Author Topic: Inlet Manifold Insulator Bush  (Read 38 times)

David S

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    • 1950 BSA A10 Golden Flash PMU121
Inlet Manifold Insulator Bush
« on: September 17, 2018, 05:32:22 PM »
Folks, The six off M8 insulator bushes used between the inlet manifolds and the fixing screws are made from Tufnol. The original Hesketh Motorcycles drawing no 1/0500 (Sheet 1) calls for a torque setting for these screws as 10lbft (14nm). Using this setting causes new bushes to crack. What happens is that the exposed outer edge of the bush breaks away.
Has anyone met this problem and found a solution? Perhaps a new material?

Miti

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Re: Inlet Manifold Insulator Bush
« Reply #1 on: September 18, 2018, 07:11:31 PM »
Hi David;

I've never seen these bushes on my V1000.  Mine has an insulating plate between the manifold and cyl head.  This is triangular, has two 'inlet' holes and three 'mounting' holes. 

Does your bike have these plates plus the bushes?  Or are the bushes instead of the plate?

Jeff
1975 Triumph Trident 750 (New Project)
1980 Yamaha XS1100 (Midnight Special)
1981 Yamaha XS1100 Sport (Trike Project)
1981 Yamaha XS1100 Sport (Reg'd 1985)
1982 Hesketh V1000 (Pre-Production Engine)

Rob B

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Re: Inlet Manifold Insulator Bush
« Reply #2 on: September 18, 2018, 11:58:32 PM »
They all have them Jeff.

Insulator Bush x 6 - Hesketh P/N 2/0513 used with P/N 0/0500 - Price £0.480ea on 12th March 1982

The insulating plates you mention (Gasket-Carburettor) are the P/N 0/0550 x 2 - Price £1.100

They split because they are 36 years old.

Cloth base Bakelite stand-off collar/flange washers are still the best you can get for thermal conductivity versus maximum temperature, although PEEK and Epoxy Glass are also good if you want a modern alternative.
1980 Laverda Jota     
1982 Hesketh V1000    
1985 Laverda SFC1000
1995 Triumph 900 Daytona Super III   
1999 Triumph 1200 Daytona Special Edition