Walbro RWJ-4 Carb, and Reading Complaints?

[centannim055]

I'm currently working on a project involving the use of diaphragm carbs on a scooter I'm building. I'm a chainsaw guy (440) and am working on a 372xp big bore (Hyway top end)

Now while the application the carb is used on matters alot, the RWJ-4 carb looked really appealing to me due to venturi size and being able to run the impulse line externally with the barb that comes out of the carb.

I am hearing 75% or more from everything I have read that the RWJ-4 is not a favorite specifically in regards to tuning complications and unstable.

The specs of the scooter are 52mm x 38mm (80cc) it will be using a Husq exhaust and unported.

If not the RWJ-4, I am looking at a Tillotson 274 that was used on the TS400 concrete cutters.

Any input would be appreciated regarding the general dislike of the RWJ-4.

 

[huskihl]

Rwj carbs are spotty. Some work fine while others are problematic. Fortunately with a 52mm Hiway 372 cylinder only making 75-80% of the power (tested on the dyno) as the stock bore oem cylinder, you should be able to get away with the original HD6 or HD12 and not have any headaches associated with the RWJ

 

[centannim055]

Rwj carbs are spotty. Some work fine while others are problematic. Fortunately with a 52mm Hiway 372 cylinder only making 75-80% of the power (tested on the dyno) as the stock bore oem cylinder, you should be able to get away with the original HD6 or HD12 and not have any headaches associated with the RWJ

Got it, thanks. From what I could gather, even with the RWJ-4 having a 19.x mm venturi, that is also with an intake boot that has a divider if I'm not mistaken. I ended up going with the Tillotson HS-274.

This will be a bit different as standard "bowl float" carbs when it comes to jets you can just swap em out, or adjust a needle for your mid-range. Other than the L/H screws, if you exceed those then you gotta start drilling.

I wish it was something where you can just unscrew and screw in different jets. Diaphragm carbs are more appealing to me, especially being able to run no matter what angle they're at.

 

[Chevboy0167]

https://www.ddmracing.com/Engines-Engine-Parts/All-Engine-Parts-Sorted-by-Function-zenaoh-chung-yang

https://cometkartsales.com/WB3A-Walbro-Comet-Blueprinted-Can-Carburetor-with-Flex-T.html