My First Norton - An Old Racer

Been posting on the Vintage Bike Racing Forum and a member suggested I also post here. I picked up this 1970 Norton Commando 750 from a retired AHRMA racer. The Norton has been sitting in the garage for the past ten years and last raced back in 2001. I own and operate four Harley Davidson's, but wanted to get into vintage racing and found this bike on craigslist and immediately fell in love with her...

The bike is going to need some TLC to get it back to race ready condition. Below are some pics and I'm sure this forum can give me some much needed advise. Not like I can run down to my local Harley Davidson Store and pick up parts. Below are some pics and questions:


As you can see the battery is strapped to the oil tank. I assume this is not stock and what would be the proper way to secure the battery?


Are most Norton racers keeping the front drum brakes or converting to disc? It has drum brakes on front and rear. Also, need to replace the tires. What would you advise as replacements?


The carbs have been sitting for almost 10 years with only a handful of cranking each year. One carb seems to be running better than the other. I know I should re-build or replace. What would you recommend? Also, if I replaced the carbs what would you suggest?


The previous owner stated AHRMA had just started requiring a catch tank back in 2001 when the bike was last raced. As you can see he modified a bottle. What would you suggest? Possibly the modified bottle is all you need or has someone fabricated a better part? Also, where would I find an oil containment pan for this bike?


I'm not liking the original upper fork yoke as it is set up. Any suggestions here? Also the tact seems to be working on and off, as well as the on/off switch is missing. Besides the tact, any other gauges you would recommend?

Also, I read an article Motorcycle Classics that talked about an Electronic Ignition Conversion from CNW. Has anyone done this and do you recommend this conversion?

Thanks for taking a newbies questions and I'm sure I will be posting much more in the near future.

OH, Boy, another yellow one. You'll get plenty of replies on your questions. Front brake can be made to work properly, but not as good as new disks. The oil tank is not unusual, it's a 69/70 version, later ones had the tank on the side and the battery sideways as well. Plenty of conversation on the carbies, up to you. People say the originals run strong through the range but wear out. Go here http://www.jba.bc.ca/Bushmans%20Carb%20 ... html#FLOAT Don't know about the catch bottle. The tach is probably the cable or drive unit. All perfectly repairable.

My 2 cents, but it looks good.

Dave
69S

+1 on the looks good ! I'm not a racer so can't help with rules etc. which you'd probably want to check on before replacing stuff. That said, JS motorsports has some modern flat side carbs at a really low price ( come set up too ), Lansdown fork internals are a good bet too. Oldbritts electronic ignition will let you run a digital tach and id really reasonable too. Cj

bryanscott said:

Been posting on the Vintage Bike Racing Forum and a member suggested I also post here. I picked up this 1970 Norton Commando 750 from a retired AHRMA racer. The Norton has been sitting in the garage for the past ten years and last raced back in 2001. I own and operate four Harley Davidson's, but wanted to get into vintage racing and found this bike on craigslist and immediately fell in love with her...

The bike is going to need some TLC to get it back to race ready condition. Below are some pics and I'm sure this forum can give me some much needed advise. Not like I can run down to my local Harley Davidson Store and pick up parts. Below are some pics and questions:

As you can see the battery is strapped to the oil tank. I assume this is not stock and what would be the proper way to secure the battery?

Are most Norton racers keeping the front drum brakes or converting to disc? It has drum brakes on front and rear. Also, need to replace the tires. What would you advise as replacements?

The carbs have been sitting for almost 10 years with only a handful of cranking each year. One carb seems to be running better than the other. I know I should re-build or replace. What would you recommend? Also, if I replaced the carbs what would you suggest?

The previous owner stated AHRMA had just started requiring a catch tank back in 2001 when the bike was last raced. As you can see he modified a bottle. What would you suggest? Possibly the modified bottle is all you need or has someone fabricated a better part? Also, where would I find an oil containment pan for this bike?

I'm not liking the original upper fork yoke as it is set up. Any suggestions here? Also the tact seems to be working on and off, as well as the on/off switch is missing. Besides the tact, any other gauges you would recommend?

Also, I read an article Motorcycle Classics that talked about an Electronic Ignition Conversion from CNW. Has anyone done this and do you recommend this conversion?

Thanks for taking a newbies questions and I'm sure I will be posting much more in the near future.

Click to expand...

Battery strap looks aged and probably not the best to rely on wrapping around the oil tank only. I have used heavy duty tie wraps. You should foam wrap the battery for vibration protection and strap down across the top only (lengthwise and short wise). Heat from the oil tank is probably no good for the battery and insulating the oil tank with the battery is not so good either.

In AHRMA I would go disk brake. The problem is that a Norton front disk brake has dismal performance even with upgrades. Chat with Mercury Mike at Vintage Brake (on the web) and he will get you going. With a stock Norton disk brake you can upgrade the friction compound and change out the master cylinder so you have a greater hydraulic ratio but I found that even I outgrew that and converted to a Norvil period piece floating rotor and Lockheed racing caliper on my Commando racer. Even that was beginning to bake. I suspect a lot had to do with the fact that I never really whittled down the weight of the bike and I was no lightweight either.

The carbs probably need a good tear down, soaking and cleaning. Check the fuel lines for brittleness and if in doubt, change them out. You will eventually want to get the carbs rubber mounted as the vibration can put gremlins in your carbeuration. As for replacement carbs, for me, I would go with Mikuni's. See SUDCO and there are a few specialist that have the Mikuni "Commando package".

That catch bottle, although ugly is fine as long as it holds the amount required by AHRMA. I ran a plastic brake fluid bottle for years but it was out of sight behind a number plate. You will need to build and install a oil catchment pan that runs from beneath the front of the engine to behind the trans and it should have a means to hold an oil absorbent pad. See the AHRMA rule book on this. You may want to look up Herb Becker as he has made a fierglass pan. You can fashion something out of aluminum or fiberglass and attach it with black tie wraps.

You need a functioning kill switch. The tach is not absolutely necessary; the intermittent tach action could be tach problems or could be a drive cable problem. I don't think you will need any other gauges.

There are a variety of electronic ignitions out there. I would go with a Boyer ignition and a HD Excell coil; this is pretty much a standard set up for Norton racers but they are starting to diverge as more options become available.

bryanscott said:

The carbs have been sitting for almost 10 years with only a handful of cranking each year. One carb seems to be running better than the other.

Click to expand...

The left hand carb appears to be a right hand unit (no tickler, pilot screw, or throttle stop screw is visible).
I can see each carb appears to have only one cable? If they are the throttle cables then they are fitted in the wrong entry positions in the carb tops as the rear cable entry is for the choke cable. [Edit]I think the carb tops are actually fitted back to front, they need rotating 180 degrees so the throttle cables are at the forward end.

bryanscott said:

As you can see the battery is strapped to the oil tank. I assume this is not stock and what would be the proper way to secure the battery?

Click to expand...

Hi Bryan,

I've used tonneau retaining straps as used on utes or flatbeds or whatever you know them as to retain my battery. Couple of bucks at the local rubber disposals store, they look like this:

One on each side of the battery holder, bolted in place with M5 screws using existing holes and a short section of Aluminium extrusion with a screw at each end to stop the strap from slipping off:

Note that I've got the battery turned around so the bar won't short across the terminals!!!!

Nice project you've got there, look forward to the tidy-up reports.

Looks good Bryanscott
The front switch hole is actually a poor form of an antitheft lock to lock the front wheel in a turned position.
Most racers will use a smaller lighter battery. Kenny Cummings would be a good guy to pick his brains on the E/I. I depends if you plan on racing the bike competitively or just bringing it back to an original state. He is a member on this site.
The Amal Mk1s are period for the bike but it looks like the top covers are reversed. Seeing that the choke slides were taken out this is not an issue. I looks like the ticklers are on the inside or you may just have two right hand carbs. Can’t see the other side. Fuel banjos look like they are from a triumph. A Norton would have 180-degree spigots. Early banjos were single each carb.
The carbs can be re-built if you want to remain original or you go to more modern period type. Light weight pistons, Longer intakes…. the sky is the limit.
CNN

Looks like a good starter project.

A lot of things to sort out.

You'll probably want to consider just going batteryless.

And get those carbs sorted out.

Plus get all the stuff you need to just get through tech.

vintagebikeracing.com will get you through the basics, and then the folks here will get the bike sorted.

Track Test , 1969

http://www.classicbike.biz/Norton/Mags/ ... Norton.pdf

Various others ,

http://www.jamiewaters.com/Frame-5-moto ... 4571796207

If you set it up so itll drift decellerateing , accelerateing , & in transition , you dont need brakes , they only slow you down .
Apparently you can check if it were built as a Production Racer originally . In which case youd not butcher anything , these days. Hemmings & N.o.C. have info .

More drivle as to ' originality ',

http://nortoncommando.com/forsale/produ ... 0Racer.htm

The poor thing has never been a Production Racer in its life. ALL Proddy Racers came with the front disc, different fork slider, CP2195 brake caliper. Early ones (1970) had the long oil tank protruding in front of the r.h. frame tube, never the one that formed the rear wall of the air filter, etcetc.
This looks like a local hero sort of bike, very local in fact. A lot of work needs to be done and a lot of money spent to be taken seriously even on a local vintage racing level. It was probably wiser to use it on public roads, or to sell it and buy something more suitable.

Welcome, Bryan.

Regardless of whether is started life as a PR or not, under the rules in AHRMA, you CAN run it as a PR in the Novice Historic Production Heavyweight class.

There was a fellow at Willow Springs in 2010 with a similarly set up Ducati.

The rule reads "1972 Production model, or like design"

Having sponsored the class and run a scratch-built 69 Bonnie for four years, I can assure you they'll let you run as long as your bike is PROPERLY lockwired, has decent DOT tires on it, and you install a nominal belly pan.

If the bike runs right, leave the carbs alone. Any replacement (beyond finding a properly matching left side carb body to swap out) will drop the bike out of the Production class.

If you think THIS bike looks a bit tatty to be on a race track, you have never been around an AHRMA paddock on any Sunday.

Rule #1: HAVE FUN!

Bryan,

You know where to find me. Let me know if I can help.

-KC

Bryan,

Take the nay sayers here on this list with a grain of salt, don't dismiss them but just keep the perspective. You are starting out racing and in the"ideal world" you start with a perfectly fettered purpose built race bike but in my not so humble opinion there is so much to learn and appreciate through the journey of riding, learning and correcting/enhancing. This is not big industry racing where the goal is to win first time out with the best equipment and best rider.

I have mentioned this to others in the past when starting out racing; there is a bit of a hierarchy to follow:

1.) Make it handle - tires, suspension, weight
2.) Make it stop - brakes
3.) Make it go - Torque and Horsepower!

This is the general hierarchy approach but you may dabble in a little of each, just focus on the hierarchy. I would say that with most AHRMA tracks, if you have a 120HP Norton and you cannot stop it well and if it turns like the Queen Mary, 350 Honda Sportsman Class bikes will lap you.

Tire options to consider are Dunlops (see RC Barker Engineerng in Florida) or AVON Super Venoms. Let us know what size rims you are running, they look like 18"

Holmeslice is one to listen to; he has been to Cafe Du Monde - Biegnet and Doughnut (Been there, done that).

AYE ; looking at the racer test , thart ' 69 ' model has the new fangled timing cover points assembly. ( same set up ) Likelyhood its a ' Build ' rather than OEM
but you dont take it for granted .
http://www.dunlopmotorcycle.com/tirecat ... y.asp?id=9
Heres the dreaded Dunlop Catledog , TT100s are still in production .



This is the old front raceing tyre form around 65 to 75 , pre ' Slicks ' , Michilen PZ2 & Perrili Phantom . Manxes , F-750 Triples & Nortons and every other man & his dog , back then .3 compounds HARD isnt gripy .



You can see the ' TRIGONIC ' nonclementure related to the cross section , short stiff sidewall & oodles of rubber down , leant over .TT100 is road derivitive tho ' R ' spec one is more like it in the carcase .



The ' R ' stamped case is the uprated race carcass that alledgedly allows a Goldwing to cross death valley at 100 mph without poping . Caseing is stiff race type.
for the old drag the ears round the bends brigade . 3.60 & 4.10 19 std , but 4.10 19 F & 4.25 18 R later used ( Thruxton motorcycles 78 & 81 I.o.M. machine .

The others may well be faster , but the chassis suits the original spec in youre into drifting .Meaning to get Pics of a Old Trigonic KR 76 ive got , max tread
on tarmac way over , min upright for less drag - better speed . TT100s ( K81 ) were the roadtrigonic type . Was thought at the time the KR tyres that theyd bend most other than Manx chassis , andcause wobbles . So the KR 76 3.00 19 F & 4.10 dunlop rear initially , but by 74 on the Tridents they ran the TT100
on the front , a 4.10 . 2dy walk down memory lane .

Theres a few areas on the engine to pay particular attention to , includeing a 7000 or 7500 rpm redline . But obviously a Half centurie old so some consideration
to see nothings ' off ' is adviseable .32 mm Carbs in theyre 30s now may slip in , if 34 or 36s wont . The fancy Amal race intakes were worth a few HP & the
bleed arrangement meant the floats didnt misbehave at sustained maximum rpms if youre looking at long tracks .

Not an enourmous component count compared to the newer 4 cyl rice burners , but the bits are bigger . If the fits are right itll stop them rattling around and
parting company .Make haste slowly is probly the maxim , if your not sponsored by Sheik Yamoney .Aeroplane fitter / riggers from the WWII era is the required
mind set . Exactitude & Patiance .And itll go faster if you polish it .

Whoa... that bike looks an awful lot like the one my buddy Jeff built back in '90's to go AHRMA racing. He was on a tight budget and was not worried about running near the front, just being out on the track. I tried to get him to use a disc brake, even a stock one, but since he started with a beat up 'S' model and he had the drum, that's what he ran. He sold it many years ago, but the stickers are the same. I think I have some old photos somewhere (pre-digital).

Bill Moeller at Bore-Tech did the machine work, but the engine was pretty mild. It's a good thing with the lack of brake power.

Vintage Brake can make those 4LS brakes work quite well.

grandpaul said:

Vintage Brake can make those 4LS brakes work quite well.

Click to expand...

No doubt this is true but if you are going to spend your money, spend it where you need to go. I would focus on a good disk brake set up, available, light weight and easy to maintain.

Matt Spencer said:

AYE ; looking at the racer test , thart ' 69 ' model has the new fangled timing cover points assembly. ( same set up ) Likelyhood its a ' Build ' rather than OEM
but you dont take it for granted .
http://www.dunlopmotorcycle.com/tirecat ... y.asp?id=9
Heres the dreaded Dunlop Catledog , TT100s are still in production .

This is the old front raceing tyre form around 65 to 75 , pre ' Slicks ' , Michilen PZ2 & Perrili Phantom . Manxes , F-750 Triples & Nortons and every other man & his dog , back then .3 compounds HARD isnt gripy .

You can see the ' TRIGONIC ' nonclementure related to the cross section , short stiff sidewall & oodles of rubber down , leant over .TT100 is road derivitive tho ' R ' spec one is more like it in the carcase .

The ' R ' stamped case is the uprated race carcass that alledgedly allows a Goldwing to cross death valley at 100 mph without poping . Caseing is stiff race type.
for the old drag the ears round the bends brigade . 3.60 & 4.10 19 std , but 4.10 19 F & 4.25 18 R later used ( Thruxton motorcycles 78 & 81 I.o.M. machine .

The others may well be faster , but the chassis suits the original spec in youre into drifting .Meaning to get Pics of a Old Trigonic KR 76 ive got , max tread
on tarmac way over , min upright for less drag - better speed . TT100s ( K81 ) were the roadtrigonic type . Was thought at the time the KR tyres that theyd bend most other than Manx chassis , andcause wobbles . So the KR 76 3.00 19 F & 4.10 dunlop rear initially , but by 74 on the Tridents they ran the TT100
on the front , a 4.10 . 2dy walk down memory lane .

Theres a few areas on the engine to pay particular attention to , includeing a 7000 or 7500 rpm redline . But obviously a Half centurie old so some consideration
to see nothings ' off ' is adviseable .32 mm Carbs in theyre 30s now may slip in , if 34 or 36s wont . The fancy Amal race intakes were worth a few HP & the
bleed arrangement meant the floats didnt misbehave at sustained maximum rpms if youre looking at long tracks .

Not an enourmous component count compared to the newer 4 cyl rice burners , but the bits are bigger . If the fits are right itll stop them rattling around and
parting company .Make haste slowly is probly the maxim , if your not sponsored by Sheik Yamoney .Aeroplane fitter / riggers from the WWII era is the required
mind set . Exactitude & Patiance .And itll go faster if you polish it .

Click to expand...

Matt, that tyre is a Triangular, a KR76, a 3.00 is suitable for a WM2 1.85" rim, the TT100, or originally K81 before Uphill's 100mph TT lap on his Bonnie was indeed Trigonic a word Dunlop made up to describe the rounded off triangular profile.

A PR will have run on TT100s, most used 4.10s front and rear, I favoured the slightly better steering of a 3.60 on my Fasback production racer.....very few people I knew ran a triangular other than on an open class racer.....and then they ran with either with a triangular rear 3.50 KR73 or later with a round profile 3.50/4.50 KR83 intermediate.....and when they started moving on to 18 rims in the late '70s the triangular disapppeared.....

If you want to run it like it is TT100s won't limit you too much whilst your are learning track etiquette. First thing is to get it running as best it can without modifying it, except make sure your clutch is not overloaded with oil, your head bearings and your swinging arm bushes and pin are good and that isolastics are set tighter than for rode use,a little tingle in the pegs is about right, then....

As far as I know factory PRs did not use drum brakes, so I suspect it is a look alike, so to complete the look best to fit readily available Norvil single disc front end with AP race caliper, should stop fine, I rode on at Cadwell in late 2010 and it was fine when we changed the pads for newer stock. You need to chek out US rules before yoy go fancier than that on the front brake. Whilst you are at it with a new front hub this is teh time to go for 18" alloy rims and use Avon AM22 110/80 race tyres, though Dunlops seem more popular with some in US racers, probably warmer and dryer at most tracks than in UK, but the Avon have good grip and wear well.

Leave the rear drum as standard, just lace on the new rim and replace the cush rubbers, try some better shocks and refurbish front end completely, as noted Landsdowne dampers would improve it and look fairly stock. Though you might want to ride it with just a refurbed front end before you invest in improvements that depend on your ability to set them up!

Progressively dump the chain for a belt drive, earlier if you get clutch slip, though that will be improved with teh right plates, clean and minimla oil in the case. Dump the alternator and go 40mm if rules allow, or just change 30mm belt a lot, my suggestion is up the primary ratio at this time, but up to you, of course you will need to change final drive to suit, but you are going to be playing with that anyway if you are fitting 18" rims.

You can run the motor near standard and have a lot of fun, or go PW3 cam and better pistons and a minor clean up of teh inlet prots around the back of the valves and 3 angle valve grind....of course you can blow a lot of money, but....from your comments you need to gain a bit more experience before you do that...what you should consider is...

Carbs...match a pair of 32mms with genuine Amal velocity stacks, but get the carb bodies carefully turned out to 33mm, most '70s proddy racers did, works better than bigger carbs for most people...and get some proper peashooters!...as loud as the rules allow...

Bryan,

Your bike looks very much like the one I picked up from ebay two years ago. Mine also appeared to have been off the track for 10 years or so. It turned out to be a very nice bike, built by Herb Becker no less, but there were plenty of minor things that needed fixing after 10 years of neglect. I wouldn't worry about changing anything; just make sure it's safe and go racing. You'll find out what you really want to spend money on and what you can live with.

What's safe and what isn't? My main concern was the miles of "rubber" tubing pushed on to plain metal stubs, fastened with hose clips and the potential for them to empty oil onto the rear tire. The drum brake isn't going to kill you, but take it easy until you get the measure of it. 10 + year old tires? you know you should replace them, but having said that I did find myself taking the bike out in practice with a 15 year old rear tire (kept in the dark) and having no problems at a "knee-down" pace.

Don't forget you're going Vintage racing and the most important thing is to get out there with your old bike; being competitive is optional.

Cheers! ~ Gary

Interesting profile to me as when I let my fronts wear down on my Cdo's 100-110's or 120 on my SV650 they end up wedge slab sided with about 1" flattened center. If was me I'd run 100 on front and 120 on rear in softest compound sold and get at least two rears at a pop. Raciing = wasted money = intense living time while ya can.



Anyone who races on unknown insides w/o going completely through it is asking for bad juju. Heck even just puttering around on unknown insides can bring on a ruined engine when everything seemed perfect just the instant prior. Ugh.