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Discussion Starter · #1 ·
Hey just want to get some opinions on this.

I have an older 8x8 Argo ATV that I have rebuilt with all HD parts and chain. I love the classics and the classics had 2 strokers in em' so that's what I'm going for this time around too, just none of the "kohler" nonsense!! :laugh_old: (Argos used 400cc Kohlers at one point) New Argos just lost the appeal to me, all black and olive drab with big clunky 4-strokes stuffed in them, I like the old orange 2 strokes, never quite, and the smoke kept the flies away!! :laugh_old:

Anyway, to keep it short, I'm looking for low-end torque, not going to be revving this thing up too much, just need it to have the power to pull in the thick mud in low gear.

Both engines will have proper clutching and properly jetted Mikuni carbs, looking at running a 20:1 as it gets quite hot under the hood and I'll be running it in summer as well as winter (snow tracks).

Wondering which engine will perform better for this task? I'm assuming the 640 due to larger bore & stroke, but then again, the 503 is a little more hp.

My 640 is the newer style with the coils mounted under the intake on either side of a large "BOSCH" box, looks like a CDI unit, but I'm pretty sure this engine has points, no? Haven't gotten around to pulling the mag off yet.

Let me know what you think

Thanks! :cool_old:
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