Ariel KG500 Rebuilding

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Ariel KG500 Rebuilding

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First Renovation

Kg500 tank.jpg

Old post card showing the type I am trying to rebuild (this is how its supposed to look like).

The 21.06.2001 at about 20.00 in the evening, the motor was started for the first time. And might I say, it was sweet sound to my ears. The great assistance from Jan Jensen, is greatly appreciated. and will (weather he likes it or not (-: ) be rewarded.

Soon there will be some photos of the bike fully assembled.

All it actually required for the motor to run, was switching the ignition cables, and fitting the carb., but a checkup from a person who knows these bikes is not in its way.

During restoration:

After the restoration (still missing the tank though):

Second restoration of the motor 30.09.2001

Next is the timing chain etc. Start by removing the generator.

remove the outside of the roller barring of the crank case, by gently heating the barring part and surrounding metal with at flame torch - When heated, get some ice cubes and place them in 1 or 2 plastic bags and rub them against the inside of the barring - With a little help, the barring is easily extracted

Close to assembly of motor

A new barring is made from correct lead-bronze, and is line bored in the crank case.

At this point I can hardly turn the crank shaft !!! I discover a line on the crank shaft, that was not previously there - Something is wrong.

It turns out that the new screws that I bought from Draganfly, for mounting the oil pump is slightly longer than the ones originally used, so a slight modification was made for this screw.

Actual breaking point measurement was done by letting a small current go through the dynamo. The wires were connected to each side of the breaker, and a Amp meter was connected in series with the power supply. This way it was easy to monitor when the the breaking points went apart. (it can be done simpler with a small light bulb, and observe the dimming of the light, as the breaking points go apart)

Do not use large currents, since this will damage the dynamo. I used something in the order of 100 mA. But the larger the currents, the bigger the difference in open/closed reading.

The manual says that: ....... Braking points should break at 4-8 Degrees After Top Dead Center....... In Advanced position, this should produce a 30 Degrees Before Top Dead Center. - If a mismatch should occur between these 2 figures, then go for the 30 Degree part.

But the trouble is, that I made some measurement data, which gave the following results: Degrees in Retarded position Degrees in Advanced position 4 Degrees 36 Degrees 8 Degrees 34 Degrees 12 Degrees 30 Degrees

A discussion was made on the [AOMCC] groups, and I concluded that the 30 Degrees Before Top Dead Center were the to go for. This was the opinion of everyone. The course of the timing problem, can - as far as I believe - only be the Auto advance unit, since this is the only variable in the system. If this was not the case, then the fault would have to be a change in the ratio between the exhaust camshaft gear and the Auto advance unit (not likely).

I have been offered a brand new BTH unit from Victor Horley. The unit is mounted when I get it home.

The AutoAdvance Unit

I received a new old Auto-advance unit from Victor Horley, which really did the job.

When the unit were dismantled, I measured the balls, which were Ø = 14,3 mm and Length = 14,3 mm. (The weight - which is the most important one was not possible to measure, because I do not have a weight that accurate)

The old unit advanced about 40 degrees on the dynamo, but the new unit did about 30 degrees (need 34 - 38 degrees according to book). So I adjusted the auto advance unit slightly, to make it move the 4/2 = 2 degrees more. This was done by removing material from the metal arm bended downwards in the picture below (done in all 5 places) Be carefull not to take too much, and you will not be within the limit described in the Workshop manual.


I obtained a 4 degrees ATDC, with a 30 degrees BTDC in full advance.

Thanks Vic.

AMAL 276

Restoration of the Amal 276 Carb. The pictures below shows the state it was in when I started renovating - I got the Carb from Henrik Larsen:

Not a pretty sight, but that the fun part - to bring this Carb. to a worthy condition.

The Carb. was first washed with a toothbrush in ordinary soap water. Then I started to remove the old paint with fine steel-wool in soap water (only to the outside). After some time with this., I managed to get it to look like the pictures below:

(Now I can actually see the type number - 276 FW/1B )

The external parts are now close to ready (needs some polish) - This is the result:

None of the internals are checked, and I quickly identify that the slide is extremely worn (can move slightly sideways in Carb.) This is fixed by getting a replacement slide. This does not fit - so the slide have to be carefully sanded to fit.

To get most control over the sanding speed, I use some 220-paper to make it slide with force, and then I switch to a 512-paper to adjust. You can se where to sand, if you take a permanent marker and color some parts of the slide, and then slide it in and out of the main body of the Carb. This way the marker will be removed where the slide hits the Carburetor wall.

Dynamo Toast

I have completely forgotten to look at the electric circuitry, since the lights went out on the fatal trip last year. After dismantling the Dynamo, I saw that the armature had been so warm that the soldering tin has heated beyond fluid and have been centrifuged off the armature, to form a ring on the inside of the dynamos shell!!

And the Field coil did look a bit suspicious, so I ended up giving the dynamo a complete overhaul.

Remember - If you ever encounter this phenomenon on your dynamo, and you are planning on fixing this your self, then remember to check the bush plate (plate where you mount the coals), because the heat generated will make the bush plate brittle, and will break under little stress. This should changed.

I will try to make an autopsy of both the Field coil, to se if it is possible for a mortal to make one by off the shelf products.

--- MCR2 RB107 "Motor Cycle Control Box" ---

When looking closer at the electrical circuitry, I needed to know more about the charge relay box, so I came across the following PDF documents on the net:

Lucas Workshop Instructions for "Motor Cycle Control Box" - TYPE: MCR2

Lucas Workshop Instructions for "Motor Cycle Control Box" - TYPE: RB107

Misc + OilFilter

I finally got time to push the kick starter, and what a rush - When Looking back at the engine completely dismantled, and you wish you were out there riding the bike, its finally time to sit on it, and enjoy the ride, instead of laying below it and changing the oil pump.

The oil pump issues was the last thing that caused trouble:

When I started the motor for the first time, it took some time (and little more throttle) for the oil to reach 25 lbs as prescribed in the Users guide, but when riding it at increased throttle, it would stay at 25 lbs. When I go to idle it would fall to about ZERO!!! - Do I need to say that I stopped the ride.

I had an idea to what was wrong, and I looked at the previously taken pictures (LINK) because I was a little concerned about the oil pumps new gaskets. These were of the normal gasket material, and when measured, it proved to be 0.4 mm thick, but the original gasket (that I didn't throw out) was only 0.15 mm thick. The oil would more or less circulate within the oil pump.

I removed the oil pump from below the engine, and replaced the gasket with the old gasket, and that did the trick. When I started the engine, the pressure would climb to 25lbs immediately, and when a little throttle was applied, it would touch the next marker on the meter.

Having experienced the wet-sumping, I decided to solve it for good, and while I was at it, wanted to fit a Oil filter:

(This has not been fitted, as the oil pump delivered from Victor Horley was able to stop the oil flowing to the engine)

Sprocket change

Oil Cooler + Small Problems.

Experiment with finding an oil cooler have resulted in the following device:

I found an oil cooler on the net that used to fit the Honda DAX mopeds, I removed everything except the cooler, and then removed the DAC bracket and created my own for fitting on the Ariel frame.

Changing front procket to 24 tooth on the KG.

Why NOT to use run on try primary chaincase !!!!

Underslung position lights are in some cases overslung...

Short Movie of Running Ariel 1

Short Movie of Running Ariel 2

Short Movie of Running Ariel 3

New Oil presure gauge.

New Oilpressure Guage -> 0-25 PSI, Eureka, reproduction, but needs to find the right Oil tube fittings.

New tank and fixing the head.

I was certain that I was suffering form blowby, and needed some new pistonrings, so to make things complete I decided to give it a Top and barrel Overhaul.

This is the Head and pistons before:

This is afterwards:

And now for fitting:

Draganfly has new tanks made from india. these are in very great condition, and comes fully cromed.

Checking the gearbox for excessive Greasing, and yes there were too much..

Cleaning out the axcess grease.

It ws found that vibrations at high speeds were due to worn bearings in the gearbox, so i finaly took it apart for complete overhaul:

the reaming and fitting of end bushes were done with help from Henrik Larsen, and making and fitting of new mainshaft bushes were done with help from Torben Olsen.

The raw panel from draganfly has now retruned from the cromer, and can be seen here loosely fitted on the panel tank. Waiting for complete assembly when the speedometer cable and DC40 trouble ligt arrives from draganfly. Please note the nice Speedometer I got from Henrik to complete the KG500 Project.

Roller Bearing Conversion Modification to Ariel KG/KH 500.

First of all I need a donor Bottom to experiment with. for this purpose I have accuried the following parts with great help from Mike Robson.

The Crank needs a little further investigation weather it is suatable or not, as the surface for the connecting rids looks abit modified. and might have been too modified to my tast:

The Left side Half of the case looks like NOS, and will not be modified at all. Ath Rigt side will be modified to accomodate to the new bearing: The Bearing that is going to be fitted is the INA.NKIB 5906 (C3) bearing which is a Normal roller bearing as well as a thrust bearing. This means that no shimming is required as it also is hold in place in the axis direction, This is the specifications: Dimensions (metric) d 30

F 35 D 47 B 23 B1 25 Approx. Wgt. lbs .340 Interchange FAG DNJB 5906 INA NKIB 5906 SKF (Eur.) NKIB 5906 SKF (EUR. Old No.) NAXB 5906

As can be seen from the drawing above, the Crank case will have to worked to give room for the Outer diameter of 47 mm, where the normal Diameter of the bearing to be placed in the case is 41,25 mm, so the hole in the crank will have to increase its diamter with about 5,75 mm. This leaves sufficient material to be left in place, and it must be remembered that the Bearing is made of steel, so alot of strength is maintained there.

The Crank will be re-groung to a Diameter of 30 mm, where it originally is about 31,8 mm. No problem here either.

I have made CAD drawing of the Setup only involving the replacement Bearing for the moment, but it will be revised to show the Oild feed as well, when I find a Timing cover so I can measyre the Space available:

Rev 1.00.01:

Download the CAD file containing the complete drawing: rev_1.00.01.cad, If you want to view it, you can use the free cadstd software, used to draf this file. Its simple, Nice and completely free..

Rev 1.00.02:

Now included the Original Design as well for comparison:

Or download the CAd file direcly here: rev_1.00.02.cad,

The big question is getting the oil pressure into the crank, but I have a couple of suggestions to how this can be done. Natually it will have to gi in through the end of the crank, but for Authentic reasons I will NOT settle for a solution that will require me to drill holes in the outer timing cover.

More to come soon. But It will be possible to make this modification. If you have any thoughts on this or any suggestions Please drop me a line.

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