os 91
12-27-2008 | 06:07 PM
#2
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RE: os 91
NO
If you force the bearings in or out of your engine, you not only risk ruining the bearing, but ruining the surface that it fits into also.
http://www.youtube.com/watch?v=TuzEco3EDUM
12-27-2008 | 06:10 PM
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From: STOCKHOLM Akersberga, SWEDEN
RE: os 91
not sure if there are any pullys readily available to pull the rear bearing? I heaten up the crankcase with an air heat gun and then use a piece of aluminum pipe to push/force the old bearings out. Start with the front bearing.
12-27-2008 | 06:26 PM
#4
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RE: os 91
The front prop drive hub will slide off and there is a Woodruff key that drives the hub that you don't want to loose. The crank will slide out
The bearing - you heat up the case with a Monokote gun and shake the rear bearing out by slamming the case against a board while hot
The front bearing you must stick a dowel up through the case from the rear and against the front bearing. Holding the hot case, slam the dowel against the board to knock out the front bearing
The bearing - you heat up the case with a Monokote gun and shake the rear bearing out by slamming the case against a board while hot
The front bearing you must stick a dowel up through the case from the rear and against the front bearing. Holding the hot case, slam the dowel against the board to knock out the front bearing
12-27-2008 | 06:49 PM
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From: NE,
TX
RE: os 91
Putting the crank case in the oven at 300 degrees for 10 minutes heats the block evenly. Whether it make a difference versus the heatgun I can't say but I replaced the bearings in an OS .91 fs 2 months ago that way and they came out with very little effort.
When installing the new bearings, reheat block and freeze bearings, they pretty much fall in that way and when everything cools a little, you can start putting the crank back in.
When installing the new bearings, reheat block and freeze bearings, they pretty much fall in that way and when everything cools a little, you can start putting the crank back in.
12-27-2008 | 07:39 PM
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From: NE,
TX
RE: os 91
By the way, where are you getting your bearings? Here are bearings just as good as the OS brand at 1/4 the price. This is what I put in th OS 91 fs I rebuilt and they work fine.
http://www.rc-bearings.com/catalog/p...05034e4df41254
If you really want the best bearings, the ceramic bearings are supposed to be better but the do cost more but are still cheaper than the stock OS steel bearings.
http://www.rc-bearings.com/catalog/p...05034e4df41254
If you really want the best bearings, the ceramic bearings are supposed to be better but the do cost more but are still cheaper than the stock OS steel bearings.
12-28-2008 | 06:39 PM
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From: NE,
TX
RE: os 91
Yes. The cam has to come out for front or rear bearing replacement. It is easy to set. There is a dimple on the cam gear (inside side of gear, you can't see the dimple when the cam is installed IIRC) that goes straight up when the piston is at TDC. If you even get it off 1 tooth, it won't run right. Just point the dimple straight up and you should be set. If you want to make it easy on yourself, make your own mark on the outside of the cam gear and case while the cam is installed and piston is at TDC. Then line up the marks when re- assembling engine.
12-28-2008 | 09:03 PM
#12
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RE: os 91
ORIGINAL: GhostRider32
Yes. The cam has to come out for front or rear bearing replacement. It is easy to set. There is a dimple on the cam gear (inside side of gear, you can't see the dimple when the cam is installed IIRC) that goes straight up when the piston is at TDC. If you even get it off 1 tooth, it won't run right. Just point the dimple straight up and you should be set. If you want to make it easy on yourself, make your own mark on the outside of the cam gear and case while the cam is installed and piston is at TDC. Then line up the marks when re- assembling engine.
Yes. The cam has to come out for front or rear bearing replacement. It is easy to set. There is a dimple on the cam gear (inside side of gear, you can't see the dimple when the cam is installed IIRC) that goes straight up when the piston is at TDC. If you even get it off 1 tooth, it won't run right. Just point the dimple straight up and you should be set. If you want to make it easy on yourself, make your own mark on the outside of the cam gear and case while the cam is installed and piston is at TDC. Then line up the marks when re- assembling engine.
