Connecting rods
On the way to more power, the connecting rods are one weak point of the 750 SOHC/4 engine.
CB 750/900/1100 rods
The connecting rods from the later ('79-) 750/900/1100 DOHC engines fit and are a bit more rigid. Unfortunately, the 750 DOHC rods are about 1.5mm shorter than their SOHC counterparts, the 900 and 1100 DOHC rods are approximately the same amount longer.
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CB750SOHC and CB750DOHC rods |
750DOHC are approx. 1.5mm shorter |
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CB750SOHC and CB900DOHC rods |
900DOHC are approx. 1.5mm longer |
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CB750SOHC and CB1100DOHC rods |
Aftermarket rods
A better, yet more expensive solution are con rods from APE (manufactured by Crower), Carrillo, Cyclexchange or Falicon. They are expensive, but worth the price - remember, one broken rod can ruin your whole day.
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Carrillo H-Beam |
Expensive, but worth it |
The Carrillo H-Beam and the Crower spec sheets are available in the Download section.
Russ Collins had steel aftermarket con rods, but they are no longer available new. There have been aluminum con rods from various manufacturers, as MTC, Yoshimura, Russ Collins and others. I would stay away from them, aluminum stretches under heat and has a low fatigue resistance and who wants to see a piston touch the head because of a stretching con rod.
A word of caution
At least the stock con rod bolts are not designed to be re-used! When tightened properly (and you should do that at any rate), they will stretch beyond their elastic limit. When re-used, they may come loosem, and if they do, it's a major havoc in your engine.The '78 F2/F3 rod bolts are said to be stronger than their predecessors and they also fit the earlier rods.