Browse Category: Suzuiki GT 380

Gear assembly

After repairing the crankcase :

I mounted all the gears before I spotted the damages caused by the lock pins. See my previous post explaining the issue.

http://mc.grenasberg.no/2019/12/30/lock-pin-repair/

I therefore had to remove it all and assemble the gears once more after repairing the crankcase.

Step 1, see the previous post, GT380 Gear shifting.

http://mc.grenasberg.no/2019/08/05/gt380-gear-shifting/

For a detailed view on how to mount the gear shifting mechanism, see how it’s done for the GT750. It’s very much the same:

http://mc.grenasberg.no/2016/02/21/gear-shifting/

One difference is of course the number of gears. Five on GT750 and six on GT380.  In addition, the CAM stopper is not mounted from the bottom side of the crankcase as it’s done on the GT750.

Step 2:

Mount the pin and spring:

Step 3:

Mounting the forks:

As always on my blog, click on the images for a more detailed view.

Step 4:

Don’t use thread lock on the screws at this point. Wait until you have checked all the functions of the gears.

 

Step 5, gears.

Front axle 

Running smooth and nice.

Rear axle:

 

Checking the shifting of all six gears:

Added labels on both axles to easy count the ratio of the gear shifting. It all looks good 🙂

No issues as I can see while shifting the gears up and down. The no 1 gear runs a bit tight compare to the rest. Don’t think i will cause any problems. I will open up the spare engine and check to verify its condition and compare the gear shifting against this one, but not today.

The outer C-ring is missing on the rear gear axle. Will borrow one from the spare engine later on.

Lock pin repair

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.

 

 

 

GT380 Gear shifting

Step 1:

The needle bearing for gear shifting cam must be installed again. Use a socket to drive the bearing in place.

The needle bearing seen from the inner and outer side of the crankcase.

 

Step 2:

Cam and forks mounted:

 

A greate help to look at the pictures taken while stripping down the engine :

 

 

 

 

GT 380 Crankcase and cylinders

Cleaning :

All parts were laid in a bath of pure paraffin overnight to loosen up the old burned materials.

Thereafter, cleaning with a brush and flushed with water.

 

Powder blasting:

The powder blasting came out pretty well, but it’s messy, powder all over the place, everywhere. Inside my body as well… The biggest benefit is clear, no dangerous particles to damage the engine. It’s baking soda and can be flushed away. The moste resistant parts are hard to get off with only powder blasting and the finish of the alu parts get’s not that nice using powder.

Since I already have invested in a sandblasting cabinet I decided to stop the messy powder thing and loaded up the cabinet for glass blasting.

 

Glass blasting:

As always on my blog, click on the images for a more detailed view.

Much cleaner and more fun to do the glass blasting. The biggest issue will be to be to get rid of all the glass particles. Rinsing in water and blow dry with compressed air is important.

 

 

Coating with oil:

 

The parts looks shiny and nice after glass blasting but will soon start to oxidize. I was recommended to use a good penetrating oil, like Omega 636 to preserve the crankcase. Let it soak for one day before drying off.

And again, blow very well using compressed air to get rid of all remains from the blasting media.

So much more fun to start the assembling of the engine when all the parts are cleaned and shiny.  🙂  🙂

Assembly of the rear wheel

Assembly

The brake shoes had little wear and were reused after cleaning and glass blasting.

New sprocket mounted

The spacer on the other side ( no 10 on the drawing)

 

New seal mounted and well greased before and after the last spacer was placed.

 

Mounted

 

Mounted on the bike, please see the drawing below for details. Remember, the entire parts manual can be found in the folder “documents”

 

 

 

 

Rear fender

Rear fender mounted:

Hmm,perhaps I should give it some scratches, if so, the first one coming later on will not be that annoying 🙂

The inner part of the fender was painted with HAMMERITE metal paint for rust protection.

 

Lamp and bracket mounted: 

The mounting holes for the plastic part of the fender were both broken. Used a plastic repair kit called Speedy Fix. Worked extremely well. Used the same kit to repair the side cover.

 

GT 380 Fork

Fork:

Hmm, a bit confused… Looks like the parts inside the fork is a mix of L and K (J) model ? Not sure, but both inner legs must be replaced with new ones. Marks and scratches on both.

 

At the moment I have ordered one of the inne tubes, 5111-33030. This is a hard to find part. Not sure if I can swap to later models. The lower part, the oute tube must be the J or K model because of the drum brake.

Sanding and polishing the outer tubes:

 

Lamp head , fork bracket parts:

What I did with the shiny parts: Sandblasted the rust at the inner side and painted. Cleaned and polished the outer part. One of the chromed parts was too bad to be cleaned. I had to turn off some metal using my lathe, sanded and polished well before I nickel plated the part. All the old chrome must be removed before the nickel plating.

GT380 Frame assembly

Frame and swingarm ready to be assembled

As always on my blog, click on the images for a more detailed view.

All bolts are reused after cleaning and nickel plated.

The front and rear wheel bolts before and after nickel plating. I use the same old nickel plating kit from six years ago when I restored my GT750 A model.

 

Shock absorbers and centre stand mounted

 

 

 

Steering Stem:

Pictures from dismounting:

The bike has been upgraded previous with tapered roller bearings. I will of course keep it so. The steering stem is different and has no threads at the outer side like the original one, only internal threads. The bolt at the top looks ugly and I will make a custom build “nut” at the top so it looks as close to the original nut as possible. Will use my lathe and milling machine to do so + nickel plate the part.

 

Next step, machining the bolt:

Turning the 10mm axle on the lathe.

10mm fine pitch 1,25mm threads.

Machining on the milling machine.

Done and polished, before nickel plating.

 

Nickel plated.

Mounted, I’m very pleased 🙂

 

 

 

Sandblasting and painting

Did some investments in sandblasting tools. Had to buy a larger compressor and decided to go for a sandblasting cabinet as well.

 

150 litre 2,2 kw 1ph compressor. Placed at the loft in my garage.

The cabinet is in the first floor of my garage, not in my MC garge ( the Man Cave )

Very pleased with the cabinet. No leakage, probably due to the fan at the rear.

 

Nice to also get compressed air in the ManCave, away from the noisy compressor.

 

 

More painting to be done.

By the way, the gas mask is not from WW2, it’s a Russian type from the cold war. Replacement filters are still available on Ebay.

 

Done, and the tent ( green house) is gone.

The serial no on the frame was masked and is only covered by primer and ink. Still visible.

Painting the swingarm

The greenhouse is ready for the first paintwork job. 

Warm and cozy indoor, minus C degrees and snow outdoor.

Ventilation is on and the 70-80 years old gas mask from WW2 will become handy.

80 years old gas mask giving breath assist while painting a 40 years old frame.

The mask is awesome, brand “new” from the war and works 100%

Primer applied.

Next day:

First layer of paint sprayed

 

Leave it to dry for the next day.

Have to say it again: not a bad idea to mount the greenhouse 🙂

No, it’s not 2k products. Not so durable but more easy to apply. The main reason to use this recipe is the following:

The paint in the can is the same type as in the spray can. Regardless if you use 1k or 2k paint you will sooner or later get scratches and marks in the paint. If so, I can easly use a brush and touch up wherever it’s needed, with the same type of paint. 
Important to use the correct type of primer, if not the paint can start to boil and it’s game over…..

The mask is comfortable to use and has a stunning look 🙂 I don’t smell anything from the solvent while working inside the greenhouse. If I later on become a doomsday prepper I already have the gas mask. I think I also have the blue nuclear brush from my military service. WW3, come and get some… ha, ha.