Regal Red - Engine
This engine had really been abused by some truly ham fisted amateurs. My first clue was when what I thought was crusted dirt turned out to be a chunk of the top crankcase that had been broken off and then glued back in place with silicon. And while I knew that the top of the alternator housing had been damaged, I hadn't realised that what I could see was body filler as the aluminium had been caved in during a prior attempt to lever off the barrels.
The really sad part was the barrels themselves. The water jacket had been cracked in a couple of places, the gasket mating surfaces were in very poor shape and the threaded hole for the top stud had been broken and then extensively repaired.
Internally, the rest of the engine actually looked OK, with the only noticeable issue being the sprag clutch bearing for the starter. This was changed at engine 51822 from being a single row bearing to be two narrower bearings. In this photo you can see the needles of the old style bearing smeared in the bearing cage. The gear itself was also changed along with the included angle of the clutch. This is all detailed in Service Bulletin GT-4 which you can find here.
In the end, I decided to just get what I had repaired - not a cheap option by any means, but as the engine was the original one fitted to this frame I felt they should stay together. The repairs were done at Trillion Industries here in Calgary, and as with other work they have done for me, it was excellent.
The original crankshaft was put to one side and will likely go to the recycler as I prefer to use a later style crankshaft as used on the M/A/B. I discussed the reasoning behind this in the previous build and you can read about it here. I have a couple of rebuilt later style cranks on hand, done for me by Joe at RPM Services just south of Calgary. The rest of the engine will be refreshed with updated parts (rebuilt water pump, clutch boss and bearing, new style clutch plates, sprag clutch, new shouldered engine studs, etc.).
One thing I was interested in having done was to have the cases vapour blasted (also called vapour honing and aqua blasting). Few places offer this service here in Alberta, or Western Canada for that matter. Rene at DucatiMeccanica offer this service in Medicine Hat. He did a nice job, and the cases now look better than new ! I will still have to polish the bits that are supposed to be shiny, but that shouldn't be too difficult.
I'm not a mechanic, and so for those out there who are mechanics most of this will be of little interest, but here are a few of the little bumps in the road I dealt with during the engine rebuild:
- When checking the head for flatness - it wasn't. Flat that is, so I spent a couple of hours lapping the head to the block using a fine valve grinding paste and light oil as a lubricant. The end result looked pretty good, so hopefully it will seal.
- Likewise the base of the block had been damaged by the previous owner and at one edge there was virtually no contact area for the base gasket to seal to. I built this up with JB Weld and then lapped the base of the block to get it as flat as possible. Some of the areas are marked by the arrow in the photo below.
- It is unusual to see all the plates burned blue, but they were so I replaced all of them. The plate at the top is a good one, then ones at the back are scrap. I also changed from the older style resin friction plates to the later style aluminium friction plates. The clutch basket itself was in good shape.
- I had the barrels bored to first over the the new replacement pistons checked for size and matched to the bores by Joe at RPM in Okotoks just south of Calgary. I have bought quite a few sets of pistons from CruzinImage out of Japan and they come as a set complete with gudgeon pin, clips and rings. When I went to fit the pistons, I could not fit the gudgeon pin clips on one piston and spent some time puzzling over why. After several minutes of faffing about, I pulled them all out to take a closer look and found one was longer than the rest ! I had a set of OEM gudgeon pins and fitted those instead, and I've sent the three CI ones back to see whether they will replace them. Other than their air inlet rubbers, this was the first time I've ever had a problem with CI product.
- I spent a couple of days sorting out oil injector pumps, and wrote about that at this link. I still have more work to do, but I do now have a pump I have some confidence in. I also repaired the injector oil lines, and an article about how I do that is available at this link.
When all was said and done, I had the engine ready to hang in the frame and after doing so took a few photos of what was starting to look like a real motorcycle.
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