JLO 400 vs. Cuyuna 440??

[hydromike]

At 4:20 in that video, that's me pulled over with my Cuyuna melted down from a too-small main jet. Oops. I'm also the freak at the end of the video flailing about after a short ride in a 440 Cuyuna-powered machine. Lots of fun. Do it! They're a fun, simple, cheap engine. Plenty enough guts to hurt you.

~m

::EDIT:: Wait a minute... Did Mike G. come in second in that race? If so, the G's are running a 400 Cuyuna in their D-stock, which is their backup engine. I just can't remember the results. Did the almighty McKay come in first? Please DVD master; send help!

~m

[George]

I think they're pretty much the same engine manufacturer. I think JLO bought Cayuna at some point. The 400 is no slouch either.

JPSwift was running with a JLO/Cayuna 440 at Ashtabula last year and did really well. He had the lead at the beginning of the race and placed 3rd by the end. He was beat by two G50B powered Superchiefs (484cc).

He's wearing the orange jumpsuit in this video.

[hydromike]

The six-bolt head Cuyuna engine benefits from substantially better breathing from the additional ports in the cylinder, and from subsequently larger carburetors. There's no subsitute for displacement, so a 440 will develop more power than a 400cc engine of identical configuration. The bottom ends of the early JLOs (2F400-2? 2F400-3?) are a bit different than the newer Cuyuna engines as well, with the newer engines having a beefier lower end.

For a small displacement, fan cooled, non-piston ported, non- reed valved 2 stroke, the Cuyuna 440s develop decent power for their size. You can replace the top end (jugs, pistons, heads) without taking the entire bottom end apart. If you're aiming toward performance and extended high-rpm use, a set of forged pistons (e.g.; Wiseco) pistons would be a good investment. If you're planning on simply changing the jugs/heads/pistons/etc., an upgraded carburetor may be in order as well. The early JLO in your BigMax would likely have a Mikuni VM32, or something that flows comparable air/fuel. An upgrade in carburetion may also be in order. A Mikuni VM34 can be jetted to accomodate a Cayuna 440 quite well.

To answer your question simply? Yes.... worth the effort. You would make a formidable racing opponent with a light BigMax/440 Cuyuna combo should you swing buy the Ashtabula 2011 event in Ohio.

Lots of folks here know the Cuyuna/JLOs inside and out. Let us know what you decide.
Good Luck!
~m

[speedycoop]

Does anyone know if it is worth the work to upsize from the JLO to the Cuyuna? Thinking about doing it this spring but curious to know if worth the effort for my old Bigmax? Thanks for any thoughts or suggestions.