I'm running out of patience for running in my Matchless! 500 miles at 30 mph is beginning to annoy me and it got me thinking, did the Army receive their bikes in this condition or were they already run in? I can't imagine brand new bikes being delivered to a front line unit and them not being able to exceed 30mph? How did the military get around this problem?

How many miles have you done on it, I always tell my customers to take it very easy for the first 100 miles which really are critical, then I tell them to just use it after that, but just don't thrash it or labour it up hills. If any faults were going to show up they would probably happen in the first 100 miles.
As to new bikes, they were issued before they went to the front line and were used for normal military use and training before they went to the front line.
Rebuilt engines were run on a test bed at 750rpm for one hour, then 1500rpm for half an hour and finally 2500rpm for half an hour. The Army deemed that at this stage they were run in and finally 10% of engines were run on a dyno for 3 hours as follows
1000rpm for 1hr (no load)
1600rpm for 30 min (10% load)
2300rpm for 30 min (20% load)
3000rpm for 30 min (50% load)
3600rpm for 25 min (80% load)
4300rpm for 5 min (100% load)
The other thing you have to remember is that in the 1940's 30mph was a pretty normal speed, it now just seems inadequate as everyone else is travelling so fast!

email (option): davmax@ntlworld.com

Bill I think life was a lot slower in those day. 30mph these days does seem ridiculously slow. But I have seen pictures of WW2 vehicles and motorcycles with 30 mph painted on them. Of course I'm sure a motorcyclist would have ignored this in an emergency.
However, I see no need to stick to a rigid 30mph on a G3! After all it's really only the piston and bore you need to run in. I don't think roller bearings require any. The main things to avoid are over reving or slogging the engine. On a flat road with the engine warmed up and on over run, I would consider a cruising speed of 40 to be OK. Gently increasing the speed at intervals as you get through the running in period.

As has already been mentioned on here. The Villiers JDL engine fitted to Welbikes, were built with greater clearances than the same engines fitted to Autocycles. Simply so that the Squadie could thrash it from day one without siezing it.

Ron

email (option): ronpier@talk21.com

Well that answers that one then, interesting stuff, thanks very much. In my long gone youth, I remember ignoring the running in advice on an old Villiers 1H Two Stroke engine I rebuilt, disasterous consiquences after the first 30 miles! but a 350cc Matchless is a very different beast, so I agree with Dave that 500 miles is a bit excessive. I'm not likely to thrash the old thing anyway. 30mph just seems so dangerous on a modern fast road with everyone else tearing past like maniacs. I've only done about 75 miles so far, but I have run it on the bench quite a lot too.

Something that is frequently overlooked if the entire bike has been rebuilt is the gearbox..an M20 gearbox contains seven bushes that also need to be 'run in' after replacement. As Ron says the big end (unless you have a Royal Enfield) and mains don't require running in. In the engine (M20) there is the piston, rings, bore and small end bush, valve guides and timing side crank bush, intermediate gear bush and cam bushes if they have been replaced...
The running in period should be 1000 miles during which time I will do at least 3 oil changes to remove the material that has worn off the various components.
I recommend the engine be treated very 'gently' for around 250 miles when under all conditions loads are kept to a minimum.
During the full running in period don't allow the engine to labour on hills in too high a gear..in that circumstance drop a gear and allow the bike to climb the hill whilst not over revving it.
As the running in period progresses beyond 250 miles the engine should be exposed to progressively higher loads..for example slightly more revs in the lower gears..but this should only be for brief bursts in the earlier stages.
At 'cruising' speeds run on a 'rolled off' throttle generally whilst occasionally 'pushing on' for short bursts.
As the latter stages of running are reached the loads should be gradually increased towards the upper range of the bikes performance.
The point is that after the initial 'gentle' period loads are progessively, but sensibly, increased. Running for a 1000 miles at 30 mph will not produce the required effect.
The problem with defining running in procedures is one of perception..peoples idea of what is 'working the engine hard' or 'driving gently' are different and governed to a degree by what they think the bike is ultimately capable of and their level of experience with older machines...and there is also the question of patience. To (partially) remove this variable the only answer is to lay down speed maximums for the different stages of running in....though even that leaves the question of how hard a rider accelerates to reach that speed and what he does on hills under load... . I have this problem all the time after returning rebuilt engines (and gearboxes) to their owners. However, after labouring long and hard over a restoration and investing considerable amounts of money and effort into a mechanical overhaul it is crazy to then try and 'short cut' the running in procedure..that is the last, and equally important stage, in producing a reliable and long lasting engine. One final point to remember..if you have rebuilt your engine and are refitting it to an unrestored bike don't forget to thoroughly clean out the oil tank!....Ian

email (option): ian@wright52.plus.com

Now there's a thought Ian, I don't know if the gearbox has been rebuilt or not? It's probably best to assume it has. The previous owner had done several jobs on the bike and the gearbox is suspiciously clean and all seems very tight and possitive. I gave it a once over, but didn't go into it too deeply, so I think I will take the cautious route and carry on plodding around the back roads for a few more hundred miles.

Sorry to dredge up an old post

I am curious, what are the conciquences of not running in new piston and rings?

lots of different oppinions seem to be existing about running in engines.

i saw a whole site that said running in should be done by racing the engine with lots of load, claiming the pressure forces the rings outwards into the bore and making them seat.
or somehting like that.

i know that when i had a 50cc moped if we didnt ru those in the rings would snap ha ha.

but we had a 125cc dirtbike, with 1 thin ring. we didnt run it in.

my brand new chinese pit bike engine came with instructions to take it easy for 2 hours.

last time i did my bsa i went slow for 300 miles
then thrashed it.
it was fine (until an unrelated timing issue melted the piston a few thousand miles later)

what about race engines?

or aroplanes? cant fly slowly for 500 mies ? ha ha

here is a quote from some internet human
"As a matter of fact aircraft engine manufacturers say at least 75% power for the first few hours. The combustion pressure holds the rings out against the cylinder wall and for good seating they want lots of pressure, so that means lots of throttle"

Hi Max,my grand parents both worked at Fords in Trafford park during the war.
The factory was taken over to manufacture Merlin engines,my gran worked in the yard outside where the finished motors were tested.Must have been a daunting experience as after only a few hours,she ran away,home,but had to return next day.
Recalled by my grandad,motors were brought out on an overhead runway and bolted into a frame by fitters.Everything connected,the motor was started and run at
half revs for eight hours.After monitoring for eight (grans job)the motor was taken to full revs for four hours.This was the running in period.The final test
was to stall the motor from full revs with a water brake,to simulate pulling out of a steep dive. if the motor survived this it was dispatched for use.
Quite a few didn't make it,hence my gran doing a runner.
The old chaps job was on conrod inspection,from forgings to finished item.The forgings weighed 11 lbs raw,and 1 lb 4oz finished if i remember correctly.After
measuring,they were weighed within grammes of each other,tied with string,dipped in wax as a set and sent for assembly.
hope this helps
cheers Rick
heres one for you Bill https://www.youtube.com/watch?v=WLOVzgew5Jw

email (option): richardholt@rocketmail.com

crikey wow!!

i bet they dont do that in chinese pit bike engine factories (thats why the crank snapped on mine!!!)


thanks really interesting stuff. total lesson

'Running in' can be mitigated to a degree by increasing clearances at the manufacturing (or rebuild) stage...I used to help building the engines for Britains top pre 65 scrambles rider at the time, who recorded over 700 wins. These were Triumph pre unit twins and were assembled with so much bore clearance that they 'smoked' slightly on start up...It was a case of 'worn' but not quite 'worn out'!!..
Other clearances were also increased and the whole engine very carefully assembled with some parts hand finished to ensure everything was absolutely 'free'...
With Castrol 'R' oil these could be revved right off the bench and raced with only a very short test run beforehand...All fine for a race engine but not a recipe for a high mileage life in a road engine. These race motors were rebuilt more than once during the 'season'....
Modern engines have benefitted from modern machining methods, materials and accuracy and the resultant improved surface finishes, reduced expansion rates and improved lubricants all contribute to the need for a shorter 'running in' period.
With older engines I believe careful running in ultimately produces a good engine and one that runs better so I still carry out the recommended 1000 miles running in period with a 'gentle' start and incremental load increases throughout the various stages.... Also, I change the oil more frequently during that time...Ian

email (option): ian@wright52.plus.com

I think it cant hurt to take it easy for the first 500 miles or so if I am not mistaken there is special oil for running in as modern oils are to good and dont let the rings bed in quickly

email (option): roger.beck@node6.com

Yes it is called supermarket oil
Tesco oil
Walmart oil
etc,
etc,

Now FWIW I gave up on traditional running in years ago.
I assemble my engines dry.
Put on my iding gear and give the bike a clutch start and then it is down the road like I had stolen it.
Find a hill roll the throttle hand along the throttle, up , down , up , down, through the gears, no labouring of the engine & more important , no idleing.
By the time I am back ( 20 min max ) rings have bedded in.
A quick oil change ( carefully filtered & inspected ) and if there is nothing sinister in the oil the & only then do I attempt to tune the engine again keeping idleing to a minimum.

Back in the "old days" I used to flood the engine in oil when I assembled them, then did the "test book" run in and about 1 in 4 needed to be redone.
Dry assembly has been 100% successful.

Bike Beesa
Trevor

email (option): wariron@tpg.com.au

I think we must originate from different planets..I'm unsure how you managed to achieve a '1 in 4 failure rate' by conventional methods or a 100% success rate with the revised version, which doesn't even meet the requirements for running in a new Triumph, Ducati etc...etc...Ian

email (option): ian@wright52.plus.com

yes nice methods

but what is an example of engine failure as a direct result of incorrect piston ring running in??

I've never read so much rubbish in a thread before! Dry assembly? Full throttle etc? Its all bonkers. Ian's way is the only way to go otherwise your engines will be knackered at best or seized solid at worst.

Ian's never steered me wrong before Keith, I don't want to make him blush, but when it comes to motorcycle innards, I have to say that he does seem to know what he's talking about.

Absolutely agree!

One small point though, If you use modern synthetic oils instead of monograde oil then the engine will not be run in in 10,000 miles if ever

Nice comments but really I'm making it up as I go along.. ...I'm always prepared to consider new ideas or new methods though and I've learnt some on this site.
I confess I don't really get this one though....It goes against everything the manufacturers recommended and also what I have learnt and experienced..and I've built a lot of engines over the last 40+ years..

If an engine has been fully rebuilt it isn't just a set of rings to be bedded in..They can be run in, in isolation, relatively quickly. It is the piston, rings and bore, timing gear bushes, valve guides and valves, small end bush and gudgeon pin and other new components such as cam gears, oil pump drive, pump parts,other bushes, even some of the working parts of the magdynamo. Also there are the numerous gearbox bushes and parts to consider as well if that has been rebuilt...However, assuming standard clearances have been applied, I would say it is the piston that is the most vulnerable part during inital running....Ian

email (option): ian@wright52.plus.com

Back in the eighties I sometimes drove to work on a WM20 in military trim, an older colleague told me once that this motorcycle brought back memories to him.
He had been in the military during the occupation of Holland in May 1940 and managed to escape to the UK.
His task as a serviceman in the UK became the running in of brand new motorcycles after they had been delivered to the forces.
So there must have been some (short) running in period for new motorcycles before delivering to front line units.

Regards,
Peter

In the US (judging by the forums), there is quite a big following for the theory of dry piston assembly and thrashing from the first moment. Some big name hot-rod racer published an article claiming more power that way.They are paranoid about bore glazing and burned oil causing rings to stick in the grooves.

There is probably some validity in the idea that modern cross-hatch honed cylinders don't require the sort of running in mileage that used to be allowed but with our old engines and seventy year old pistons, there are all sorts of reasons to take it gently.

Personally, I'm convinced that vertically split crankcases need to go through a number of heat cycles with fasteners re-tightened before they sit together comfortably.

The major advantage to careful running-in in my opinion is that any faults which may develop can be rectified before they become too serious. Better a cylinder which 'nips' than one which welds itself.

Would my valve guides have been better not run-in ? They couldn't have been worse !

Apparently at Nortons during the war, due to fuel shortages, the engines were bench-run for twenty minutes on the local town-gas supply rather than road tested which had been the practice.

The military speed warnings are not to protect the engine - they're to protect the personnel from the vehicles.

30 MPH was a normal speed in 1940? That must have been very dusappointing to the 12 and 16 cylinder Cadillac, Packard, and Lincoln owners...
The Ford Model A 4 cylinder did 50 MPH in 1928, which is why they sold 5 million of them.
The slowest 1940 H-D model - the 45" WL - did 85 MPH.

email (option): sales@victorylibrary.com

I rode an ex war Indian V twin once. It was the slowest thing that I,ve ever had the misfortune to get my leg across

When I was in the army (many years ago) convoy riding in Germany was still VERY slow. Ideal for running in !