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400E stroker conversion?

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Hi guys, its been a while since ive done any mods to my drz and with christmas coming up i feel its time to splash some hard earned!

ive always wanted more torque, so from what ive read on here (an excellent resource btw!) a +5mm stroker is the way to go.

however, i would like to keep using standard E model pistons and keep the mega reliabilty of this engine. to do this am i right in thinking i need a 2.5mm cyclinder spacer?

What other things would you guys suggest to get the most from this setup? an mrd/ssw and kickstarter are on my list but what about valves etc? Pros/cons and advice on this subject will be greatly appreciated!

thanks for your time fellas

pete

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hotrods now has a +4mm stroker that doesnt use a spacer or special pistons.

if understand correctly you want to use a stock bore set up with the stroker crank.you can certianly do that but doing a 94mm big bore kit and leavin the stroke stock makes the more sense.

cost the same parts wise but is much less work.

the only reason i would do what you are describing is if the motor had a rod failure and you were replacing the crank any way.at that point the cylinder is likely bad any way so oyu be doing a 94mm big kit too.

as far as valves go,how many miles do this motor have on it now? what is it used for?

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hi Eddie. yes you understand correctly, i would like to keep the standard bore size, mainly for the ease of sourcing and price of parts. the motor has 10000miles on the clock and is used mostly for hard road riding (sustainted high revs) with the sm wheels and a little bit of winter off-roading.

what would be the power differences between stock bore with +4 rod and said 94mm bore kit?

As reliability goes, which would be most likely to fail?

Im compitent with doing the work myself (son of a grease monkey) so time isnt really an issue.

thanks for the reply

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they will basically be the same power wise.

neither is more likely to fail the other.

its your call if you have the flywheel puller and case seperator and all the tools and time to do it then by all means continue on.

you can do a big bore kit in the frame.

at 10,000 miles you willl need to do the top end stuff (piston kit,valves,springs,cotters,retianers etc) while its apart any way.

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thank you for your time Eddie, on your advise and even more searching i think i will go the bb. time to order parts!:bonk::excuseme:

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I do have to split my bottom end apart. I have some of the same questions it seems. Are there any great threads or further reading anyone can direct me toward? I want to install a stroked crank and bore/sleeve my stock cylinder. Suggestions? Does anyone know the largest bore I can do on a stock cylinder?

BTW: 2002 DRZ400e GP motocross/desert race riding mostly.

Thank You.

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I do have to split my bottom end apart. I have some of the same questions it seems. Are there any great threads or further reading anyone can direct me toward? I want to install a stroked crank and bore/sleeve my stock cylinder. Suggestions? Does anyone know the largest bore I can do on a stock cylinder?

BTW: 2002 DRZ400e GP motocross/desert race riding mostly.

Thank You.

94mm on any of the OEM or OEM like castings is the largest bore recommended. Larger and you get in to head sealing issues.

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Sooo, if I bore stock cylinder 4 over to a 94mm and stroke the crank with a +4, will I then need to replace the cams?

Or, is it reccommended to just bore to 94mm and no stroker crank?

What combo of work have folks found to work best with minimal issues later?

Thanks for the info.

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yes .. RHC cams and valves / springs are needed to make the motor breathe with the stroker and + 4 o/s bore

you can fit the big bore kit only , i recommend you jet the carb and fit a decent full system to get some decent gains .

these motors are reliable and well engineered , you can modify them with the proven parts . like hotrods cranks , RHC or hotcams , cylinder works big bore kits as a example .

clean oil and air filter and general maintenance are required

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Sooo, if I bore stock cylinder 4 over to a 94mm and stroke the crank with a +4, will I then need to replace the cams?

Or, is it reccommended to just bore to 94mm and no stroker crank?

What combo of work have folks found to work best with minimal issues later?

Thanks for the info.

94mm bore, 4mm stroker combo, fresh head with new valves, springs, seals and cotters all built right will be as reliable as an OEM motor

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Where do I get my head work done right. I live in So Cal. Is Eddie my man? Can I send head away to him? I'm doing the case and cylinder myself. Thanks for the input

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