Carb insulators

Anybody know which cylinder head to inlet manifold insulator part number is with a 32mm port hole?

Try 06-3458

Be sure to use a sealing gasket on both sides of each one if they are the hard micarta variety.

Player#3 said:

Try 06-3458

Click to expand...

I did.....they have a 30mm hole.....

Steve

Old Britts shows 063458 for 32mm for years 73-74 but 062700 for 72. They also have alternates available under part number 18-063458 . A phone call would probably clear it up.

Maybe you have the right number, but got sent the wrong part?

Russ

It may surprise ya to try both the undersize and the right size manifold with and w/o the lip step flow turbulizer at head entry. I lost carb bowls and carb and manifold fasteners until I used rubbery type thick-ist gaskets at the seams beside some heat blocking also keeps some tension on the fairly lightly torqued fasteners with pot metal flanges. Practice makes perfect and Cdo's are perfect example to practice and practice and practice on. You might also find extra length of intake path is nicely noticed too.

hobot said:

It may surprise ya to try both the undersize and the right size manifold with and w/o the lip step flow turbulizer at head entry. I lost carb bowls and carb and manifold fasteners until I used rubbery type thick-ist gaskets at the seams beside some heat blocking also keeps some tension on the fairly lightly torqued fasteners with pot metal flanges. Practice makes perfect and Cdo's are perfect example to practice and practice and practice on. You might also find extra length of intake path is nicely noticed too.

Click to expand...

Since my inlet tract length is already 10.5" from the head I don't think the washers will make much difference, in fact I am not sure the insulators will either, I have some 30mm....I want some 32mm...will probably call Andover Norton direct.....

There are other part numbers shown on 750s, but I am not sure which would be Combat 32mm....

Well SeveieA nothing like trial and error to get surprising power joys that then can be written down as possible rule to follow in your particular case. Few mm's up/dn of intake length ain't going to be noticed but some nice intake turbulence to ease around bends can be. My experience with Combats is once opened up to full intake power flow potential > it runs out of rpm survival next few 100 rpm. Somewhere in the mid 60's hp level one must use caution to snap throttle in 1st and snicking 2nd or hesitates till tire hooks up. If your essentially factory Combat don't scare ya to get set like drag pilot before throttle up to flat run out from under in 1st and 2nd oh well neither did mine following the accepted wisdoms. Purely accidental in my case so not bragging on being smart just frustrated shock after scabbing sutff on for mere initial run in -

If you've got a Dremel you could just open up the 30's to 32mm. Take about 5 min each.

I saw this thread last night with no replies but could not find the paperwork for the insulators I got for my 74 850.

Andover Norton show # 063458 right up to the Mk111 model, the early part has a different number.

I wonder if the thick version is an improvement but direct from Amal and in a 32 mm if available.
Grind it at your own peril without a mask, especially if they are Bakelite.

http://www.ebay.com/itm/AMAL-5MM-EXTRA- ... 54096c9d52

Hi Steve

Don't use them on the race bike. Just a paper gasket. Don't forget the alloy tube to support the length of rubber hose, or you will end up with "bellows"

Chris