JLO 400 vs. Cuyuna 440??

[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.

[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

[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]

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

[speedycoop]

Thanks to all for your guidance and input, it is all very well appreciated. I think I will do it this spring...who knows maybe I'll be out there racing with you all sometime...hahaha. Having fun ridin!! Thanks again, Chuck

[Model Citizen]

::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

I pulled out the official results sheet. Yes, small main jet Guy, the McKay driven by one of those Kinyon guys came in first, Mike G was second, & Swift came in third. You were too busy burning your hand to remember. It was one of the best races of the day.

Bridget

[George]

I think you might be right Mike....even though Mike was running a Superchief, I think I do remember Don saying something about them running with a backup engine.

This race was great to watch.

[hydromike]

I think their "primary" engine in the racer was a Cuyna/JLO 440-8, and the "backup" was a 400, if I remember correctly.

[jpswift1]

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.

I was right behind Hydromike and we were leading the pack out of the gate, both of us with 440 Cuyunas. Those are GREAT engines! I think I lead the first two, maybe three laps until I started having carb issues and then I dropped back. I probably should have spent more time working on my jetting......I just got a carburetor off ebay, threw it on there and raced. You can take Cuyuna 440 jugs and heads and bolt them onto the bottom end of a JLO 400, simple as that. That's what I did, and I'd highly recommend the upgrade. Those little 440's can be made into firebreathing monsters with some top end work.

[speedycoop]

Hey I like simple maybe I can do this job before spring.....picking up my scorpion 440 whip on saturday. Thanks for the input.

[jpswift1]

It's very easy to do. You could actually just bolt that 440 right into your machine. The bolt pattern on the bottom ends of the 400 and 440 are both the same as well.

[hydromike]

...picking up my scorpion 440 whip on saturday.

Did you get the Whip that was on Buffalo Craigslist? There was one on there for a great price last month when I looked....

~m

[speedycoop]

Yup I bought it...hope it runs cuz the sled a wreck. I have a couple of 4 wheelers I am working on so won't get to the whip project for a bit but can keep you posted.

[amcfreek]

if you look currently there is sombody selling cdi style stators on evilbay
wanting about the same ammount you could prob by the whole seld for on c/l
i have a cdi version of the 440 i was wondering if the older stator and fly wheel will fit the 81 ish 440 428cc i have , can i change it back to points for now? as the cdi box is bad i have stripped a layer of the hot glue and looks like bad solder joint but unshure if i can get it apart enough to test and repair bad cap/scr internal cdi parts..
sled i got the engine off of had a crap load of work but had no spark and a twisted ski post
i shoulda aquired the track and suspension as somebody adapted something newer with more travel onto it/ looked like a late 80's arctic cougars

thanxz

[jpswift1]

I never did a CDI conversion on a Cuyuna, but you might want to talk to 6x6world member Don or Hydromike on that. I'm not 100% sure, but I thought I heard something about a CDI box from another manufacturer will work with a Cuyuna. Maybe one of those guys could chime in on it.