Does anyone have any good articles or videos on how to rebuild the bottom end on these? How to split/reassemble/balance the crankshaft in particular. I’d like to do my own maintenance just to save the hassle of shipping. Top ends are easy, but I can’t find any videos that go into detail on the bottom end. Kart republic has a series on kz rebuilds, but they don’t mention anything about the crank (unless I missed it).
You need a press and an assemble that goes in between the crank so that you could press the pin out.
Then reverse order. Crank pin should be flush with the crank halves
You also need a truing stand, copper hammer (minimum 600g), vice, flat wedge and a dial gauge
While we are on the topic, I haven’t done one of these bottom ends yet. Is the crank a press fit in the main bearings, and are the mains a press fit in the cases? I ask because on my mod honda, those are both zero clearance slips fits. I loctite the bearings in the cases and let the crank float.
Mains are an interference fit in the case halves, but warming the cases up should be enough to drop them in. On the crank, the main bearings should not be an interference fit.
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With the KZ now using roller bearings for the mains, the crankshaft fits very easily back into the main bearings when assembling, so a similar fit to your Mod Honda, allowing for axial play.
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there are several very good videos on y tube tht expalin pretty well and one can observe pretty well what is required and method variances,if you have the equipment/means then do it.dont be afraid to try,Im totaly self taught and do all if my own repairs except cylinder plating and foundry work ,other than that its all done in house/my shop,you can do it.
What are you using for the hone?
A Nikasil cylinder is not DIY. Millennium or US Chrome. You tell them specs you want. For Moto engines, I would include the new piston, and tell them fit I wanted vs the piston skirt, and the diameter/cylindricity tolerances. I would think a KZ cylinder would be similar.
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