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The 2-Stroke Garage => Turning Wrenches => Topic started by: Czakky on December 15, 2019, 10:21:11 AM

Title: Crank Seals
Post by: Czakky on December 15, 2019, 10:21:11 AM
There are basically three crank seals on an rd350. Big one, smaller one and the keyway o-ring.
Do you guys put the two main seals in dry on the outside?

Also, which way does the nub go on the o-ring?

I thought I had a pic of the o-ring...

Thanks
Title: Re: Crank Seals
Post by: Striker1423 on December 15, 2019, 09:06:27 PM
The nub on the o-ring fits in the keyway slot on the crank. The nub faces out from the motor towards the drive gear. Will need to use a pick and guide it into place. Don't tear it.
https://www.aircooledrdclub.com/smf/index.php?topic=50421.0

This topic is A MUST as far as I'm concerned to rebuilding the RD motor. It should work as a general guide for the R5.

You can put the seals in dry as the case halves will squish them nice and tight anyways. But, if you're paranoid, go ahead and put a bit of yamabond on them. Won;t hurt anything, just if you have to split the cases again you will have a mess to clean off the seals. I didn't use sealant at the seals and they don't leak, so that's my  :twocents:.
Title: Re: Crank Seals
Post by: SUPERTUNE on December 16, 2019, 07:09:53 AM
If you look at the mag seal, there is a open side and a closed side to it...CLOSED side faces crank.
When I did Paul's RD build, the previous shop put BOTH seals in BACKWARDS!  :eek:  :bang:

Primary seal has nubs on it, they will face the main bearing to use as a location and squaring up the seal when installed.

Here's the backwards pic's

Chuck


(https://photos.imageevent.com/supertune/paulsrd400/large/20180810_143355.jpg)


(https://photos.imageevent.com/supertune/paulsrd400/large/20180810_143320.jpg)
Title: Re: Crank Seals
Post by: Czakky on December 16, 2019, 07:29:22 AM
Copy that. Thanks guys!
Title: Re: Crank Seals
Post by: m in sc on December 16, 2019, 09:13:34 AM
footnote:

as a -general- rule of thumb across all brands, castellations (nubs) on a seal will always face a bearing.  reason being is allows lubricant to get to the seal side of the bearing.  :twocents:
Title: Re: Crank Seals
Post by: motodreams on December 16, 2019, 09:55:38 AM
M makes a good point there and something I always follow.  They are essentially spacers for oil to enter
Title: Re: Crank Seals
Post by: Greaser Greg on December 16, 2019, 09:11:30 PM
Is it completely foolish to consider reusing engine seals? They haven't been run much, and are less than 5years old. I know it's cheap insurance to get new ones, but if they are ok to use, why not? 
For this particular instance, I removed seals from and engine that were installed with the ridges (r5) not removed!  There are a couple of pinch marks that will need to be filled with Yamabond after removing ridges.
Yay, or nay?
Title: Re: Crank Seals
Post by: Jspooner on December 16, 2019, 09:36:01 PM
Get new ones.
Title: Re: Crank Seals
Post by: m in sc on December 16, 2019, 10:19:17 PM
agree. new.
Title: Re: Crank Seals
Post by: Greaser Greg on December 16, 2019, 10:54:49 PM
 :cheerleader:
Title: Re: Crank Seals
Post by: Greaser Greg on December 17, 2019, 01:23:11 PM
Is it possible to replace R5 main seals without splitting cases? Advisable?
Title: Re: Crank Seals
Post by: m in sc on December 17, 2019, 01:48:35 PM
possible? yes. recommended, no.
Title: Re: Crank Seals
Post by: KANDY on January 17, 2022, 11:00:53 AM
Quote from: SUPERTUNE on December 16, 2019, 07:09:53 AM
If you look at the mag seal, there is a open side and a closed side to it...CLOSED side faces crank.
When I did Paul's RD build, the previous shop put BOTH seals in BACKWARDS!  :eek:  :bang:

Primary seal has nubs on it, they will face the main bearing to use as a location and squaring up the seal when installed.

Here's the backwards pic's

Chuck


(https://photos.imageevent.com/supertune/paulsrd400/large/20180810_143355.jpg)


(https://photos.imageevent.com/supertune/paulsrd400/large/20180810_143320.jpg)


I find RD400 the seal on Generator side is backwards, should I Split the Case and reverse it.
Title: Re: Crank Seals
Post by: m in sc on January 17, 2022, 11:59:20 AM
yes, unfortunately you should.  :twocents:
Title: Re: Crank Seals
Post by: KANDY on January 17, 2022, 12:07:39 PM
 :bang: :bang:
Title: Re: Crank Seals
Post by: Diablo007 on January 23, 2022, 03:17:16 AM
A while back I was trying to figure out which way the seals were supposed to face on my RZ350.   RTFM...yup in the manual it stated the printed side faces out, the lettering faces out.  I'm guessing this is standard practice.
Title: Re: Crank Seals
Post by: Diablo007 on January 23, 2022, 03:33:55 AM
Oh, regarding Yamabond...Yamaha states to not use it on seals.  A friend and respected tuner told to that I should use it.  I'm kind of curious to how many recommend which.
Title: Re: Crank Seals
Post by: pidjones on January 23, 2022, 07:01:43 AM
Quote from: Diablo007 on January 23, 2022, 03:33:55 AM
Oh, regarding Yamabond...Yamaha states to not use it on seals.  A friend and respected tuner told to that I should use it.  I'm kind of curious to how many recommend which.
Hondabond was the only way that I could get the forward blanking plug to stay in my RD400c. But, that's the only place that I used it.
Title: Re: Crank Seals
Post by: m in sc on January 23, 2022, 07:15:09 AM
ive used it, VERY sparingly on seals that don't have a locating lip that think may be an issue w out it. never had a problem, that's just my experience. I've heard both, and technically you shouldn't need to use it.  :twocents:
Title: Re: Crank Seals
Post by: Diablo007 on January 24, 2022, 03:21:12 AM
M, your post made things click in my head. The advice was to use it on the plugs for the transmission, and possibly other seals w/o a locating lip.