1972 B25SS FRONT ENGINE MOUNT

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CliveD
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1972 B25SS FRONT ENGINE MOUNT

Post by CliveD »

Hello all,

Hoping some of you B25SS owners out there can help me with some measurements and info please

1) What is the internal distance between the arms of the front engine mounting bracket?
2) How wide is the front mount on the engine itself? Is it the same or less than the bracket width?
3) Can you post a photo showing the front mount arrangement please?

Any help would be much appreciated.

Cheers
Clive
JerryT
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Re: 1972 B25SS FRONT ENGINE MOUNT

Post by JerryT »

Afternoon Clive,
Hope these help. 48mm Is that accurate enough for you?
The engine is out of the frame and in a jig. Hence the box section seen in the top photo.
Jerry
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CliveD
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Re: 1972 B25SS FRONT ENGINE MOUNT

Post by CliveD »

Thanks very much Jerry, that is really excellent. So the gap in the frame and the width of the engine are identical - there is no spacer involved?

Clive
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SteveS
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Re: 1972 B25SS FRONT ENGINE MOUNT

Post by SteveS »

Correct, no spacer required

THIS IS INCORRECT - please ignore and see comments below
Last edited by SteveS on Tue May 12, 2020 7:43 am, edited 1 time in total.
Steve Sewell
CliveD
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Re: 1972 B25SS FRONT ENGINE MOUNT

Post by CliveD »

Many thanks Steve
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minetymenace
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Re: 1972 B25SS FRONT ENGINE MOUNT

Post by minetymenace »

Mine dosent have a spacer, but pretty sure it should. It is on the parts list!
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beesa71
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Re: 1972 B25SS FRONT ENGINE MOUNT

Post by beesa71 »

Too true there should be one between the crankcase and the front RH engine ‘plate’ (83-2004).

There should also be the one on the RH side of the engine between it and the frame (83-2005).

There should also be one between the outside of the RH front engine ‘plate’ and the exhaust pipe mounting bracket (68-4925).

When we had these made in Stainless (still available!) we found that if it had an ID of 7/16” it would fit (better than having non at all really) in all three locations and for all years/models.

Regards to all OIF’ers in these Worldwide troubled times. keep safe everyone.

Paul.
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SteveS
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Re: 1972 B25SS FRONT ENGINE MOUNT

Post by SteveS »

I stand corrected, parts list shows the distance piece :shock:

I've checked all my oif bikes and some have the spacer and others do not. Looking carefully where there is no spacer the engine mount has been squashed inwards by previous owners (?). The frame mount is only 1/8" thick so if the front engine bolt is tightened with no spacer it will crush. If you look at the frame mount picture supplied by JerryT you can also see the left side of the mount is a little distorted.

The crankcase front engine mount measures about 46.228mm (1.82"), the frame just under 50mm. My notes(which I should have read before I responded in my first reply) show spacer dimensions as id 3/8" x od 7/8"x Thickness 3/16" (4.762mm). This is for the B25 oif with the 3/8" front engine bolt (B50 has a 7/16" bolt).

Please can someone confirm dimensions for Clive?
Steve Sewell
CliveD
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Re: 1972 B25SS FRONT ENGINE MOUNT

Post by CliveD »

Thanks for all your help and comments guys. Truth is my bracket does not look particularly bent, certainly not by 3/16 of an inch and there is no room for the spacer. Engine and frame are from a 1972 Fleetstar and strangely the front mounting hole is closer to 7/16 than 3/8. I was struggling to get the engine back in the frame, the whole thing was sitting too far over to the right with no room for the bottom spacer, but have now achieved. Again thanks for the help, much appreciated.

Clive
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Re: 1972 B25SS FRONT ENGINE MOUNT

Post by minetymenace »

CliveD, <12fs frames are no different to any other oif B25, except they were all painted black. A 50 year old bike could have had anything done to it, mine got a new engine mount the other year, and I was asked if I wanted it positioned to accommodate the spacer or not. As I just wanted to get going I said forget the spacer, it now looks like an original engine mount that appears square with no spacer, no one would know apart from the fact that the hole is a regular circle not a mangled slot!
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malcward
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Re: 1972 B25SS FRONT ENGINE MOUNT

Post by malcward »

Couldn't get one of my B50 engines out of the frame, due to the previous owner missing out all the spacers.
Had to remove the rocker box studs out one by one, take the box off and lift the engine up vertically.
Quite a time consuming job, bsa fitted them for a reason.
Cheers Malc
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