Author Topic: 1970 Skidoo Alpine 640er  (Read 2944 times)

Offline PINHEAD

  • Garage Guru
  • ****
  • Posts: 142
Re: 1970 Skidoo Alpine 640er
« Reply #20 on: August 18, 2015, 07:38:24 PM »
got a picture of where you run yours? Just for an idea.
I will try this weekend to get you some pics in the city working right now.

Offline needs2snow

  • Rookie
  • *
  • Posts: 20
Re: 1970 Skidoo Alpine 640er
« Reply #21 on: August 24, 2015, 07:09:19 AM »
Recieved my cables thursday. Just going to wait for the gaskets to come for the intake. But the neighbor used his camera to see what the pistons look like and the walls. Everything looks good, do I need to tear it apart and rebuild it? I have around 120 in each cylinder.

Offline zuknomad

  • 'Viceroy de Vintage'
  • Hardcore Sledder
  • *****
  • Posts: 4473
  • ice is nice
Re: 1970 Skidoo Alpine 640er
« Reply #22 on: August 24, 2015, 09:11:40 PM »
120 pounds in each cylinder is perfectly acceptable; better yet is that they are so even with one another. If the crank bearings feel smooth as you roll the engine by hand, there is no reason that you should have to rebuild an engine with compression like that. You should think about replacing the crank seals, however, or at least the PTO side. Old seals that leak are a leading cause of 2-strokes that won't stay running (or end up burning down). See if you have an oily mess where the shafts come out of the case. If so, you will need to remove and replace your crankshaft seal(s).
'anyone can drive a new sled, it takes some dedication to run crap'

Offline needs2snow

  • Rookie
  • *
  • Posts: 20
Re: 1970 Skidoo Alpine 640er
« Reply #23 on: August 24, 2015, 09:20:43 PM »
I can do that by not taking the entire thing apart?

Offline zuknomad

  • 'Viceroy de Vintage'
  • Hardcore Sledder
  • *****
  • Posts: 4473
  • ice is nice
Re: 1970 Skidoo Alpine 640er
« Reply #24 on: August 25, 2015, 08:27:03 AM »
I've done it on Suzuki engines with no problem. I do not know about that particular Rotax. As a general rule, if your seals do not have a rib around the outer diameter of them, they can just be driven in without separating upper and lower case halves.

Pic below shows tools used to pull one on a Suzuki single, mag side. I prefer to bend the lip down and drill through that, so that I have no chance of hitting the bearing or getting shavings inside the case.

Wish a Ski Doo guy would chime in here, I would appreciate some other opinions...


'anyone can drive a new sled, it takes some dedication to run crap'

Offline cruelpaul

  • Hardcore Sledder
  • *****
  • Posts: 6619
  • We got six.... Do you?
Re: 1970 Skidoo Alpine 640er
« Reply #25 on: August 25, 2015, 08:12:51 PM »
I've done it on Suzuki engines with no problem. I do not know about that particular Rotax. As a general rule, if your seals do not have a rib around the outer diameter of them, they can just be driven in without separating upper and lower case halves.

Pic below shows tools used to pull one on a Suzuki single, mag side. I prefer to bend the lip down and drill through that, so that I have no chance of hitting the bearing or getting shavings inside the case.

Wish a Ski Doo guy would chime in here, I would appreciate some other opinions...



Great idea on bending the seal over before drilling. I heard that's Ullers method too  whistle

I've installed plenty of crank seals without splitting the case. I use an anaerobic sealer as a lube/ sealer when putting the new seal in. I have even shaved off the dreaded "rib" with good results provided its not a hi performance engine.

http://www.starmarinedepot.com/permatex-anaerobic-gasket-maker-6ml.html?gclid=CjwKEAjwpPCuBRDris2Y7piU2QsSJAD1Qv7BCFqsdUlVxCnnquzL4ZCqbMtH5gfMJaFK7qrA69jJ5hoCNmjw_wcB

cp
people who mind don't matter and people who matter don't mind...