|1947 Matchless G80|
Carburettor : 89B/1AK
When an engine becomes very sloppy it needs tightening up. Sloppy engines are glorious but broken ones are not. So the G80 has a new big/small end, piston, bushes, valves/springs, gearbox bearings, sprockets and chain, voltage regulator, gearbox bearings and tyres. Also there are plenty of other odds and sods to make it as good and as reliable as possible. The oil pump worm gear was very broken and it's a wonder that it worked at all so for this reason alone the call to rebuild was justified.
This Matchless has a very soft engine which makes it perfect for green lane work and will pull from very low revs without any fuss just like a steam engine. There are no flat spots or vibration zones and the motor spins like a Swiss watch when cruising. In fact the good manners and docile capability of the motor could make the rider winder if this was a 350 at times but as soon as the throttle is opened the extra torque of the 500 makes itself known. This chuffing docility is almost like a side valve but without any of the 'flatness'. The motor usually spins into life at the first kick whether hot of cold and the retard lever can reduce pinking when climbing hills. Cruising speed seems to be in the 40-55mph zone and the exhaust note is a non-offensive dull thud which only seems to frighten sheep. Accelerating hard reminds you that this is a 500 OHV.
The cycle is a little high and a little heavy when coming from earlier machinery but would probably be lower and lighter when coming from more modern machinery which just goes to show that any motor cycle test is as much about the bike you've just stepped off as the one you've just mounted. The riding position is extremely comfortable and the teledraulics and saddle springs make the ride very easy on the bones. The riding position almost feels like an off road bike and it feels at home on the rough. The brakes are fairly good and are easy to use. There was some strange weave felt at the front when approaching 60mpg but this could have been due to high winds. Handling is fairly neutral and any rider who's in not too much of a hurry will find swinging through the bends to be very relaxing.
The clutch is light and has no bad habits. Although Burman gearboxes are generally crunchy and slow, this one feels almost like it's new and neutral can be found easily in any circumstance. Ratios are well chosen for 'green laning'. (I have since 'upped' the gearing by one tooth  and this is even more comfortable for the G80)
Everything works as it should and it is a pleasure to ride. It reconfirms my belief that 1940s motorcycles are the best 'well kept secret' in the old bike world with their all round good manners, low stress design , mostly cheap and available spares and a charm which became lost somewhere in the 1950s. Who needs and exotic when you can have one of these?
17 Aug 2008 - Delivery : I have just taken delivery of the Matchless today and took some photos before doing anything else. Then the cleaning started. The petrol is old and smells bad so that will be replaced tomorrow. I've cleaned the magneto pickup brush and soldered the HT cable pickup disc. The paint comes up quite well and so does the alloy. The magneto delivers a good spark so there is no reason why it shouldn't start. There is compression but not that much so maybe the rings are a bit gummed up or maybe the bore is worn. One of the fork legs has a repair where the mudguard stay attaches. Much if the paint is original factory paint which is a good reason not to restore it. The cables are being oiled at the moment and everything needs lubricating. The battery is dead but the electrics seem to work ok. The oil is about to be drained and replaced. There are grease nipples all over the bike and these need a good splodge of grease. The wheels are about to come off to inspect and grease the bearings. I'll post more photos soon when it's been cleaned up and taken for a test ride against a scenic backdrop.
20 Aug 2008 - Firing Up : A package arrived from AMC Spares this morning which contained a few goodies and it was time to fire up which it did quite easily and the exhaust note is fairly subdued for a big thumper. There's no great flood of oil when the motor is running and the motor settles down to a good tickover. There is a certain amount of engine clatter but nothing too alarming for an old motor. I took it up the lane to see how it works and everything did work fine except the front brake. The clutch works well and neutral is easy to select. The back brake is good. But the front brake is horrendous!
28 Sep 2008 - First Proper Test Ride : After fitting new front brake and clutch cables and sourcing the 'correct' headlamp glass it was time for a discovery ride. At last some sun and some time. The Matchless fired up right away and was taken for a test ride around the countryside. At first the engine seemed a bit clunky and slow but after a few miles it seemed to blow away the cobwebs and became quiet and very soft. The punch seemed to increase after about ten miles. The clutch slips when the throttle is opened too much and the brakes are almost useless. I could have ridden for many more miles but the brakes became worse! I can't wait to take this Matchless on a proper long ride now, maybe to Lands End and back and just need to sort out those brakes. All engine restarts were first kick. The handling is stable and the ride comfortable. I like it a lot!
12 Nov 2008 The back wheel came off today. The rear brake shoes are very greasy and will be sent for new linings.
17 Dec 2008 The wheels are on, the brakes work quite well although they have a certain woolyness to them as you might expect but they do scrub the speed off quite well and are good enough. The hubs have had their grease changed with lithium grease. The big news is that it passed its MOT today! Let the riding begin.
19 Dec 2008 Today the G80 had its first proper road test. Everything seems to be working very well and there is nothing that lets the bike down in any way. I did go off road but with road tyres it's not a good idea although it does seem to like mild mud plugging but is far too heavy for serious mud plugging. The motor is very smooth and cruises in the 40-55 range. There is a strange steering feeling as you approach 60mph which needs investigating and may just be tyre pressures. I've received a package from AMC Spares with a new rear wheel spindle to replace the worn spindle and a new rear stand spring as the current spring has lost its mojo which makes the stand clunk around.
20 Dec 2008 Today the G80 had a second test with a long ride around Exmoor. We were in the clouds when on top of the moor and the air was full of mist. Everything continued to work well until near the end when there was some fuel starvation but this will probably be some dust in the tank blocking the float needle so I may have to use some tank sealant to fix this. Apart from that the trials are over.
March 2009 The rear axle (bent) was replaced as well as the rear stand spring. The rear lamp has been replaced with a Lucas MT211. The silencer mounting has fractured and bee repaired but I am looking for the original silencer which has a different type of mounting.
Spring 2010 The engine is quite worn and before the summer comes it's a good time to give the G80 a birthday. The refurbished parts include... New big end, small end, engine bearings, rebore & piston, valves & springs, gearbox main bearings, tyres, voltage regulator, battery, regulator, sprockets & chain.
Summer 2010 The Matchless is back! I have run him about 40 miles but the exhaust valve train has gone slack and I suspect that there is something wrong with the valve lifter mechanism which I need to examine. It is silky smooth and fells almost like a new bike. I really should have had the carb rebuilt at the same time because it has a slightly flat spot low down which I think is due to slide wear. (Update. The carb has been rebuilt)
Spring 2011 The exhaust valve has seized twice now and in both cases the pushrod was bent. The guide was found to be tight and has been opened to a clearance of 4.5 thou. Also, there was no oil reaching the rocker gear. This is the final hurdle and you can find out more about the oil pump blues here.
July 2011 The G80 is at last back on the road and is clocking up some running in miles. Running oil is being used and I'll change this for normal oil after 500 miles. Note the silencer has changed to the original type.