Draining sump?

[epatterson]

I was told I need to drain the sump of the flathead I am trying to get back to running order. Stupid question-How? The only bolt I can find that might be the drain is located under the primary right above the frame where there is a "cut out". And when is it appropriate to drain sumps? Every oil change, before storage? Thank you in advance for any help! Eric

[Rollo]

Eric,

First off we need to know what flathead you have. I am going to make an assumption here that you are working on a HD VL???? If that is the case you should have a crankcase drain next to the rear cylinder. It will be a little lever with a spring below it and a catch bolted to the rear cylinder. Put a drain pan under the drain hole and simply push the lever down and hook it under the catch and oil will drain from the crankcase. Should be between 2 and 5 ounces. Once it has drained, close the drain lever and use the hand pump on the oil tank to pump 2-3 pumps back in to the motor. Your done. If you have a UL there should be no need since it has a recirculating oil system, same with Indians. Earlier bikes or other models may be different and others will have to weigh in on those but what I have outlined covers VL,UL HD's and 36 and up Indians. I drain my VL's when they have been sitting for a while. They tend to wet sump into the bottom end and it makes then easier to start and not belch out a ton of smoke until the oil burns off. I actually catch the clean oil in a clean pan and use it as make-up oil for the tranny. Make sure you grease the tranny seal fittings as this is what keeps the oil in there. They have brass seals and need the grease to keep the oil in. You ought to buy a Riders Handbook and Steve Slocombe's book on VL's. Re-prints are readily avaiable of the Riders Hanbooks and you can contact Steve either here or his ad in the AMCA magazine.
Hope this helps.

Tom (Rollo) Hardy
AMCA # 12766

[epatterson]

Thank you for response! I feel a bit silly-of course you would have to know what kind of flathead, sorry! It is a 45 inch HD and I believe it is a GE model (the numbers/letters stamped under the front cylinder on the left side include GE, so I am assuming). It has an oil pump, so from your above response, I take it that it would not have a sump? Thank you so much for your help! Also, if you know of any manuals/books that would be helpful, I will get them! Eric

[Chris Haynes]

If it is a GE Electric start pull the spark plugs, put a pan under it, and crank it over. If there is excess oil in the bottom end it will evacuate it by itself.

[epatterson]

Thank you for the help. It is a kickstart with a magneto. Will kicking it over accomplish the same thing? Thanks again-Eric

[Rubone]

Eric,
All the '37 up 45 engines and Big Twin Flatheads are recirculating oil systems. None of them have a true sump. However the engine oil is in a remote tank and is gravity feed to the engine through the feed pump (the one on the cam cover). This pump has check valves in it to prevent the oil draining from the tank into the engine. They do not always do their job, especially over an extended period of time. Therefore engine oil will drain into the engine and slowly fill up the crankcases. The worst case scenario is that enough oil is in there for the engine to hydraulically lock due to the oil filling up all the space needed for the engine to spin. This is extremely rare but can occur.
The first thing to do is to try and determine if the oil has drained into the engine. Is your oil tank dry? If so it has likely drained down. DO NOT refill it yet. Removing the plugs allows the engine to rotate freely when kicked. does it spin easily? If not DO NOT force it. On a 45 engine the excess oil will be blown out the breather opening, the oblong slot in the plate under the cam cover behind the brake pedal. It will make a mess! Removing the crankcase plug will allow it to drain, but be careful as that plug is not intended to be used much and is easy to strip. If you remove the timing plug as well it will allow air into the engine and help it drain.
Not all bikes leak into the engine so yours may have or may not have. The best way to prevent it in the future is regular use. Often just an oil change and fresh clean oil will flush out the system and allow the check valve ( a 3/8ths ball bearing) to do its job.
Good luck
Robbie

[epatterson]

Thank you for the info! I have kicked it over and spins easily. There was no leakage near the pump and nothing was forced out the breather opening. I have already changed the oil previously and there was oil in the tank. Thank you for taking the time to share your knowledge! I appreciate it. Eric