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BGM silent blocks too big?

Posted: Thu Dec 31, 2015 9:21 am
by Nerdy Norm
I've just fitted a pair of long-type BGM silent blocks into my Series 2 LI engine. One thing I've noticed is that with the silent blocks pulled fully into place, the inner metal tube protrudes towards the inside by around 1mm.

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I haven't yet tried fitting the engine to the frame, but I'm fairly sure that this extra couple of mm is going to prevent it fitting between the mounting holes. It seems that I have 3 options:

1. File down the tube so that it's flush with the engine casing
2. Try to pull the tube out slightly
3. Pull the whole silent block out a little

What would be my best option?

Re: BGM silent blocks too big?

Posted: Thu Dec 31, 2015 9:34 am
by Grumpy225
That's actually normal. You need to run the correct frame cones with those mounts and it will be fine.

Re: BGM silent blocks too big?

Posted: Thu Dec 31, 2015 9:37 am
by Nerdy Norm
Aha, that sounds promising! I have a new (longer) engine bolt, as well as the matching cones, so fingers crossed ...

Re: BGM silent blocks too big?

Posted: Thu Dec 31, 2015 10:26 am
by Daggs
I've done a lot of rebuilds and only had that problem once (not a BGM mount) The engine would not fit in place. I resolved it by removing the projecting tube with a fine disc cutter.

Re: BGM silent blocks too big?

Posted: Thu Dec 31, 2015 12:09 pm
by GP240
That is the correct way they should be, to prevent the engine case from touching the frame. Eliminate vibration (=silent block).

noticed you have a 'F' stamped above the mount, often wondered what this meant, other casings have a letter stamped above the casing lower damper mount.

Re: BGM silent blocks too big?

Posted: Thu Dec 31, 2015 12:11 pm
by Nerdy Norm
OK great, I'll hopefully get the engine back in the frame over the long weekend.

Interesting about the letter stamp - maybe a QC mark? From memory, there's a different letter stamped on the other lug.

Re: BGM silent blocks too big?

Posted: Thu Dec 31, 2015 6:15 pm
by vegansydney
As you can see from the Innocenti blueprints below the tube is meant to protrude by 2mm.

Image

Unfortunately, as you can see from this image (appropriated from the GSF) there is a wide variation in sizes from aftermarket manufacturers :roll:

Image

Re: BGM silent blocks too big?

Posted: Thu Dec 31, 2015 6:22 pm
by Nerdy Norm
Interesting, thanks. I've measured the frame gap as well as the mount width, and it looks like I've got around 1mm to spare.

All will be revealed over the weekend hopefully :)

Re: BGM silent blocks too big?

Posted: Fri Jan 01, 2016 11:42 am
by nuttyboy
Change of subject ,,were u get the cool blue prints

Sent from my KFTT using Tapatalk 2

Re: BGM silent blocks too big?

Posted: Fri Jan 01, 2016 11:45 am
by bristolmod
nuttyboy wrote:Change of subject ,,were u get the cool blue prints

Sent from my KFTT using Tapatalk 2
I believe a lot were rescued from a bonfire years ago at the factory (unbelievable yes!!)

Chris