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I have been surfing the forum, but couldn't find an answer. I have done the Shep's method a few times on different bikes with great success. Being able to replace the mechanical seal without pulling the engine is very helpful.
So now I am rebuilding an engine and have access to the backside of the rear cover and could enlarge the hole to fit the complete new seal, but.............why would i do that? Will the seal last longer? Will the back plate leak at some point?
The seals I have replaced with Shep's method seem to be holding up great. I am willing to do the "Flapping", if someone can tell me the advantage of doing so.

Thank you
 

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CX650 motor project into a CX500 Turbo Frame - ongoing
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If I've studied this correctly, the advantage is having the ability to simply pop in a new seal that's readily available and not have to modify/pull apart/reuse the smaller seal. The danger of course in modifying your case is if you do mess it up you'll have a lot more work that just swapping seals. Considering the cheapness and availability of rear covers for your model I'd think it worth the risk. If you do it right the next replacement should be a lot quicker and easier. Also considering how easy of a job it is I'd be curious to see what a machine shop would charge a walk-in customer for it.

I've seen nothing that says the seals last longer; you are really using the same seal either way. It's just the carrier that's different.

And take my post with a grain of salt, I'm new to these CX500's so I could be wrong.
 

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As long as the adhesive used is suitable the Shep method is just as viable as full seal replacement.

I've done many both ways now.

As outlined above by jbutler81 one advantage of full replacement is having the hole prepped for the next time making it a drop in replacement for the future. Offset against this is the fact that the Shepped seal is always ready for another Shepping.

Six of one, half a dozen of the other.

Choose your poison.
 

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I'd think he advantage of enlarging the hole is that if the aluminum cup becomes damaged while removing a failed seal (or comes out with the insides if you used too good an adhesive) you might not have to remove the engine to replace the deal.
I believe the first technique Shep described was or replacing the entire seal with the engine in the frame by pressing against the frame to press it in.
 

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The cup is stainless and quite robust.

I doubt that breaking any adhesive bond and doing subsequent cleanup is likely to damage it.

If replacing a really old one it is likely to be already detached from the cup.
 

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CX650 motor project into a CX500 Turbo Frame - ongoing
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Am I understanding this though? If you open the hole, you still later on replace it by only opening the water pump cover, you don't have to open the back case to replace it, correct?

I've skimmed through the process for the 650, in which I see a lot of back covers coming off and they press it out from the inside. So now my brain is a little scrambled. I'm pretty sure you don't have to take the back cover off to replace these?
 

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The 650 cover is already the larger seal size so needs no flapwheeling.

The change from 27.8 mm to 28.3 mm was made sometime in the 81 model run. 78,79 and 80 are all smaller seals. 81s are a crapshoot. 82 and 83 all the larger seal from factory.

Do the Shep method if you are not comfortable with removing the rear cover.
 

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CX650 motor project into a CX500 Turbo Frame - ongoing
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The 650 cover is already the larger seal size so needs no flapwheeling.

The change from 27.8 mm to 28.3 mm was made sometime in the 81 model run. 78,79 and 80 are all smaller seals. 81s are a crapshoot. 82 and 83 all the larger seal from factory.

Do the Shep method if you are not comfortable with removing the rear cover.

I know it's the larger size and I don't have to mess with it; I'm just now talking about if you can or can't remove the whole seal without taking the whole back cover off? Or is there a method for removing the seal without removing the cover? In the case that you -have- to remove the back cover to get it out I would highly recommend the Shep method as the cover doesn't have to be removed and would make it easier for the less mechanically inclined.

In the case of my 650, it's a total tear down so no worries. But to answer the OP's question I would go towards the Shep method to avoid having to remove the rear cover.
 
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I know it's the larger size and I don't have to mess with it; I'm just now talking about if you can or can't remove the whole seal without taking the whole back cover off? Or is there a method for removing the seal without removing the cover? In the case that you -have- to remove the back cover to get it out I would highly recommend the Shep method as the cover doesn't have to be removed and would make it easier for the less mechanically inclined.

In the case of my 650, it's a total tear down so no worries. But to answer the OP's question I would go towards the Shep method to avoid having to remove the rear cover.
I actually lost track that you aren't the OP.

I think he should Shep as a short answer. I use Bostik or permatex ADHESIVE silicon.I've had the centres come out of new seals so I don't trust the adhesive they use.

I used to be an advocate of full replacement. Now not so much. That cup can pretty much be considered a permanent fixture. Stainless steel will be the last trace of humanity on this planet.
 

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Cover needs to come off to replace entire seal
In this case I would go with shep. For the OP's situation I guess there's no reason to risk your case since the bigger seat has no benefits. Since my case is apart of course I'll just pop mine out, and in the future I'll shep it.
 

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I actually lost track that you aren't the OP.

I think he should Shep as a short answer.
lol yeah I just happened to be pondering the same situation, Sorry for the confusion.


Found this post about a homemade tool for removing the whole seal, I'd be vaguely worried about a metal shaving from puncturing the seal seat...the glue process of Shep seems way easier.

 
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