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R27 Oil Slinger Replacement

elfenbein

New member
I checked You Tube for a video of the engine disassembly...no luck. Just got the bike. As far as I can tell it is original, last ran in 1977. I want to tear the engine down to change the slinger and check the crank and the rest. I need advice about that part of the project. I will appreciate any help. Regards, Elfenbein
 
Welcome to the forum, Elfenbein! What year R27? Is it a later model, like mid 1960s?

As for the slinger work, or much else, I don't think you're going to find anything on the web to walk you through this. I've had both of my vintage bikes overhauled...I basically did the external teardown but handed the engine to a professional mechanic to tear into the bottom end. If you have experience doing this sort of thing, then you might want to give it a try, but IMO it does take some special skills and possibly some tools.

My suggestions are:

- check with Vech at Bench Mark Works http://www.benchmarkworks.com ; they can certainly sell parts and could even do the work if you so chose

- Cycleworks has some videos...I see a video for a R26-R27 top end overhaul. https://www.cycleworks.net/ There also seems to be a many-in-one tool to work on the engine.

- Barringtion Motor Works published a restoration and service manual for the singles. http://barringtonmotorworkspublications.com/gallery/26/141 These are quality books and will certainly spell things out in detail to do the work.
 
Bike Details

The bike was built in August of 1964. The last license plate is from 1977. It has about 8K miles. I haven't had an opportunity to get into it, but I have heard that the oil slinger condition is critical, and that the crank has to come out before you can get at it.
 
Yes, you are correct. Bikes built before 1970 did not have oil filters. Instead, these slingers which were disks with a "cup" around the edge were used to help centrifuge out the particulates from combustion. If the build up in the slingers gets too much, it will block off oil flow to the crank bearings. In the "old" days before detergent oil, the products of combustion were not held in suspension and when the bike was parked, all that stuff would slowly fall to the bottom of the pan. But with newer oils, they are designed to hold things in suspension so that the filter can trap them out. So, in that regard, newer oils don't work well. They are however of much better quality. Typically what people will do is to just change the oil more often but use the better oil.

So in your case, with so few miles one has to wonder if the slingers are full or not. They might not be, but the first time you start the engine with all of that old oil inside the case or coated on the walls, it will come off and could fill up the slingers rapidly. Or not. The slingers could be just fine. But the only way to know is to remove the crank to get to the slingers. Unfortunately, there's no way to inspect the slingers in place.

Typically what people have done, and I did on my two vintage bikes, is to do a mechanical restoration and change fluids and run the bike for a period of time, say 1000 miles. Get to know the bike. Then take it down to fix the things you found and to have the slingers changed. In my case, after about 30K miles on my R69S, the slingers were about 3/4 full. On the R25/2, the slingers were relatively clean and must have had engine work before I got it...the cylinders were already first over so someone had been in there before.
 
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