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I've seen liquid cooled 600s and 670s in Doos but never heard of a liqid in the 640cc. If it ever existed it's news to me but ya never know. Perhaps some sort of prototype? Are you saying you found one?
 

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Discussion Starter · #3 ·
I bought a pair of NOS cylinder sleeves for my 82 Alpine. Upon further investigation of the L.A. Sleeve catalog the ones I bought fit a l/c 640. They list 2 different sleeves for 2 different 640's. One says Alpine l/c 640 and other says just 640. Both are 76mm bore but the outside dia.of the sleeves are different. The l/c sleeve being 3.255" and other being 3.235". I have never heard of any other 640 and never a liquid cooled Alpine so I don't get it.
 

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Must be a typo, I've never heard of a liquid 640.
 

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I have seen a "640 Rotary Valve," Water Cooled, Case & Crank for sale on ebay twice in the last 6-7 years! The Tag said (76mm x 70mm) 635.3cc Type 640, not Type 643, (76mm x 68mm) 617.0cc! At the time, I wasn't interested in that big of water cooled engine and didn't know it was really rare. Just like most people have never seen, or heard of a 380HO either, but they were made overseas. I believe the AD said 1992 or 1993, 640, which makes sense, since the Type 643 - 617 was only made for two years, like 90-91, they probably had a bunch of 76mm Bore Cylinders left over, and the 670 with a 70mm Stroke also first came out in 1992. So my guess is it was a 93-94 engine, since it had the Dual Pickup Slots on the Case, it also was a Provision 8 Case which first started in 1993. I have never seen a 1992 engine with Pro8 Case. Somewhere on one of these 9 computers, I probably have the Photo's from the AD, unless they were on the Hard Drive I lost.

Provision 8 670 Case looks like this on PTO end, 1993 to 1999!

Provision 4 617 Case, I don't know what year Pro4 Case's started, but ended in 1992, before Pro4 it was Provision 3, Holes like a V, before Pro3, they had No Holes, were called Non Provision!
 

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Discussion Starter · #9 ·
Thanks everyone for the info. RotaxFlyer you were a great help, you definitely know your ski-doo's.

So it looks like I have a pair of cylinder sleeves for one of these 76mm liquid cooled engines I won't be needing. If anyone has a use for them let me know.
 

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Thanks everyone for the info. RotaxFlyer you were a great help, you definitely know your ski-doo's.

So it looks like I have a pair of cylinder sleeves for one of these 76mm liquid cooled engines I won't be needing. If anyone has a use for them let me know.
Out of curiosity, if you have these 640 LC Sleeves, can you measure from the Top of the Sleeve to the bottom of the Ports in mm?

Intake = ???mm

Exhaust = ???mm

Been up all night and a little brain dead, but Intake Port should be the lowest Port, I think. My guess is 70mm from the Top! Since it had a 76mm Bore with a 70mm Stroke. The Height and Width of the Exhaust Port would also be nice also.
 

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Discussion Starter · #13 ·
Im on to you now RotaxFlyer. i came across an old post you started a few years back. A post about a liquid cooled 640. You have been on the hunt for years haven't you. The L/C 640 is your Sasquatch. The mythical beast that leaves just enough to keep you looking. but there's no real proof of it actually existing. well don't give up flyer.

if there's anything I can do to help let me know. Cause it's bugging the s#*t out of me not knowing what these dam cylinder sleeves go to. I even talked to the manufacture that makes them and they don't even know what they go to. How is that even possible I asked. The answer "We don't keep very detailed records of all the specific models and years each sleeve goes to. and we might have just had the wrong information all Along, but I did find a couple out in the warehouse I'll give you a deal on". And that's where I abruptly ended that conversation.

you find it someday flyer. Let me know when you do.
 

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Here you go RotaxFlyer. Hopefully you can read the numbers. And I also checked the bore and the widest spot I can find is only 75.15 mm?

cak
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A New Sleeve comes undersize so you can Bore and hone it to your desired 76mm Piston after it's installed. The photo on the right the Big Port bottom 72.4mm is in the realm of a 70mm Stroke! As is in the first photo Transfer Port at 71.3mm! The first photo large port has me confused, I'm going to have to dig out a 670 Cylinder and look at it, it's been a while since I looked at one.

I'm also trying to ascertain if they used 125mm Rods or 132mm Rods! I know this (76mm x 70mm) 635.5cc 640 LC existed, I seen one on ebay for sale, twice years ago. At the time I had (2) Complete 670's and parts to build maybe another two more, so I didn't really need the Engine. I also had fallen in love with the Air/Fan Cooled motors about that time frame for their simplicity, light weight, low cost, and still, make good hp for my plane. A 92hp 670 is way overkill for my single seat airplane. I only looked at that 640 account the guy said it was a 92-93 in his Ad. It had a Provision 8 Case so I think it was a 93 motor. He just had the 640 Case and Crank for sale. Somewhere I probably have the photo's from the Ad unless they were on the Hard Drive I lost! I want to say the guy's Ad was from Canada also. So must be very rare, just like the 380HO is really rare. I only found them sold in Alaska(USA) and Norway.

Best thing to do is compare them to an actual 670 cylinder to see where they differ. Even 670 Cylinders aren't the same Height, and 670HO Cylinders Ports are different.
 

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Was there ever a liquid cooled Rotax that had piston port induction ???? I am thinking not ?? Both the sleeves in pic have piston port intake ports.
 

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I did find this Info with a Google search.

http://www.ebay.com/itm/1970-71-72-73-74-75-82-Ski-doo-640-TNT-Alpine-Nordic-Valmont-Cylinder-Sleeve-x2-/141832539640

(A Set of Two) LA Sleeve Brand_Part # FL-1176_These out of the packaging will accept standard bore size 76mm pistons, They are also boreable to fit the piston diameters you have if other than standard size--nice if you can get oversize pistons for cheaper.

Fits:

1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 Ski-doo model 640_635cc Twin Fan models for TNT_Alpine_Nordic_Valmont. Also fits Ski-doo Rotax 300_320 model engines 1967 1968 Super Olympique_1967 1968 Alpine_1967 Super Alpine, 1969 1970 Olympique 12/3_1969 Olympique 320_Single models
 
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