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Discussion Starter · #1 ·
I was just wondering why on 4-stroke sleds you can take the connecting rod off with two bolts but on 2-stroke sleds you have to have the crank disassembled? why don't they make it so you can remove the connecting rod easier?
this might be a dumb question but im just curious.
 

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good question. The 4-stroke sleds rev higher as well...
 

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that is not why. 4 strokes have a oil pump instead of an injection pump and can produce oil pressure to lube a friction bearing. 2 stroke engines rely on atomized oil to lube the bearings on the crankshaft, and with no pressurized oil being directly injected into the journals of a friction bearing, a 2 stroke would destroy a friction bearing in a matter of minutes, this is why a roller bearing is used on the rods of 2 strokes. You are able to remove the rod off the crank on friction bearings without a press because friction bearings are 2 piece and roller bearings are one piece making it impossible to remove without pressing it apart.
 

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They use a different style lower rod bearing. The 4 Stroke has a insert bearing were the 2 Stroke uses a needle bearing.
The needle bearing would not last with a two piece rod cap.
4 strokes have a full pressure oiling system so the insert bearing needed to maintain oil pressure.
 

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Discussion Starter · #5 ·
ok that makes sense. i just finished replacing the connecting rod bearings on a t660 an was thinking how much easier it would be if you could take the connecting rod off like on a 4-stroke.
Thanks for the info.[thumb]
 
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