WR400 connecting rod

I've got a special order wiseco piston, WR400 rod with a 426 jug 2mm over, so 444 at 13:1

when it's time to replace my only option is press on a 426 rod to match, cant get replacement pistons anymore as far as I know at least

cant get replacement pistons anymore as far as I know at least

They only made a handfull of those pistons. They were about 12% heavier than the OEM piston and accelerated rod breakage when guys installed them in engines with a lot of hours on them.

The 426 rod is just better all the way around. :cry:

Are they heavier due to the extra 4mm diameter? or more material somewhere else?

I've got so many hours on the bike, last year it was rode 8 hours a day 2 days a week

Are they heavier due to the extra 4mm diameter? or more material somewhere else?

They used a different forging process with those pistons than they do on the new YZF250 big bore pistons. The YZF250 2mm over pistons are actually lighter than stock by about a gram (I don't remember the exact amount off the top of my head).

So in answer to your question it's probably a combination of the process and the size of the piston.

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