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General Category => General Discussion => Topic started by: Thirtyaughtsix on May 07, 2016, 11:23:51 PM

Title: 850t Final drive question
Post by: Thirtyaughtsix on May 07, 2016, 11:23:51 PM

(http://thumb.ibb.co/hBd1gF/20160508_000155.jpg) (http://ibb.co/hBd1gF)

Is the item on the left supposed to sliiiiiide in to the item on the right, or is that supposed to be an interference fit?

Spoiler alert, it slides right in
Title: Re: 850t Final drive question
Post by: n3303j on May 08, 2016, 12:40:09 AM
It should be an interference fit.
Rule of thumb  is that any properly engineered ball bearing setup retains both the inner and outer races on their respective diameters so that all "bearing functions" are done by the balls and races and not by the races and the adjacent surface.

Doesn't have to be a tight fit, but enough to ensure the bearing is functioning as designed.

If all other parts are okay an acceptable repair could be made with RC-680 Loctite properly applied.
Title: Re: 850t Final drive question
Post by: Thirtyaughtsix on May 08, 2016, 02:18:01 AM
It should be an interference fit.
Rule of thumb  is that any properly engineered ball bearing setup retains both the inner and outer races on their respective diameters so that all "bearing functions" are done by the balls and races and not by the races and the adjacent surface.

Doesn't have to be a tight fit, but enough to ensure the bearing is functioning as designed.

If all other parts are okay an acceptable repair could be made with RC-680 Loctite properly applied.

Ok, locktite it is
Title: Re: 850t Final drive question
Post by: rodekyll on May 08, 2016, 03:14:36 AM
Hmmm.

Please wait till someone who works on these gets a word in.  That's not me.  But I've been involved with some and none have had dressing of any kind at that race, and the bearing flange was easily removed.  I'm not saying what I've seen is right, and you could have a different situation, but my experience is different than what I'm reading here.  I'm not trying to jump on n3303j (is that a tail number?) because I don't know for sure.  I just don't want you to get in a hurry and maybe make an expensive mistake.

$0.02

Title: Re: 850t Final drive question
Post by: Thirtyaughtsix on May 08, 2016, 04:12:27 AM
Hmmm.

Please wait till someone who works on these gets a word in.  That's not me.  But I've been involved with some and none have had dressing of any kind at that race, and the bearing flange was easily removed.  I'm not saying what I've seen is right, and you could have a different situation, but my experience is different than what I'm reading here.  I'm not trying to jump on n3303j (is that a tail number?) because I don't know for sure.  I just don't want you to get in a hurry and maybe make an expensive mistake.

$0.02

I agree, I don't want to break any more stuff than I have to, and I did come here to crowd source the best option so hopefully we'll get some more input here. There's no rush, plenty of other stuff needs worked on yet
Title: Re: 850t Final drive question
Post by: n3303j on May 08, 2016, 09:30:59 AM
Final Drive Bearing on my '66 R60/2, '81 R100RT, '96 Ural and '77 MG 850T3 were all pressure fits on to the spindle that carries the ring gear. In turn the outer race was a pressure fit into the alloy housing. A bit of heat and the alloy casting would expand dropping the spindle with bearing on to the bench.

I pull all final drives apart when I buy used bikes. Great time to check for proper wear pattern  or hidden disasters that could drop me on the ground. Findings have been anything from "no problem" to "I have to find a new housing!".

Loctite isn't permanent but does require some serious heating to remove (about 400F). This won't destroy your parts if done with care. A home oven is a good controlled heat source.

N3303J was my Cessna 150 for about 8 years and 1,000 hours. Finally wore out the motor and couldnt justify the cost of replacement. She was sold January 2002 and lives sort of abandoned in Texas. I think the person who bought her had work done he couldn't pay for and the aircraft was seized by the mechanic.
Title: Re: 850t Final drive question
Post by: rodekyll on May 08, 2016, 10:28:07 AM
Lots of pilots on the forum.  I ground looped my Cessna and later lost my ticket for medical reasons, but I still tinker with the airframes.

I'm not disagreeing with you, November.  What you are saying is entirely true and reasonable.  I'm just saying that I've got a few scattered units in a tote on the back porch right now.  I don't recall the splines on any of them being loctited into the bearing or needing 'interference fit' level disassembly techniques like pounding, presswork or heat.  Since I know Guzzi does things the odd way sometimes I'm hoping one of our rear drive-shimming gurus will straighten us out.  I know I'll learn something.
Title: Re: 850t Final drive question
Post by: Dick on May 08, 2016, 11:01:45 AM
Sliding fit. Not interference fit. Don't loctite.
Title: Re: 850t Final drive question
Post by: Thirtyaughtsix on May 08, 2016, 02:40:49 PM
Well gentlemen, it seems to be 1 for locktite and 1 for sliding fit
Title: Re: 850t Final drive question
Post by: kidneb on May 08, 2016, 02:50:52 PM
Sliding fit. Not interference fit. Don't loctite.

   This
Title: Re: 850t Final drive question
Post by: rodekyll on May 08, 2016, 02:52:58 PM
It's a perfect time to point out that we're all entitled to our own opinions, but not to our own facts.  :boxing:   :boozing:

Or can we settle this with a poll?

Where are the grown-ups when you need them?
Title: Re: 850t Final drive question
Post by: Chuck in Indiana on May 08, 2016, 03:36:03 PM
I'll vote with Dick..  :smiley: :popcorn:
Title: Re: 850t Final drive question
Post by: rodekyll on May 08, 2016, 03:38:30 PM
I'll vote with Dick..  :smiley: :popcorn:

Predictable -- for a guy.   :laugh:
Title: Re: 850t Final drive question
Post by: Idontwantapickle on May 08, 2016, 09:56:03 PM
Slides in,  no press or locktite.
Title: Re: 850t Final drive question
Post by: jacksonracingcomau on May 08, 2016, 10:25:30 PM
Ditto, never seen, used or needed Loctite, probably couldn't hurt but fixes a problem I've never seen.
Rebuilt / resealed many, all sliders, not baggy nor press fit
Come apart same way after pinion gear wears out
Title: Re: 850t Final drive question
Post by: Thirtyaughtsix on May 08, 2016, 10:53:29 PM
IT IS SAID. I will forgo the locktite. Thanks to all
Title: Re: 850t Final drive question
Post by: Chuck in Indiana on May 09, 2016, 05:59:48 AM
Predictable -- for a guy.   :laugh:

Yup.. :cool: