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HELP? Advice on 302cc big bore stroker (82x57.2)

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Does anyone have experience with this 302cc mod?

82mm piston, and 57.2mm Hot Rods crank. (Stock is 78 x 52.5mm and 12.9:1 compression)

I'm looking for more low-end grunt for trailwork, occasional enduros. I have an 270X kit (Athena), which is fantastic mod for low end grunt.

270 = good!

302 is probably better, but do you have it, and do you like it?

Edited by WA_trail_rider

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If your talking about the max rpm kit with the ice cube cylinder its fricking awesome.

If your building your own i dont know.

Big difference is the max kit uses a longer rod, stroked oem honda crank and a taller deck which requires modifying your upper engine mounts.

case mods are needed to fit the crank.

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Hi Shovle65, thanks for your reply. Are you riding one of these now?

I was planning to use HotRods 57.2mm stroker crank and any of the 82mm piston kits. Prefer not to do case mods, I'd only do it if it was simply exchanging parts.

Thanks for warnings about upper deck, case mods, engine mounts. This looks like more hassle than I want...

Found a useful thread:


Anyone else have done this 297cc or 302 on the 250X?

Edited by WA_trail_rider

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Yes. Im riding and racing one of these now.

Only racing enduros though.

Main reason for the 302 conversion was i was begining to hate the wide ratio transmission due to my riding style. Needed the bike to lug better and the stroker crank has definitely fixed that.

I dont know much about the hot rod cranks but when i researched the mod noticed max rpm didnt offer the kit with anything other than a OEM honda crank due to strenth. (according to them) Plus all there kits with hot rod cranks were a lot cheaper.

Seems that the longer rod was needed also do to added stress on the crank which required the taller cylinder and longer studs.

The cylinder used increased the cooling capacity as well.

Case mods are minor enough to return the bike to a 250 with no problems.

I assembled the motor and had the case mods done myself.


PS. the stock x clutch cant handle much more than stock. You will need to convert to a r clutch pack without the judder spring at the minium.

the x crank and the r crank are differnent in weight and stator used.

I would have just got a new bike but it seems that no one make a bike like this so far. Maybe in a few years. :thumbsup:

Was hoping that the new KTM 350XC would lug better but from what ive heard so far it doesn't.

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