Oh yes, Big bore...

72hp?

Might actually end up going this way

http://www.ebay.com/itm/BOMBARDIER-...Parts_Accessories&hash=item53f4310da6&vxp=mtr

I'm worried that the cylinder might be different but the part number for the cyl on the max bmw parts fiche corresponds with all the rotax dual spark 650's. The rotax in the ds650 is also a dual spark... Trying to find out if the cylinder is sleeved or if it has been bored and replated. If it is NOT sleeved I'm going to go ahead and pull the trigger on it. Otherwise I'll order the piston, rings, pin and gaskets, then send out my cylinder to be bored and replated. :thumbup:

after poking around some more looks like that cylinder is not a direct swap.

http://www.team-pami.com/cms/?q=en/catalog/46/parts_service&page=3

this german team used to do lots of g650 tuning. you can get a 103.5mm piston and i'm pretty sure they do boring and replating. i'm not sure if they still do it though. but it would be worth a shot. plus I'm pretty sure they do "for street use" performance mods as well.

I know about team pami. Try to contact them and you'll see why I've never had anything of theirs. They just don't respond Also the pricing is outrageous. $600 for a piston? The JE 105mm piston kit with everything I need is $200, the boring and plating work is $300.

Mr.F said:

I know about team pami. Try to contact them and you'll see why I've never had anything of theirs. They just don't respond Also the pricing is outrageous. $600 for a piston? The JE 105mm piston kit with everything I need is $200, the boring and plating work is $300.

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it says cylinder and theres no description. i figure it would come with the piston, cylinder and gaskets. but that sucks that they arent doing anything anymore.

dpelt73 said:

it says cylinder and theres no description. i figure it would come with the piston, cylinder and gaskets. but that sucks that they arent doing anything anymore.

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I figured it was just the piston because the cams are expensive as balls and they could only possibly be cams. Anywho I'm not sure if they are or aren't doing anything anymore, they've just never responded to any of my emails.

I guess when I look at it again their pricing isn't all that bad on some things, moot point considering there is no communication.

might have lucked out. Found a guy selling the 720 kit for a hundred bucks. Calling around some places to see about boring and plating the cyl.

Mr.F said:

might have lucked out. Found a guy selling the 720 kit for a hundred bucks. Calling around some places to see about boring and plating the cyl.

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the 720 kit as in the piston with rings? and you'll be boring and plating the stock cylinder? if so let us know how it goes.

is the 720 kit one of the rotax brp pistons?

It's the JE kit for the ds650, it usually comes with piston, wrings, pin, clips, and a sleeve. The kit I found and bought for $100 did not include the sleeve, which wouldn't use.

I will hopefully be sending the stock cylinder to millennium for bore and re-plate. I say hopefully because I'm not too sure about being able to punch it out that big. I was looking over the stuff on the team pami site and I never noticed until now that for the newer generation rotax singles, the single exhaust port head singles, they don't offer anything bigger than a 103.5mm piston and cylinder. I'm hoping that's not because a 105mm bore will not leave a sufficient cylinder wall thickness. Or maybe the piston is different. Will know for sure when it's in my hand, and if it's a no go, then I didn't lose much.

got myself all worried about it now, so I went on fleabay and found a cylinder from a f650gs http://www.ebay.com/itm/130690986237?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649

Single exhaust port, so same cylinder, double checked the numbers on the front of the cylinder, same exact part. It's cheap enough and I'd much rather take the risk with old parts than my stuff. I have also looked into the piston some more, and I'm certain it will fit. When I search the piston part number on maxbmw the same part goes as far back as the 93 650's.

Now the biggest thing is getting that cylinder here and verifying that the cylinder wall is thick enough to take 2.5mm of material out. From what I've read .045" is the minimum acceptable wall thickness. So if the end that goes into the crank case is at least 3.643mm thick, I should be good.

Will update as I get more.

you may not even have to go a full 2.5mm out. measure your piston first when you get it and get whatever company that's doing the boring bore to the piston manufacturer's recommended oil clearance. Most aftermarket piston manufacturers ask for a lot tighter oil clearance than stock because the different piston material.

dpelt73 said:

you may not even have to go a full 2.5mm out. measure your piston first when you get it and get whatever company that's doing the boring bore to the piston manufacturer's recommended oil clearance. Most aftermarket piston manufacturers ask for a lot tighter oil clearance than stock because the different piston material.

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the company I use asks that you send a piston in or buy one from them. Guessing they've got everything covered, they haven't let me down yet :thumbup:

Mr.F said:

the company I use asks that you send a piston in or buy one from them. Guessing they've got everything covered, they haven't let me down yet :thumbup:

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thats a good company right there. I've heard too many people boring the cylinder out the same amount that the piston was increased, just to find that it wont run right cuz the cylinder is too big.

As far as the head, found lightweight retainer valve spring kit and +1mm valves from kibblewhite. Local shop is quoting me $500 for all the work if I bring the parts. I'll probably do that later, but it's good to know the option is so easily accessible.

Mr.F said:

Piston showed up today.

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the packaging actually says bmw 650 on it. is that the 105mm or the 103.5mm piston?

I noticed that also, it's the 105mm. Getting excited, cylinder will be here by Friday.

Mr.F said:

I noticed that also, it's the 105mm. Getting excited, cylinder will be here by Friday.

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so you're boring a "donor" cylinder to see if it works?