Triumphrat

RoadWarrior

Aside from the obvious difference between the two cranks, what are the differences between the two. As in, which one runs smoother, is there a flatter power curve on one of them? Has anybody rode a 360 twin and a 180 twin and notices a difference?

666Bonneville

360º and 270º you mean?

the 270 will make more torque but trade in some HP. so you'll get off the line with more grunt.

conversely the 360 has less torque so it will pull more on the the top end of the RPM range.

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RoadWarrior

270? Strange. Well, thanks for the input!

22676

er yeah..............there is no 180 degree crank on these things.

mikeinva

both make about the same power the 270 is the ticket on flat track bikes because it makes the bike hook up better on dirt.with the same mods and cam timeing both make about the same ft/lbs and hp the 360 is even fireing so its smoother on black top.

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RoadWarrior

Thanks for the input man. It figures that a 360 2cyl will be smoother than a 270. And now to rewire the bike..

oldroadie

That's pretty much it. I have both and that's how they are, it's worth noting the 360 does vibrate more at higher RPMs. They'll both do the ton so top speed isn't really an issue.

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justbrian

Not even so much "more" torque with the 270, as the 360 actually "specs" at one additional ft/lb, but the torque curve is moved lower into the rev range with the 270 (~4500 rpm) as compared to the 360 (~6000 rpm), meaning you don't need to rev as high to get into the peak of the torque range.

The trade-off is that the 270 runs out of breath a bit earlier, but I can tell you from experience that ARK/after market silencers make a huge difference in this respect.

mikeinva

the reason the 270 stock motor wont run as good at high rpms is the cam nothing to do with it being a 270 .The flat track guys turn the 270 9500 rpms and get mid 90s hp from them.

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sweatmachine

if the engines were not counterbalanced, the 270 motor would be a lot smoother than the 360. Guys w/ xs650s disassemble the cranks (stock 360 like the bonnie) and reassemble them to 277 degrees (the closest they can get with the stock crank parts) to gain some hp and also smooth out the vibes.

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