Tim Raindle wrote:
Hi Mario, Robert is correct in fitting an old petcock from a chief.
The thread IS NOT 3/8 24, DO NOT TRY AND FIT A SCREW THAT SIZE !!!!
it IS 1/8" National pipe thread (NPT) which has a tapered thread of 27 threads per inch, which is the thread on the fitting of Roberts old chief gas tap.
Not sure when this changed, but my 24 Chief does NOT have a 1/8"NPT thread for the oil plugs. It does use a straight thread and I believe it is a 3/8 24 thread. I was under the impression the Scout was the same. My 31 Chief does have an NPT thread but I thought they had been changed.
I had original plugs that fit properly in the oil holes, it had a shoulder and a small gasket on it. I made a number of spare plugs with a shoulder and a small hex head rather than the silly slotted head. The plug used a small fiber gasket. I've seen many early cases that had this thread but were changed to 1/8" NPT
This worked well, but for the Cannonball, I wanted a faster way to drain the crankcase as I ran oil control rings and changed oil every gas stop, about 50- 60 miles. I also wanted to be able to quickly drain off excess oil if needed, or test the level, by opening the top plug. So, I machined special fittings to adapt small petcocks. On the case end it was 3/8" 24 with a shoulder and a fiber gasket. On the other end it was a 1/8" male NPT, from there, a close ratio 90* elbow and a petcock. It was very cozy to get it all in there but it worked great!
When we stopped for gas I had a small can that fit under the drain. Open the lower valve quickly to drain the oil, gas up, add 2 stroke oil to the gas (1 1/4 oz per gallon), close the drain, open the overflow valve, 2 1/2 pumps on the hand oiler and as soon as it started dripping out the overflow petcock, close that one and off we go. It worked great! I still use it today. The only drawback is if the bike sits for a long time I want to double check the oil level before starting, so I drain it all out and reset the oil level. If the oil is thick, it takes for ever to drain! However, when riding, it's plenty hot and it runs right out. Also, about every 2000 miles I flush the crankcase with diesel fuel to get all the crud out.
Interesting thing on oil, every 50-60 miles I drained out about 3-4 oz and it was horrible looking, like it had been in a 2 stroke diesel engine for years! That's why I changed oil so often. Even at that, the most oil I ever used in 1 day was just less than 1 quart (64 oz), and at the end of the day I would drain my waste cans which held 32 oz total. That was running hard, 45-50 mph fully loaded with sidecar and passenger.
OK, OK, Chief, chief, chief..... But it applies to the 101 as well, the chief is just a scout on steroids! Hope this is helpful information.
