I started to remove the accessories around the engine so I can split the case and start to deal with the insides. The easiest place to start is the gear selector assembly. It is only retained by a spring catch.
This is another part that has had a copped a belting at some time. As the photo shows, the keyed end is bent a fair bit. Fortunately I have a straight one on the spare engine, so I will leave this one until reassembly.
The next part to remove is the stator for the generator system. Should be simple however, because the barrels are already removed the stator just rotates the crank whenever torque is applied. I tried making my own strap type tool to hold the stator while i removed the retaining bolt. The nut is pretty rusted so that didn't come close to working. Then I noticed that there were a couple of tapped holes - awesome!
This elaborate arrangement of bolt, spanners and bench held it steady so I could belt the nut with a spanner. The next problem was removing from the end of the crankshaft. I tried the puller over a couple of days with a lot of penetrating oil. I ended up being concerned about damaging the stator (below). Sometimes it is better to stop and think through the problem.
So the solution was insert a couple of short bolts into the tapped holes with large washers on the end; use these for the puller to work on (meaning the puller would not damage the alloy outer rim) and then apply heat as evenly as I could. I heated the part for about 20 minutes ensuring there was a lot of tension on the pulley. I was about to quit when it suddenly released! Moving on...
Hi there, your blog is perfect, exactly the same bike and what I needed. Could you be a little more specific as to how to remove the stator and magneto. I have a puller and have tried everything. What exactly did you heat?
ReplyDeleteThanks.
Hi Kurt,
ReplyDeleteThanks for the compliment. Unfortunately I haven't updated for a long time, but will be fixing that next month. So the magneto coil comes off with the cover on that side and is held in with screws so is pretty easy to remove.
The Stator on the other hand is a nightmare. I have removed two from different engine and both were equally hard. First you need to have a method of securing the crank from rotation. I had already removed the cylinder barrels so on my second engine I had to jam a screwdriver into the teeth at the rear of the stator. This is far from ideal, but on the first engine I secured the piston to the case and broke the piston. hence the spanner arrangement in the photo.
I firstly soaked the thread area in the centre with penetrating spray (for rusty bolts/nuts). Did this twice a day for about three days. As far as heat goes, I tried heating with a butane torch (similar to a primes torch for soldering) but could;t generate enough heat. I then went with a MAPP (butane/mixed gas) torch which delivers a much hotter flame. This provided enough heat to remove the nut with a impact wrench. once that was off, I fitted a three arm flywheel puller (much better than the bearing puller above) which allowed me to thread three high tensile bolts into the thread holes in the stator. Then just kept tightening down and tapping around the outside rim of the stator with a rubber mallet. Once it budged a little, it flew off. Did all the tightening whilst it was still hot.
Hope this helps, good luck.
Duncan
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DeleteThank you, Duncan, for the prompt reply, and the correction on parts lol. Yes, the stator is what I am having nightmare with. Everything you've suggested, unfortunately (including the rubber mallet) has been tried. It won't budge. I've done a ton (excuse the pun) of research, your site by FAR is the best in step-by-step help. Have you ever run into the woodruff key shearing on these? Some forums suggested that it might be the cause for the immovable parts. If that's the case, what are my options, short of just scrapping the crank?
DeleteThank you sincerely,
Kurt.
In the two engines I have worked on the woodruff key has been fine. It appeared to remain in place and the point of friction has been the shaft to stator. In fact on both engines I have removed the woodruff key by hand. I thought I might have to give up on mine - I encourage you to keep going. Unless you have no time, you have nothing else to lose! In thinking this one through I thought about cutting off the stator. My thought was It might be best to remove the magnets first (unscrew or drill out the screws) as mine are both in good condition. That way if I bought a second hand replacement, I could always swap in the magnets if required. I would think a dremel or similar to cut radially towards the crankshaft and then drive a wedge to split apart, or at least loosen.
ReplyDeleteYou're right on keeping it moving along. I really appreciate all the help and taking the time to reply to my questions, by the way. Back up plan at this point is just swapping out the 750 motor, which has 43k miles on, for a 920 which should bolt right onto the frame. More bang for the buck. At any rate, I'll keep you posted on what happens and I look forward to more updates on your page. Got you on my favorites bar now, so keep up the good work!
DeleteMany thanks,
Kurt.