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104mm piston group buy??

Excellent price on what sounds like an excellent piston.

How will you go for weight?
 
Weight is unknown at this time. I'm not too concerned about this. Will have to put up with whatever it is. My goal is a piston for 1000 engine hours.
 
I'm interested but need to know weight and exact dimensions before committing

Cheers !

Have to wait for the weight until they receive my sample. Can you help me to choose darton sleeve? Do you have any part numbers or specific information on it? Sleeve will dictate a act diameter and at this time not decided yet. Perhaps something that you or somebody else used before around 105mm. I think Darton has excellent and prefered quality sleeves.
 
Have to wait for the weight until they receive my sample. Can you help me to choose darton sleeve? Do you have any part numbers or specific information on it? Sleeve will dictate a act diameter and at this time not decided yet. Perhaps something that you or somebody else used before around 105mm. I think Darton has excellent and prefered quality sleeves.

When I had Travis put my 660 together, he wanted to have the piston so he could measure it and determine the final hone diameter for the sleeve. So, the piston comes before the sleeve...or at least for the pressed-in sleeve for my older/separate cylinder engine.

Especially for $220, you can consider me in. I just picked up a 2001 FE501 that'll likely need a rebuild in the near future. Might be nice to have a piston all ready to go for that.

Maybe you guys can educate me on the liner o-rings. If making a custom liner, wouldn't it be possible to just design for the smallest cross section o-ring, or are the oem o-rings already the small (I think the small o-rings are .060" thick) section? Clearly I've never had one of these engines apart - I sold my '08 before it needed to be split.
 
I'm counting on some commitments to buy it from me. It sucks that minimum order is 12. I have two 550 and 644 so I need 3 Pistons with 23.5mm compression height. 628 needs 24.5mm. I think that most people would have this engine. So I'm thinking of getting twelve of those too. Plus twelve sleeves. Am I crazy to spend so much coin hoping that someone would buy it from me? I will post on Husaberg
Facebook too.
 
If you just made them all to the 24.5mm compression height, and with 1mm deeper valve reliefs, couldn't you just have the ones you need at 23.5mm faced off to that from 24.5mm?

Also, a note of caution, you may want to measure your piston height at TDC to the top of the liner for each engine. You may need something other than 23.5/24.5 mm to get ideal quench. That's the part I missed when selecting parts for my 660. I thought I'd need a piston with 23.5mm compression height (stock for the 600) to go with the custom Carillo at 130mm (stock for the 600). However, if I had done a better job of measuring when disassembling, I would have found that I needed a longer rod. We ended up switching to a KTM 560 SMR piston (24.5mm) from the 'Berg 550 Wossner I had originally purchased for the project (23.5mm) and then Travis still had to deck the cylinder down and install a manual cam chain tensioner to get the quench into a reasonable gap but still have enough throw to tension the chain.

My plan for the 501 (to turn it into a 606) will be to use your piston and design a custom Carillo rod to accommodate it based on careful measurement at disassembly.

Oh, and I imagine that I could just cut down one of your sleeves to work in the 501 cases? Maybe I should commit to buying one of those as well.
 
If you just made them all to the 24.5mm compression height, and with 1mm deeper valve reliefs, couldn't you just have the ones you need at 23.5mm faced off to that from 24.5mm?

Also, a note of caution, you may want to measure your piston height at TDC to the top of the liner for each engine. You may need something other than 23.5/24.5 mm to get ideal quench. That's the part I missed when selecting parts for my 660. I thought I'd need a piston with 23.5mm compression height (stock for the 600) to go with the custom Carillo at 130mm (stock for the 600). However, if I had done a better job of measuring when disassembling, I would have found that I needed a longer rod. We ended up switching to a KTM 560 SMR piston (24.5mm) from the 'Berg 550 Wossner I had originally purchased for the project (23.5mm) and then Travis still had to deck the cylinder down and install a manual cam chain tensioner to get the quench into a reasonable gap but still have enough throw to tension the chain.

My plan for the 501 (to turn it into a 606) will be to use your piston and design a custom Carillo rod to accommodate it based on careful measurement at disassembly.

Oh, and I imagine that I could just cut down one of your sleeves to work in the 501 cases? Maybe I should commit to buying one of those as well.

You are right that we can get 23.5 mm from 24.5mm and all would be covered. But it would require machining. For me and some others it is pain in the ars. I'm trying to make drop in big bore that lasts 1000 engine hours. I'm. Taking 3 Pistons for myself at 23.5mm and three at 24.5mm. I'll keep two Liners. The rest will be available. Maybe I'll get three Liners for 550 too. I'd keep two.
 
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I don't think you are crazy but if the weight is more than about 340gm you will have a hard time selling them imho
 
Bushmechanic what are your thoughts on just plonking in 570 104mm piston? They are under 340g they are available to buy singular as opposed to 10 or more.
 
I can weigh a Wossner 570 piston/kit and/or the 104mm CP. im sure the CP is up near the 340g mark. Way over constructed and a heavy pin.
 
Hi Polska.

Haven’t been on here for a long time but seen your post over on the HAS page.

I’d be interested in at least 1, if not 2 of these pistons. I have both 644 and 628 engines but would be happy with both of them at 24.5mm CH if I do the 2.

Yes weight will be a factor for me too but I’ll follow this thread for now and see what eventuates. I think if you really want longevity, reciprocating mass should be at a minimum especially with the bigger valves and carb. But I also realise it’s not easy to have everything!

On a side note, I was reading that my KTM 1090 Adventure R has 103mm pistons. Would love to compare dimensions of these to our Husa ones to see if they are doable....

Welcome to pm me if needed

Regards

Damo
 
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...And it appears that the 1190 uses a 105mm piston! And it may even use a 20mm wrist pin!
 
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...And it appears that the 1190 uses a 105mm piston! And it may even use a 20mm wrist pin!

Maybe it would fit? Don't know. But quck search showed $350 each! And no asymmetrical design.
 
1190 piston top of pin bore to top of piston 15.9mm.according to a friendly eBay seller that measured for me.as opposed 14.5 needed for 628.
 
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Incidentally, has anyone else noticed that the 628’s displacement is exactly 2 pi deciliters? Kind of funny. Metric humor?
 
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Bushmechanic what are your thoughts on just plonking in 570 104mm piston? They are under 340g they are available to buy singular as opposed to 10 or more.

That's a good idea except the piston crown might not be ideal for the old engines head and stroke , ie compression ratio valve placement and squish band shape. Pictures, actual weight and dish volume etc would be useful but I'm about to hop on a plane will check later.
 
Idea to check 1190 valve angles aswell, Id expect them to be less which may present a problem or not, no idea how much piston to valve clearance the 650/628 has to offer.
Edit: Probably what Bushie is saying. Just thinking out loud you know :)
 
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