The upper part of the crankcase was glued using Loctite 574 as sealing. In the same way as I did on my GT750.

The Loctite 574 does not harden in air, only under pressure. A very common type of sealing for all type of crankcase.

Closing the crankcase:

All bolts are labeled with numbers. If you look close at the image you will see the number 25 is written into the case, just below the yellow arrow. That’s the order of the torque settings. If the crankcase is clean it’s easy to see the numbers. Mount all the bolt on the top side but don’t thight too much at this point. Make sure the crank is moving freely before turning the case onto the other side.

Since I have stored the bolts on a picture glued to a carton It’s easy to pick the right bolts with the correct length. All of them have been cleaned and polished. The S mark indicate bolts with more strenghts than bolts without the lable. The S bolts are for GT models but not for GS models. The GS bikes have labels with 7 on, not S. I found only GS bolts mounted on a spare crankase from a late GT model, 76-77. Not sure if that was original from the Suzuki factory or if someone had swapped them all. On my GT380 engine I mounted all the S-bolts I had except from a couple of 7-bolts.

Torque order:

Bottom case:

In addition to my picture above you will find the torque order in the manual and it’s written onto the case.

Top case:

From the manual:

In Nm:

8 mm bolts: 20 Nm

6 mm bolts: 13Nm

DONE:

After months of doing nothing on the GT380 I’m now back on track. This fall has been very busy and I had to focus all on work and not much spare time to invest on my GT380. Hopefully it will be better the following winter and spring.

Two weeks of Christmas vacation has been good and I was able to get some steps further on the project, but then…..I spotted a disaster.

 

Two of the lock pins holding the bearings at the gear shaft in place were squeezed all the way down into the crankcase. I should have spotted this at a previous stage, but what now. Is it game over. Do I have to get a new case ? Cracks on the other sides as well due to the brutal force into the aluminum.

Previous owner must have done this without thinking properly before assembling the engine. And on both gear axles…This is what happens when you rush into unknown stuff without taking the time needed to think twice and think it through.

I have a spare engine I can use,  but consider all the work I had put into this it’s worth giving it a try to fix this one. And if it works I will still have two GT380 engines.  This is how i did it :

Step 1:

Drilled and milled holes at the rear side and was able to push the pins out.

Step 2:

Drilled 2,5mm hole from the top side. Threaded 3mm and inserted a set screw and adjusted to the correct depth.

Step 3:

Gluing using Speedy-Fix

If something is too good to be true, .. it’s not true. That was also what I thought about Speedy-Fix, cost nothing from E-bay. Can it work ? Yes, I have tested it extensively on plastic, wood and metal. It really works. A totally damage plastic side cover was saved using this powder and hardener.

I could have TIG welded a tap onto the pin and pulled it out, but I don’t have any welding tools. Since the aluminium already had cracks I don’t think it added much structural damages to do the drilling and milling. A lot of materials left and if the gluing fails the set screw will still be in place.