1976 Suzuki GT750A

[Olafskii]

I started work on the 1976 Suzuki GT750A this week.  This is the bike that came from a little wrecking yard in Endako.  The goal this winter is to assess what needs fixing and get the crankshaft rebuilt.  The crank rebuilder at Mongoose Machine in Port Coquitlam is going to retire in the near future and I'd like to get the crank done (and two T500 cranks) while he's still working.     


Bike stripped and ready for engine out


I set two choker slings making sure that they avoided fragile SIRIS valves SIRIS inlets and oil injection hoses. Then I carefully laid the bike on its side and pulled the last two bolts.  Engine lifted out nicely.  I did lots of cursing when building the structure for the overhead hoisting monorail.  But this sure beats hand rigging.
 

[stevecrout]

Excellent to see the rail in use!  You're making me wonder if I missed a bet by not installing one myself. It's also good to see a little bit of clutter on your work benches.  Mine were clutter free for about 3 days then the chaos began. Now I have about 4' free of a 20' bench. Good luck with the Suzuki!

[Dennis]

That hoist sure looks handy.

Peace & Grease, Dennis

[Olafskii]

Engine on the bench


The head bolts came out textbook fashion--only a little heat needed for one of the 8mm end bolts.  Head and head gasket came off with a bit of light tapping with my mallet.  The bores are stock 70mm but a definite wear mark at the top of each bore ~.01 to .015mm so the engine will need a first oversize rebore.  I doubt that the mileage on the clock when I bought the bike (2140 miles) was correct.


 

Olaf

[Olafskii]

Right and center pistons are in good shape. A bit of scuffing on the left piston.


The left and center wrist pins have visible wear grooves from the locating shims.  No sign of heat damage but a little flaking on the left wrist pin bearing surface.  All indications that the engine has done some miles.


The starter clutch and water pump drive gear came off without a hitch.  The white nylon gear is the water pump drive gear.  It's cracked (which is normal after 40 years for these bikes) and will be replaced.
 

The gear indicator sending unit wasn't working.  It was immediately apparent why not.


Olaf

Olaf

[Olafskii]

On the other side of the engine, one of the alternator brushes had a broken wire so the charging system was probably not working properly.  The right side crankshaft seal under the alternator was leaking which also points to my suspicion that this engine has some miles under it's belt.
 

The clutch cover was a pain in the arse to remove.  While most of the engine has never been disassembled, some numpty has tried to remove the clutch cover using screwdrivers.  Fortunately they didn't do any real damage.




Olaf

[Olafskii]

The clutch has seen better days.  But, I have it on good authority that the not too badly worn clutch basket can be rehabilitated by careful dressing the basket fingers with a file.  A new stack of fiber clutch discs can be had for US$35.00 from a Japanese vendor.  This works out to about CAD$70 to my door with taxes and shipping. 
 

[Olafskii]

Water pump cover removed.  Impeller is in nice shape with no evidence of bodgery and the gasket is original--so, the water pump is original.


The final reveal; crank case split.  The connecting rod lower end bearings are worn but not yet out of spec.  Since the crank will be pressed apart to replace the seals, the lower end bearings along with con rods will also be replaced. Gear clusters are in nice shape with shift dogs showing some but not excessive wear.  Shift forks aren't worn or bent.
 

Olaf
 

[Olafskii]

The crank has now gone down to Mongoose Machine in Vancouver for a rebuild.  I won't get it back until February.  In the mean time I've cleaned up the engine casings, cylinder barrel and all the screws and then 'dry assembled' without any internals.  The dry assembled engine hull went back in the frame along with the exhausts and carbs.  This all took a couple of hours but freed up my workbenches for another project.
 
I hate the silly pod filters and have sourced a proper 1976 Suzuki airbox from Ebay for an unreasonable price.



Olaf