Hi ladies and gents,
Sorry for the slightly odd request but bear with me.
I'm 54 and so missed the era when Brit bikes were the normal day to day transport but oddly I loved them at 18 when jap bikes were the choice of the young.
I bought a 650 ss cafe racer which I thought was fantastic as an 18 year old. One day trusted mechanic I knew who was much older and wiser took the bike for a spin only to tell me that was the flattest ss he had ever ridden and that it was clearly a miss match of parts. Had I not asked him to ride it I would have thought that was how they were, and been happy.
Now many years later and having restored a reasonable amount of bikes i have a 16h., which i built over last winter. I love it and understand its limitations. It crossed my mind however that like my 650ss 35 years before, is this how it should be. I fail to understand how such a bike could ever pull a side car with two men and a machine gun.
It hops along quite happily at 40 to 50 which is enough for me, but on a moderate hill its decidedly ahsmatic.
The gearbox is fun but very agricultural even by pre unit standards.
Neutral to first also is a serious clunk even when warm. I am meticulous about the clutch lifting strait but can't get it anywhere as tolerable as my other pre units.
Any advise would be greatly appreciated.
...wasn't used by the Army with a sidecar - That task was for the 633cc Big 4, with a modified cylinder head that they retained after the war. The RAF used 16H outfits but mainly around airfields which are of course mostly fairly flat.
It's a delicate subject, but most riders are probably slightly heavier than the norm eighty years ago. Nevertheless, it should tramp along fairly well. There seem to be significant variations in 16H cylinder heads and as the part numbers didn't change, it's difficult to pin down what happened. Compression can usefully be raised by skimming the head.
Probably the most important thing to check is valve timing. They will run with widely varying timing but there is always a best position for the pinions.
The gearbox is long travel and any wear will exacerbate that. It's quite difficult to get the clutch to behave consistently if the original postage stamp type Ferodo inserts (or worse still, replacement corks) are in use....It's worth looking at options such as friction material bonded to the basket, or an alternative set-up from a later clutch.
Mine will whizz up to an indicated 60mph but at that speed it feels quite busy.
This 1940 article is an interesting read, if you haven't seen it before.
... my first "proper" bike was a 1948 16H with a Watsonian Avon chair. It would crack along at 50 - 55 on the flat 2-up with camping gear, and when I passed my test and chucked the chair away it would get up to 60 or so fairly readily but struggle to do much more. An ES2 engine to convert it to a Model 18 made it more sprightly but still not fast.
My current 1952 ES2 has the laydown box which I think is much better than the dollshead or other upright versions as it doesn't have those wear-prone external linkages. I don't have any trouble with the ferodo inserts, and the mushroom clutch plate lifter means it lifts pretty straight without any tinkering. What is crucial is to make sure there is minimal end float on the mainshaft however. There's a bronze thrust washer in the gearbox that wears and makes good gear and neutral selection tricky. RGM have them as well as the steel washer they bear against.
The laydown doesn't have as sweet an action as the later box but is pretty good for its era.
Have you checked ignition timing? Full advance at about 7/16" before TDC. Some books have a later figure. When I first ran mine it was very disappointingly sluggish because it was too retarded. You're not going accelerate up though the gearbox going up hill as you might on a Dommie, but it should be fun to ride and it's easy to believe that even the side valve bike was one of the faster machines on the road in its day - compared with the typical family car in the 1930's!
I have overhauled the gearbox completely with all new bushes and shims from rgm. I think the clutch plates are my prime suspects as I have the old corks rattling about in the basket.
Q. What alternative clutch will fit that is compatible and potentially better.
Will go over the valve timing again.
Q. Dave, you talk about a later timing figure. Mine is set at bang on 7/16 th. Is this the later setting.
Mine is 1938, and has a military dolls head and was used in the war at an airfield in Devon which fits what Rich says.
Information on these bikes seems scant and there appear to be as Richard alludes parts variations for no traceable reason. I suppose we were at war.
Mine is 37. I actually set my ignition to 7/16 when the lever still has about 3/32" still to pull. But it makes no difference if I do advance it that little bit, so it sounds like ignition on yours is OK.
David's comment about family cars from the 1930s rings true. I drove an Austin 7 of that era some time ago. It felt really unstable. It is very narrow and tall so that the slightest undulation in the road is magnified by the swaying of the car body. I got it up to 30 mph and that felt similar to 140 mph on my then CBR600 Honda. The gear change is difficult with precision required on the double declutched down changes and good timing when changing up. I would think that your 16H was a rocket ship compared to a Austin 7. As for a Vincent Black Shadow............
A 16H in good order should reach 70mph solo or 60mph sidecar under good road conditions. The solo engine sprocket is 19 teeth and sidecar 17. Your bike is most likely fitted with a magneto that has tight wire advance so you need to make sure the lever doesn't vibrate back to retard when riding. The engine gives it's best power (14 BHP) between 3,500 to 4,500 rpm so you should change down early enough when the engine starts to labour.
The most problems with the Norton clutch are caused by plate distortion and if you fit the solid friction (Surflex) type you should only fit 4 pairs instead of 5 to give enough clearance. The later AMC clutch is no better and in some ways worse. BTW. Eric Oliver won 4 sidecar world championships using the same clutch as the 16H.
WD16H rear drums (and I believe most modern replacements) are 43t instead of 42t so most will be running slightly lower gearing than the makers intended for road use. However, if Roger's is running out of steam on hills, that isn't the problem.