Break in tips for rebuilt 1941 Chief?

[41Chief]

Hello,

After many years and many dollars, I am just about ready to fire up my 1941 Chief.

Any tips on the proper oil to use and change intervals would be greatly appreciated. The engine was rebuilt and the company that did it sent me some instructions for the break in, but after moving I have lost the instructions. The engine was rebuilt many moons ago, but after work, the kids, grandkids, ... putting the old girl back together took a LOT longer then anticipated.

I would prefer to use synthetic oil as soon as possible, but will defer if you folks think that is a bad idea. Basically, I will only use the bike a handful of times a year to go to Daytona or bike show now and then. It will not be a daily rider / commuter. I live in Florida where it gets HOT now and then, but at this time of year, it is not all that bad. Florida has no significant hills, I will be riding single most of the time on back country roads with an occasional sprint on the interstate. Mostly stop and go or winding country roads under 55.

Also, the bike was running before the rebuild but was tired. When I started it before, I would remove the oil cap, and make sure that I could see oil returning to the tank. In reading some threads, I notice that to properly prime the pump I should remove some plug on the oil pump and let the oil from the tank drain into the pump until it overflows. Sounds like making a big mess to me, but is that what I should be doing? Sometimes when I started the bike up before, it must have lost prime because nothing was being returned to the tank. So, I had to get a squirt can and inject oil into the oil return and then just hope that it would start pumping. Is there a better way to make sure that the pump does not loose prime, or at least not run dry at startup until it does starting pumping?

Anyway, any tips or suggestions would be appreciated. I will post some pics of my 'new' bike after I get all the sheet metal back on which will probably be in the next week or so.

Thanks

[Bubbalowe]

The manual instructions for breaking in are timeless. While synthetic may be a better lubricant it does have a bad habit of seeping through paper gaskets.

[PRG]

Howdy sir,

No synthetics, break in or otherwise. Google ZDDP, flat tappet motors and oil containing zinc (yes, we have roller rockers, but) Most accessible (Autozone) containing this is Valvoline VR1 20-50. Oil pump. No need to pull any plugs to bleed. On the supply side it does not “pump” as the seal between its output and the timing side main shaft is merely a felt washer. It only acts as a metering device to supply oil from the tank above at a measured rate. The real pump is the scavenge which returns oil up to the tank. On starting, this side of the pump will occasionally only clear itself if you either rev the motor or take a short ride around the block. Do not be alarmed if you don’t see an immediate return as essentially oil is just accumulating in your sump and your motor being even more liberally lubricated. Long before your tank is emptied you will know you’re not returning oil as a choking cloud of oil smoke will have alerted you as your engine is trying to hydraulically lock itself with no space left in the sump to accomodate and the oil now forced past the rings.

[kitabel]

I change the oil at 100 miles, then 500.
Don't let it idle.
After a few heat cycles re-torque head bolts and base nuts.
Check valve lash for changes, over hundreds of miles the valves will sink a few thousandths and tighten the lash, adjust to factory specs when this happens. Zero lash (valve does not completely close) makes that cylinder stop working.
Rings seat from gas pressure, an occasional 1/2 throttle helps.
Check plugs for color - any difference is frequently an air leak in the cylinder with the lighter plug.
Avoid prolonged hard throttle during break-in, which means slightly too much spark advance (5°) is not only harmless but beneficial.
Close the throttle from cruising speed from time to time, the vacuum draws oil into the cylinders.

[PRG]

Howdy chaps,

Poster indicates this motor was built eons ago so modern narrow gas expansion rings unlikely unless Bonnie pistons fitted (most were Egge or similar 25 years running ago, forged just coming on the scene, expensive and not easily sourced) probably standard four ring tension based in which bed in will not benefit much from throttle application techniques. Many small shops rebore cylinders and may run a hone down but rarely plateau hone with a berry ball of similar. You have no idea what your RA is on your cylinder walls, go lightly on initial run in of this motor if the above not known, 4 ring tension based have a lot of drag anyway and especially on a fresh build. Why four rings when others were going to three? Indians lubricate the majority of components needing such by windage produced with the up and down movement of the pistons forcing crankcase gases through those narrow baffles. Much back pressure produced and it took four rings on these loosely run piston clearances at the time to keep oil out of the combustion chambers.

Head bolt retorques. You’ll soon discover this requires removing your tanks and then grinding down a socket to access the bolt under the top frame rail at the seat post. Shine a light between the head and cylinder deck to determine if you might be so lucky as to have copper gaskets fitted, no retorque necessary. If fiber it may require up to three retorques before they settle enough not to fail at the exhaust valve area (as witnessed by black combustion residue seeping out)

[Lipdog]

From what I've read, you want to use 50 weight, high zinc in these bikes, not 20W50. Is that incorrect? For the oil, the three high-zinc oils I'm aware of are Valvoline VR1 (nice because you can order it at AutoZone, etc., pretty cheaply), Brad Penn, and Driven (Joe Gibbs). I've used all of them in my cars and bikes that don't have catalytic converters (high zinc kills them). These oils are great for older engines that aren't used often. Get the Dino variety, not the synthetic or blend.

Separately, I'll have my tanks off next weekend to test fit my new welded tanks from Iron Horse, replacing the old leaky ones. I have copper gaskets, but want to check the head torque anyway. What is the correct torque for heads and cylinders (mine is a '48 Chief)?

[tomfiii]

Another oil:Lucas: https://www.summitracing.com/parts/LUC-10712

[Architect]

+1 on Brad Penn oil, the "Original Green Oil"..... I like 60wt in my Flathead and Shovel. I also like it being green, helps with leaks when you at least know which component is leaking. But we could do thirty pages on oil, everyone has their favorite. Good luck.

[Lipdog]

I also like it being green, helps with leaks when you at least know which component is leaking.

Personally I like to taste it to be sure I know what's leaking. Gas, antifreeze, and oil all have distinct flavors

[Bubbalowe]

+1 on Brad Penn oil, the "Original Green Oil"..... I like 60wt in my Flathead and Shovel. I also like it being green, helps with leaks when you at least know which component is leaking. But we could do thirty pages on oil, everyone has their favorite. Good luck.

The analysis of Penn Grade shows dye added for the color.
Some mining companies tint different lubes to help troubleshoot leak sources.