Dominator 99 - Essential Mods. ?

Not much wrong with a std bike. Stay away from hotting up the motor , std bearings pretty bulletproof. Don't think belt drives are worth it, less reliable by all counts. Electronic ignition good. Modern tyres good if room to fit. Cylinder barrels like hens teeth so if working leave well alone. Balance may help smooth things a bit. TLS brake with stiffening kit better but still not up to modern standards.Forks benefit from mods. Minor tweeks to lube system help but speeding up or bigger pumps more grief than help.

As Robert says I doubt if a hotter cam will be much benefit. Unless the red mist descends I wouldn't expect you to spend much time exploring what happens at over 6000 rpm. If you do buy one with a good magneto I would not be seduced by electronic ignition. They are good but not better. Hope you find what you want and enjoy it! My guess is that unnecessarily fettling has probably wrecked more good machines than anything else!

Oh dear, all the things we did to them when we were young and foolish. A good, standard one with a decent magneto is as good as you can get. My one has 12 volt electrics with a solid state voltage control box as that lets me have the most useful modification you can fit - hot handlebar grips. TLS brake? Not really, the SLS one can squeal the tyre. Tuning the engine? NO. Electronic ignition? Not for me. Alloy rims? Up to you.

The Best modification you can do for a classic is to modify your riding style. Stay off motorways ,burble along, leave loads of braking room, plan rides well away from clutch cooking traffic. get a proper life,relax,retire!.

You are clearly going after an alternator bike in wideline frame. Not a bad choice. The main mechanical changes after that date were an improved cylinder head and better gear ratios.

Modifications? First make sure it it set up well, runs nicely and doesn't leak oil all over the place. I would suggest going for a good electronic voltage control, so you can easily fit modern 12V lights and lots of LEDs. Otherwise, leave it largely standard.

Do 'rider' mods like oil filter (I mounted a Commando filter plate on a strip between the right rear engine plate bolts, and fed the scavenge oil pipes over the gearbox) and oil breather catch bottle. Mine's a plastic drink bottle behind the gearbox, fed by a plastic tube from the timed breather (previously used as an oil tank return pipe) and the oil tank breather (a battery vent tube)

Oil pressure, on early machines with the 3-start oil pump drive, is usually very low when hot - but it isn't really a problem - my big ends are unworn after 85,000 miles. Well, 1/4 thou on the left. I intend to look into fitting a Commando pump with bigger gears, which may be fitted with the 'slow' 3-start drive gears of the early machines. You have to make major modifications to the engine to fit the 6-start pump drive gears - different timing cover, crank case drillings, rocker spindles with no scroll. That's a lot of work.

Paul

If you go for more oil pressure you should also fit drilled rods and shells ,better oil rings,valve seals , open up oilways bigger pipes etc, not worth the bother.

On the early bikes with the 3-start oil pump drive, the oil pressure sinks VERY low when the oil is hot. The Commando pump has a wider set of gears. It will mean a greater oil delivery, but not nearly as much as if you went for the 6-start pump gears. As I put in my earlier post, that mod requires complete alteration of the oil system. My idea is a useful increase on VERY little pressure when hot. I intend to put a pressure guage on my machine shortly to see how horrifyingly low it does get....

Paul

Due to the centrifuge action of the crank design the supply pressure is only part of the story, it may be unintentional but the crank will draw enough oil to survive even if the pump can't keep up. If a new std pump was needed but not availiable I would fit the bigger one but would increase supply to the pump to obviate the possiblity of cavitation .

Even modern tyres are a bit of overkill if the fitted tyres are not too old,the Dommy handles ok with the Speedmaster and SM rear. To be truthfull ,knowing that new owners are a bit keen to put their own stamp on the bike ,we are trying hard to put forward a few low risk "improvements" that won't wreck the thing!!.Happy hunting.

I have put an Avon GP2 rear and F2 front on my '58 88. Look reasonably period and perform better than the bike's capability (also means i have a use for part worn tyres off the Manx!)

Now that I LIKE

Not having a Manx to recycle tyres from (worn heroically to the edge...), I am having to think what tyres to fit to my Model 88. It's got time expired TT 100s on it for now. I am thinking of 90/90/19 and 100/90/19 RoadRiders. Comments?

Paul

Previously michael_crehan wrote:

I have put an Avon GP2 rear and F2 front on my '58 88. Look reasonably period and perform better than the bike's capability (also means i have a use for part worn tyres off the Manx!)

Previously robert_tuck wrote:

If you go for more oil pressure you should also fit drilled rods and shells ,better oil rings,valve seals , open up oilways bigger pipes etc, not worth the bother.

Now leave well alone the model 99 is fast enough for anyone, and drilling holes in shells and rods makes for LESS oil presser not more oil pressure

The late 1964 650ss had the six start oil pump and to compensate the large end bearings they drilled holes in the shells and rods for less oil pressure, put on the system Yours Anna J

Previously paul_standeven wrote:

Now that I LIKE

Not having a Manx to recycle tyres from (worn heroically to the edge...), I am having to think what tyres to fit to my Model 88. It's got time expired TT 100s on it for now. I am thinking of 90/90/19 and 100/90/19 RoadRiders. Comments?

Paul

I think the RoadRiders look too modern on Dommies. If you need more grip and feel I would go for the combo I have (but they do wear quite fast). Otherwise I would use Safety Mileage MKII rear tyre with a Speedmaster MkII front. Classic look in a modern compound - you will be grounding your stand and exhaust before these let you down.

http://www.avon-tyres.co.uk/motorcycle/speedmaster-mkii

Take care with 90_90 Avons on the front if you have 7" forks and original tinware. I have a spare front 90_90 in the shed because it is too wide to use.

Me too!, I think some 90 x90 are 5 mm wider than others. AM 26 wider than AM20??.

I too had to go for 3.00x19 Speedmaster on the front as a Roadrider was too wide to fit. I can endorse the Speedmaster/SM combination as being pretty good all round tyres.