Heyo gang,
So, I am finishing up the little touches to get my beloved 1944ish BSA WM20 ready for a restart.
Back story:
About 12 years ago, I had to go off for my new career (duty calls!) which basically meant the new Amal carb and bits I had installed then, had to wait. A long time. She sat safe and sound and dry under a cotton cover inside my (heated and air conditioned) home for the last 12 years staring out my sunroom door to the beautiful forest out back - so not all bad.
Fast forward 12 years, with Covid19, I have had ample time to sit down and fix things up.
All new cables (all of them)
Petrol tank empty and clean
Carb clean and inspection (Brand new, never run Amal carb)
Petcock modernization and new rubber petrol lines with filters and such
Electrical check up with new bulbs (still sorting)
Fresh Oil and a clean filter for the engine, tranny, and primary case
Thorough Clean and lube the chain
New Pannier bags.
Tires still check out as good LOL (no cracking!)- they only had 50km on em and still nubby.
So, with it having sat so long, I want to make sure I minimize damaging an engine that has sat for 12 years or so.
My thoughts: New Spark Plug (NGK B6HS gapped to 0.18")
A touch of oil (Or I have read WD40 or Automatic Transmission Fluid) in the engine combustion chamber to help lubricate the piston.
Suggestions on proper steps I should follow before giving her to old tickle n kick?
Brad
email (option): You can look me up in past posts :)
If it has sat bone dry for that long has the mazac body swollen, so maybe drop the oil pump and check for full and free rotation?
In similar circumstances recently I took the plug out squirted some engine oil into the bore, then turned the engine over until I could see oil returning out of the tube that the filter sits on. That made sure that oil was in the pump and sump for the first firing. You will probably have to kick it over dozens of times, but it will flow through eventually.
email (option): John.childs1@btopenworld.com
Hello,
Yes, I think John Childs' advice is good. The thing to think of is that anything engine, gearbox or clutch related will need oil for those first few moments of start up, or you'll do some damage. Make sure everything has oil: bores, valves, primary, and gearbox. Then kick it all through a few times. Let it stand if you can, so the oil can get into the crevices. Have a drip tray ready because you'll be overloading the system and the excess will tend to splash around (especially at the breather pipe) when you do start up. You should probably regrease the forks etc., as well.
I once had a wm20 which had stood for a couple of decades and the gear selectors had rusted in place, even though plenty of oil was to be seen in the bottom of the gearbox. I could have just filled the gearbox with oil, kicked it through and left it for a month or two, I suppose, but I elected to take it apart. The rust had done no real damage.
Enjoy your bike!
Allan
email (option): allanmatchless@yahoo.com
Hey gang,
So a quick update on things.
Took your advise and put a 1.5 capfuls of engine oil (precise measuring!) into the combustion chamber. Also Replaced the sparkplug with an NGK B6HS (which I still have to gap to 0.18" before tightening). I also cycled the engine a number of times (no compression) and I do in fact of oil pump operation, within the first 2 or 3 turns.
Some more for you, which I found concerning.
Backstory - I bought the bike from some guy in the USA 14 years ago. I tore it all apart, cleaned it up, replaced a pile of stuff, and re-assembled it. I didn't rebuild the engine as well, it ran. That new oil was the stuff I emptied 2 days ago. So it was old. However that also meant the 50-100km on the engine (Odometer didn't get rebuilt/didn't work), was the same as what was in the oil filter.
So I cleaned the oil filter in petrol today, and noticed some very small metal filings. Silver in color, and is easily picked up with a magnet. Metal fragments (0.1mm and smaller / very very fine) in oil filters always came out in the petrol wash.
This has me concerned. I do not suspect filings this small to be normal, or is it expected in the oil filter? I should note these filings would have accrued from the time it was ran about 12 years ago.
Or is an engine rebuild in order?
Thoughts?
Brad
email (option): You can look me up in past posts :)
In other news, with the recent oil fills in the engine and tranny, I have sprung some minor leaks I am looking at fixing. Mostly on the transmision - a very very small leak from the kick starter shaft, and a more significant one come from the primary output side at the drive chain (self lubricating chain anyone?)
Brad
email (option): You can look me up in past posts :)
The metal fragments in the engine could be there from any time in the past...They might come from a currently failing component but equally, they might be left over from a previous engine failure where someone was lax in cleaning out the crank cases and the filter...
It might have had the valve seats recut in situ at some point...Recutting seats was a common procedure in those days and it can be done 'in place' with a side valve...Contamination in that case is hard to avoid to a degree....
It may be that the crank nut has come loose at some time and the fragments are from the main bearing spacer on the drive side, which will wear away in that event...
I think I'd be inclined to clean out the filter, run the engine for a few miles, perhaps with a flushing oil and then check everything again..If it looks OK, or there is less contamination, do it again and see how it looks after, say, 100 miles...
It would be a shame to rush into a rebuild if it's not really needed....
The leak from the kick start shaft/bush is probably just caused by wear of the shaft and the bush. The bush is hardened steel but both parts will wear over time.. Also, they don't wear evenly as the kick start never does a full rotation..I have fitted a small O ring into the tapered part at the rear of the bush...It is held in place by the quadrant when it is inserted...
I also ground a very small radiused groove into the quadrant shaft on one bike and fitted an O ring to that..I was worried initially the shaft might snap at that point (though it is at least 1" in diameter)..It never caused a problem though...
The gearbox will leak until you fit a sealed bearing at the drive end (with the inner seal removed). M20's predated modern oil seals and sealed bearings so the oil retention features are both crude and ineffective by modern standards... The bearing number is 6207 2RS and it's metric so readily available....However, the M20 gearbox can be a sod to get operating nicely after a rebuild so I'd save that for when you want to do something else to the box, or perhaps if you have the primary drive off the bike...
The leak won't do the gearbox any harm as long as you keep it topped up..I would recommend checking the oil level in the box at about 300-350 mile intervals......Ian
email (option): ian@wright52.plus.com
Hey guys thanks for the answers. Brad, thanks for the questions.
I just got my KM20 running after long inactivity. Also not sure how it was protected. I did the oil in the engine. Cleaned the carbon off the intake valve, rebuilt the carb including lapping the leaking float needle, now it runs very nice.
BUT my transmission is leaking. Looks like I to have the automatic chain Oiler. I suspected that seal. Thanks for confirming that and mentioning that it is not an easy job.
Brad, good luck on getting her going. I need choke, three kicks with compression released and throttle open. Choke off, ignition advanced, 1/2 throttle and a good kick with it just a little past TDC.
Starts usually on first kick. Sometimes I need some chock even though it has been very hot here. Once it it running for about a minute no chock required.
Good luck
email (option): cbhaws@verizon.net