Are there bigger bore kits than a 440 for the 400EX?

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Apr 22, 2001 | 11:31 PM

WhatRULookinAt

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All I've seen are 440 kits for the 400EX, are there any other big bore kits out there?

Apr 22, 2001 | 11:45 PM

demonic660R

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Curtis sparks racing makes a 465 and 505 big bore kit.

Apr 24, 2001 | 04:31 PM

fivel250rman

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They make a 350X into a 500,you'ld think they could go bigger.

88'250R many extras

Apr 24, 2001 | 04:42 PM

AdamPhillips

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theres 480 and 505 kits. thats the biggest ive heard of.

Apr 24, 2001 | 05:04 PM

misfit400ex

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Does Curtis Sparks Have a web page or somthing

Apr 24, 2001 | 05:23 PM

86atc250r

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http://www.sparksracing.com

Apr 25, 2001 | 10:33 AM

Blodg500RX

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Don't know if this is true or not, but some of the motor builders claim the 400EX becomes unreliable above 440cc. The reason a 350X can be made to 500cc with no pboblem is because the crank has more room for a stroker and the cylinder head studs are spaced farther apart than the 400EX (allowing a thicker sleeve when over-bored).