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Old 11-06-2007, 07:09 PM
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Default Rear bearing on 21bf.....

I am trying to get the rear bearing out of my 21bf.... the front bearing fell apart.... lost the bearing race and the balls fell out... the motor has 3 gallons or so on it..... I have new bearings on the way, but I cant get the rear bearing out... I have tried heat 300 in the over for 15mins...that did not work so I tried 320 for 20 and still will not come out.... is there any other way short of a bearing puller.... (did not want to buy one if I did not have to...)


Thanks
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Old 11-06-2007, 08:41 PM
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dude, I think a bearing puller is your last option. plus I could borrow it from you when I need to pull a bearing
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Old 11-07-2007, 12:11 AM
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try an alternating process between freezing then back in the oven repeat process 3 to 4 times dudes at my club done this on a os v-spac with the same symptoms as yours, bearing race inbedded in case typical v-spac
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Old 11-08-2007, 05:35 PM
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From what I remember, you have to heat it till the case starts to smoke. That would be the oil in the case starting to smoke, not the actual case. Grab it quickly with a glove and tap the back of the case on a block of wood. it should fall out. Same for the front.
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Old 11-08-2007, 07:14 PM
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320 is too cold. Go to 350-375.
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Old 11-08-2007, 07:29 PM
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ok will try..... thanks
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Old 11-09-2007, 12:51 PM
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Make sure you clean it real good before it goes in the oven & ya I was going to say 375 to 400. WITH THE CARB REMOVED.
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Old 11-09-2007, 01:02 PM
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Get a 1/4 inch wood dowel and a good leather glove.
Heat the oven to 500 deg, place the block in for 5 minutes.
Remove and use the dowel to tap the bearing out.
Works every time, just be sure to remove the carb before .
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Old 11-09-2007, 01:46 PM
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Originally Posted by RBMike
Make sure you clean it real good before it goes in the oven & ya I was going to say 375 to 400. WITH THE CARB REMOVED.
Also, make sure to remove any o-rings in the carb throat. Not sure about your case, but my P5X has one in the throat. I'm sure you'll smoke it if you get the case hot enough to remove the bearing.
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Old 11-09-2007, 08:17 PM
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400 degrees for 20 minutes. i would wait till you have the new bearings first. put the new ones in the freezer while you heat the motor. as soon as you pop the old one out, drop the new cold one in.
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Old 11-10-2007, 07:18 AM
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Originally Posted by sickboy
400 degrees for 20 minutes. i would wait till you have the new bearings first. put the new ones in the freezer while you heat the motor. as soon as you pop the old one out, drop the new cold one in.
I put the bearings and crank in the freezer. Pop out the old bearing and drop in the new bearing with the crank. The crank helps to get it in the case, plus you can insert the front bearing also with a hot case with the crank in it too.
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Old 11-10-2007, 07:59 AM
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When yo uget the bearing/s out be sure to look inside where the outer race seats and be sure there is no snagged aluminium that might have happened when the bearing was put in at the factory. If so use a sharp exacto knife and clean it out,same for the front. Like the other fellow said freeze the bearings and crank together (just leave the front bearing off crank but leave in freezer ,this is the last bearing to install. Heat engine case (free of all gaskets and o-rings INCLUDING the carb retainer) to 400-425 degrees this should only take 10 minutes tops after oven is up to temp. and drop in the crank and main bearing, after that remove the front bearing from the freezer and install it ,becareful not to push the crank and rear bearing back out.
Allow things to settle for a minute or so and spray the crank and bearings with WD-40 and rotate the assembly to be sure it all spins nice and free.
If the crank doen't want to spin free i't because one or both bearings are not fully seated , you may need to lightly tap the back of the crank with a hard wood dowl and a hammer to seat it fully. Be sure not to get any dirt in that new bearing from the dowl and hammer !!
Re-assemble the engine and have fun!!
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Old 11-10-2007, 05:04 PM
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This looks like alot of work, just send the motor and bearing to me and I'll put the new bearing in for you for free. Heck send the whole thing and I'll mod it for you for free, the last Bf I modded was flippin fast. I ran it instead of my 21-5! (It's on ebay right now for sale)

Rex [email protected]
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