A65 Carbs

[Pete Gill]

Dear All
I would like some advice please on these 2 carbs that came with a non running A65 I bought earlier this year.

They are both 930 carbs but on disassembly for cleaning and renovation I discover they are different . The left one has a brass insert in the body  ( which on thinking about it is possibly  the remains of the pilot jet?) the right one has no jet in place there.
I do have other bikes with 900 series and 600 series carbs on them but they all have no brass inset as pictured on the left.
Is this just an early 930 carb and the right one a later model?

[Allan G]

thats a screw in pilot jet that has been over tightened (or grown within) in the body and sheered when someone has tried to remove it.

If your original carbs have the pressed in bush, then you do not need the screw in pilot jet... However you DO need to have it removed otherwise running issues will follow (ie if it flows ok, then you will have cutting out issues)

[Pete Gill]

Thanks Alan,
So is it likely this carb body will also have the pressed in pilot jet behind the air screw?
Or did these just have the one as pictured?

[Allan G]

The number on the side of the carb will give an almost definative answer, but unscrewing the mixture screw and looking though with a torch should show a brass bush/tube (admisttedly it'll probably look a little tarnished in colour after all these years), but you should see a reduction in size to 0.017" hole if nothing else, otherwise it'll be the full bore size all the way down.

All concentrics, even the premiers being made today still are threaded to take the early pilot jet setup, 2 strokes tend to run fine but 4 strokes (and mostly the triumph daytona) had issues when throttling off and bringing the bike to a stop, which would cause the engine to cut out. the solution from 1969 was to fit the pilot jet bush, this was then used accross all makes and models with 4 stroke engines and on many 2 stroke engines also.

[Pete Gill]

Thank you Allan for your help.
I've just checked and the carb in question is a left 930/10, the other is a R 930/66.
The left one does not appear to have a pilot jet under the air screw whereas the right sided one does.

I think I ought to look for another left 930 body with a pressed in pilot jet so that i can at least try to get a balance when the bike is running.

Pete

[Allan G]

Hi Pete, yes this would be a good move. The idle
Mixture has a huge effect over the whole range so a matching carb will be. Big help.

The new carbs from Amal are very good and made out of aluminium instead of Zamak like the originals so will outlive the bike and probably the next few generations of users. Not cheap but worth the upgrade and give the bike a fresh lease of life.