New mixers arrived on the hill

[85RZwade]

Brought these home from Portland last week, where I was able to visit Mr. Ron Black:



OEM RZ350 carburetors taper-bored to 29mm (I think I mistakenly said 30mm elsewhere) with divider plates installed and supposedly jetted to suit. Anxious to try them on Ol Faithful.



They might end up on the Rd or LC, who knows?

[mnein]

What do the divider plates do?

[85RZwade]

Mr. Gagnon can explain it better  than I:

https://richstayloredporting.com/vintage_Venturi.html

That being said, these carbs I brought home have dividers only on the engine side.  Here's a little more from the man who did the mod:

https://www.rb-designs.com/rb_designs_llc_004.htm

[Evans Ward]

I like that mod! Didn't Ron Black retire? I had him rebuild a crankshaft for a 4400 mile original 1967 YR1 I restored. I tried so many crank builders who wouldn't or couldn't take on a crank for the RD's grand daddy but was referred to Ron who not only took it on, but did an outstanding job with it! I sold the bike on eBay shortly after to a gent from New York State. Referred him here but not sure if he joined? If you want to see it, it's here on the site from about 5-6 years ago.

I've gotten used to the stock carbs ride- wise as well as pulling and rebuilding. I have a second set that I plan to put together as a spare for myself with both sets jetted the same.

[soonerbillz]

John Ritter advised me to get my carbs modded with the divider plates. He was quite certain it would improve low speed performance on my R5.

[pdxjim]

RB modded my TDR carbs at least 10 years ago.

He bored them to 29.5mm and added his engine side divider plates.

Tough to say what difference it made as we did a lot of other stuff at that time also.

[85RZwade]

Yes Evans, Ron is mostly retired. His shingle is technically still out, but he told me most things are off the menu. He agreed to bore my LC cylinders, but not cut the head. He said he's also done modifying carbs.
I'm looking at Bill Wilson and Rich Gagnon to cut my head; they both seem eminently qualified, but I'd sure like to read about some personal experiences. Or a recommendation for someone else if ya have strong feelings.

[Evans Ward]

Scott Clough out west or Ed Toomey in S.C. on east side would be two more recommendations. I lucked out and bought a used nice RZ head from a seller in TX about 3 years ago. After receiving it, it had initialed on the side SCR so I scored big time.  When we set the squish on it during a full engine rebuild, it was dead on. 

[Gil Gallad]

if it's not too stupid a question, what do the dividers actually do? 
cheers, gil.

[Hawaii-Mike]

Here you go: https://www.rb-designs.com/rb_designs_llc_004.htm

[soonerbillz]

if it's not too stupid a question, what do the dividers actually do? 
cheers, gil.

From what I understand they create separate "air intake channels" that reduces turbulence and increase flow speed mainly to low speed circuits.

[tony27]

if it's not too stupid a question, what do the dividers actually do? 
cheers, gil.

Basically they make the carbs act like they're a smaller diameter than actual size until the slide gets opened above the dividers, similar to how a 2/4 barrel carb works on a car