New to the forum

[sole survivor]

Hello everyone. my name is Doug Farrell and I live in SoCal. And this is a great site with a wealth of knowledge which I have already used. I have been riding motorcycles for 40 of my 51 years. i currently own an o4 Triumph and 06 Suzuki SV650. But as i age my interest in vintage vehicles just gets stronger. I have a '75 BMW 2002 that is a track car and a '69 Dart which is streetable but is home at the 1/4 mile. It was time to search out my first vintage motorcycle. What better than a Norton Commando. I found/stole a 70 Fastback and its been a labor of love getting it running again. When I got her she didn't run. Nothing I have ridden in the past or present even comes close when I am on that bike. And while the ethenol has started its attack on the gas tank and the rear faring has spider web cracks it still looks beautiful to me. It hauls ass I assume because the previous owner installed a Norris cam and the RH6 head milled down .010 on both the head and cylinder to boost the compression to 9.8:1(best guess). New oil, plugs, wires, Pazon electronics, shimmed master cylinder, rebuilt disc brake caliber(I know. Its a '70..the lower forks are of off a '73 though Phil Radford says that discs brake were an option in '70. I can't find proof of that anywhere but I don't question what he says), and rebuilt drum brakes got her back on the road.
Phil Radford did the machining of the shift cover with new bushings so it doesn't leak. Adjusted the clutch and put on a single 34mm Mikuni(until I can afford two new 32mm Amals..I still kept all the original parts) and she lifts the front tire from first to second gear on full excelleration.
So now the questions. She shimmies on the freeways of L.A. but not on smooth roads. I think the stock Dunlop tires tread design is causing this on the parts of the freeway that has those rain grooves cut into the concrete. Is there another tire that looks period correct but gives the ride of modern bikes? And is this smimmying causing wear and tear on the swing arm to frame connections? I have added some photos so you can see her. Also..what are these handlebars called? And why my do my photos appear to be cut off? Are the images to big?

 

[aceaceca]

You did real good there doug! Welcome. What city?

 

[pete.v]

Welcome. Beautiful machine you got there.

Yes, everything on two wheels seem to shimmy or at least swerve on rain grooves but maybe more on Commandos. If it is smooth on other roads then perhaps that should be your guide. You can tighten it up a little at the cost of comfort in an other way. I would say that if you run the interstates more and safety is your concern, then tightening 5 thou on the front may suffice.

Maybe it's just time for a check up in the isolastics. Anyhow, a little "trial and error" is usually needed to get it right.
Let us know how it works out.

 

[ILLF8ED]

Hi Doug,

The shimmy is due to the K81 tires. Also happens with older Avon Roadrunner thread pattern. Many of us use newer Avon AM26 tires that have a modern tread. Recommend these for modern freeway surfaces. I bought and rode my first Commando in 1973. Was stationed at March AFB, Riverside. The Avon GP tires that were original were even worse than K81 on the freeways of SoCal.

Do you have any relative named Don Farrell, age 57-58?

 

[sole survivor]

You did real good there doug! Welcome. What city?

Torrance

 

[sole survivor]

Hi Doug,

The shimmy is due to the K81 tires. Also happens with older Avon Roadrunner thread pattern. Many of us use newer Avon AM26 tires that have a modern tread. Recommend these for modern freeway surfaces. I bought and rode my first Commando in 1973. Was stationed at March AFB, Riverside. The Avon GP tires that were original were even worse than K81 on the freeways of SoCal.

Do you have any relative named Don Farrell, age 57-58?

Thought the tires were the culprit. The ISOs are rock solid. I don't have any relatives around that age. That I know of!

 

[swooshdave]

Its a '70..the lower forks are of off a '73 though Phil Radford says that discs brake were an option in '70. I can't find proof of that anywhere but I don't question what he says), and rebuilt drum brakes got her back on the road.

I doubt they were a regular production option but the disk brake on the Production Racer was available in 1970. Of course it doesn't look like the regular Lockheeds from 72-on.

 

[swooshdave]

Hi Doug,

The shimmy is due to the K81 tires. Also happens with older Avon Roadrunner thread pattern. Many of us use newer Avon AM26 tires that have a modern tread. Recommend these for modern freeway surfaces. I bought and rode my first Commando in 1973. Was stationed at March AFB, Riverside. The Avon GP tires that were original were even worse than K81 on the freeways of SoCal.

Do you have any relative named Don Farrell, age 57-58?

Thought the tires were the culprit. The ISOs are rock solid. I don't have any relatives around that age. That I know of!

Of course you don't want the Isos too solid. :mrgreen:

 

[DogT]

Real nice looking FB Doug. The handle bars look like the current crop of replacements. Here's an original next to my new one which looks like yours. I got mine from Walridge, I think it's an Emgo, but it may be a UK Wassal, not sure.

Your photos only look cut off. Use control-down arrow and it will come to full size, but then the fonts are real small.

Looks like you have the new version prop stand, good thing. You may look into vernier adjusters for the isos, if yours are fairly new, Hemmings sells a kit that you can use without replacing them, then you can adjust them to your liking. Take a look at the swing arm mount and make sure there is no play in it to the cradle and that it has some upgrade for the spindle to keep it tight. It's prone to loosening in the cradle without proper upgrades.

Do something about the tank, you don't want that stuff in your carbs or head.

I'd like to steal one like that.

Dave
69S

 

[slupdawg]

Ditto on the K81's. Just went for a ride today (a nice autumn ride, by the way) and noticed how the tires felt slick on the paint vs the asphalt, and how much they like to follow the parallel grooves they cut into many highways. I like the look and response of K81's. Many do not. Probably try Avons next to compare.

 

[Matt Spencer]

Nice machine . The problem with the K 81s is that there stable , leant over , & under leading throttle . 8)
Some tecnical thing about ' a centre rain groove ' too , alledgedly, as well as the ' Trigonic ' wavering till leant
& balanced with the throttle .The main brakeing being effected upright , eased in TRANSITION to lean , effective
healed hard over . Pulling up HARD cranked well over in a panic stop (logging truck) , in the dry , convinced me
considerable brakeing is available on the sidewalls .Far more rubber is on the road with the pegs near scrapeing.
They were designed to minimise rolling drag by haveing a narrow contact patch UPRIGHT to enhance top speed .
A relation of the ' KR ' series race tyres .

 

[Hobot]

You shouldn't have lived this long and still function Matt. I've noticed good grip on leans but I hardly ever do that but in crisis too. If front skips out release it and stab rear to jerk upright then re grab front upright. Xbackslider showed us as over shoot example he had to get back upright while flying over the line realizing too fast to brake leaned.

Sole Survivor handle must have a story behind it. May not want to know.
Beautful rig but rare to hear about front lifting power delivery. I"ve had that and like in Nortons, nay seek it out. I notice you have an extra label on the tank, looks like its says Norris D. One of my first eye opening Norton events concerns an ancient drag racer bored with end of life jumping about knee slapping Yelling HOT DAM THEM NORTONS JUST LOVE THAT NORRIS D + CAM, on and on ... impressec the hell out of my novice minc, so my hot rod special has one to try. Glad its livable cam.

 

[Matt Spencer]

Isolastics ' Rock Solid ' in BOUNCE , or set TIGHT . No clearace can lead to broken frame ,unless cranks balanced around 72 %
A 2 though feeler guage should slip in freely .

Id suspect a ' drag racer ' would know what a ' Open Throttle ' was Hob . Is the glass half empty or half full ?
No half measures here .

 

[sole survivor]

Well..thanks for the accolades. The last three posts..well.. what?

Matt..What?

Hobot..uh oh and what?

Matt..What?

All I know is the bike is fast and fun. Maybe to fast for me. But love is love and I love this thing.

You guys are talking different language than I'm used too. I know the tank will need to be relined.

The rest of the stuff...you may have to dummy down for me. I am a good mechanic. But I didn't recognize some of those terms you guy used. :roll:

 

[DogT]

The Matt and hobot items, you just have to read real, real fast and see if you can comprehend, and then move on. Works for me.

Dave
69S

 

[davamb]

G'day SS and welcome.
Nice machine - missing a sidestand spring?

Something to add to my "100 things to see before I die" list - Hobot and Matt meeting face-to-face. Twins separated at birth I think.

 

[Hobot]

Commando's like softer isolastic doughnuts than harder or they tend to transmit more vibration, ugh. Old rubbers can age both ways, hardened up oxidized or softened decomposed by oil. Best clapped out but smooth sailing C'do I've tried had the softened by oil cushions. So I studied up on all the test results of the few who have tested the rubber selection and then just beveled mine to almost a peak and worked a treat set close to factory gap .010". Get the adjustable as long term labor savers able to dial in w/o a lot of hassle.

The danger for me an factory isolastics and lots of power, no matter how tight and proper iso's set, at some point in accelerating turns, especially those with lumps, it suddenly becomes a flopping fish off the deck. Its easy to flash past the point of no return before you discover this deadly quirk so be aware and work up to it to know to avoid it.

Don't understand your guip about open throttle and drag racers Matt, even mini bikes pull wheelies on WOT clutch drops. I just know some C'do engines can lift the front before topping out in first 2 gears. I want one that floats front in 4th, or 5th if I can afford it.

Oh yeah, good idea to check brake fluid level on each gas stop for a few hundred miles or so to make sure its not leaking and blowing away till its all gone one good pull down to Nothing at all.

 

[Matt Spencer]

Throttle : Drag Racer ; ' OPEN ' == W.F.O. , some people consider ' open ' to be when it starts to come off the throttle stops , opening .

Dunlop ' TRIGONIC ' tyres . The Latest thing out in the late 60s . TRIANGULAR cross section , apex down , on road .

Contact Patch , is l o n g and narrow , opposite to the modern whizz bang tyres . There contact patch is more like a scooters . :lol:

Like a long narrow hull on a yacht , or surfboard . The tecnique for manouvering can be at variance with that of a short wide one .
Transition , in lean , from Upright , where heavy brakein can be used as the forces are in line, so can be used determinedly , need easing.

I tend to ' Bend Swing ' . knowing the roads and brakeing points , at my ' turn in point ' Id ' let the machine over ' , to run in a pretty much
constand radius , through to the corner exit . ( Country roads , you understand :wink: )

So , we have ' Over ' and ' upright ' . The area round 10 to 20 degrees ' Bank ' with trigonics is the ' Transition ' , to Leaned .
Once your over say 30 degrees bank , the tyre is laying far more rubber on the highway , alowing full ( or at least greater )
use of the throttle and brakes , again . Wah Hoo .
Up the top of ' Pine Hill ' was a big right even radius sweeper on the main road . To quick to explore a safe max , due to ' impediments ; .
Thats curveing uphill, out , and over the crown of the hill .' My ' sideroad comes in past 3/4s of the way round .
IT is a dipping constant radius left hand sweeper , after the crown of that rise .

Probly date back to the Bullock days , progressive rates of change so as not to stall out the team .


The lefts got a granite wall on your left shoulder . Puttering up the way gets you here ,
Dropping the machine hard down to a left bank , and you can glance down over your right shoulder / knee etc . ALL the way down the highway approaches to the right.If ' alls clear , dropping it in second , the camber lets you nail the throttle and slingshot from 30 mph to 60 mph
at the drop of a hat , and then ' fine tune ' your speed in the last third of the bend to Merge with the left lane on the bend of the highway .
Or , if ' All Clear ' Hit Afterburners . not recomended , adised or tried , but discrete backing off of the previous throttle setting youll crest
the next rise at 80 while monitering potential obstacles . :? :shock: :wink:

However , this was ' some years past '. Current mindless zombies in tin boxes would imperil ones progress .
Not to mention traffic lights and roundabout in the general area . PROGRESS !? CIVILISATION ! ? AARRGGH

XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX stupid thing doesnt work .

XXXXXXXXXXXXXXXXXXXXXXXXXXXXXX blankety computors .
This second one illustrates a downhill pig of a bend ,
bottom of picture , to top .Hard to pic the undulations , and a lot of the roads are unobservable as constant radius bends , which are
however usually following the undulateing contours .
This suckers off camber on the outer half of the left lane, remember where driveing on the left shoulder . In winter , cold wet and clammey ,
at around 25 mph , This things impossible .If your not following a foot or two of the centre line , even then , as it lebels of from a down hill sweep to nearer level , its loading up the tyres more .If youve gone a mile an hour or two over the dreaded crawl , Shell drift left on the begining of the sraight .DUNLOPS , you could feel , control to a degree , and have feedback , during it.
The ancient 70s Road Runners , you were a passenger , though they came in again a few foot before shed clobbered the curb . Youd sit on it waiting .Not my idea of enjoyable . Dunlops = Good . Ancient Avons . No Sorry . And , this is going quitely .
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX the wonders of modern tecnology .
Heres a vresonable piece of ' The I.O.M. ' all need a state of
High Alert , the wits engaged and the ability to pull up extremely smartly ( KR76 tyre Front ) Clean dry roads and perhaps after dark when its quite so as to see lights of approaching ( side roads :shock: ) cars . Probly far to high a traffic density these days , and there probly not looking far enough ahead . :cry:

But theres some mighty fine curves she'll sit on , nice and steady .Took a few in anger once at 60 mph . Just a nice light drift kissing the intersate pipe gently undulateing . That bend 45 was the ordinary safe ? cruising speed , at high alert .

Hence the term ' Bend swinging ' , Drop it at the correct pont , let in run through banked , with fine corrections on bank or throttle , and
let er up onto straight with throttle . :roll: :wink: Being ready at all times to apply full anchor , avoid small childen , and kick dogs .

Now , what was the Question . :wink:

 

[dave M]

Don't worry SS. most people on the site can write intelligible English, however some would never use just a few words when 600 will do! I once described Hobot as the Jack Kerouac of the motorcycling world, with his stream of conscious (or is that unconsciousness?) posts. However now I feel his writing has been elevated to the level of Hunter S Thomson - after he was shot out of the canon!

One of my ambitions is to meet Hobot and drink some moonshine and play a little banjo together. Learning a new language is always fun.

 

[Hobot]

oh brother Dave, thanks for honorable mention but boy howdy no more toasts to hobot please, got me a hangover twice from that at the Empire rally.

Now lets get back to bikes as that's all that really matters and w/o them C'do's in our blood hardly any of us would have much to do with each other : )

So, we don't hear of that many pressing their rides to lift the front, I sure ain't going try that on my plain Jane Combat which might be able to on 19T sprocket. Yet its something I crave now so exciting to read of those who dare use em up before they die. I want to hear more on SS and his antics on a Norris D power plant.

Matt I've interviewed ancient 125cc guys so know about their two position handling, Bee line upright or full snap over leans, nothing in between. When I start to kick up heels on any bike I wait till last instant deep into turn to throw em over about as far as they will go as that sets up the best grip and angle then can hold that or back off some as turn requires. All cycles can tolerate much higher short spikes of traction and aim than they can hold long steady states that give time for resonance to build up.

You are so right about the new elites becoming shod like step though scooters so hindered in really snagging G's in turns. I think its mainly power to weight advantage moderns have over the narrow tire vintage racers. [Except un-tamed C'do which fish flop to chase after a earnest sports bike] I lost count of the Perrelli's, Dunlops, Avons, Brigstones, non DOT race tires I've finished off on SV650, all the way to the edge grooves or only get 2000 miles out them, but there's a 1000 miles worth on either side of center band. After 45' or so they feel like scrubing a tennis ball to turn compared to the ski like grip of our skinny tires.
I've got twice the fling mileage on my SV than my C'do's and know why I consider it a freaking corner cripple compared to tri-linked C'do. Others w/o same opinion just ain't tried a rear 'rump' rod yet is all.

I like to ride at night on and off hwy but after two dead deer strikes I now try to avoid it but when caught out I race over 80 like Harley gangs charging each other over a crest, I will never ever let another deer knock me down from the side again.
[video]http://www.youtube.com/watch?v=Xq42E3xtrxc[/video]

[video]http://www.youtube.com/watch?v=ZQRv1H9_v4A[/video]