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Does anyone know if a 1971-73 CB350 Engine will fit in a 1968-70 CB350 frame?

Can you swap parts (crankcases, cylinders, crankshaft, starter, etc) between a 1971-73 CB350 engine with a 1968-1970 engine? I've got a 1970 engine and a lot of the parts on ebay are from 1971-73 bikes.
 

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Most of the internal parts are the same and yes, the engine will fit the earlier frame - I don't think there's any difference at all. There are many knowledgeable members here who have 350s and they'll chime in. A good place to look up part numbers and compare interchangeability is cmsnl.com - this is the CB350 area

1968 https://www.cmsnl.com/honda-cb350k0-super-sport-1968-usa_model430/partslist/#.W1yD_2eWy00

1970 https://www.cmsnl.com/honda-cb350k2-super-sport-1970-usa_model431/partslist/#.W1yEBGeWy00
 

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The cam, bearings, rockers and rocker box are different on the fat cam models.
The kicker shaft and guts are different for the early models too, i think.
70 and on would be the same, I suspect.

The exhaust studs on early models are different too.

Engines will swap into frames without issue
 

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Discussion Starter #4
The cam, bearings, rockers and rocker box are different on the fat cam models.
The kicker shaft and guts are different for the early models too, i think.
70 and on would be the same, I suspect.

The exhaust studs on early models are different too.

Engines will swap into frames without issue
Not sure what a fat cam model is. I have a good top end. 150 PSI compression on each side but I think I have a rod or crank problem. If I buy a '71-73 bottom end will my '70 top end
(pistons, jugs, head)
bolt on with no problem?

Based on the comment above "
The kicker shaft and guts are different for the early models too, i think. " Sounds like the transmission and kickershaft will not transfer from a '70 to a '71-73'? is that correct?
 

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Kick starter was before 1970 model from the engines I've torn apart. The rest of the parts will interchange but may be constructed differently. For example the crankshafts use different bearings but will swap over without issue. The mid year range heads had some material issues so later heads are more desirable but again it will all swap around. That goes for CB and CL engines, no difference other than the serial number prefix.

If you can, stay with later parts. If in doubt look at the parts manual to see where the parts breaks occur. If you need pictures send me a PM, I have most of the variations of parts.
 
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