Goffys '61 Dommi

Written Jan. 2015

 

My old man was always one for a bargain & during his lunchbreak often looked at the ads. in the papershop window & one day he spotted one for a partly assembled 1961 Norton Dominator 600. Rebuilt engine & gearbox £50.00. He paid £40.00 & brought it home somehow.

This was mid 1974 & I was a spotty youth & hadn't even passed my test, but I'd had a Cub, a couple of C15s & Starfires & I knew a bit about old bikes (but not as much as I thought) it was worth a try at putting it together..

The engine & gearbox were in the frame with nice shiny ally engine plates & most of the rest of it was there with a good looking fiberglass tank (Dunstall). The seat was a matching fiberglass unit with a built in numberplate section which I didn't like the look of, so I cut the back off, re-glassed it & mounted the rearlight in the back so it looked a bit like the then new Kawasaki 2 stroke triples.

I'd never have bought one of the stinking 2 strokes even if I did have the money, but I thought but they looked good. The clutch, brakes & sprockets were all OK so it was more or less a re-assembly job. The alternator came from my stock of Starfire spares (can't have too many of those), the shocks cleaned up & resprayed. The rear mudguard was St./St. so with a bit cut off the front, it fitted well with the help of a Barracuda front mudguard bracket holding it in place. The front mudguard was a new St./St. one from our then local British Bike Shop, Goddards in High Wycombe. Also from off their shelf came ally mounting brackets & stays to suit the forks + John Tickle headlamp brackets. The original oil tank & toobox was used. I had a chrome headlamp shell with an Ammeter already so I drilled the rear of the battery box for light switches. They were behind the frame so couldn't be seen, quite neat I thought. The Ammeter never worked as I didn't know how to wire it in.

It had come with Dunstall rearsets & clip ons, but I built it first with straight bars & fitted indicators as in the photo above. These were mounted straight through the sides of the fiberglass seat & kept getting knocked off so were quickly removed permenantly. The carb was missing, but I had a Concentric lying around & it seemed to run OK. The carburation was probably a bit out but what did I know, and I ran it around for a couple of years without any reliability problems. Amazingly the supposedly rebuilt engine & gearbox must have been built well as I didn't have to take it apart for a long time.

The handling was always superb. It had come with a Dunlop KR76 racing front tyre & with a TT100 on the back I thought I was Barry Sheen & frequently left my mates behind on the twisty bits

Bits dropped off that I hadn't bolted on properly but it was reliable enough but never fast. I took it to The Isle of Man for the TT a couple of times without trouble but carried some extra padding as the seat was too thin. This was later recovered, badly, by a friend as seen on the right but the bike was pushed to the back of the garage shortly after as the mains started to rumble & was left for several years as I had a Commando by then & the Dommi was the slow poor relation.

 
 

In the early 1980s I dragged it out again, and in an attempt to make it go, it was built with a Commando camshaft. On a Dommi the crankcases breath using a timed breather through a hollow camshaft to the outside world via a pipe that exits just inboard of the primary chaincase. A Commando camshaft is the same profile as a 650SS cam but solid. The cases were drilled a la 850 Commando so they breathed into the timing chest & a breather union was attached to the front of the cases where a dynamo would have been on earlier engines.

A later higher output oil pump & six start drive fitted. I used an earlier timing cover which allowed a pressure feed to the rockers again like a Commando. The rocker spindles were turned through 180 degrees to reduce flow upstairs, but oil seals to the guides weren't fitted. Common knowledge says seals & plain rocker spindles are required but with just turning the spindles it didn't burn much oil.

A friend sold me an ally. oil tank, it looked home made but quite presentable. It didn't have an inlet for the crankcase breather so this just went out the back, which was alright while running in but when I gave it it's first real thrash on the way to a British Bike rally in Holland, most of the contents of the oil tank disappeared. The breather pipe was picking up some of the oil thrown around in the timing cover & dumping it all over my mate following behind. A bit of bodged replumbing with the pipes stuffed into the top of the oil tank & sealed with rag solved the problem temporarly. Shortly after a second hand Commando front brake was fitted. This had AM4 linings & even without a stiffener plate worked very well. The seat was originaly a Wideline short racing seat base modified & lengthened to suit the Slimline with the std. shorter tank, then recovered in leather. The distributer had been replaced by a magneto rebuilt by High Gear Motorcycles (long defunct), which when I discovered didn't spark the warranty had expired (they said).  
 

I fitted a Commando rear wheel, sprocket & gearbox sprocket which is the more usual 5/8" x 3/8" rather than the 5/8" x 1/4" original, and also gives a much easier to use QD function.

On a run to another rally one of my mates did his party trick & spun his combo through 90 degrees & stopped right in front of me. Well I hit him, hard enough to bent his A10s frame, buckle my wheel & forks & slightly twist the yokes. I put it back together with a new front end but it didn't handled as well.

The Commando camshaft wasn't a great sucess. I'd used the std. Dommi radiused followers instead of flat Commando ones & possibly as a result the performance was never as good as I'd hoped. The cam also turned out to be one of the famous Norton Commando Mk111 chocolate cams & only lasted a few thousand miles.

On another run to the West Country one of the captive nuts on the back of the clutch that the clutch spring stud screws into came adrift & dropped down onto the chain & went around the clutch & engine sprockets. This made a frightning noise & bent the mainshaft before I'd stopped. I removed the mangled nut, cobbled it together using the two remaining springs so the clutch hardly opened and made it to 3 miles from home before the magneto packed up again. So back to the back of the garage it went again.

Moving on nearly 20 years this time..

I had often thought that this would be a retirement project, but a couple of years ago I thought I'd have another go with it & have the engine built properly this time.

 

I started by having the frame beadblasted then straightened by Maidstone Motoliners, so it would handle properly again.

I've always liked nickle plated frames, having built a Commando in the 80s & my Norbsa in the 90s with nickle frames I thought I do it again. It involves drilling & tapping lots of holes which are later plugged, to wash out the plating fluids afterwards, but the end result is worth the effort. This time I had everything either nickle or Chrome plated & used only St./St. fastners. The ally. engine plates are anodised. I did think of trying to build a bike without any paint, which is possible, just. but I thought it might look a bit silly. Only part of the plating is shown here, which was done very well by Vehicle & General Platers, Arlesley.

The engine I had built by Mike Pemberton aka Pushrod Performance. This time I used a PW3 Dommi cam from Mick Hemmings. This involved machining of the crankcases & barrel. I used the std breather arrangement, though the other breather pipe is still there & blocked off. The usual new mains, big ends, pistons & valves. Three of the guides were loose in the head so Mike made up oversize guides from Colsibro with seals. Plain Commando rocker spindles are also fitted just in case.

 

The primary is a Norvil Commando type clutch & belt drive. This caused a few headaches as the clutch was binding on the mainshaft sleevegear. The clutch & the gearbox was taken apart several times before the problem was identified by Les Emery & it was returned to Norvil for fixing. It gave a surprisingly heavy feel to the lever until a different diaphram spring was fitted but it is still a little heavy as the centres on the Tomaselli levers are wider than the Nortons original 7/8"

To remove the gearbox on a Featherbed you amazingly have to remove the engine first then the gearbox + plates in one lot as the lower gearbox stud fouls the frame, but Will Horgan from Stainless Classics makes a threaded sleeve assy, so if you do have to remove the gearbox the whole lot doesn't have to come out. Handy during my adventures with the clutch. A lot of my St./St. fastners came from Will Horgan.

New chromed stanchions and new sliders are fitted

 

I never got on with the clip ons, they looked good but it's too damned uncomfortable to enjoy the ride. I had two goes with them in the past so I didn't bother this time & stuck to straight bars. These are mounted onto the plain ally yolks using BSA handlebar clamps with custom made taller versions on the underside of the bar. The riding postion is very comfortable apart from the tank which digs into the inside of my legs. It does feel small, maybe I'm just bigger & fatter.

The ign. is provided by a Pazon Surefire with a magneto replacement body & gives first kick starting almost every time. High output alternator, & an A Reg One Reg./Rec. looks after the charging, Quartz Halogen bulbs & LEDs for the lights.

It has new (or more likely old reconditioned) chronometric clocks and one has been turned 180 deg. in its case so both cable outlets are on the inside allowing the cable runs to be inside the headlamp brackets. Not shown in the photos.

The front brake has new Norvil shoes with a stiffner kit and is taking a long time to bed in, should have had the shoes skimmed to suit the drum I suppose.

 

I'm never building another bike with a ally. tank, I only have to look at it & it scratches. Does look pretty though. Tab II in Wales made it for me with two petrol taps, but they are a bit of a fiddle to get to with the frame tubes in the way.

The seat is the same seat, cut & re-glassed to suit the new longer tank & recovered in leather by Tony Archer in Huddersfield, a top class job.

It started easily after the rebuild and after the ritual several times round the block nothing dropped off. It's done about 500 miles now including a 180 mile round trip to Brighton for the Ace Cafe Reunion last year with only a loose footrest to tighten up at the side of the road.

The PW3 cam certainly does give it more power but you have to use the revs more, still not as fast as a Bonnie but it does handle & steer bloody well.

 
Starting bottom right & going clockwise you can see spots of rain on the pavement, this was the start of a downpoor, by the time I'd got it back into the garage I was soaked.

It always vibrated a bit, mainly through the bars so I thought I'd have a go at rubber mounting them. On the right is the BSA/Triumph system which is a pain as you have to thread the bars through the clamps then fit it to the yokes & add the levers etc. afterwards. I used the rest of the bits with the metalastic bushes & threaded the St./St. handlebar clamps I had already fitted to take a stud.

The end result is a great improvement. I can still feel some vibration, but it is reduced by about 80% & makes the bike much better to ride. It'll now cruise at 70/75 comfortably.

 

I originally fitted a charge warning light on the ign. switch bracket which is mounted below the seat so of course I can't see it when I'm riding, so I've fitted a Battery Status monitor to the handlebars. This LED glows different colours to show charging, overcharging, low battery Voltage etc. Not really necessary as the charging system is fairly bulletproof, but I've only got room for a small 2.5AH gel battery so if somthing happens I want to know immediately.

 

I've fitted our new new indicators which take std. 23W bulbs or LEDs.

I don't think they look out of place.

 

 

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