1973 GT750 – Engine In !

The project continues !

I had the engine fully assembled on the bench and so now was the time to think about who to call to help lift it into the frame – these things are damned heavy, awkward to manage and I’m not getting any younger. Come to think of it, neither are any of my friends ! We (worldwide GT750 folks)  recently had a thread on this topic which can be read here. The normal method is to left the engine into the frame from the right hand side and then somehow support it while attempting to slide in a couple of the engine mounting bolts. This can be a harrowing, possibly dangerous adventure when doing it by yourself as the risk of injury is high, and a male bonding experience if a friend helps you, as you get to learn new, colourful and highly descriptive words that extend and add versatility to your vocabulary !  It seemed like a good opportunity to try another option.

A method I’ve use previously for removing the engine has been to lay the frame on its side, unbolt everything, and then lift the frame off the bike. Many people have also done the reverse to re-install the engine, so I thought I’d give it a try, and I’m pleased to say that it worked like a charm ! With the engine blocked up securely so that it wouldn’t fall over and damage my lovely oil stained concrete floor, I just lifted my frame over the top and into position, slipped in a couple of bolts to secure it and then gently lowered it back so it sat upright on the motorcycle lift – job done ! The whole process took about 20 minutes start to finish with no back ache, no mashed fingers, no colourful language and there isn’t a scratch on the paint that I can see – to the right is a photo of the freshly re-united engine and frame (just ‘click’ for a larger image). Doing all this work on the lift, had the advantage of being able to adjust the working height so it was comfortable, and so much easier on the back. Recommended.

From there is was a simple step to re-install the front forks, and then get the frame back up onto the centre stand so I could remount the swing arm etc..

Richard, the fellow who runs the PinkPossum web site did a small write-up some time ago about a simple conversion for the swing arm on the GT750 which I wanted to try. Starting in 1977, the newer model Suzuki’s had needle roller bearings in the swing arm which helped to improve the handling. The standard swing arm bearing for the GT750 is actually a fibre bush which works OK when new, but tends to get sloppy over time. There are bronze bushes available as direct replacements, although you have to be careful that you get some that actually fit ! The ones sold by PartsnMore for example have too big an OD and so need to be turned down somehow before they will fit into the swing arm. Proper sized bronze bushes are available from the Kettle Club in the UK who sometimes also sell them via eBay. On a couple of bikes that I’ve pulled apart for spares, I’ve noticed that the metal bushings seem to have lubrication problems as there have been signs of significant scoring. Of course that could also just be due to poor maintenance, but I wanted to try Richard’s needle roller conversion (details can be found here) as it just seemed like a better idea.

Finding the bearings here in Calgary was not a problem, although I understand that Timkins has recently sold their needle roller production division to Koyo and so the brand names may change. I was slightly concerned initially as the fit is just a tiny bit on the loose side.  I suppose it would be nice if there were a .001 less clearance, but once fitted in the frame and bolted up it actually feels fine with no noticeable play at all and I’m quite happy with it. A photo of the pivot shaft, with the two new spacers (left and right) together with the Timkins B-1412 bearings, two per side is to the left. Note that when this assembly is installed into the swing arm, you need a thrust washer of some sort at each end as the spacer protrudes about 2 mm – as Richard of the PinkPossum site suggested, I just cut the old fibre bush lip off, and used this as it is the correct thickness.

The radiator has been cleaned out, pressure tested and painted and is waiting for me at Crossroads Radiator here in Calgary, so I’m on to the next steps of paint, and getting the rest of the bike bolted together !

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