Updated: 03/15/13
 This page shows the JBM stainless clamp and some of the
damage that can be caused by improper clamping pressures.
JBM stainless clamp has a range of 46 to 69 mm.
This clamp is suitable for some of the larger carburetor
sockets we manufacture, and is different from common auto-
parts store clamps.
 This clamp is  lined with an extra long stainless band to help
prevent cutting of the rubber by the worm housing. It is
important that the surface of the rubber not be torn or cut as the
cuts will propagate. In most cases the factory clamp works just
fine, and can be reused many times, but if you need new ones,
we think this stainless clamp from
JBM is a good solution. It
works on all the sockets sold by
JBM Industries..
  •    Clamping too tight will cause a tear or cut where the
    surface of the rubber is drawn down near the clamp. It
    can also cause cutting on the inside from the edge of the
    carburetor spigot if too sharp. This is the area of most
    strain.  See examples seen here.
  •    Clamping too loose will allow movement of the
    carburetor in the socket. Movement of the carburetor
    spigot will tear and chew up the rubber on the
    mechanical locking bead inside the rubber socket and
    could result in thrown carburetors.  
  •    Tighten the clamps only enough until you are sure there
    is no movement of the carburetor spigot in the rubber
    socket.  Some factory clamps may have a limiting
    spacer that can prevent proper tightening on JBM
What is TSR compound? What kind of rubber is it? What are the qualities of it? Is it

TSR compound is a patented rubber compound that only
JBM Industries is using for
the manufacture of high quality fuel resistant rubber parts in light sport aircraft and
vintage motorcycles.  ( Working -10 to +275 deg. F )
The qualities of the TSR rubber are that it has high fuel and chemical resistance so
works well with fuels that contain ethanol.  It also is very resistant to heat, ozone, and
age cracking. Age cracks are the small surface cracks seen in old rubber that can be
seen with just a slight bending of the rubber. Usually you will see many of them, and
they will not be very deep, but they do weaken and soften the rubber, causing more
flexing and so more age cracks.
Many elastomer's get age cracks, and on some rubber, such as natural rubber they
might look bad but cause little weakness. On other types of rubber they can degrade
and weaken it quite a bit.
To check for age cracks, it requires a small amount of bending or flex to see them
open up. Rubber parts should be checked for age cracks frequently.
  • TSR material is not any stronger, or indestructible, than other rubbers.  
  • JBM Industries uses two types of this rubber with different frequency response,
    depending on the part we are making. It does have a bit different "feel" to it and
    has a very high specific gravity, so it is heavier than other elastomer's .
Go to: JBM Home Page    Rotax page    Carb Holder Page    Rubber Flange page  
CV Diaphragm Sizes page     JBM "About Us" page       How to order page
This photo shows what "Age Cracks" look like.
Ethanol causes lots of problems
Carb Holder Failure on Vintage Motorcycle caused by
regular pump gas that contained ethanol.
Go to: JBM Home Page    Rotax page    Carb Holder Page    Rubber Flange page  
CV Diaphragm Sizes page     JBM "About Us" page       How to order page
See problems with Rotax 912 Rubber Flanges.
$3.80 each
JBM Warranty Link click HERE.
Worm Clamps for our Aircraft Carburetor
Sockets.  Working range 1 13/16" to 2 3/4"
These have special liner tail for soft rubber installation.
These clamps are large enough to fit our Jabiru sockets.