Crank Seals

[Czakky]

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

[Striker1423]

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  .

[SUPERTUNE]

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!   

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

[Czakky]

Copy that. Thanks guys!

[m in sc]

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. 

[motodreams]

M makes a good point there and something I always follow.  They are essentially spacers for oil to enter

[Greaser Greg]

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?

[Jspooner]

Get new ones.

[m in sc]

agree. new.

[Greaser Greg]

 

[Greaser Greg]

Is it possible to replace R5 main seals without splitting cases? Advisable?

[m in sc]

possible? yes. recommended, no.

[KANDY]

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!   

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

I find RD400 the seal on Generator side is backwards, should I Split the Case and reverse it.

[m in sc]

yes, unfortunately you should. 

[KANDY]