Post by: Filmcamera on December 29, 2024, 11:26:47 AM
The time has come to try and fix the leak I have from the engine to the clutch.
I changed the rear main seal less than 5 years ago and although I may have done it wrong a cursory inspection seems to show it as ok.
Before I install a new one I wanted to post a picture of the leak and see if there is possibly another reason apart from the rear main seal.
It might not be totally clear in the picture but there is a trickle of oil coming from the area just underneath the spline.
Post by: Laitch on December 29, 2024, 02:29:57 PM
(https://www.motobrick.com/gallery/4/1601-291224142504.png)
Post by: Filmcamera on December 29, 2024, 05:01:59 PM
The question now is, do I replace the rear main seal again or hope it is just the o-ring?
Next job after this one is replacing the freeze plugs... that has me a little nervous.
Post by: daveson on December 30, 2024, 07:09:41 PM
I'm guessing you noticed a leak from the bell housing drain hole, then the first thing you're thinking is, does it smell like gear oil or engine oil? I hope it won't be too controversial when I say that gear oil smells even worse than rotten cauliflower.
The next thing you're thinking is, if there's any oil stains on the clutch plate, that could be from the O-ring in front of the clutch basket, leaking. If the rear main seal leaks, that could just fall to the bottom of the bell housing from behind the clutch basket, and run out the drain hole. Then you're thinking, could a leak from the seal end up on the disc from all these parts spinning at high speed?
The next thing you're thinking is, do I want to go back in there again soon? Or do I want to replace both for peace of mind?
Post by: Scott_ on December 30, 2024, 11:34:33 PM
Look at your input shaft of the clutch basket to see the wear line of the seal.
If there is a slight groove, you will leak again.
3 options....
1-set the seal more proud of the housing so that the seal lip edge rides on a fresh area of the shaft, IIRC there was/is a TSB that says to set the seal about 1-2mm proud of the engine block to address this issue when replacing an original seal. Don't set it flush. Make sure you clean the shaft surface.
2-replace the basket so you have a fresh new input shaft, then it won't matter how deep you set your seal.
3-don't fill your engine oil above the center dot. It won't then set there and pool at the shaft for potential leakage when not running.
Post by: Filmcamera on December 31, 2024, 12:58:37 PM
It got all over the clutch, so much so I started to get clutch slip, I have ordered a new one.
The last time I installed a rear main seal I did leave it slightly proud, maybe half a mil. I am pretty sure I am going to replace it, as Daveson says, I have come this far... when I do I will leave it further out.
I do see some wear on the exterior of the clutch basket, the inside looks OK but it is hard to tell. I found a used one for $40 on ebay so I went ahead and ordered it, new they are over $400
I also ordered a new o-ring and a new compression ring. Since I live in CR I won't get them for a few weeks but meanwhile I have lots of oil to clean up!
Post by: daveson on December 31, 2024, 05:45:59 PM
You want to make sure that another clutch basket is identical to the original, I can see some potential problems. You want to make sure that there is clearance between the back of the clutch basket and the engine casing. You want to make sure that there is clearance between the clutch basket and the face of the seal. You want to make sure that the thrust washer clearance remains unchanged with the new clutch basket.
If the clutch basket isn't identical, here are some ways of measuring the thrust washer clearance:
https://www.k100-forum.com/t15958-how-to-understand-the-k100-engine-output-shaft
If not identical, it might be easier to just linish the shaft.
Post by: Scott_ on January 01, 2025, 11:41:30 AM
The factory change went from .4mm recessed to .5mm(+.1mm) proud of the engine case. Basically a 1mm change in total.
Post by: daveson on January 01, 2025, 03:59:11 PM
Post by: Filmcamera on March 03, 2025, 06:11:31 PM
I installed the new rear main seal and the new clutch.
Everything seems to be buttoned up correctly and the gearbox went back no problem.
I can click the bike in and out of gear and the rear wheel spins freely in neutral and doesn't move if in first.
The issue is the clutch doesn't do anything. It feels like the spring is fully compressed so pulling the clutch lever does nothing.
Not sure what I have done wrong. I followed two different videos very carefully (Chris Harris being one of them) and have done this before with no issues.
This time however even tightening the clutch pack bolts I could tell something wasn't quite right.
Any suggestions?
Post by: Laitch on March 03, 2025, 11:35:43 PM
The issue is the clutch doesn't do anything. It feels like the spring is fully compressed so pulling the clutch lever does nothing.Does that mean the clutch hand lever can just moved back and forth with little effort?
Post by: daveson on March 04, 2025, 01:29:55 AM
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This time however even tightening the clutch pack bolts I could tell something wasn't quite right.
Any suggestions?
Are you sure the guide pins (or location dowels or whatever the proper terminology is) were in line with their holes before you tightened the clutch bolts?
Post by: Laitch on March 04, 2025, 12:04:21 PM
Post by: Filmcamera on March 04, 2025, 12:13:42 PM
Post by: The Mighty Gryphon on March 04, 2025, 04:16:25 PM
Post by: Laitch on March 04, 2025, 05:42:47 PM
Everything seems to be buttoned up correctly and the gearbox went back no problem.In the quote above, the two sentences are in disagreement. When a procedure doesn't feel right, that usually is considered a problem. Complete disassembly to the starting point will probably be necessary.
This time however even tightening the clutch pack bolts I could tell something wasn't quite right.
In Reply #10 there was a question about the clutch hand lever. Perhaps the answer to it could give us a new clue.
Post by: Filmcamera on March 04, 2025, 05:45:53 PM
Post by: daveson on March 04, 2025, 08:34:45 PM
This time however even tightening the clutch pack bolts I could tell something wasn't quite right.
Any suggestions?
What does this mean. The bolts were harder than usual to torque, or easier or... If easier, I'm thinking about the possibility that the ring for the clutch basket has fallen out while it was moved around in the workshop. I was wondering whether to ask a question about the diaphragm spring, then I thought nah, better not. A bit of wishful thinking says to me, it would be good if all you need to do is adjust the clutch cable.
Not sure if the original clutch basket was replaced or the new one used.
Post by: Laitch on March 05, 2025, 10:08:04 AM
Yes, there is little or no resistance when pulling the clutch lever.Is the transmission-mounted clutch lever moving when you pull the clutch hand lever?
Post by: Filmcamera on March 05, 2025, 01:07:33 PM
Post by: Laitch on March 05, 2025, 01:48:04 PM
Post by: Filmcamera on March 05, 2025, 02:31:57 PM
Post by: Laitch on March 05, 2025, 03:26:31 PM
(https://www.motobrick.com/gallery/4/1601-050325145708.png)
(https://www.motobrick.com/gallery/4/1601-050325145902.png)
Post by: Filmcamera on March 05, 2025, 03:35:29 PM
The longer tapered end is against the diaphragm spring, except I am not sure it is actually touching it
Post by: Laitch on March 05, 2025, 04:08:33 PM
Maybe somebody here will come up with something else to check but disassembly, close inspection and measurement along the way is where I'd be heading.
Post by: Filmcamera on March 05, 2025, 04:18:15 PM
That way I will be back as I was (except for the new rear main seal) and can start eliminating possible issues from there.
Post by: daveson on March 05, 2025, 04:44:01 PM
If the clutch nuts were easier than usual to tighten, that would match with the ring missing between the clutch basket and the diaphragm spring, and would explain your other symptoms.
Post by: Laitch on March 05, 2025, 10:38:15 PM
Post by: Past-my-Prime on March 08, 2025, 10:40:24 AM
While mine is a K75, so may differ, when I reassembled after replacing the clutch pack, it seemed to go together very easily. That is because I had the spring backwards. I don't recall if the clutch would not engage, or would not disengage but I did have to take the ENTIRE THING apart and turn it around: then all was well in my little corner of the universe. The upside is I'm now more adept at removing / reinstalling all the bits from the clutch back to the rear tire and everything that attaches to it.
Sounds like your problem is a bit different but to the extent that misery loves company, you've got company!
Post by: Filmcamera on March 09, 2025, 10:11:01 AM
There is also one small video where I am removing the clutch pack. If you look carefully you can just see the spring decompressing as I undo the allen bolt, is that normal?
My next step will be to remove the new clutch basket and install the old one again, do you think I can get away with reusing the nut since the bike has never actually moved with the new nut installed?
(https://www.motobrick.com/index.php?action-gallery;su=user;cat=27;u=3823)
https://www.motobrick.com/index.php?action=gallery;sa=view;id=4598 (https://www.motobrick.com/index.php?action=gallery;sa=view;id=4598)
(https://www.motobrick.com/index.php?action-gallery;sa=view;id=4602)
(https://www.motobrick.com/index.php?action-gallery;sa=view;id=4600)
(https://www.motobrick.com/index.php?action-gallery;sa=view;id=4599)
(https://www.motobrick.com/index.php?action-gallery;sa=view;id=4601)
Post by: Laitch on March 09, 2025, 03:46:54 PM
There is also one small video where I am removing the clutch pack. If you look carefully you can just see the spring decompressing as I undo the allen bolt, is that normal?The spring applies tension on the pressure plate to engage the clutch. What you note is tension being released. In real life, the clutch rod would push against the spring to relieve tension on the plate.
I really don't understand your method of investigation, Filmcamera. I would have reversed installation step by step. Is this the order in which you approached inspection. The clutch carrier (housing) would be the last part removed and likely wouldn't be removed at all.
- Unbolt and remove the clutch cover.
- Remove the clutch disc.
- Remove the pressure plate.
- Remove the diaphragm spring and ring.
- Leave the clutch carrier bolted in place.
- Compare the dimensions of the replacement parts to the dimensions of the parts they replaced.
As far as the clutch nut is concerned, some people have reused them without incident. Whether the engine was never run after the installation could be irrelevant.
Post by: Filmcamera on March 09, 2025, 07:40:24 PM
- Unbolt and remove the clutch cover. - Done
- Remove the clutch disc. - done
- Remove the pressure plate. - done
- Remove the diaphragm spring and ring. - done
- Leave the clutch carrier bolted in place. - done
- Compare the dimensions of the replacement parts to the dimensions of the parts they replaced. - done, except for the new clutch carrier which I cannot easily compare with it in place.
I have exhausted everything I can think of except the new clutch carrier being somehow the wrong one, that was why that was going to be my next step, however, before doing that I wanted to ask if it was OK to re-use the nut and also to see if the pictures I posted led to an "ah-ha" moment from any one of the many of you who know so very much more than I do about fixing bricks.
Post by: Filmcamera on March 10, 2025, 12:18:59 PM
Post by: Laitch on March 10, 2025, 12:27:10 PM
Post by: lewisnort on March 11, 2025, 04:47:44 AM
I ask as I was having rear main problems and suspecting that the shim was missing but that section of my basket is smooth.
It really really didn't seem like a shim was on there but I definitely couldn't see those rivets, well not on the engine side at least.
Edit: I'm being stupid never mind
Post by: Laitch on March 11, 2025, 12:41:57 PM
Edit: I'm being stupid never mind:laughing4-giggles:
Post by: Kaos on March 15, 2025, 12:49:12 PM
WhatsApp Image 2025-03-08 at 18.03.09_9e7aff69.jpg (36.91 kB . 432x576 - viewed 271 times)Would explain the lack of resistance on the clutch when the pushrod's direction is installed correctly
Edit, I am not sure of the actual name which i will now be searching for
Edit 2: DIAPHRAGM SPRING! is the name is was looking for, the bulging side should be facing out/backward
Post by: Laitch on March 15, 2025, 03:07:58 PM
Hold on insnt the Clutch-springplate facing the wrong way?It looks to me like the "bulging" side is facing rearward but that curved surface can produce an optical illusion when viewed at a distance in a two-dimensional photo. Only Filmcamera can answer the question.
Edit 2: DIAPHRAGM SPRING! is the name is was looking for, the bulging side should be facing out/backward
Post by: Filmcamera on March 16, 2025, 08:45:59 AM
Today I am going to finally have a chance to remove the clutch basket and compare it with the one I had before...
Post by: Filmcamera on March 17, 2025, 06:46:25 PM
1. The new one seems to be marginally taller, maybe 1/2 a MM
2. The new one also seems to have a wider collar at the bottom just before the splines start.
I do not have an accurate way of measuring bu by eye there are differences.
Anyway, I am going to reinstall the ol done and see what happens.
Sadly that means waiting at least a month because try as I might I could not remove the o-ring without damaging it so I need to order a new one and wait for it to arrive before I can proceed.