Thread: Polaris crank bearing opinions
08-21-2009, 12:47 PM #1
Polaris crank bearing opinions
For those of you familiar with Polaris cranks, I could use some input. I’ve been busy rebuilding 650-785 cranks and my supply of the 6207 and 6307 bearings have been exhausted. These bearing are used in many Polaris watercraft 2-stroke engines and are somewhat unique. In the case of the Fuji engine, the 6207 is pinned and the 6307 is pinned and also has a snap ring. The pin is used to keep the outer race from spinning in the case. The problem is that local bearing suppliers can’t get me the correct bearing with a pin or their asking prices are as outrageous as buying them from Polaris (which isn’t going to happen). I’ve had little luck searching the internet as well. The good news is that I have located the correct bearings (without the pin) at a fantastic price. Now the domestic produced Polaris engines such as the 1050, also use 6207 bearings (without a pin) so apparently Polaris thought the pins weren’t necessary on later production engines. In my opinion, I think the slight “crush” placed on the bearings when the cases are torque together should hold the unpinned outer races from spinning unless the bearings seize which in that case, your looking at a rebuild anyways. By the way, I have seen several Fuji cranks with seized main crank bearings and the outer race still spun in the case as the small roll pin just sheared off.
Your thoughts and opinions on using unpinned bearings and any “workarounds” such as adding a pin or securing the bearing, etc., would be greatly appreciated.
08-21-2009, 01:08 PM #2
08-21-2009, 01:27 PM #3
beerdart, thank you so much for the reply and the links!! I also thought that Loctite would work but I wanted to see if anyone else felt the same way.
08-23-2009, 12:31 PM #4
08-23-2009, 07:03 PM #5
1FASTXC, thanks for the reply. I decided to go with the unpinned bearings as I'm sure they will work. I was able to buy new FAG brand 6207 bearings for $5 each and 6307 for $17 each. At that price, I can rebuild a 650-780 crank with all new rods and bearings for under $225.
08-23-2009, 07:44 PM #6
08-23-2009, 08:02 PM #7
10-08-2009, 12:31 PM #8
- Join Date
- Jul 2008
- England.Great Britain . UK
hi check they are c4 bearings as these are what polaris use, they allow for expansion when running. normal bearing will bind. overheat and lockup.
10-08-2009, 02:25 PM #9
10-08-2009, 03:29 PM #10
The pins may not be needed so the 6207 will work, but what about the 6307 with the ring? Why not just get a 6307NR, it comes with the ring and is not too hard to find.
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