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Most powerfull YZ400/426

4 posts in this topic

wondering if any1 has does extensive engine work to there yz400/426


Mine has

Hotcams IN/EX Cams

Oversize valves

Polished ports and combustion chamber

High compression piston

Hotrods crankshaft and rod

Wiseco clutch basket

40mm Keihin carb off 08yz450, bored

FMF exhaust system


looking at geting a programmable MSD CDI and Dynotuned


All work performed by me


Runs a compression ratio of 14.5 : 1

Runs on E85 race fuel (wheat blend, not the cheap stuff u get on pump)


runs great, no probs with the E85 and seals, no corrosion. its alcohol, it keeps everythig clean.

there are alot of myths about the E85 fuel and bikes. i have stored half a tank in by bike for 2 months and it ran fine, carb was still spotless.

only alcohol based Fuels will handle a 14.5:1 compression ratio, it auto-ignites nearly 100 celcius higher than gasoline.


i used to own a 2008 KTM 530 EXC-F and this yz400 just puts the 530 to shame.

its the most powerful dirt bike ive ever rode (ive owned ALOT)



want to know if any1 else has something as worked

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stock bore and stroke

got the hotrods con rod for a 2000 YZ426

bought rod and crank early last yr. i looked just then for crank but couldnt find hotrod one apart from the one MT posted. am certain it was hotrods but, just for a different model.

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