74 750SF main jet size- 5 or 6MM?

[TeddyG]

What size are the main jets for a 74 750SF- 5 or 6mm? I don't see the mm size in the Green Book and need to order some
Thank you

 

[The Sock]

Main jets now, in the UK, are, generally, three or four sizes down from what they used to be. Petrol (gasoline) is thinner than it used to be.
Go figure?

 

[hooksey]

140 from memory.

 

[Haggis]

Teddy is talking about the thread size I think....

 

[Exmoor beast]

What size are the main jets for a 74 750SF- 5 or 6mm? I don't see the mm size in the Green Book and need to order some
Thank you

Order Dellorto jets not generic ones - you’ll be chasing your own tail. Plenty of old bikes running stock main jets.

 

[Haggis]

I've had a few beers, so please someone double check me....
6mm

 

[Lyndoneil]

Telephone Duccatipaddy if in doubt.

 

[TeddyG]

Thanks guys- my cheapo micrometer decided to act up but it looks like it's 6mm threading

 

[Paul Marx]

Mains are 6 and pilots 5mm.
Paul

 

[Tippie]

A 6mm main jet? It might run a bit rich
Isn't communication a bastard

 

[Tippie]

Laughable but I have had a few Dellorto bikes come in with a main jet lying in the drain plug, no effect on running until over 3/4 throttle and most people ride with throttle in the lower half.

 

[Vince]

It had some relevance to my particular problem. The Airo-style tank cap I have is airtight with an O-ring seal. If I filled the tank enough to cover the bottom of the breather added to the tank it would start self syphoning especially in direct Sun, out of that breather. I needed to break the vacuum effect, so I drilled and tapped that Airo cap to fit a Delordo main jet. It all ended up working well in the end. Crazy stuff.

 

[bazzee]

A 6mm main jet? It might run a bit rich
Isn't communication a bastard

Perhaps jetted for methanol.

bazzee