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KM20 Running

I got so oil, made up a fuel cell, and started kicking.
I got it running. An old rats nest along with peanut shells exploded from the exhaust pipe.
Made a mess of the shop, bits of burning nest and peanut shells. Got that mess cleaned and went back to the bike.

It runs, just not very well. I have to work on the carb. It is starving for fuel. Probably air leaks in and around the carb and maybe the jury rigged tank.
Anyway it runs and it will only get better from here. The magneto may also be a little weak.
Thanks to everyone who reached out with advice.
Hopefully another one back from the dead.

email (option): cbhaws@verizon.net

Re: KM20 Running

Update
The fuel problem was with My jury rigged fuel tank. Got that sorted and we got on the right track to tuning.

So for a few questions

The only Non-detergent oil I could buy today was 30 weight. I did not run the bike long or even put it into gear. It was at no load. I have ordered AeroShell 50W non-detergent. Temperature is in the high 80 to low 90’s. Man it is hot.

I have a tell tail I just hooked up. It shows no pressure.
The oil is being circulated from the tank to the engine and back again. It has a good flow.

How much oil should be flying around in the valve compartment? The one behind the stacked rifles? I was running with it open and not much oil was entering. Everything had oil on it but I thought oil would gushing around?

All oil was drained out of the engine oil tank, and transmission. The chain case has a red fluid in it. I suspect transmission fluid. Is this OK?

It idles nicely, but right now coughs at sudden full throttle. The throttle needs to eased on. I need to hook up a big fan and do some more tuning. Did not want her to over heat. I saw 350F on the exhaust header and 275F on the head.

The bikes exhaust is surprisingly clear. No blue or black smoke.

Hopefully we are done with blowing rat turds and grass out the exhaust.


email (option): cbhaws@verizon.net

Re: KM20 Running

Charlie the oil pressure on these is very low! Something like 8 PSI if memory serves. It's fed from the pump to the cam spindles and big end roller bearing....The rest is basically mist feed. As long as it's returning is usually good enough.

ATF in the primary case is ok. It's a dry clutch and just lubricates the chain, cush drive and clutch rollers. The book calls for ordinary engine oil.

There is a sprung loaded ball valve situated behind the plug at the bottom of the timing case. You might want to take it out and give it a good clean up with WD40 and a cotton bud.....Or similar! Fit a new ball and give it a sharp tap with a skinny drift to create a good seat..... When these leak it can allow the oil in the tank to slowly drain into the crankcase "WET SUMPING" Ron

email (option): ronpier@talk21.com

Re: KM20 Running

The anti drain valve is on the feed side of the system 'downstream' from the pump and operates at approx. 7 psi when the spring loaded ball lifts of its seat....The pump can deliver a pressure way over that when pumping against a 'blind' gallery, around 60psi before oil starts to bleed back past the gears due to back pressure....

However, once the anti drain valve is off its seat it is an 'open' system which does not rely on high pressure like an engine with white metal big end shells...The system just needs the right volume of oil and the operating pressure is negligible...

Oil feed to the valve guides etc. is through a hole in the top of the crankcase face inside the tappet chest. The supply is in the form of oil mist that is forced up through the hole as the piston descends on the downward stroke... After the engine has been run for a while there will be a little residual oil at the bottom of the tappet chest but it is basically empty as any accumulated oil drains back through the supply hole...With the tappet cover removed and the engine running you will hear the air movement but it takes a while for any oil to become visible on the exposed surfaces...Ian

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

Re: KM20 Running

Ian Wright
The anti drain valve is on the feed side of the system 'downstream' from the pump and operates at approx. 7 psi when the spring loaded ball lifts of its seat....The pump can deliver a pressure way over that when pumping against a 'blind' gallery, around 60psi before oil starts to bleed back past the gears due to back pressure....

However, once the anti drain valve is off its seat it is an 'open' system which does not rely on high pressure like an engine with white metal big end shells...The system just needs the right volume of oil and the operating pressure is negligible...

Oil feed to the valve guides etc. is through a hole in the top of the crankcase face inside the tappet chest. The supply is in the form of oil mist that is forced up through the hole as the piston descends on the downward stroke... After the engine has been run for a while there will be a little residual oil at the bottom of the tappet chest but it is basically empty as any accumulated oil drains back through the supply hole...With the tappet cover removed and the engine running you will hear the air movement but it takes a while for any oil to become visible on the exposed surfaces...Ian
Many thanks to Ron and Ian,
I should be getting my 50W oil in a few days. Then it is riding time.

The video on how to start the bike was great. My bike is a little hard to turn over. When I get her to the compression stroke and engage the exhaust valve lifter the bike still has high compression. I check to see if the Exhaust valve is lifting and it is. Just still hard to only move a few inches past TDC. I have been stomping on the kick started and hoping for the best. So far no kick backs. This bike needs boots on to start it. I got to get my jungle boots out with the steel shank to protect my arch. Which is sore this morning.

Today the fuel tank has been conditioned the 96 hours required for the POR-15 coating to fully cure. Time to fuel her up and go for a short ride.

Are there any bronze or brass parts in the transmission? I use Redline transmission oil in my modern Harley-Davidson’s. It sure makes the Harleys shift quieter and easier to find neutral. By the way the stuff is bubble gum pink. After some more research I may give it a try.

A big thanks to all who have made suggestions.

By the way I do WWII re-enacting as as a member of the 1st ID, the Big Red One. I portray the 1st Recon Troop Mechanized, high boots and all. I am looking to get a set of British shorts and shirt in the North African Campaign style. This year the shows have been canceled in the US. Getting ready for Reading PA next year. I may contact the British group who sets up just down for us. They may want to display the bike at the event when I am not using it for crowd and convoy control.

email (option): cbhaws@verizon.net

Re: KM20 Running

Again ordinary engine oil for the gearbox 40 or 50.

If the engine has "wet sumped" the oil can cause drag on the flywheels making it harder to start. The answer is to drain the crankcase first. But since you've had it running with no smoke, I assume it's not the case? Ron

email (option): ronpier@talk21.com

Re: KM20 Running

Charlie, I had heard that in the USA, you can get 30 and 50W old-style oils at anywhere that sells supplies for farm machinery. Farmers use it on their old tractors of course.

Re: KM20 Running

There are a lot of bronze bushes in the gearbox so modern Hypoid gearbox oils are not recommended...As Ron says, your 50W (or alt. 40W) engine oil is the correct thing for the BSA gearbox with the ambient temperatures you are running in...

If you are absolutely sure the valve lifter is lifting the tappet (and valve) I would check the primary chain tension, if it's very over tightened it can make the engine stiffer to turn over...The engine should turn over very easily with the valve lifter raised...Ian

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

Re: KM20 Running

Ian Wright
There are a lot of bronze bushes in the gearbox so modern Hypoid gearbox oils are not recommended...As Ron says, your 50W (or alt. 40W) engine oil is the correct thing for the BSA gearbox with the ambient temperatures you are running in...

If you are absolutely sure the valve lifter is lifting the tappet (and valve) I would check the primary chain tension, if it's very over tightened it can make the engine stiffer to turn over...The engine should turn over very easily with the valve lifter raised...Ian
I will check out the exhaust valve lifter again. I did open the gap a bit as it looked to close. All the book says is clearance. I suspect as thing heat up the gap closes so I wanted some room for comfort. Maybe toooooo much room. The fellow who owned it three owners said it was always hard to kick. I was working on the kicking process before it had any oil in the gear case or engine. I will check the chain case next.

Am 6”1” and weigh about 195 pounds so kicking it without the process is not a big deal for me. That is if it starts on a kick or three. I saw the video with that easy kick through. I need to get mine to that state because I am 73 and sooner or later I will need a new right knee.

email (option): cbhaws@verizon.net

Re: KM20 Running

Years ago New Jersey was called the Garden State because of all the farms. Not so anymore. Not even Tractor Supply carries non-detergent.
Amazon has AeroShell for $100.00 a case and two weeks delivery. I used to AeroShell in my Piper Cherokee many many years ago.
Aircraft Spruce Company has it for $44 dollars a case and two day delivery UPS for a $17 USD. Sometimes Amazon is a rip-off.

email (option): cbhaws@verizon.net

Re: KM20 Running

Years ago New Jersey was called the Garden State because of all the farms. Not so anymore. Not even Tractor Supply carries non-detergent.
Amazon has AeroShell for $100.00 a case and two weeks delivery. I used to AeroShell in my Piper Cherokee many many years ago.
Aircraft Spruce Company has it for $44 dollars a case and two day delivery UPS for a $17 USD. Sometimes Amazon is a rip-off.

email (option): cbhaws@verizon.net

Re: KM20 Running

It's often difficult to achieve the amount of clearance shown in the manual for the valve lifter and still get it to operate (lift the valve off its seat)...Clearances do not reduce very much when the engine gets hot but it is important that there is some clearance between the lifter and the tappet head when the exhaust valve is fully closed...

As long as there is minimal clearance and the tappet head is free to rotate with the engine at working temperature that's OK...

Because of the 'silencing ramps' on the cams the valve is only fully closed for a very short amount of its rotational movement. Therefore, always follow the same procedure as you would when setting the tappet clearances to ensure it's in the correct position before making adjustments to the valve lifter...ie When the inlet valve is closing and the inlet tappet just becomes free to rotate as the valve spring pressure comes off it, the exhaust is fully closed...

It can be a test of patience to get it right but if you have an M20 with good compression it definitely needs to be operational...Ian

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

Re: KM20 Running

Ian Wright
It's often difficult to achieve the amount of clearance shown in the manual for the valve lifter and still get it to operate (lift the valve off its seat)...Clearances do not reduce very much when the engine gets hot but it is important that there is some clearance between the lifter and the tappet head when the exhaust valve is fully closed...

As long as there is minimal clearance and the tappet head is free to rotate with the engine at working temperature that's OK...

Because of the 'silencing ramps' on the cams the valve is only fully closed for a very short amount of its rotational movement. Therefore, always follow the same procedure as you would when setting the tappet clearances to ensure it's in the correct position before making adjustments to the valve lifter...ie When the inlet valve is closing and the inlet tappet just becomes free to rotate as the valve spring pressure comes off it, the exhaust is fully closed...

It can be a test of patience to get it right but if you have an M20 with good compression it definitely needs to be operational...Ian
Ian
I can not agree more. I was adjusting this morning at 5am my time. Could not sleep any longer. The older I get it seems the less sleep I need. It should be the other way around. Anyway, when adjusted I just get compression release. The way the lever was set-up on the handlebar it was hitting the clutch bracket. Plus the cam on the handle bar lever my be a little worn. It is hard to get enough take up so the valve lifts and the valve not having enough clearance when the lever is released.

The problem with this bike being hard to kick is great compression and not enough lift. Seems Like at three owners just suffered with the problem.

I will keep fiddling with it until I get it perfect.

Thanks

email (option): cbhaws@verizon.net

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