ETZ 250 CLUTCH REMOVAL

[nice2day]

Hi chaps. It's great to be back working on the bike. You might be able to remember me from last year but I was diagnosed with skin cancer on my face of all places and had some pretty drastic plastic surgery making me look not unlike my avatar...
Anyway . Could anyone please help me as regards getting the clutch off the crankshaft?. I've tried extreme measures and even bought another puller …the expensive Martin Burwins one. I also chatted with Martin but found that all the suggestions he made were in effect what I had been doing anyway. I'm now at the stage of stripping the threads of his puller if I tighten any harder. Before anyone suggests this, I have been tapping the puller and have left penetrating oil to soak down the shaft for about a week!
Martin did scare me though as he admitted out of a few thousand strip downs he did have a couple that refused to come off so stripped the engine still with the clutch in place and somehow used a hydraulic press to shift it...Lord knows how you could do this though. Anyway maybe I'm the lucky owner of the one that is not going to come off without sawing it off

I would appreciate any one's anecdotes or help with this one....very much obliged as ever.

Les

[Kruh]

When you say taping the puller I imagine light hits. Strong hits with a hammer on the head of the bolt while its tight can help.
Another thing I'd recommend is heat, lots of it. That should expand the clutch taper; introduce some movement between the mating surfaces.

I also had a well stuck clutch on mine. The way I did it was to combine all of the above.
Thighten the puller, heat up the clutch, strong hits on the bolt, tighten again, hit and repeat until you successed.

[nice2day]

Hi Kruh. Very many thanks for your reply and suggestions....You are right, I have given relatively light hits so will try much heavier ones next time. I did try heating the centre boss but I was a little concerned that it might damage the bearing by tempering the steel, but obviously I can replace this bearing once I have the clutch removed. I hope I don't damage anything else on the clutch but I have few options so I will heat it up much more with the blow torch...then fit the puller and then bash the bolt end pretty hard and re-tighten the puller in stages.

Bashing the end of the bolt with a lot of force is a slight worry as the force could distort the alignment of the big end as this is offset from the central force going inwards on the main-shaft and consequently bending forces are at work. Anyway, if this does not work I will be really depressed. I will try again tomorrow and will let you know how I get on...Many thanks again.

PS: I am intrigued as why the clutch becomes so difficult to shift. I can only imagine that there must have been some rusting occur during initial assembly as the whole assembly runs in oil

Les

[nice2day]

YIPPEE....WOO-HOO!...I can hardly believe it but I've got it off!. I was inspired by what Kruh said so instead of waiting until tomorrow, went out to the garage...With a MAP gas torch I let rip with the heat on the threaded centre boss until it was showing signs of becoming severely hot and then quickly fitted the puller, tightened to my maximum strength and then smartly hit the end of the bolt...just one hit. BANG!.. the clutch shot off. Boy was I thrilled....I'm now waiting for everything to cool down and then take the clutch apart to inspect for damage. By the way the taper looked uncorroded and gave no clue as to why it was such a tight fit...All I can say Kruh is very many thanks again for your assistance, it made quite a difference to my approach knowing that someone else had the same problem and you managed to overcome it. My heart is still racing with the thrill of getting the clutch off...All the best to this forum....

[Kruh]

You are welcome. I'm glad it worked out.

Mine was slightly corroded, after sitting for over 30 years. In your case, not sure, its likely that someone tightened the clutch too much previously.

[Blurredman]

Well done.

I myself have also taken apart an engine which had been discarded in the side of a garage for 15 years. It was very rusty.. With lots of hard whacks (just like the Terry's Chocolate Orange adverts..) and gradual tightening of the bolt on the puller, I eventually got the clutch off that particular problem child!

Sory to hear about your health, too..

[Puffs]

Good you got it off!

If it bothers you, update your avatar?
But seriously, let's hope that was it.

[nice2day]

Cheers Puffs, nice too be in touch with you and I like the avatar joke too...actually I was obviously exaggerating a great deal. The reality is being left with an enormous scar after they rotated the side of my face so they could fill the hole up. Still hurts quite a bit maybe a bit better in a couple of years
By the way I rebuilt the clutch today dead easy and pleased I remembered to mark the 3x main parts to allow original alignment I note it has balance drillings in the drum...See you soon hopefully....Les

[nice2day]

Many thanks Blurredman appreciate your kind words... Sorry my thanks to you are out of sync as I only saw puffs message to start with...Hope you and all other MZers are keeping well ...Les

[Puffs]

That looks intense Les...

The face has a higher number of nerves & muscles than anywhere else in your body, so yes, I believe you when you say that's painful. But it should normalise relatively quickly.

The biggest risk with skin cancer is metastases elsewhere; what I meant with 'let's hope that was it' was, that if they got it all in time, you shouldn't have any other problems.

Wishing you well, and I hope it normalises quickly & that it doesn't bother you on the bike!

[nice2day]

Thanks Puffs. Yes you are right in all you say. Severed nerves have left much of the area permanently numb, the rest is like having electric shocks when touched. I even had to buy an electric razor as I couldn't feel anything and was carving my skin off with a wet razor. 5 years of surveillance to go but you just carry on.
By the way I dropped the needle bearing onto the concrete floor, because I forgot it was inside the drive gear. The nylon cage cracked so I'll have to buy another one now. Just a warning to others of how brittle these are...All the best....Les

[Puffs]

Surprised to hear nylon cracks that easily... Maybe age / temperature?
Anyway, no biggie.

[nice2day]

Yes. 32 years soaked in old oil as well as the thousands of heating cycles must have made the Nylon brittle. ...Les