LCGB Forums

Can anyone recommend a decent heat gun, I need to change my silent blocks.
Also how long should new silent blocks be left in freezer.

I use a flame thrower

Rothenberger torch I use

I use an old fashioned plumbers blow torch. I put the silent blocks in the freezer as soon as I get them not sure if a domestic freezer gets cold enough though but a well known racer (no longer with us) told me he did it so I've done it ever since. But when getting it out the freezer don't touch it with your bear hands as the heat from your hands will put it back to room temperature

I prefer electic heat gun as it isn't as hot but definitely hot enough. The high heat from a flame can make you get it very hot, but only at the surface.

I've got my dad's old black and decker paint stripper gun.

If I listen to 2 songs on the radio (or stairway to heaven just once), that's hot enough.

Any decent air gun will be sufficent - go for one thats rated at 2000w and you wont go far wrong.

Plumbers Map gas torch will work but also has the ability to melt Aluminum if you dont keep it moving.

dont forget you heating an area not a specific point - so make sure you swap sides

Spit on the part that you are heating - if it boils - its hot enough.

Freezer - have put bearings in but never mounts. I'll try next time.

I never bother freezing. If you drop something from say 20 to -5c, it definitely helps, but you can raise to over 100c easily with a heat gun. Plus it isn't usually 20c in my garage.

At work, we use liquid nitrogen to fit geet big bearings but they're more like 500mm diameter.

Thank you for all the replies.

Never used heat or frozen the mounts beforehand. It's far too easy to apply too much heat to the mounts which are deliberately bonded to keep the rubber in a stressed condition. This is obviously relevant when transferring mounts from one case to another, as you would with the early SIL two hole 'solid through' mounts.

My homemade insertion/extraction tool uses old ball bearings to overcome the friction that otherwise exists between nut/washers/tool. Thrust bearings would be better, but none were available where I worked to 'test'

removing and inserting new silent blocks without relieving the interference fit , but by the use of force will reduce the interference and the grip.

I found heating the casing lugs quickly to approximately 120 - 140 degrees C while not heating the silentblocks does the trick.

Mikedale wrote:removing and inserting new silent blocks without relieving the interference fit , but by the use of force will reduce the interference and the grip.

I found heating the casing lugs quickly to approximately 120 - 140 degrees C while not heating the silentblocks does the trick.

Correctly manufactured engine mounts will have had the smaller diameter created by means of drawing or swaging. This is part of the manufacturing process to deliberately induce the desired engineering properties to the rubber.

In some instances, such mounts have been used many times in various crankcase with no noticeable loss of fit. If 'the use of force will reduce the interference and the grip' were to have a cumulative affect, then the mounts would not be useable several times.

However, there is more to the 'grip' of the mounts by the case than just interference in layman's terms. Expansion & contraction will have been designed in by Innocenti to occur as part of the desired fit of mounts to case.

I got a Ferrex 2000w heat gun from Aldi.

Turned out casing was hot enough after a half hour ride and mounts put in freezer overnight, went in with no drama.

Changing silent blocks hasn’t cured the vibration coming through handlebars
When I push scooter forward and apply front brake I have a loud clonking sound when compressed

jonoy wrote:Changing silent blocks hasn’t cured the vibration coming through handlebars
When I push scooter forward and apply front brake I have a loud clonking sound when compressed

Is it just the pin on the right link knocking in its 'slot' in the hub? Or loose head bearing?

I did a video but the file is bigger than the 2mb that can be sent on the forum
The vibration came on suddenly