550sx pro series crank rod questions

[87kawi650sx]

Hey guys. Been a while since I've been on here. Years ago I got new 550 crank that's been welded, and has pro series rods. Finally got around to building a motor I'd like to use it in. Went to put the pistons on today, the end of the rods that accept the wrist pin/bearing had slop when I installed the piston. I took it apart to measure. The ID of the pro series rods measure 21mm, vs a stock crank which measures 20mm. I emailed IMS, but does anyone know if they made a heavy duty crank rod, that might have taken a beefier wrist pin bearing? Or have any other ideas?

[87kawi650sx]

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[87kawi650sx]

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[WFO Speedracer]

Doubtful as it would require special made pistons, but here is another idea maybe it takes a thicker bearing. Seadoo for instance makes two different 657 crankshafts, either one takes the same pistons and pins but the bearing sizes are different. You would probably come a lot closer to finding a bearing to make that work than a piston...............

Like this one ; https://www.amazon.com/B1005-16X21X2.../dp/B005KLQJ6S

[wmazz]

My Guess is you purchased someones custom crankshaft.

I call stuff like this "Shelf Parts". The parts that don't work
end up on a shelf. Then someone that doesn't know why
the parts were on the shelf decides to sell the parts.


Bill M.

[87kawi650sx]

Looked around for some bearing yesterday. Found these, same ID and legnth and factory 550 bearings, but 21mm OD instead of 20mm. Hopefully they work. And hopefully this is a stock stroke crank

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[WFO Speedracer]

You know I posted you that link about two days ago right ?

[Bionic racing]

Is that a T type crank? Or full circle ?

[87kawi650sx]

You know I posted you that link about two days ago right ?

Sorry, didn't see that! Appreciate it. They fit great.

[87kawi650sx]

T style crank