Pistons/rings

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corvine
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Pistons/rings

Post by corvine » Wed Sep 13, 2006 5:01 pm

The bore/stroke on a KR250 seem to be the same as the KR1/s can they be interchanged, are the little ends the same. Does any body know the distance between little end centre to piston crown on the kr1, where the ring pegs sit, has anyone ofered them up to each other to see any differences. And then do kawasaki still sell KR1/S pistons?
Many thanks.

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StrokerBoy
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Post by StrokerBoy » Wed Sep 13, 2006 5:36 pm

You can still get KR250 pistons (13001-1189) new, last time I tried anyway. Try asking a Kawasaki dealer to order them, or use Z-Power. Rings (13008-5065) are a different matter but I'm working on it.

I don't have any data for the KR-1/S but I can measure my KR250 bits if anyone else can do the same for the parallel-twin ? 56mm bore x 50.6mm stroke ?

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Post by corvine » Wed Sep 13, 2006 7:21 pm

I obviously started out on a complete tangent and will have to do some ground work next time! what about gaskets are they still available?
I'm just thinking as I write this I,ve got your number from when I bought some manuals off you, maybe I could give you a call if thats all right?
Many thanks.

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col
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Post by col » Wed Sep 13, 2006 8:48 pm

kr1 is the same. 56x50.6mm.
piston part # 13001-1354.
rings part # 13008-1121

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Post by StrokerBoy » Thu Sep 14, 2006 9:01 am

corvine wrote:What about gaskets are they still available?
I've got your number from when I bought some manuals off you, maybe I could give you a call if thats all right?
Yeah, no problem. :)

You can still get gaskets too, as far as I know. You need to know part numbers 'cos most dealers have no idea what a KR is and they'll just say "no". If you don't have a Parts Book I can send you a copy, but I've finally got round to scanning the whole thing and have put it on my site : http://kr250.org/KR_partsbook.htm

Someone gave me a tip about a place that has warehouses full of NOS parts and I've put an order in for some KR bits that were previously unavailable (inc. rings). But I haven't received anything yet and I'm not convinced it's gonna work out. But if it does, I'll let everyone know. :wink:

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Post by corvine » Thu Sep 14, 2006 12:48 pm

"a place that has warehouses full of NOS parts"
Some kind of utopia where the rivers are of two stroke and spark plugs grow on trees... or just plain drugs!
Can I call you about 9 tonight? Many thanks.

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Post by StrokerBoy » Thu Sep 14, 2006 1:22 pm

corvine wrote:Some kind of utopia where the rivers are of two stroke and spark plugs grow on trees
I'm not getting too excited about it until a box arrives with everything I've ordered. I've been let down before by people telling me it's "in stock" then telling me later that "there's none left anywhere on the planet". :roll:

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Post by StrokerBoy » Thu Sep 14, 2006 11:17 pm

corvine wrote:Can I call you about 9 tonight? Many thanks.
After we spoke I double-checked my parts books :

The pistons, rings, small-end bearings, gudgeon pin, circlips and base gaskets all have exactly the same partnumbers in both the A (ordinary) and A2 (S) books. Obviously the barrels, head and head gasket are completely different. Hope this helps. :)

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Post by StrokerBoy » Tue Oct 10, 2006 4:43 pm

StrokerBoy wrote:Someone gave me a tip about a place that has warehouses full of NOS parts and I've put an order in for some KR bits that were previously unavailable (inc. rings). But I haven't received anything yet and I'm not convinced it's gonna work out. But if it does, I'll let everyone know.
corvine wrote:"a place that has warehouses full of NOS parts" - some kind of utopia where the rivers are of two stroke and spark plugs grow on trees?
StrokerBoy wrote:I'm not getting too excited about it until a box arrives with everything I've ordered. I've been let down before by people telling me it's "in stock" then telling me later that "there's none left anywhere on the planet".
OK, the verdict's finally in...

...predictably disappointing. :(

It seemed promising because you can enter part numbers on their website and it tells you whether they're still available or not. So I put an order in for various KR parts that I'd failed to find anywhere else but were apparently "in stock" here.

Two months later :shock: a tiny box arrives containing a couple of the minor items and a receipt, showing that all the other items are "no longer available".

So when their site says "in stock", it really means that Kawasaki still list it as a current part but there's none left... :roll:

If anyone wants to try it anyway, Click Here
Kawasaki KR250 Tandem Twin (x4) & KS-II 80,
Yamaha RD350LC,
Suzuki GSX-R750RK & RB50 Gag.

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StrokerBoy
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Re: Pistons/rings

Post by StrokerBoy » Mon Nov 06, 2006 11:18 am

corvine wrote:The bore/stroke on a KR250 seem to be the same as the KR1/s can they be interchanged, are the little ends the same. Does any body know the distance between little end centre to piston crown on the kr1, where the ring pegs sit, has anyone ofered them up to each other to see any differences. And then do kawasaki still sell KR1/S pistons?
Many thanks.
S'not good news I'm afraid. KR1 rings are much shallower than the tandem-twin ones and the piston itself is shorter. :( Gudgeon pin appears to be the same though.

Tandem-twin on the left, parallel-twin on the right :

Image
Image
Kawasaki KR250 Tandem Twin (x4) & KS-II 80,
Yamaha RD350LC,
Suzuki GSX-R750RK & RB50 Gag.

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Post by StrokerBoy » Wed Nov 29, 2006 5:32 pm

I haven't found a source of new KR250 piston rings I'm afraid. :( But have I found a compatible alternative ?... :shock:

Tambo was after a cheaper alternative to KR1 rings and took a risk on some for a KMX125 (but +2mm oversize to give a 56mm bore). No good - they're completely different to the KR1 rings in everything except bore size. :cry:

But, he kindly sent them to me to have a look at for the ol' tandem-twin. 8)

Looks promising so far. The shape of the ring ends is the same, the depth and thickness looks the same, and there's one flat and one tapered ring (top one) as per the KR. I've not done any measuring yet and I'm slightly worried that the KMX rings have a bigger ring gap, but I'll try them on a spare KR piston/barrel and do a bit of measuring at the weekend.

If this does work out to be good news, the icing on the cake is that you can pick up new pattern KMX rings for about 3p a dozen ! :lol:
Kawasaki KR250 Tandem Twin (x4) & KS-II 80,
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corvine
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Post by corvine » Thu Nov 30, 2006 1:00 pm

Any idea what oversize KMX125 pistons look like!!!

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StrokerBoy
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Post by StrokerBoy » Thu Nov 30, 2006 2:34 pm

corvine wrote:Any idea what oversize KMX125 pistons look like!!!
No. You buy one and send me a picture ! :lol:

Gotta be worth looking into though eh ?
Kawasaki KR250 Tandem Twin (x4) & KS-II 80,
Yamaha RD350LC,
Suzuki GSX-R750RK & RB50 Gag.

corvine
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Post by corvine » Thu Nov 30, 2006 5:50 pm

Yep OK it's my turn! will find a cheap one on ebay.

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Tambo
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Post by Tambo » Thu Nov 30, 2006 8:24 pm

Any idea what oversize KMX125 pistons look like!!!
You might be onto something there going by the photos with the KR1 piston as a comparison.

The sizes I have for the KMX are ; 4mm overall longer than a KR1 (64mm), 3mm longer from the top of the gudgeon pin to the edge of the crown (25mm), and the same dome height at 2.5mm. The peg positions are slightly different from the KR1 at 28.5mm apart, but it's only 0.5mm.

Judging by the photos, it doesn't sound far away from a KR250 ?
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