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Clutch Replacement cock up updated

Started by Bikerbill, 16/05/23 - 21:33:39

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Bikerbill

Hi everyone
I have been working on bikes and cars about 40 years, but now and again the spanner of doom pays a visit just to put you in your place. I have changed more clutches than you can shake a stick at, but it's things which you don't consider, simple things, things you have done many times without an issue which inevitably cause issues, and in this case quite a bit more money. The reason i replaced the clutch was that under heavy load, the clutch would slip and this engine has 34000 miles on it so due a replacement.

I am not going to do a step by step "How to" on the clutch replacement as a quick browse on the web will find a tutorial for the Varadero 125. I am however going to point out a few things which held me up doing the clutch replacement.

(1)  How hard can it be to simply remove the radiator cap? Well, after a lot of skin shredding (i never removed the fairings) and struggling to get a firm grip on the cap, i could not get it to budge, it would only move a small amount. That was a bit strange, so i used my inspection mirror to see if it was damaged or been glued on or something.




For some reason Honda thought it would be a great idea to hide a screw to lock it in place. Okay not such a stupid idea as it will prevent high pressure boiling water squirting over the rider, but at least it could have been fitted in a position for easy access.

(2)  Removing the water pipe from the casing after draining the radiator. This added another 30 min to the job, what a pain. There is hardly any room between the pipe elbow and the frame. Having removed the 8mm bolt i used a small pry bar to lever the flange away from the case while wiggling and pull up on the pipe at the same time, and eventually pulled it free.

(3) Having removed the clutch cable and all the bolts from the case, and as they say in most DIY manuals, simply remove. Yes good luck with that, it took 45 mins of tapping and whacking the case with a rubber mallet before there was any evidence of movement.

Replacing the clutch plates went without an issue, i measured the clutch springs i removed to see how close they were to the wear limit and they were exactly the same length as the new ones, so the problem was not with the springs. I also inspected the plates and the friction plates. The friction plates measured on average 3mm, the wear limit according to Honda is 2.6mm, so replacing them was a good call. I then spent a good few hours trying to remove the old gasket from the engine block, this is very challenging,(remove the dowels before you start) as there is very little room to work at the bottom of the engine. While i was scrapping away, i spotted a loose spring underneath the clutch basket. Surprised at what i found i wondered where it came from. It turned out to be the clutch lever return spring, it must have come separated from the lever during the thrashing of the case during removal. Reinstalling the spring is quite straight forward the small tang fits in a hole at the end of the lever and the longer one in the slot of the case.

Clutch lever return spring



Clutch lever spring aperture



Spring fitted



Here are some photo of the worn plates












As a foot note to this, change all the plates at the same time including the judder plate and spring. If you look closely at the metal plates you will see some hot spots.

This is where things go badly wrong.
Putting the case back on the engine should be simple, i have never had any real issue with this part of an engine rebuild, i built 2 125cc engines and 1 200cc engines last year, so no stranger to this step, until VARADERO 125..

Where on most engines you lube any shafts, seal etc. then slide the case evenly to ensure every thing is in place, bosh job done. This is the method i used on my Varadero, bad move. What i should have done, was consulted the workshop manual and read the paragraph stating, the shaft of the water pump shall be inserted in it's orifice and the impeller tighten to a specific torque, then and only then assemble the case to the engine. I didn't do that, but the engine went together reassembled, oil the full works until i discovered a huge puddle of coolant on the workshop floor. 
I drained out what was left of the coolant and took the water pump off to see if a seal had an issue, well, i wasn't disappointed i found this....







and this is part of the mechanical seal, this seal was broken because (1) the shaft drive of the water pump caught it during the reassembly (2) i never did the job correctly.

The consequences now

(1)  Buy a replacement Mechanical Seal
(2)  Drain the engine
(3)  Strip the engine down again
(4)  Buy replacement gaskets for reassembly
(5)  Press in replacement Mechanical Seal
(6)  Rebuild Engine

I know a lot of people hide their mistakes, especially in youtube videos, but i feel you learn more form getting things wrong sometimes. One thing i can take away from this is, read the workshop manual, even if you have decades of experience.

The cost of cockup repair.

[1] Water pump housing seal      £5.99
[2] Clutch Cover gasket              £9.49
[3] Mechanical Seal                    £23.95
[4] Coolant  2L                          £12.65
[5] Distilled Water  1L                £2.99
[6] Engine oil 2L                        £37.90
[7] Oil Filter                              £6.50

Total additional Cost                  £99.47

Biker Bill






Bikerbill

atimofejev

Biker Bill, good writing, you covered all the issues where one can go wrong, with excellent conclusion: read the workshop manual.

Based on the most frequently watched YouTube video on the subject, there is a step where water pump impeller is removed.
There is no need of doing that. Only the water pump cover has to be removed just to turn the impeller a little bit for it to engage with the shaft.

In the workshop manual, it advised not remove the impeller, unless service of the pump itself is necessary.




Bikerbill

Thanks for your input atimofejev, and you are exactly right, just wish i had spent a few mins reading the manual.

I am going to put up the process of replacing the mechanical seal when I do it  :)

Biker Bill
Bikerbill