Just wondering - carb question

[JPSmit]

recently I've been watching the SU/ Weber conversation.

My Zenith Stromberg (which trumps them all ) is in the shop for the second time making me wonder if a future swap is in order.

Here is a Spitfire (ie. 1500) website where one option is motorcycle carbs. The dealer charges about $1300 for them.

https://www.triumphspitfire.com/carbchoices.html

Recently, I saw these advertised for $150.00

https://tinyurl.com/5uyydd

Assuming I had access to someone who could fabricate - which I do - how difficult would it be to manufacture an intake manifold? I guess I am especially wondering whether there is a magic length for the manifold pipes to be - etc. etc.

thoughts?

 

[RickB]

I knew I had looked at someone else using R1's recently so I had to find it.
This is over on a Datsun bbs - but many things apply.

Ratsun Yamaha R1

Check out all the pics, you can see some manifold work there too.

 

[Morris]

Why not go with the Euro-spec twin SU set up as detailed here:

https://www.brit.ca/~tboicey/midget/midget_overdrive.html


(midway down page)

 

[aeronca65t]

I am racing on a single motorcycle carb (an S&S 2-1/16" pumper carb for Harleys).

It works fine at 3500+ rpm. Not so good at lower speeds. Multiple carbs would create even a fussier engine.

When my car was on the street, I had great luck running a single HS4 carb on the stock 1500 ZS manifold.
The carb doesn't bolt on. You need to "slot" the holes in the carb with a rat-tail file. Takes about 10 minutes.
And depending on where you get the HS4 (mine came from an old Volvo), you may need to adjust the angle of the float bowl so that it is "level" (easy).
Mine worked quite well with the stock needle and the jet nut adjusted down about 16 flats. Very simple carb.

 

[Hap Waldrop]

The European Midgets 1500 came form the factory with a twin HS4 set up, you see them on Ebay from time to time for sale, this would be a nice touch.

 

[budk1953]

I put the duals on mine, just have to notch for rear carb bowl and move radiator expansion tank.

Like Hap said - check ebay, that's where I got mine.

 

[Morris]

You can pick up a set of carbs here:

https://www.quantumechanics.com/categories.php?op=newindex&catid=5

 

[JPSmit]

I've thought about the duals and even contemplated bidding on some in Scotland this summer - unfortunately I can't bring myself to cut the body after all the work done.

It's not likely to happen - but the idea of 4 carbs....

 

[Morris]

Hey JP,

Did you see the single Mikuni kit on the Pirace site you posted on another thread?

That looks like a pretty good deal at only $575. Mikuni makes a fine carb that has powered most of the motorcycle world for years.

 

[aeronca65t]

The single HS4 that I fit to my stock 1500 manifold cost me $20 at a flea market. :laugh:

 

[JPSmit]

The single HS4 that I fit to my stock 1500 manifold cost me $20 at a flea market. :laugh:

this is much more my budget :laugh: At this point I'll see what the guy at the shop says - but I can imagine that relatively soon I'll look for something else.