Tidbits off the Internet for the Zenith 28 clone made in Argentina:
1.) 200 to 300 C.I. engines. 2.) 38 mm (1.5") throttle bore. Unlike Carter and Rochester, this carburetor has a removable venturi sleeve similar to the Zenith 28/228. I wish Daytona would share the sleeve diameter. This carburetor mounted on a 261 intake manifold will be 1.5" opening up to 1-11/16?". (My first thought, flow turbulence?) 3.) On a Jeep forum, a member contacted Daytonparts.com and a salesman made the statement that, "Our Daytona Universal replacement 1bbl carburetor will flow up to 195 cfm." Unfortunately it wasn't stated if that spec was @ 1.5" or 3.0" Hg. Note: At 1.5" Hg., a previous old posting here (May 55 Hot Rod) says 182 cfm was measured on the Rochester B made for the 261. 4.) There are options, that only a retail business can purchase, but these were not described. 5.) The manual says the adjustable main jet is preset for most engines for a correct fuel/air ratio. (My thought, yeah and bullfrogs have wings). For altitudes above 3500ft, follow the adjustment procedure (as described). Some owners have reported, at lower altitudes, they had to drive a distance, stop, re-tweak one revolution then repeat until it ran best. Last step was readjust idle speed to OEM spec.
Personally I would avoid buying any Chinese made carburetors (automobile, string weeder, chainsaw etc.) especially off of ebay. There is no quality control. Buy from a USA company (even if they import) that will provide timely replacement parts and have good technical support. A business that will take it when stuff hits the fan.
Excellent, thanks for all the added information Buoymaker. Im sure it will be helpful to those interested in these carbs. As stated before, im still very happy with its performance. I would be hard pressed to tell the difference between the UN2 and the Rochester B. Its good to have another option, and if you want to go for a dual carb or triple carb setup and don't want to hassle with older carbs, this is a good way to go also.
If the engine is large enough it will flow 300 CFM. A displacement range between 200 and 300" cannot be bridged by just a venturi change.
Of course it can; just ask the folks that sell them!
Is there a sarcasm emoji?
Last edited by carbking; Fri Feb 07 2020 03:14 PM.
Good carburetion is fuelish hot air The most expensive carburetor is the wrong one you attempt to modify If you truly believe "one size fits all" try walking a mile in your spouse's shoes! [image]http://www.thecarburetorshop.com/Avatar.jpg[/image]
The intent of my last post was mainly to provide information. I'm not "fer" or "agin" the UN2. I'm just shaking the apple tree hoping to get a ripe apple to fall.
Wouldn't the Carter YF 4371S be a better "universal carburetor", to use on a 261, than the UN2? Disregarding issues that may require modification to the throttle linkage, vacuum advance and choke etc. Listed application for 230, 250 and 292 engines. Throttle bore 1 11/16" Main venturi 1 5/16" Metering jet 0.104" Metering rod (3 step) 0.078", 0.052", 0.045"
If yes, why not clone the Carter YF instead of the Zenith 28/228? Difficulty in manufacturing? Patent issues?
2/16/2020 Update: Received complimentary fitting from Daytona Carburetors. I was told by Ron, one of the technicians that these fittings are exclusive to them. It is a 3/8ths to metric. The Metric side goes into the Carburetor. It doesn't bottom out, its the flared kind, so just snugged down. Now the setup looks much better with the glass bowl filter. Now just enjoy driving it. Will soon update with city MPG's.
Last edited by ClassicsR4Me; Thu Oct 01 2020 12:02 AM.
Obviously, I have no special insight as to which was chosen, but manufacturing cost always includes the number of precise machining operations (removable venturi adds expense), toxicity of components (cadmium is poisonous), number of individual parts (separate choke horn, throttle body?), etc.
2/17/2020 Update: Today I hooked up my small trailer to take some metal to recycle (around 200 lbs.), I have to admit, to be completely honest, under load I could notice the engine did have quite a bit less power than with my Rochester B. I wont say it was a remarkable amount but still noticeable. It was a small trip I took, perhaps a 3 mile round trip, but on the up hills I did notice having to go deeper into the pedal to power uphill, where I hadn't had to do with with my Rochester in the past. I'll continue testing the UN2 with an open mind. My Rochester can go on it later if I like and I do have a 235 engine I can try it out on to see if its a better fit for it. Still content with its better drivability in town, but will have to try a heavier load next time to see how it performs.
Last edited by ClassicsR4Me; Tue Feb 18 2020 12:43 AM.