1977 Suzuki T500 engine strip

[Olafskii]

This winter the goal is to get 3 cranks rebuilt--one of the GT750's and a couple of my Suzuki T500's (or in this case a GT500)  The GT750 crank is now down at Mongoose Machine so the '77 GT500 is next. 

The bike was found at Oly's woodworking in the Hart where it had been mouldering away in a chicken coop. It's a 106700-series serial number so one of the last GT500s to be built in Hamamatsu. I'm new to T500's but have done a few GT750s. Hopefully my learning curve will be measured.


In the shop, ready for engine removal


Engine out and on the bench. Exhaust bolts were not seized! A few case screws were missing but none of the remaining JIS screws were badly mashed.
Aside from some 'inch' bolts holding the back of the exhausts, everything looks good so far. I built the stand so that the engine can be tilted forward to access all the case bolts on the bottom. When I tilted the engine forward to build the stand, about 1/2 cup of water ran out of the left cylinder exhaust port. We'll see shortly damage has resulted. Over the next few days & weeks I'll post photos


The cylinder heads came off easily with no seized bolts but the barrels were another matter. They didn't budge even with some attempts at persuasion from my mallet. So, not wanting to break any of the cooling fins I decided to make a draw plate similar to what I use for my GT750's. For the GT500 of course, the draw plate is much more simple because just one barrel at a time needs to be pulled.

I obtained a chunk of 6"x6"x3/4" plate. Using one of the aluminum head gaskets as a template I drilled few holes and tapped a few more, and I was in business.


Barrels off, wrist pins out and onto the generator / ignition side of the engine. The timing rotor came off easily with my little steering wheel puller. The insides of the rotor looked pretty good. (I'll include a full report on my inspections once the engine is completely stripped)


Olaf

[Olafskii]

In the bike's past life some muppet didn't have the impact driver that's often needed to remove the seal plate screws on the countershaft output side.  I'm guessing that he wrecked all the JIS screw heads with a worn out Phillips screwdriver. Two of the screws had been removed and replaced with slot head screws (fortunately the replacements had correct 6mm ISO threads and not 1/4" SAE threads). The other two screws had been subjected to an amateurish and unsuccessful attack with a dull drill bit.  I carefully cut some slots on what was left of the screw heads and managed to loosen them with my impact driver.


Olaf

[Olafskii]

Clutch off, necessary retainers and case bolts removed and then the 'reveal'.


The left side crank bearing (the one close to the taper) is extremely rough and will be replaced when the crank is rebuilt.


3rd and 4th gear teeth on the clutch shaft are knackered. This shaft is sold as a single unit with all 5 gears machined as part of the shaft or press fit.  There are no good options; Nova Racing in the UK make replacements for £650 or Classic Suzuki Spares in Holland have a couple of NOS shafts on hand for €650.  If I put the old shaft back into service the bike would only be suitable for occasional riding to local shows.  My usual habit of riding 5-10k kilometers per season on my 'insured' classic bike would be out of the question.   


On the bright side, the transmission shifted through all the gears very nicely, the bearings are all nice and smooth, there is no shift fork wear to speak of, and the gear dogs were all nice and square. The thrust washer was missing from the bottom of the oil pump drive gear--probably an assembly line oops when numpty-san came to work hung over.


The next priority is to build a box for mailing the crank to the rebuilder.  I'll report back assorted measurements once the crank has gone out for rebuild. 

Olaf

[Olafskii]

The crankshaft was packed in a custom built wooden box and has gone down to Mongoose Machine for rebuild. Postage was $37 +$10 Fuel surcharge.  (I think it's time that Canada Post stop blaming their cockbag prices on fuel cost).


I cleaned and detailed the cases.  With the accumulated road grunge cleared away a better picture has emerged of the person who worked on the engine in it's past life.  It turns out that he was not a mere muppet, but a weapons grade idiot!  He broke the bottom cylinder cooling fins when he tried to lever up the barrels.  He also put big divots into bottom case with appears to have been a cold chisel in an attempt to separate the cases.  Every JIS fastener is mangled and every capscrew head that's bigger than 14mm has vise grip marks on it. 
Fortunately the cases aren’t cracked and in spite of the chiselling, don’t appear to have been separated.  So, buddy never took his 'skills' to the gears or crank.  Also, the chisel divots are all under the engine mount tube so not easily visible.  there is still enough machined surface left to seal the case halves. 
I'll dress up the sharp bits  of the divots and maybe fill in the biggest ones.  I’ll hafta develop my welding skills a little but also plan to weld repair the broken cylinder barrel cooling fins


Olaf

[Dennis]

Ouch!  You never know what you will find with old machines.   

Peace & Grease, Dennis