Browse Author: tore@grenasberg.no

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.ย  ๐Ÿ™‚ย  ๐Ÿ™‚

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 ๐Ÿ™‚

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

 

Lamp and bracket mounted:ย 

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.ย 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 ๐Ÿ™‚

 

 

 

GT380 wheels, mounting of spokes

GT380J, mounting the spokes:ย 

The procedure of mounting spokes is well explained in an earlier GT750 post. Please read the post before continue on this one.

GT750 post:

http://mc.grenasberg.no/2018/10/28/front-wheel-spokes-mounting/

 

Front wheel:

 

As described in the GT750 post, always start with the spokes at the inner side of the hub. And don’t mix the spokes. Inner and outer are different. Get the details from the post mention above.

 

Turn the wheel and continue with spokes at the inner side of the hub.

Arrange the spokes before mounting the nipples.

Both inner sides done.

Next step: mount the spokes at the outer side of the hub:

Turn the wheel and and mount the remaining spokes

Done, all spokes are mounted.

 

Rear wheel:

Do the rear hub in the same way as shown for the front hub.

 

The adjustment procedure will be the same as shown in the GT750 post:

Adjustments:

http://mc.grenasberg.no/2018/11/04/spokes-adjustments/

 

 

GT380J Front and rear hub

Step1

Cut off all the spokes and remove ball bearings.

Step2:ย 

Cleaning and glass blasting.

Step 3:

Grinding. Did no grinding to the rear hub. You can still see the scratches from the spokes. Will not be that visble when new spokes are mounted.

On the front hub I grined quite a bit to get rid of the bigges scratches. Started with P250 paper and thereafter P1000.

Step 4:

Rear hub after polishing:

 

Front hub after polishing:

Step 5, bearings

Mount new bearings, don’t forget the spacer in the middle before you mount the last bearing.

Be gentle when driving the bearings into position. Allow some slack to the spacer so each bearing can individually move freely.

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.ย 

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 ๐Ÿ™‚

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.ย 
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 ๐Ÿ™‚ I don’t smell anything from the solvent while working inside the greenhouse.ย 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.

Paintwork in a greenhouse

Greenhouse in the Man Cave:

The heat is always on in the Man Cave and the temperature will be ideal for painting. A greenhouse will give the protection needed for the work. Can’t use spray cans without a tent for protection.ย A low cost greenhouse will do the job.

As long as it’s winter outside and freezing cold the paintwork has to be done inside.

Quite easy to assemble, took me only about 30-40 minutes.

Ventilation in place + an unused gas mask from WW2.