Yamaha TX750 Restoration: Engine bottom end disassembly.

After I finally got the engine stand modifications to work, I wasted no time in getting some work done on the 750cc parallel twin power plant. I had previously pulled off the top end (cylinder head, cylinders and pistons) so it was time to start the much more complicated bottom end. Here are some things I did in a little over an hour in the shop.

First was where I left off after pulling apart the top end. I was trying to get the clutch assembly apart. This was before I got my wiz-bang Japanese impact screw drivers. In the process I stripped the head of one stuck clutch spring retaining bolt. I whipped out my Dremel tool and cut some slots in the head of the bolt. With these I used a chisel and a ball pean hammer to get it unseated and was able to get it out without any damage to the clutch basket which is what you see here.

Some dollar store cake pans make for fine disassembly tools. I just pull apart some piece of the engine and set it in the pan. Now I don't have to search the shop for a missing bolt, nut or spring. This is the clutch assembly. I will need to check the springs and discs for wear as well as replace the spring retainers that got mangled in the chaos of pulling it all apart.

Bagging and tagging in full effect. Using the cheap cake pans I collect all the pieces and parts of some component of the bike. I then label the appropriate sized baggie and dump the pieces in. No missing parts and no hassle identifying what is what in the following days, weeks or in my case months later when I finally get around to rebuilding a particular piece.

Looking into crank case from the top end shows the connecting rods and the cam chain sprocket on the crankshaft. At first glance everything seems to be in good order. I did notice lots of flash from the aluminum casting process. I will take some time after the cases are apart and stripped down to remove this with a grinder. The flash isn't harmful to the engine, but it does give dirt, grime and other junk a place to gather. It also inhibits the smooth flow of oil from various places in the engine from getting efficiently back to the oil pump pick up.

In this pick I removed the oil filter adapter that allows the use of a BMW motorcycle filter element instead of the impossible to find stock Yamaha one. In the pic right in the puddle of oil from the filter you can see some black sludge. I wasn't happy to find that. I hope it doesn't predict bad tidings when I look at the main bearings.

I will have more posts with quick updates as I quietly nibble away at the engine. Hope you come back for more.

Blue