Looking for the difference between the 103 a and b motors. I have the chance to get a low mileage 103 engine. If it wont fit my 2012 SG I dont want it. Is there a quick visual check to know the difference?

Tks in advance
Ray

 

the B motors are solid mounted (softails) and have internal balancers.the A motors are rubber mounted (touring & dyna models)and don't have the internal balancers.the motors are very easy to tell apart visually and are not interchangeable (if you have a street glide,yours is a A motor)

 

Tks KIRBY
I'll check it out

 

A simple way to compare is at a local dealer showroom! The B motor crankcases are a different shape, to enclose the balance shafts.

 

Also on the b motors there will be external oil line fittings around the cam chest area to allow for the external oil tank on the softtails.

 

'B' motor



'A' motor



Look closely at the crankcase.
You can easily tell the difference.

Here's the inside of the 'B' motor



As mentioned they are not interchangeable

 

Is it just me or does the inside of a b motor look like a twisted metal clown lik3 something steam punk??

 

Just you.

 

Insane clown lol...good observation