Model 5 Short Stroke performance

Started by John Stanley, June 19, 2012, 01:10:21 AM

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John Stanley

Thanks Paul, glad to know its right.   The fairly steep hill i climbed the other day didn't even slow down the bike, but I was in 2nd gear.

About 15 friends from Canada, Washington and Oregon are visiting for an annual ride this weekend, and this afternoon I took the sunbeam out for a little demonstration ride.  They All want one!  I frear its the only one most will see as they are very rare over here.
John

phutton

Hi John,

I have always found my 26 M5 to be happy between 45-50mph (by guesswork!), so your figures seem about right. Sidevalves do tend to have plenty of torque, but run out of puff once the revs get high.

The general advice in the manual is to set the pump so that "an occasional puff of smoke appears from the exhaust when the engine is accelerated, but not otherwise"! I have always followed that advice, and have had no problem.

Paul

John Stanley

Have been riding the 1926 Model 5 Short stroke a bit.  Not really naving any experience with these, I dont know what to expect in the way of performance, although I did restore a 1928 BMW R52, and a 28 Harley.

Although I have not tried to check it for top speed, it really seems to like cruising along at about 45 to 47 MPH (by GPS).  The bike gets to this speed as quickly as you can go through the gears, with no hesitation, but does seem to flatten out.  I am using the recommended total timing advance, and may experiment a bit with that if someone feels it would help.

Have been completely comfortable riding it, and have now got the pump regulated where I want it.  After a 25 mile ride last saturday there was 3.5 ounces of oil in the crankcase.  I start out with 3 pumps which is almost exactly 3 ounces.  After about 10 miles I had to make a steep climb and about half way up it, I gave it about a half pump as "Insurance".  Also added a pair of ball valves, on each side of the oil pump so I can have instant start up of the pump and dripper without priming.  I suspect this is about as perfect as i am ever going to get it.