SU needle/seat/float

[TulsaFred]

I need to rebuild my HS2 carbs, but can't find a good source for rebuild instructions. Lots of tuning and some exploded views, but little on specifics of rebuilding.

Anyway, the first problem I run across is the need to replace my needle/seat in the float bowls. It looks like the float must be removed to do this, but the float appears to be held in place by a press fit shaft, which is fairly flimsy and a little corroded. How to remove without damaging the float assembly?

Fred

 

[Billm]

Fred
Here is a good book on the subject:
https://www.spridgetguru.com/TuningSU_Crbrttrs.html

as for that pin- what I do is open up a pair of pliers, put one jaw on the tower that is holding the pin (one holds "light pressfit", one is a slip fit) and one about 1" away on the far end of the pin and GENTLY squeeze the pliers.
The pin should move easily.
Channellocks are good since they have long handles and you can control them better.
BillM

 

[TulsaFred]

Thanks for the excellent tip and link/book Bill.
That is a great reference book! and it's free

Fred

 

[TulsaFred]

Are Grose jets signficantly better than the needle/seat valves that come in the rebuild kits?

 

[elrey]

I have had good results with Grose-Jet valves, but many folks prefer Viton tipped needles. Most rebuild kits come with standard needles.

 

[Billm]

I and many other people tend to stay away from Grossjets-
Apparently they have modified them lately (last 10 years or so) so that they work now but they used to be terrible!
BillM

 

[TulsaFred]

Hmm, the reason I thought about it was the mention by Jim Taylor (RIP) in his SU carb notes:

"The use of Grose-Jet float valves has done more to improve the reliability of SU carbs than any other single improvement that I am aware of. The double ball design meters well and shuts off tight. The balls rotate in the flow stream so wear patterns are minimized. The balls are retained so they don't fall out on disassembly of the float lid. The only problem I have ever encountered is that the seating ball will stick shut if left sitting with stale fuel in it for 6 months to a year. But that's not the only place stale fuel causes problems. "

I guess like other things, YMMV.

Fred

 

[DrEntropy]

TIP: Viton tips.

 

[TulsaFred]

Are viton tip needle valves available as a separate item for purchase?

BTW, my HS2 carbs have a plastic float and hinge, the only metal is the hinge pin. How is the correct float level set on these plastic floats?

Fred

 

[John Kuzman]

Fred -

Moss addresses the issue of the non-adjustable floats here:

https://www.mossmotors.com/graphics/products/PDF/378-470.pdf

 

[Billm]

If anyone knows how to put that in the WIKI please do!!
BillM

 

[TulsaFred]

Thanks John!
that's exactly what I needed.
Basically you use washers under the needle/seat to adjust float level if necessary.

Fred