roller chain in the new
style cases (KZ440). The 440 has a hyvo chain (link plate).


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Can you use the whole 440 motor? Or at least what there is of it?