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Triumph TR6 - Quick Carb Question

I have the twin ZS carbs that came stock with my 1970 TR6.
A vacuum advance line runs from the distributor to an adaptor on the top of the front carburetor.
A second vacuum line runs from the distributor to the bottom of the rear carburetor.

There is no adaptor fitted to the top of the rear carb, but there is a threaded hole where one could be.
Should that hole be plugged?

Dennis Silance

Does it suck air?

I don't believe it would, as there dosen't seem to be a air hole at the bottom (comparing it too front carb).

I do not have the car running at this time.
A few more items left to attend before the big "turn of the key".
It's been a two and a half year tear down and restore campaign, but we're getting close.

I re-did these carbs so long ago and don't recall questioning this back then.
Looking at all my "before" camera shots, I can't find any of that particular carb at the right angle to see if there was something i.e., plug, etc. in that hole.

I guess it wouldn't need anything if it's not open to the intake.
It just seemed odd though....

Dennis Silance

The factory changed the configuration almost daily.
My '71 only has the vac line to the rear carb on the bottom...nothing on the front carb. My rear carb has a brass plug threaded into the hole you refer to in the top of rear carb.
I would make sure it is plugged up.
Rick Crawford

Earlier cars has 2 do-hickys on the dizzy. 1 was port vacuum the other was the other vacuum.
This might be complete BS but I am trying to recollect old conversations.

Yes that hole on top of the rear carb needs to be plugged or you will have a vacuum leak which in turn will make the dual carb set-up more difficult to synchronize. As odd as it may seem, it is the correct hook-up.
For some tr6 people, the confusing part to your question is that most distributors have only a vacuum retard. Your distributor has the rare vacuum advance and retard which was available on the tr250's and early tr6'.

This thread was discussed between 08/09/2007 and 18/09/2007

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