why change for 440's to 4 stroke

[goldhunter_2]

well I have been reading a searching old threads online and I know I want the more HP engine but so far it seems the big trend is to remove the 2 strokes 400, 440 etc and replace with lawnmower engines (4 stroke) and I just wounder WHY? is mixing gas that big of deal

[Mike]

I don't think that mixing gas is a problem. Usually it is more of a reliability issue (I'm asking for it now...wait until hydromike reads this).

I just mean that 4 strokes are pretty much a "plug and play" engine. The 2 strokes are more temperamental based upon temperature, elevation, etc. and require constant adjustment. Usually once you get a 4 stroke adjusted for large elevation changes you can ride all you want without further adjustments.

However, when it comes to comparing stock motors, the 4** that you mentioned is hard to beat for power and sound.

[George]

HydroMike, myself and others have opted to convert just one machine to a 4 stroke. We tend to use those on the big group trail rides. This is so you can go out and not worry about stopping to replace plugs or tinker with the carb. However....a few people bring the 2 stroke macines to events as well for those times when you just want to get together with a few guys and drive like a lunatic.

My next atv purchase will probably be a larger trailer so that I can bring both types of machines to next summer's events.

[goldhunter_2]

Mike,
I can somewhat understand the "plug and play" idea but not really the reliability issue if you buy a new 2 stroke or four stroke they both hold up to me anyway. even if you rebuild a old 2 stroke you obviously have to get it dialed in at frist but after ward no problems but maybe that is what most are trying to get away form. I just found it interesting that what seems like the majority would switch to lawnmower engines and give up the HP and speed.

George,

and drive like a lunatic

but those are the best days I guess my line of thought was it was more practical to have a machine that could run like a lunatic in the morning and putt putt around after the other guys in the afternoon.

I am not as firmluar with the JLO engines as say the rotax or yamaha ski engines I know the yamaha jet ski engines in the two cylinders are pretty much bullet proof an the ultralight or seadoo/rotax are like a ford (Fix Or Repair Daily) mostly because of the rotary gear set up . I may have to find some engine parts breakdowns to look at on the JLOs before I decide on that particular 2 stroke engine for my power plant

[hydromike]

(I'm asking for it now...wait until hydromike reads this).

Oh come on now, Mr. Moderator; I'm not THAT bad. At least you didn't call them useless. You've actually pretty much nailed it right on. Four stroke engines develop a lot more HP and torque in the lower RPM range where crawling along and serious trail riding are really demanding for them. I wouldn't give up my 4-stroke for anything in the world (something I NEVER thought I'd hear myself say). It's a tractor, and will just about climb a vertical face while barely moving. A comparable 440 really has to develop RPMs to try to climb the same slope. The two stroke simply isn't generating enough power in the low RPM range to lug the machine up. Since (I would wager) that 99% of amphibs are geared toward trail riding now-adays, it only makes sense that most people would try to build/buy machines with the powerplants geared toward that motive.

The counter of the whole argument, is that if you really, really want a performance experience, I don't think there is any replacement for a big two stroke. Okay, Whipper's machine is a replacement, but I'm not going there. It's a whole 'nother league.

Bottom line? You can't beat a big hp four stroke for really technical stuff, or all-day trail riding. You also can't beat a 6500 RPM blast down a trail, across a field, or down a track. They build RPMs so ridiculously quickly, it can get interesting.

~m