All back together

I have been a bit absent on adding posts. When you start to reassemble a project like this, you just go and don't slow down.

I had a number of problems along the way and I will add those.

But first, here is the final product. (I have not yet added the Nimbus decal to the tank at this point)

Gearbox back together - and cleaned up

Putting the gearbox back together was simple and quick. I also cleaned it up. It is looking good!
All the springs are new.
Unfortunately, I forgot to include these screws and nuts with the stuff I had zink plated. I can include them in the next batch.

Engine crank

The bearing are in good condition. I cleaned out all the oil tubes/holes. Everything here seems to be in order.

Clutch plate

Removing the clutch disc is simple. The screws come right out with an impact screw driver.

There is definite wear on the bottom plate. Not sure if this should be replaced. Must ask Lars.

The clutch disc itself is greasy. I spilled some oil on it so I must do a good job degreasing it.

I must also check with Lars if there is enough life left on the disc.

Looking good!

I attached the front wheel next to test it. The motorcycle roles smoothly and easily.
I will have to remove the front wheel when I install the engine. It will be easier without the front wheel and fender.

The Nimbus is looking great even in this state.

The passenger seat

The seas had been hand painted by someone over the years.

 I had the springs and the seats cleaned down to the metal. The seats were painted cream and the springs were chemically blackened.

To fit the rear seat, I greased the rubber bushes and fitted them onto the seat first. Then I attached it to the rear fender.

Wiring the tail light

When I had the rear fender painted, I had the holes patched. Over the years the someone drilled many holes and added a bad patch. I thought it would be best to have the damage correct.

I drilled the holes new and wired the lamp.

Bolting in the rear wheel

With the rear wheel properly assembled, it was time to bolt it onto the frame.

It slit into place easily and bolted right on. It looks fantastic. The colours are beautiful and the new shiny nuts sparkly nicely.

Trouble with the rear axle

My garage is partly open to the weather. It is dry but very cold in the winter. I gave myself the flu while working in there a few months back.
After 2 months of freezing weather and holidays to warm countries, I continued work again on the Nimbus.


I had a lot of trouble assembling the rear axle and shaft gears.

I discovered that I should NOT grease up the rear shaft hub. Don't do this:

The grease nipple on the side will allow me to add grease later.

When I put the whole thing together, the wheel would not turn. It was all too tight. There several reasons for this. Too much grease in the hub and I forgot to add the shims below the bearing race on the shaft bearings.

Several months ago when I put shaft bearings in, I forgot to add the shims below the lower bearing race.

I had to take it out again. After several attempts with the torch I was able to get out both races. The paint was ruined and I will have to touch it up.

I also had to steam clean the bearings again and re-grease them.

Rear wheel assembly

Greasing up the bearings and inserting the axle.

Greasing up the shaft drive receiver parts... don't remember their names:

Bolting it into place.

At last the cover.

Cam shaft reassembled using engine assembly grease

I coated all the pieces with engine assembly grease then put everything back together.

Adding the extra O-Ring to the rocker arms

John come up with the idea of placing an o-ring at the base of the rocker arm before you add the paper gasket. This will further protect against leaking.

Valve lapping

Craig at Scooter Works told me I had to 'lap' my valves and explained how it increases compression.

I bought the lapping sticks and the grease and went to work while watching old episodes of Star Trek TNG.
Removing the spring and then replacing them was very quick this time.

I first used the course and then the fine grit. The results look good. The top one below looks good.

A lot of improvement can be seen on the right one. The left one has not been done yet.

Ultrasonic cleaning of the carb

I have my carb cleaned using an ultrasonic washer.

Here are all the pieces:

Here it is back together: 

Some parts in the diagram I do not have (circled in red). Some of these parts are for different models of the carb. 

Font wheel speedometer screw

To replace the front bearings, you have to remove this screw. It is reverse threaded so it must be unscrewed clockwise. There are arrows on it to show the direction to remove.

You need a special tool to remove it. I don't have it yet. I just ordered it. I tried to remove it with other tools and by heating up the housing, but it just doesn't work.  Now I must wait for the delivery.

Drive shaft bearings - removing / replacing

Thanks to Scooter Works (my friend's classic scooter repair shop) in London, I learned the trick to removing and replacing the bearing outer rings.

Because the outer metal casing is cast and the bearings and rings are hardened steel, the outer metal casing heat up quicker than the bearing ring.

Heat up the casing with a torch. When it is hot enough, you can just pull out the ring.

Replacing the rings is even easier. Heat up the housing, freeze the bearing ring, and it will just drop in.

The bearing must be completely greased up before dropping it back in.

Here are the bearings and rings.

Heat up the casing.

Freeze the bearing ring.

They just drop in without any effort.