Dommy SS Barrels

So it seems plausible that early pattern finned barrels were fitted to pre- down draft head 88SS bikes and stamped accordingly. I can't really tell much from the Vic Willoughby road test images of the fast pre-down draft 88SS tested in Motor Cycle in May 1961. If anything the fins on the barrel look like the later version, but there is no really clear shot. This bike was stated to have twin 1 1/16" carbs and the big valve head, Manxman cam, different (lighter) pushrods, revised valve springs and a stiffer crank. It had a siamesed pipe also. The result was a claimed 36 brake horse and a spectacular top speed for a roadster 500 (albeit with a following wind).

Russell Spencer said:

So it seems plausible that early pattern finned barrels were fitted to pre- down draft head 88SS bikes and stamped accordingly. I can't really tell much from the Vic Willoughby road test images of the fast pre-down draft 88SS tested in Motor Cycle in May 1961. If anything the fins on the barrel look like the later version, but there is no really clear shot. This bike was stated to have twin 1 1/16" carbs and the big valve head, Manxman cam, different (lighter) pushrods, revised valve springs and a stiffer crank. It had a siamesed pipe also. The result was a claimed 36 brake horse and a spectacular top speed for a roadster 500 (albeit with a following wind).

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I will be trying to build the 62 version of 88SS with the DD head. However I will be ever so slightly detuning it since over here the thick journal 88SS cranks are almost impossible to find here in north america. A lot of folks are not even aware that there was a stronger crank... I don't want a blow up machine...so I am using the radiused lifters to truncate the normal SS/atlas profile. This cam in a 500 must be super hot...

I built a similar machine in the mid 1960's .A std 61 88 fitted with the 650 cam and carbs ,a fantastic bike that just felt so right to rev and ride hard ,and would cover ground better than many 650's.

They both sound like fascinating bikes. I would be really interested in dyno figures on that motor, Dave. There is little hard data on the effect of the changes Norton made to the Dommie 500 motor over the '50s. 29 brake horse is always cited for the original, but then there was the Daytona cam, higher CRs, bigger valves, twin carbs, then the downdraft head. There was the 36bhp claimed for the Vic Willoughby non-downdraft bike, which had, from what I can tell, all the other changes, but I have never seen a quoted figure for what the downdraft 88SS was putting out. I wonder why that is, and how good that head really was?

To make an 88 really fly its necessary to get the valve timing spot on using a degree disc to check.If I remember correctly the 8 degree lead of inlet opening to exhaust closing was important. Also to match up the port size with the carbs. Those inlet sleeves were put there after extended testing.

Again all the pre commando stuff here in the US is very scarce both hardware and real/good/accurate information. Have always been interested in the early "daytona" cam and only heard that the QR cam is the same basic profile with the added "ramps". I own a QR cam from the 59 bottom end but never have held or been able to measure an early daytona.
The 22729 (88ss/650ss/atlas/20M3) cam seems so very hot for the 500. After enough road testing, I may set up my dyno for measurement numbers. Even the dunstall setups recommend an advanced cam. We will see...

I have a few exotic bikes to ride but my ideal classic is the 61 88SS but in the UK finish of dark green and Dove with the splayed carbs. I can't see the point of Building a bike that looks like a 650 SS but is not.If starting from scratch I would build a Lowboy lightweight Dunstall , the 497cc motor pulling along a 400lb lump capable of handling twice the power does not work for me.There is so much cast iron that can have alloy substitued on these bikes. I would not worry about 88 reliability, I drag raced mine for years using 7000 revs as a standard, when I eventually did kill it with a solid seizure at 95 mph after a whole day flat out ,left a long tyre mark and the rods/crank survived to be re-built ,but never went as well again. I saw the bike recently for sale 50 years later,now looks like a fake 650 ss!!.

I very much miss the country ID being on the peoples icon...it is quite clear that the difference of the Brits access to noton parts is a world of difference to here in the US. In our New England club we have only about 100 members spread over an area the size of England. I currently am the only guy owning a 500 in our club. There is possibly two 650's and the rest are atlas'. I am not aware of a single 99 in this part of the country. There is probably only a half dozen featherbed on the road in all new england.
A lot of what I own has come from every part of USA and some from Canada.
If I want to go fast, I use one of my 3 Ducati's or my 72 combat

Most of the S/H parts that I see (and want) on E-Bay are in the US, We do have suppliers in the UK but much of the stock is pattern and of suspect quality. The US was a huge market and bought in quantity ,although spread over a vast area, I don't think we are much better off for parts(except for earlier stuff) its just we are so very different in so many ways.Bikes that do turn up here have usually done at least 30/40 thousand miles and had many owners .They almost never got used for a few k and then left in the barn. As an example my 500 single has had a dozen owners ,a replacement frame, a later engine ,an earlier gearbox, and forks from an earlier bike.It was properly restored at least once 25 or more years ago.I suspect it got bombed in the war years .Some owners were clever engineers,the last few total bodgers. I meet up with 20/30 other random classic owners on Sundays and there are usually 2/3 Nortons pre 67 ,sometimes very exotic stuff, £ 100,000 value Ducatis,HRD Vincents, Rudge's all sorts. In that way ,we are lucky, lots of old (very!) places to ride and green lanes.I also meet up with ex Norton factory staff from the 60's ,Not many left now.

Hi, I have the remaining of a 99ss engine in my shed a friend's gift, good cases n°97658, rods and crank, and head (22707), but no cam, the cylinder is to the limit (with radiused followers), but some fins were cut as donors eek, and the bores are rusty beyond use, so I am looking for a decent barrel .......but here in France , no way , I am searching all over the bay (UK and US)...........!!!

Cams are easy and cheap,Atlas ones will fit ,but not designed to be used with radiused followers ,might be ok but may have too much lift.Barrels are the real issue,till some new ones come along, Liners can work but are suspect to me as I have seen barrels with liners showing through from the outside.My 99 has perfect plus10 barrels because it was run for 30K plus miles on orriginal bore then written off in a bad smash and stored as parts for years before I got it. I now run a filter on the carb!!.

parts book PS214 (61-62) pg56 pn 22729 camshaft 88SS, 99SS, 650SS
parts book 63-65(88SS, 650SS,650/99 & Atlas) pg 9 A81 22729 camshaft _ALL
Commando parts book (20M3) camshaft 22729
Don't think it has to much lift according to Norton. Radiused lifters cost more to make, So they quit using them, however they will "truncate" the profile which reduces the overlap and as I hope will reduce the rev range. I don't need/want a 9000rpm engine. This 88 I'm building will only be a street engine.
In the 70's I used to build my own engines in my race car and was lucky enough to win club championship 2 years in a row.