View Full Version : Connecting Rod side play? '28 B Single

06-08-2010, 10:21 PM
Sorry for posting many questions but i haven't found a repair manual for this engine and i'm trying to rebuild her by hook or by crook. My question is how much side play should the connecting rod upper end have? Would i be safe in using the specs for an early 61" or 74" (.025" to 1/32")?

Much Thanks,

06-09-2010, 04:45 PM
The TOTAL piston to gudgeon pin bush clearance should be 3/32 give or take a few thou.
Gudgeon pin bushes of varying lengths were available to achieve this.

Some of the following may help also.

Gudgeon pin in con rod (reamed) 1/2 thou
Gudgeon pin in con rod (honed) 1 thou
Big end roller clearance 1 thou
Timing side mainshaft clearance in the bush 1 thou
Drive side mainshaft roller bearing clearance 1 1/2 thou ( one and a half thou)
Ignition advance on the piston 5/16 btdc

Hope this helps.