hero

It’s done and back together after quite a long winded saga.

Thanks McMan 56. Thats what I did and eventually it came off. I bought a 22 mm speedi sleeve for the crankshaft seal to run on but it was a really tight fit on the crank even thought the measurements were all in tolerance. However, all was ok in the end. A new crank bearing from AG was a standard type ball race and not the roller type that was fitted. I had to make this a slide fit by wet and drying the shaft. In the photo you can just see the sleeve for the seal and the new bearing. Thanks to all for the great advice.

Paulc you’re right. The original sleeve is still on the crank and it doesn’t want to come off. I thought it was part of the crank. The bearing is supposed to have an inner flange of 25mm but the face I have on the crank is 33mm. I feeling a bit daft now!

Thanks Paulc. I did see adverts for the bearing that seemed to offer the sleeve as part of the package. However, in the description it said there was an outer flange but no inner. I presume that the sleeve is therefore heated and shrunk in place. I need to take a closer look. I am near Salisbury in Southern UK.

I can get a 25x62x17 sealed bearing with inner and outer flanges from lots of suppliers, even SKF. The main advantage of the original is that it allows end float because the L/H side is pressed onto the crank and casing so any end play there is not possible. I would need to ensure that there would be some sideways movement in the inner flange of the new bearing against the slightly damaged crank. The original NU305E bearing is also readily available. Sorry Konrad, I know you intended to stay out of this one.

I think the bearing face on the crank is more important than normal because it’s not where a contained inner part of a race fits but is where the rollers contact directly. A sealed, normal type, enclosed bearing might be the answer if I can find a 62x25x17. Whilst this type of bearing is usually used in wheels, I’m not sure if it’s suitable in mains situations.

Thanks for getting involved Konrad, I had not considered a sealed bearing. The original bearing on the flywheel side is definitely shot for the same reason the crank is, water ingress, and so a new bearing is necessary anyway. JB Weld has served me well on fairings in the past but did not work well on pitted forks ( between the triple trees, not on the lower legs ). The rest of the engine seems ok so, if low cost or used spares were available, then it would be worth the effort. I’ve come this far it’s worth a bit more thought yet. The overall condition of the bike is scruffy but I hate sending anything to the scrapyard, it’s my age I guess. The crank is still contained in the L/H case as it would appear that the bearing on that side needs to come out with the crank before it can be removed from the crank itself. Do you know if that is correct?

Thanks Kurtas, I did come across the Speedi-sleeve and considered using one in each area. The downside to that is that I / someone, will have to split the crank in order to put the shaft in a lathe to have the areas trimmed down the 2mm required. It would make a nice repair but possibly expensive by the time it was all pressed back together (plus the cost of a flywheel). I was hoping someone would have a crank somewhere lurking in the back of their shed but it appears not.

Interesting, presumably the shaft would have to be removed from the crank web to do this. The problem might be the cost of such work and where to find someone who could do it. It might even be more cost effective to have a new shaft turned down.

The flywheel was jammed on my 241 engine after shearing the woodruff key. I finally got it off and split the cases to see what was required for a full rebuild. Unfortunately, after 20 years in storage, there has been water ingress. This is only on the magneto side and the Crank is badly pitted on the bearing shoulder and where the oil seal fits. It would be a shame not to be able to save another 241 from the heap. Has anyone got anything to help or ideas?

Cut off f;ywheel and remainder still on shaft. All removed now though. A new flywheel should be easier to find than a new engine I hope.

As no-one came forward with a reply to my question above of how to remove a flywheel with a sheared key from the 241 engine that will not come off the shaft, I had to suppose that ( most fortunately ) it has'nt happened to anyone else. However, I was still stuck with what was probably a "write off" engine. If the flywheel wont come off then its not even possible to split the cases or remove the crank etc rendering it no more use as an engine. Even more difficult than getting the flywheel off is getting a replacement engine. I did get the flywheel off and (completely open to critisism of my method), here is how I did it; I took a 41mm holesaw and cut completely through the centre of the flywheel. This actually ruined 2 cutters and, of course, the flywheel. The outer part of the severed flywheel came off and I could see the coils. I was then left with the remainder of the flywheel on the shaft. I was now able to use a hacksaw blade along the remaining part, in line with the crank although I did have to shape the end of the blade in order not to damage the coils. The blade had to be hand-held and wrapped in a cloth to protect my fingers. I made 4 cuts very carefully at what I thought was the right angle of the taper and every now and then, refitted the puller to try. The puller eventually pulled it off the shaft. There is a graze or 2 along the shaft but it cleaned up well enough. Another bit that took some effort was getting the remaining part of the woodruff key out of the shaft slot. The story is quite short really in comparison to how long the job took but I can now move on, tear the motor apart and replace any parts that are worn. Pictures were taken and they're not very pretty.

I've tried both those methods... a bit wary of too much heat with the electrics so close behind the flywheel I'm assuming the key sheared and the flywheel continued moved round the shaft dragging what's left of the key with it. The bike was running (after 20+ years in a shed) then suddenly stopped Now it just kicks back through the kickstart So i'm left with maybe a makeshift attachment for a half shaft puller? Or cut the flywheel off - if thats possible? But i'm open to other suggestions

My 1986 241 has sheared its woodruff key and the flywheel is now jammed on the shaft Ive broken a puller trying to remove it Any ideas on getting the flywheel off?