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Discussion Starter · #1 ·
I've seen suggested here numerous times that a more economical way to go when replacing a mechanical seal is Yamaha part# 11H-12438-10-00. I've also seen while perusing the many discussions on this subject that it's possible that the hole that receives the seal may vary slightly from year to year.



If that's the case, I'm wondering if anyone could be kind enough to inform me with reasonable certainty whether or not the Yamaha seal would work on my '81 Custom.



Seondly, are there any tips as to the installation of this seal? The Honda manual, of course, assumes I have an endless supply of "special tools" but unfortunately that's not the case. I'm a bit concerned because I've seen here a few accounts of people finding these seals downright uncooperative when asked to fit into place.



Any suggestions or referrals to helpful links would be as always greatly appreciated...thanks, gweric
 

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Please take a few minutes to add your bike's year and model to your signature.



From what I've seen, bikes from 82 and later use the larger size mechanical seal. As far as I know, all mechanical seals currently available are the larger size, including the Yamaha seal. Since your bike is an 81 it most likely takes the smaller size seal.



The size referred to is simply the seal's metal cup diameter. The seal innards are the same.



Shep's method can be used to replace the old seal innards with those from a new seal. It is not necessary to pull the engine, which is a great advantage.



If you are pulling the engine anyway, you can still use the larger size mechanical seal. But it will be necessary to enlarge the rear engine case bore for the seal slightly. This is not difficult and can be accomplished using a drill and a dremel flap wheel.
 

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Discussion Starter · #4 ·
Please take a few minutes to add your bike's year and model to your signature.



From what I've seen, bikes from 82 and later use the larger size mechanical seal. As far as I know, all mechanical seals currently available are the larger size, including the Yamaha seal. Since your bike is an 81 it most likely takes the smaller size seal.



The size referred to is simply the seal's metal cup diameter. The seal innards are the same.



Shep's method can be used to replace the old seal innards with those from a new seal. It is not necessary to pull the engine, which is a great advantage.



If you are pulling the engine anyway, you can still use the larger size mechanical seal. But it will be necessary to enlarge the rear engine case bore for the seal slightly. This is not difficult and can be accomplished using a drill and a dremel flap wheel.
 

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Discussion Starter · #6 ·
Thanks, Dave and Stitch for your time and advice. I have once already cured a small coolant leak through the "weep hole" by the Shep method, maybe three years and about 15K miles ago and the job has held up flawlessly.



I'll be replacing my stator in the near future and I guess I was mistakenly under the assumption that a mechanical seal replacement was just an automatic step if you had your engine out and the rear cover off but, since I've done the "engine in" repair once already and every thing's stayed dry since, I should just leave well enough alone.



A few years back, I had a serious oil leak due to a blown rear cover gasket and at that time, seeing that the adjustment for my cam chain was maxed out, I replaced the chain but not the tensioner or guide. Would you advise replacing those parts this second time around, or just let the new chain (well, a couple years old) live with those original parts.



I guess I'm kinda caught between two schools of thought: "If it ain't broke, don't fix it" and "an ounce of prevention....."



Any suggestions on the subject, once again, are truly appreciated.....gweric
 

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Thanks, Dave and Stitch for your time and advice. I have once already cured a small coolant leak through the "weep hole" by the Shep method, maybe three years and about 15K miles ago and the job has held up flawlessly.



I'll be replacing my stator in the near future and I guess I was mistakenly under the assumption that a mechanical seal replacement was just an automatic step if you had your engine out and the rear cover off but, since I've done the "engine in" repair once already and every thing's stayed dry since, I should just leave well enough alone.



A few years back, I had a serious oil leak due to a blown rear cover gasket and at that time, seeing that the adjustment for my cam chain was maxed out, I replaced the chain but not the tensioner or guide. Would you advise replacing those parts this second time around, or just let the new chain (well, a couple years old) live with those original parts.



I guess I'm kinda caught between two schools of thought: "If it ain't broke, don't fix it" and "an ounce of prevention....."



Any suggestions on the subject, once again, are truly appreciated.....gweric




I think you know my answer.I developed my technique to make the job easy,quick and prevent the inherent dangers of doing it the,"Official" way.People have ruined the metal cups/seal and in some cases even ruined rear engine covers.Why bother taking the risk?

There are people all around the world who have used my method with loads of miles on the engines,myself included,with no problems




PS

I can change a Mech seal on one of my CX faster than I could change the oil and filter on my old Ford Mondeo/Taurus!!



Bloody horrible job
 

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Discussion Starter · #8 ·
I think you know my answer.I developed my technique to make the job easy,quick and prevent the inherent dangers of doing it the,"Official" way.People have ruined the metal cups/seal and in some cases even ruined rear engine covers.Why bother taking the risk?

There are people all around the world who have used my method with loads of miles on the engines,myself included,with no problems




PS

I can change a Mech seal on one of my CX faster than I could change the oil and filter on my old Ford Mondeo/Taurus!!



Bloody horrible job






Thanks, Shep, and, yes, I had a feeling which way you would with your advice. In fact, as you were advising me on the subject I was mentioning in a reply to another helper here that I had already at one time used your method with great success. It's good to know that a drippy seal can be rectified without major surgery....thanks again...gweric
 

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Appreciate this type of thread. Replaced an o ring on the tube going

into the water pump last week. That stopped the majority of the

coolant and allowed me to see a very "small" amount of coolant coming

out of the water pump weep hole. Been testing my bike to find problems

before painting, since this bike was not running when I purchased it.



Will install the seal without removing the engine.



This forum is one of the most helpful forums I have seen!



Thanks to Everyone and Happy New Year!
 

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There's a user on this board "Doward", who was hosting group buys of the mechanical seal.

He was selling them for around $21 delivered, he hasn't been on the board in a while. The last time he was seen on here he was posting about waiting on a new batch of seals to come in.
 

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There's a user on this board "Doward", who was hosting group buys of the mechanical seal.

He was selling them for around $21 delivered, he hasn't been on the board in a while. The last time he was seen on here he was posting about waiting on a new batch of seals to come in.


Thanks for the info. Will try to contact him.



If I don't get in touch with him, will buy the Yamaha seal.



Thanks!
 

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Thanks for the info. Will try to contact him.



If I don't get in touch with him, will buy the Yamaha seal.



Thanks!
I can vouch for his seals. Worked very well, and the cheapest option. I have done two bikes that way.
 

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How often dose the oil seal go bad?



Replacing just the seal and not the metal cup allows you to do it with the bike in the engine and that means without taking off the rear cover. But to change the oil seal the rear cover has to come off right?
 

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How often dose the oil seal go bad?



Replacing just the seal and not the metal cup allows you to do it with the bike in the engine and that means without taking off the rear cover. But to change the oil seal the rear cover has to come off right?


Yes the rear cover has to come off for the rear Water pump oil seal.



They don't seem to go often when in regular service.They tend to get brittle when the bikes have been left unused for years.Like most seals that don't get lubrication from a running engine they dry out and decay.
 

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Regarding your cam chain tensioner, I'd leave it alone. They seem to break at random compared with other motor parts. When it breaks, the motor will still run but will be noisy. You'll be able to ride your bike home and in the process, nicely shave down a bolt head in the motor. Then you'll officially be one of us. The shaved down bolt head doesn't hurt anything FYI and can be left shaved down.
 

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Discussion Starter · #16 ·
Just one final word of thanks to all those who helped walk me through my stator replacement and all the associated issues that come with it. I put the tank and the seat back on the bike yesterday afternoon, rolled it out of the garage, straddled it, turned the key and said a little prayer before I hit the starter. There's always that moment of anxiety as you reflect on your work, dreading the possibility of having made one small misstep deep deep inside the beast that could throw a lot of work out the window and leave you with no choice but to start all over again. It can be enough to ruin your day, to say the least.



I have to say, the bike's running better that it has in a year. I've been on it now for two days and am still looking for excuses to run downstairs and jump on it again. What an improvement. I had become an expert at coaxing the bike up to speed and diving for the breakdown lane when she just didn't feel like carrying on. She's hot to trot now and as you can tell, I'm thrilled with the results.



Thanks to all you guys out there. Your tips were invaluable......gweric
 

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Just one final word of thanks to all those who helped walk me through my stator replacement and all the associated issues that come with it. I put the tank and the seat back on the bike yesterday afternoon, rolled it out of the garage, straddled it, turned the key and said a little prayer before I hit the starter. There's always that moment of anxiety as you reflect on your work, dreading the possibility of having made one small misstep deep deep inside the beast that could throw a lot of work out the window and leave you with no choice but to start all over again. It can be enough to ruin your day, to say the least.



I have to say, the bike's running better that it has in a year. I've been on it now for two days and am still looking for excuses to run downstairs and jump on it again. What an improvement. I had become an expert at coaxing the bike up to speed and diving for the breakdown lane when she just didn't feel like carrying on. She's hot to trot now and as you can tell, I'm thrilled with the results.



Thanks to all you guys out there. Your tips were invaluable......gweric
wow,doesnt that bring back memories for me,this time last year.i know how you feel.doing the work with this lot watching over your shoulder.guardian angels spring to mind


congradulations
 
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