[Grand Designs] project - my ETZ 250

[dirtsurfer]

@Guesi is this crank suitable for a regenerated exchange? it rotates

[Guesi]

Well I don´t know if it pays to send it to germany and back. Maybe there is someone in GB who can regenerate a crank.
Important is not only the conrod, but also the side where the clutch is located. This side is often damaged...

[Puffs]

This all looks quite dreadful, and all your bearings will have corrosion on them. Even if they rotate freely & with little apparent play, they're likely to run noisy and fail soon when you start running the bike. My advise is to replace all bearings (main, conrod, but probably also gearbox, wheels, steering head) & seals. A conrod set is cheap & doubtlessly they can press & balance in Oz. Otherwise buy a complete crankshaft. You may also need a rebore & new piston (including pin - small end).

[dirtsurfer]

I wasn't really contemplating reconditioning the crank. I reckon its buggered. I am just hoping that the crankcases are salvageable. I expect to replace all the bearings and seals within the cases - a complete overhaul of the bottom end and gearbox is the first order of business.

This all looks quite dreadful, and all your bearings will have corrosion on them. Even if they rotate freely & with little apparent play, they're likely to run noisy and fail soon when you start running the bike. My advise is to replace all bearings (main, conrod, but probably also gearbox, wheels, steering head) & seals. A conrod set is cheap & doubtlessly they can press & balance in Oz. Otherwise buy a complete crankshaft. You may also need a rebore & new piston (including pin - small end).

[Blurredman]

You'll be pleased to know that these engines are incredibly simple to put together

[Puffs]

You can probably re-use the crank halves, unless the crank pins (ignition side & clutch side) are badly corroded. A bit of corrosion on the crank halves is no big deal (though racers polish them to reduce friction). Just saying that pressing & balancing a single is not very difficult, if you have a press.
Crankcases - have a look. If those are gone too I reckon it gets expensive.

[dirtsurfer]

Failure on the cheap clutch puller



The clutch remains in situ.

I haven't had much luck with getting the rotor off either. Now waiting for the correct tool to arrive. The bottom end/crankcases are now soaking in diesel

[Skyeport]

Damn, that sucks.
I'm about to make my own, hope it lasts better than that one.
Good luck.

[Guesi]

We have a word that says:
If you buy cheap you buy twice.

My extractor costs 39 Euro, but it lasts a life long

[Puffs]

Everything always lasts a lifetime, it's just that this bolt's life was a bit short.

[Andy_C]

When I took the clutch off my ETZ 250 it took a lot of persuading !

I used the proper puller and what I did was to tighten the scew as much as possible, then apply some heat, bashed it with a mallet and I woudl find that the bolt would turn perhaps a quarter of a turn more.

I just kept on repeating that time after time, and eventually it came off.

Problem that I think you may have is that the clutch is rusted onto the taper, which may make it virtually impossible to remove - looking at the state of that engine perhaps a replacement motor might be in order, it's just finding one, they do pop up on E-Bay fro time to time.

Good luck.

Edit - there is one on E-Bay at the moment - https://www.ebay.co.uk/itm/mz-etz-250-e ... SwOFBag1E6

[Blurredman]

This also happened to me regarding the bolt breaking..

I did notify the seller on e-bay who basically said 'Impossible!'.

I just use a high strength allen key bolt and that works very nicely!

[dirtsurfer]

When I took the clutch off my ETZ 250 it took a lot of persuading !

I used the proper puller and what I did was to tighten the scew as much as possible, then apply some heat, bashed it with a mallet and I woudl find that the bolt would turn perhaps a quarter of a turn more.

I just kept on repeating that time after time, and eventually it came off.

Problem that I think you may have is that the clutch is rusted onto the taper, which may make it virtually impossible to remove - looking at the state of that engine perhaps a replacement motor might be in order, it's just finding one, they do pop up on E-Bay fro time to time.

Good luck.

Yeah. the generator rotor is definitely rusted on but the clutch side didn't look too bad . I tried the rotor with an M10 bolt and using the technique you describe but I bailed out fearing I might snap the bolt and make the task even harder. I figured that my bolt did not have enough purchase (threaded area)


So now I'm waiting for the proper tool to arrive from our mate Guesi . The Clutch puller came from Hungary with some other parts but the bolt it uses is actually made of pretty soft material.

Someone told me that soaking in diesel can help to penetrate frozen parts so until the proper pullers arrive the engine is having a good soak


Worst case scenario I will cut the generator rotor off with an angle grinder. The crankshaft is [insert your favourite Australian expletive] 'ed anyway, but I would like to save the clutch if possible.

Edit - there is one on E-Bay at the moment - https://www.ebay.co.uk/itm/mz-etz-250-e ... SwOFBag1E6

Did you notice the engine number on that ebay engine? I actually contacted the guy before I noticed that. He says its because it came from the wreckers yard

[Andy_C]

Engine No:

Must admit that I did not look, but having looked I see what you mean - wonder if that is why the vendor states that he has a receipt for proof of ownership?

Can only surmise that it may have been stolen at some point in time as the Eng No has been obliterated, why else would it be?

As to whether you would buy it, I guess that it all boils down to the purchasers conscience.

Cant see any others for sale at the moment.

[dirtsurfer]

This all looks quite dreadful, and all your bearings will have corrosion on them. Even if they rotate freely & with little apparent play, they're likely to run noisy and fail soon when you start running the bike. My advise is to replace all bearings (main, conrod, but probably also gearbox, wheels, steering head) & seals. A conrod set is cheap & doubtlessly they can press & balance in Oz. Otherwise buy a complete crankshaft. You may also need a rebore & new piston (including pin - small end).

Yeah. It looks like I'll be doing all of that