Output Shaft Thread Damage

There is no mention of if the spare engine actually works.

[johnnyrod]

Swapping a gearbox shaft on these involves stripping pretty much everything, as the crankcase splits left and right, not top and bottom. As said above, get someone to look at it, especially if you're not going to post a photo.

[squirrel_hunter]

Just to clarify a couple of things, the mate who has taken a look at it is a bit like me when it comes to working on bikes. He does all his own work. He just finished building a Harley based flat tracker, and a very nice job of it he's done.

To get the bike anywhere for someone else to look at will be a bit difficult owing to the fact I can't ride the bike without a front sprocket nut (see start of thread), and I don't own a van. I could take the engine back out but the die route looks positive at the moment. I don't intend to cut a new thread, that is not required, only a little tidy up.

As requested here are some pictures:







The spare engine is a known good engine owing to the fact I removed it from the bike the other week, not that this really has a bearing on the threads of the output shaft. The spare engine is not intended to go back in, the original SH2 engine is what has been put back in the frame and is the engine with the shaft issue hence why I would like to avoid rebuilding it as I've only just finished doing it from the last time...

[Fen Tiger]

You have probably thought of this but...I have been wondering why the nut has stripped the thread. Can't believe you have cross threaded it (having read your enjoyable rebuild thread). One possibility is too much force being applied. Not by your feel but if you used a torque wrench. I had one which went way out of calibration and was allowing too much force to be applied. I know certain trades require annual recalibration of torque wrenches so this is not uncommon. Hope you get the thread sorted.

[glang]

Looking at the pics I would still try packing the nut out a little so as to tighten it onto a different part of the shaft thread. Using a second castellated washer from the other engine looks to be perfect as you would still keep the locking arrangement as intended by the design. Give it a try - it wont cost anything.....

[mikerj]

Don't bother with a die. For starters the shaft will be hardened, and secondly trying to use a die on threaded splines can be next to impossible.

Minor thread imperfections, burs etc. can be removed with a dremel and a cut-off disc used (gently) as a precision grinder. A file will likely just slide over the surface.

[DomP]

Fen Tiger has a point regarding torque wrench calibration. When fitting my R&G fully faired crash bungs the recommended torque on the through engine bolts felt far too much so I went on feel. On smaller bolts I don't trust torque wrenches too much, obviously the front socket is the other end of the spectrum circa 145nm?

[squirrel_hunter]

Torque wrench calibration is an interesting point and something that I should investigate more, but it didn't have any impact on this problem. I can't remember if I was even using the torque wrench when the nut first went I know I did have it out ready. I usually do things up by hand first before getting the torque wrench on to help prevent over-tightening if there is a problem. The nut requires 145nm which is a fair force and I am sure I was no where near the pressure on the wrench required to achieve that.

And for reference I use Halfords Pro wrenches.

[squirrel_hunter]

Well this took a little longer to update then I intended. I bought the Laser 5924 Wheel Stud Thread Restorer - HGV from a seller on eBay and as I wanted it a little faster decided to try delivery to my local Argos store. I get a message from eBay to say its there ready for collection so I head on down to pick it up. Half hour stood waiting while they look for it they come back to say they can't find it and to call eBay. I decide to go back the next day just in case they discover it, but no. Useless. Apparently if they have a bag of customer orders delivered they just scan the bag and don't bother checking the contents. Marvellous.

Anyway email to eBay and a refund is given. I order from another supplier to a different Argos and it arrives without issue. I feel sorry for the first seller but as it was a tracked order they should be covered. Just the process that Argos has to receipt orders in is not fit for purpose.

But now I have the tool. Took a couple of attempts to get it lined up on the shaft as the die is a snug fit in the holder but once it was on it did its job. There was some damage to the thread near the start of the shaft and this is what was preventing a new nut to go on cleanly. Took about 3 goes to clean it up, each time the nut went on further by hand until eventually I felt confident to try a new sprocket nut. And on it went, tightened up nicely and the tab washer is on.



The rebuild continues...

[maviczap]

cool!