BGM engine mounts.

[Scooter Paul]

I've just fitted a pair of these to replace a set of Casa Lambretta ones that failed almost instantly! ( in fairness they were probably the early version ones that have now been improved). Is it my paranoia or do the BGM ones transmit more vibration than others? They are correctly fitted.
Paul.

[Tractorman]

Both my BGM ones are considerably better than the scootopia ones I tried for 17 miles.

[Scooter Paul]

I've used the original series 2 cones in the series 2 frame. I have a worry that the longer SX type silent blocks use a different cone. Or am I wrong?
Paul.

[Tony Hart]

I've used the original series 2 cones in the series 2 frame. I have a worry that the longer SX type silent blocks use a different cone. Or am I wrong?
Paul.

Changed the cones in my Eibar S2 when I put wider silent blocks on. Not sure what the differences are but know that there is suppose to be some

Tony

[dickie]

I think it's just a chamfer on the edge of the newer cones for the large silent blocks to help with fitting the engine.

Although to be honest I'm not sure if I read that or dreamt it.

[Warkton Tornado No.1]

The chamfered cones are the wide ones.

Ideally you should match the cones to the engine mounts.

They pull in to the frame as the bolt is tightened so it’s not easy to check prior to that, but the wider cones are intended for wide engine mounts, the narrower cones for narrow engine mounts.

A mismatch can cause the outer diameter of the engine mounts, or even the engine casing, to rub on the frame which is disastrous for handling…

[Digger]

The chamfered cones are the wide ones.

Ideally you should match the cones to the engine mounts.

They pull in to the frame as the bolt is tightened so it’s not easy to check prior to that, but the wider cones are intended for wide engine mounts, the narrower cones for narrow engine mounts.

A mismatch can cause the outer diameter of the engine mounts, or even the engine casing, to rub on the frame which is disastrous for handling…

You can also end up with the engine hanging on the cones with the bar removed - not good for a one man band!

[Scooter Paul]

Thanks for the replies. My, probably original small type cones, I didn't really look, fit flush with the end of the tube. I'm still not clear in my head what the real difference is so ill have a look. I have both type of cones in my spares to compare.
Paul.

[peejay]

i have the BGM mounts in my RT 225 Series 2 motor, lovely and vibration free.

is it possible that you have the engine bolt nuts done up too tight?

[Warkton Tornado No.1]

I am ‘knocking on’ a bit & some of the stuff that comes up on this site is great because it tests the mind.

Like peejay, much of my experience will have been gained both on & off the track.

In any situation that may involve remade parts & a mix of Series I, II & II there can be a marriage of harmony or misery.

I didn’t personally come up against the problem of the ‘wrong cones’ but know somebody that ‘chased his tail’ for a long time with handling problems of his Group Four & was gracious enough to relate the problem.

All engine mounts are compliant in not just absorbing the vibration, but in pulling in so that the internal tube is hard up against the faces of the cones.

By design, the outer part then flexes & twists whilst in situ as the back wheel goes up & down.

I apologise if I’m overstating the obvious here, but if that outer steel tube comes into contact with the cone or frame, then there will be friction & jerkiness as the result. Vibration will also obviously increase.

My belief is that the later, wider, chamfered cones are the best default if they will allow the engine to fit in the frame as they should prevent the above scenario, whether with short engine mounts or long.

That is all I’m trying to communicate & cannot comment on the current crop of remade engine mounts.

From personal experience, the best for racing are the ‘solid all the way through but with two holes’ type known as ‘Indian’ that were available from the Eighties.

Again, from personal experience, the worst for anything other than a static display machine or somebody that enjoys the numbing sensation of having their vision blurred, are the ‘solid all the way through but with no holes’ type that tempted my purchase a few years ago.

About eight miles was more than enough to learn the error of my ways……

[Scooter Paul]

I really appreciate the time that other members have taken to reply. I've never really thought about how the silent blocks work though I should have as I used to race a bike that had silent block swinging arm bushes which had to be preset. Anyway what is clear is that I had already changed the cones for series 3 type. I'd obviously had it in my mind they were different and made the swap. I have snugged up the mount bolt and taken it for a test ride. Whatever I've done it's much better now.
Thanks again.
Paul.

[Warkton Tornado No.1]

That is brilliant that you've given positive feedback & hopefully nobody else will fall foul of such an easy mistake some of us didn't know could be made.

[HxPaul]

If you fit the engine mounts (or silent blocks)to the engine and then fit the engine to the frame,dont fasten the nuts up on the engine bolt until the engine is in position because if you nip the nuts up before the rear shocker is fitted when you lift the engine to fit the rear shocker the rubber in the mounts will be strained.