Pulling apart my next project. RZ250 w/350 pistons

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Gavin
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Pulling apart my next project. RZ250 w/350 pistons

Post by Gavin »

If you have been following my other thread about the RZ250 you will know it's now parked up in the corner waiting on the fairings and tank to be done. So onto my next basket case.
I acquired another RZ250 F1 that has had a set of 350 barrels added. Looks like it had been run like that for a while but something went seriously wrong and I'm stripping it down. When the head came off I found one piston had metal bits inside it and as you would expect a nasty pitted surface on the piston itself.
Image
Image

And a comparison shot of the head showing a different operating burn.
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You can see the pitted cylinder clearly.
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I don't know where the bits have come from but the crank doesn't make a full circle so I suspect when I get to it, there will be something broken off or jamming it. I'll send it off to Link when it's out.

So now question time.... Do I measure the piston or pots to find the current piston size? Both pots measure 64.44 or 64.51 if I put a little pressure in the calipers. I'm guessing I have a 64.5 2nd oversize - could someone please confirm before I order the new piston kit.

Thanks
G








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86 RZ250F restored. 84 RZ500 rebuild in progress, 73 CT3 in progress
JonW
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Re: Pulling apart my next project. RZ250 w/350 pistons

Post by JonW »

Pull it all apart first Gavin, the cyls could be scored badly needing a rebore etc.

Looks to me like the crank seals failed, but could be anything of course. pull the cyls and the crank and lets see some pics...
James W.
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Re: Pulling apart my next project. RZ250 w/350 pistons

Post by James W. »

Gav, Jon is correct, best you strip it down & carefully inspect the whole plot..

& I'd def' recommend getting those bores properly/professionally miked up for rebore sizing- before ordering the new pistons..
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Re: Pulling apart my next project. RZ250 w/350 pistons

Post by BRG1200 »

Don't go any more oversizes than you have to, barrels are getting fairly scarce, not that you don't know that.
Ex UK, now in Adelaide. LC250/350. DT175. Shed full of sh1t in the vague form of dismantled rusty RD’s and RZ’s.
Gavin
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Re: Pulling apart my next project. RZ250 w/350 pistons

Post by Gavin »

Thanks for the advice. I started to add up the replacement bits needed just to get it running again, and found it would exceed the value of the bike as a whole, so I decided to move it along on eBay. I did put a shout out to Forum members if anyone wanted it, in the Bikes for sale section. It's over reserve so it will still tomorrow. Can sell the spare tank for it now too.


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86 RZ250F restored. 84 RZ500 rebuild in progress, 73 CT3 in progress
BRG1200
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Re: Pulling apart my next project. RZ250 w/350 pistons

Post by BRG1200 »

Good luck with the sale
Ex UK, now in Adelaide. LC250/350. DT175. Shed full of sh1t in the vague form of dismantled rusty RD’s and RZ’s.
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