This is an continuatuion from Do’s and Don’ts Part 1
Please read that first

If your engine is brand new from overhaul I would say, you must do the break in with mineral oil so the piston rings settle good. You can use singlegrade or multigrade as long as it is mineral. If  you use fully syntetic from the start the piston rings will not settle and you may get a bit blowby and excessive crankcase pressure and then again oil leaks from valvecovers and elsewhere. Give it 1000km on mineral oil and then switch to syntetic multigrade oil. The syntetic oil will allways lubricate better and give you a happier engine if it is broken in first. I run on Castrol Edge 10W-60 on my Yellow Chief. There is no singlegrade mineral oil on the market today as good as that one so… An sidevalve engine engine can run extremely hot and therefor need premium oils if they are used hard.

One of the main parts in your engine that really care about oil is the piston rings. They need some special attention and you must do it right. The original Indian piston has 3 wide compression rings and one oil ring. I could say a lot of what I experienced with that setup, its nothing wrong with it and it took me through two Europe tours and everything was ok. But then I started pushing limits and I learned a few things. First, on the original pistons the ringlands are wery narrow and weak, and the topring is very close to the hot edge of the cylinder top surface. At least on my 80” engine with pop up pistons. So I made up some new pistons with modern rings, beefier ringlands and lowered the topring down the bore. When choosing the ringtype you must not just buy any modern rings as they may not be compatible with the Cast iron cylinder. Today rings can have many different type of coatings and profiles that make them work as good as possible under the conditions they are placed, and if you don’t take care about this it may be wrong for you.

But for my Chief I chose some rings with coating for Cast iron bore, the topring is half the width as the original ring and its gapless. The second ring is special for oil control and also narrow and the modern three piece oil ring is specified with a special tension to avoid excessive wear and friction of the old cylinders. This exact recipie is not fully described here but you can get them from me or Jørgen in Sweden if you promise to follow my break in procedure and take the piston that fits with them. With Castrol Edge and this setup I did 5000km on one liter of oil down Europe, two times. That is dangerous to say as you won’t believe it but it’s the truth. I still run this setup and didn’t open my engine since 1998, 75 000km ago. But now I use a lot of oil as I have not been babying my engine lately. Now I use one litre for 500km and I feel its time for a top end overhaul, but since the compression is spot on I tend to wait with the overhaul.

While I am at pistons and cylinders, in the crankcase there are some baffles where the cylinders attach, The front bore has smaller baffles and the rear cylinder hole has large baffles with just a slot for the conrod. Don’t machine these away as they help the oil rotating in there to be distributed evenly between front and rear cylinder. If you take them out most of the oil goes up into the rear cylinder, this one can start smoking, sparkplug foul and such, while the front one don’t get oil and piston getting hot, front cylinder pinging from detonation and such. These problems are difficult to adjust away with carbs, ignition and sparkplug types.

In this picture the baffle’s are missing…

In my primary case and gearbox I use two different oils. I have a 1RS bearing behind the clutch on the main shaft. This means it has one simmering and is sealed on one side. The holes in the gearbox wall below this bearing is sealed on my bike with two plugs. This way I avoid mixing of primary and gearbox oil. There is a big difference in the oil characteristics needed for the primary and gearbox. I have seen many fill a single grade motor oil in their transmission, then it successfully don’t do anything real good. Then they may spend years discussing clutch slippage and at the same time the gearbox grind teeth’s every time they put it into first. If this is the case I would blame the oil. In the primary we need an oil that is very thin to get a quick acting clutch and also has good lubrication for the chain and dot make foam. A very thin hydraulic oil can do this, also a Sportster primary oil or a automatic transmission oil witch I use. Its perfect for the chain and designed to operate with clutches.  In addition I have filed some grooves on my original fiber discs and drilled some holes in them as well to make the oil move quickly in and out of the clutch pack. It doesn’t grind teeth in first and it doesn’t slip. The original style clutch has now done 75000km and attended all slow races I could find, drag races, deep snow, alps and dynotime.

My std style clutch was installed in 1095 and gave up on my way home after the 2017 Int. Indian rally in Sweden. Well done clutch!

In the gearbox I use a oil called Redline 80w-140 gear oil. It’s the only GL5+ oil I have found that is compatible with bronze bearings. And its Polyol Ester based and therefor oil film thickness is super strong and cushioning for the gears. It is not recommended for use in synchro boxes and the slipperiness will make the synchro rings slip, that is a good sign.

Normal GL5 oils are not compatible with the bronze bearing in the lay shaft and it has aggressive additives to make it work with hypoid gears, and the bearings will fail. But even if I use the bronze bearing compatible Redline oil I have needle bearings in my lay shaft. I stated using Redilne oil in my Chief since it increased the rear wheel horsepower by 12Hp on my 210Hp Ford Escort. That transmission oil is just great.

  1. Very nice written article with some eye opening revealing facts. It’s hard to argue against experience. But what is your reason for chosing full bucket pistons and not skeleton pistons that theoreticly should be lighter and give less friction?

  2. The full skirt piston give you a lot larger support against the cylinderwall and when you put oil in between the sound (noice) from the piston rocking or skirt knock will be a lot less with full skirt I beleiwe. These sidevalve engines need a lot of skirt clearance, specially with forged piston. I have tested from 0.1 to 0.17mm skirt clearance an if it was slipper style piston they would not sound or perform good.

    The std rings is responsible for most of the friction in a piston assembly but the ring design I use is under half of the pullforce you need to move the piston down the bore.

    So I think a full skirt design on a Chief is ok

    Ole m

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