How much tension should i feel when rotating the transmission main shaft?

John Lusignan /

How much tension should i feel when rotating the transmission main shaft on a 1978 Yamaha Chappy LB50PE? The video shows what I mean. When I tightened the case screws it seems that the shaft got really hard to turn. Not impossible by any means, but the crankshaft turns freely and the transmission shaft takes plenty of torque to turn. My first engine rebuild and just want to make sure I have everything right. Thanks in advance! John

Re: How much tension should i feel when rotating the transmission main shaft?

hmm, never done one of those but tightness isconcerning. id start tapping around w a block of wood looking for the chance of seating that bearing thats off kiltered.

Re: How much tension should i feel when rotating the transmission main shaft?

John Lusignan /

Pat

Thanks! So you think there might be a bearing that's not seated right on one of the shafts?

John

Re: How much tension should i feel when rotating the transmission main shaft?

I bet it'll free up once you run it.

Re: How much tension should i feel when rotating the transmission main shaft?

Eric Migliorino /

John,

Something is wrong. Both shafts should turn freely. Also, much easier to turn those shafts if the piston is not connected to the connecting rod.

My guess, without closely examining, is the balls in the rear shaft are not in correctly. Those balls will either pop up to lock the gear in place or fall into the shaft allowing the shaft to spin without engaging the gear. The pin that pops out of the rear shaft controls whether you are in high, low or neutral by how far in or out that pin is position. Because it's binding, I suspect the balls are your issue. Also check to insure you have all your spacer washers in place too.

You will have to split the case again and work through it. Try spinning those shafts without putting the other half of the cast together. Do you get the same binding?

Good luck and yes they should spin freely.

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