commando camshafts

I suggest that riding on the dirt, and riding on the bitumen are two completely different things, and the bike design heads in two different directions.

Duh, of course riding on dirt is not like riding on pavement because ya can not dig in an edge on pavement nor THE G*&(!%. Only similarity is going fast-harsh enough - soon as ya let off loads on tarmac or dirt the tires pretty much instantly regrip, not so on THE Grass, THE Grit, THE Mud THE Ice. At least dirt riders regularly get into straight steering at speed but not so the road racers. Flat trackers never let up the power spin while turning cause if they did bad ju ju. I want to expand the expected flight envelope of old floppy rubber baby buggy. So is Sir Eddy but deer knocked him out of riding reflexes.

I was always puzzled when ex-dirt riders like Kenny Roberts transferred their skills to the bitumen. To me the effort in doing that seems extreme. What happens on the dirt at relatively low speed, becomes horrific on the bitumen. But it seemed to work for the Yanks. I suppose that like most things, it is all in the mind, but I cannot imagine approaching a left hander on the bitumen at high speed and turning to the left and gassing it to chuck the rear end into a slide, and holding it there right around the corner.

There are bikes that do that, they are called super moto

Unread postby acotrel » Wed Sep 19, 2012 3:19 pm
I was always puzzled when ex-dirt riders like Kenny Roberts transferred their skills to the bitumen. To me the effort in doing that seems extreme. What happens on the dirt at relatively low speed, becomes horrific on the bitumen. But it seemed to work for the Yanks. I suppose that like most things, it is all in the mind, but I cannot imagine approaching a left hander on the bitumen at high speed and turning to the left and gassing it to chuck the rear end into a slide, and holding it there right around the corner.

Click to expand...

It is Horrific on anything i've tried doing it on except for Ms Peel which invites me into it. Not all the off pavement flights are low speed either. I generally travel faster on THE Gravel than the hi way as no police to worry about just pure luck into blind turns or crests. You should do a track day to learn if enough power to skip out the rear it don't keep sliding unless you keep forcing it too. The dirt guys can do it by power but generally the supermotards do it with rear brake. Guess which way goes in and comes out faster funner. A Neutral cycle will not tend to fall over further unless made too nor hi side back up beyond just upright unless you force it too on purpose. Sweepers don't seem like long turns anymore just a series of short front float straight sprints punctuated by instants of trip out fling ups, I call it faceting turns and there's two ways to do it. Worse cycle turn traction is long held leans [which trail brake makes way worse] but cycles can take insane instants of jerk arounds done fast enough nil time for chassis-tire resonance to build up. Once you get nerve and bike enough to take it, decreasing radii are sought out for the extra thrill spiraling the G's up quicker or just make em all like that. Keeps me awake at night flashing back on what's to come.

here is something for you to see if you like a GP bike sliding.
http://www.uponone.com/videos.php?id=2129
If I remember he was an aussi also

acotrel said:

I was always puzzled when ex-dirt riders like Kenny Roberts transferred their skills to the bitumen. To me the effort in doing that seems extreme. What happens on the dirt at relatively low speed, becomes horrific on the bitumen. But it seemed to work for the Yanks. I suppose that like most things, it is all in the mind, but I cannot imagine approaching a left hander on the bitumen at high speed and turning to the left and gassing it to chuck the rear end into a slide, and holding it there right around the corner.

Click to expand...

That be flat tracking on tarmac which looks wild as can be but its really a way to relieve loads not add em up to turn sharper. Main use is not to lose momentum. It takes a leap of faith to do the first time but after that its great fun when plenty of run out width after apex. The faster you go into it the easier it is to induce and control. i ran into this as an inward G force limiter so do everything I can not to get crossed up sliding outward, unless just for tire and traction wasting fun. When going fairly fast but not trying to go faster i sometimes use this to line up with new exit path in narrows on THE Grit, usually on an up hill banked slope so gravity helps stop the slide out before hook up for the forward thrust.

Here's further extensions of this I want to get down. Sort of have to lose control the instant before controlled flight launches.

Yes, bill - & he is very skilled in fast wet track riding too.
When the 1st Trans-Atlantic match races were run, back in the `70s in Britain, the dirt experienced U.S. riders were amazed at the way the Brit riders froze if they went off track & on to the dirt, whereas -if there was any advantage to be had by using it -the U.S. riders would go for it deliberately..

I forgot to list that is Casey Yarrow going for it deliberately. He got to cheat a bit though by hitting a rise to help lift and get the twist done in air before touch down. Yo'all have seen it happen off the level paved surfaces too usually with bad juju. The cam part of this to me on Peel is need to smack the rear with rocket launch power right at the instant of hi side hook up. Rear is kept spinning loose right up to that instant of hook up pivot point as tire suddenly distorts wider to NAIL IT! If ya over do it then the manevour turns into lazy wide crossed up flat tracker slide only useful in stadium wide spaces. I can sort of practice this safely by increasing zig zags in straight lane til frame twist/spring back starts to lift a tire or two, whohooie. Only one rig I could turn that into a supermotard skid instead of a fish flop. Its very hard on drive train, almost equivalent to a standing start clutch drop. Digital traction power response to set tire spin just right w/o over doing it and no delay one to one wrist to tire patch reaction. ahhhh. The balloon tires I've tried it on can't take the load they break loose too easy on edge and then wallow on hook up distortion, that suddenly has all bike mass and momentum piled on it. so hard to feel-KNOW which part of its wide patch it launches off of, which affects both direction and lean at fly off but also how fast its kicked to twist before impact. Its fun making all this up of course on imaginary Ms Peel.

& Of course, the showboaters do it one-handed.. http://www.youtube.com/watch?v=5jv2miNdHFE

Shows exactly what I mean, flat tracker drifts are a load relieving maneuver so only need a hand on the throttle to keep the rear spun up till aligning with front, then see how the balloon tire walks around on its patch. Not a big deal on such low loads but if another rider to avoid or funneled into narrows it'd could be enough to upset the apple cart. Wet pavement like this even easier as long as not leaning much, which means rear must be spun even more loose, which means even less acceleration out of there. It is a good way to keep momentum up if room enough to get away with it. Faster more tricky dangerous way has least amount of time spent on instants of sliding rear and way more on straight line hook up. Study ice spiked speedway racers for another way around spun up rear w/o drifting. Side cars can do it too. Also can't run a whole course that way or tire would abraid to blow out. Fun stunts on tap with power to spin at will.

In your own time....

Please explain how this might help me choose a camshaft or camshaft setup for a Commando? :roll:

Its ALL Here .

http://www.kawasakitriplesuk.com/phpbb2 ... ?f=2&t=906

Advanced Tecniques . .http://www.youtube.com/watch?v=WgjG1U-D ... re=related

I was reading an interview with Agostini the other day. He mentioned the difference between the 500cc MV3 and the Honda 500 four. He said the honda was more powerful, but the MV3 was a better package. I got the impression that he used to brake hard into corners, then accelerate very early around them. It sounded like the bike was very nimble and the steering was set up for his own riding technique. I always wonder about guys using excess power to pull slides, they might be as useless as doing wheelies ? If I personally really need to knock speed off in a hurry, I usually stand the bike up, brake hard then lay it down again and get back onto the gas. It is a survival strategy - I was brought up in the era of very bad tyres, if it moved an inch you were on the deck. If I ever run off onto the grass, I always do things slowly, and keep the bike upright trying not to turn it unless I really have to, then brake gently. Our local circuit has 50 % a tight twisty section, and three long straights. Generally you must choose how you set up the bike. My commando engine is set up for torque, and I always use a close ratio box, so the tight stuff suits it better, and I am very used to whipping around the tight bits. The ends of the straights are a problem when the 1100cc CB750s get going. The biggest problem has been the very high first gear, it limits the overall gearing you can run, without cooking the clutch on the starts. The commando engine seems capable of pulling loads of gearing. I wasn't smart enough t o use a standard commando first gear with the rest much higher and close together, so I now have the six speeder. I have yet to try it, and I am still waiting for the changeover selector drum to reverse the direction of the change mechanism. I believe it will be really great !

How does this relate to Commando Cams, obviously it does not to you or most the others bothering to read my crazy sounding stuff, but I can see ole acotrel sure does.

Acotrel when I took Code's Corner school on 900 Ninga's at a rural non banked fairly narrow tract, 3 students flew off the tarmac and then crashed some yds out on clump grass and sandy desert soil. I sort of got run off track when a group of students didn't stick to the inside of curve but wandered way out where I was about hugging the outer edge of long long sweeper but going like 50 mph faster so nothing for it but shoot straight off into the rough stuff close to the ton freaking out of course till I reminded my self I'm a Gravel'r and Grass'r so did exacty as you state, relaxed to let speed bleed down while dampening forks and feathering both brake till easy to take 40-50 mph and swung back around to get back on track. The other fellas were either ambulanced away or one life flighted.

I ABHOR Wheelies, Stoppies and Sustained Slips=Slides as counter productive for best acceleration or deceleration or turning and survival. With power levels short of tire spin it don't hardly matter what cam as long as it don't detonation with the octane and timing used. But once basic power able to spin rear, then power response to throttle on tire makes a lot of difference. Here we get into non obvious factors very few seem able to discuss but in-famous phenomena of power hits on tire hysteria known as the "Big Bang theory".

Almost everyone is only looking at straight line performance when considering cams and rpm and response, BFD. it takes more brains than pilots got to control the throttle-tire response in newer sports-racer elites when leaning much. This is where Peel's real focus is to wipe their butts in leaning conditions and not loose much if any ground in the opens, so not only must Peel hardly slow for turn but she's in dragster acceleration before even leaning and stays on it though sharp or wide turns easing on more power as tire allows on becoming upright again. To handle loose conditions is a strange mix of very light long held inputs to very aggressive short instants of rear spin chirp skips and short drifts. To me it feels like magical hand directing rear thrust some what back into the turn instead of totally outward tangent thrust over the edge. Until one is familiar with breaking loose on purpose its a scary mystery zone that limits maxing out more securely. Notice I never ever talk about using forks as that is still in limited glee level of ordinary handling bikes I'll have nothing more to do with but embrass as much as I can. Where everyone else is seeking level-ish torque level I seek spiking torque curve to over come the increased traction of tire speed. But my Norton should not unpredicablly spike torque, just instantly put out enough torque to set tire spin just right till hooks up suddenly for even more power spike handling. Camshafts and rpm have direct effect on handling in these conditions. I claim if not for triple linked compliant isolastic chassis I'd be as naive as rest of the world on the new physics available on two tire craft with power to spare.

sounds like this things a G P bike for the road , which isnt a bad thing , if all the dissenters didnt get up that day .
May be a bit impractical as a everyday roustabout .Though appears it mightnt have been its design objective .

NOW , ' Slide ' and ' Drift ' arnt the same animal . Excepting a ' powerslide ' . Here countersteer has a differant connotation .

Tecniques for Snow , where its thrown against the drifts in a drift , to create a berm FOR traction enable greater adhesion and velocities .

THEN we have what is the ' Rythym ' or delay in accepting control inputs . A greater lag generally indicative of good inertial security , though premeditated opperation neccesary .

opposite extreme as per Picture , where responce is instantaeneous , but requireing more immediate rider interaction . Theres a thing .

Id found the Norton could slide the rear if prevoked , but its natural inclination was to a ' Two wheel drift ' , and understeer on off cambers , its ' slide ' automatically transfering
to both ends . Now with the CAM ( ) when the swine was in the powerband , the RESPONCE was INSTANTAENEOUS . Unfortunately the powerband was over the speed limit
except in first gear . :mrgreen:

I find it very difficult to compare what happens on a race circuit with what happens on the road. I think my Seeley must be very different to a standard commando. I've never noticed a pronounced powerband, though I usually don't use it below 3000 rpm. With the battle axe tyres, it never seems to move but is very nimble, and self steers out of corners. It comes on with a real rush, and with the close box, once it is mobile it is very difficult not to over rev it. I've never tried to ride it on public roads. I think I would get booked for exceeding the highway speed limit in first gear in the old 4 speed box - which was as high as a standard commando second gear .
From my experience with Triumphs, when I've used race cams, separate pipes, twin carbs there is s usually a good kick up the backside at about 4000 rpm. I never feel that with the Norton, it just pulls like a train from low down and I think the 2 into one pipe helps that happen. They are a different type of motor, and I use a different approach to getting them going faster.
I think that the next time I rebuild the motor I will fit a combat cam and advance it 6 degrees. That will give the same opening points as I currently use, but exhaust closing will be more sensible due to the longer duration. The 850 cam is currently advanced 15 degrees.

acotrel said:

I find it very difficult to compare what happens on a race circuit with what happens on the road.

Click to expand...

+1

Yes, you get the corner cripples who espouse their own delusional riding prowess when they had never been their in the real world. The Seeley is different from a well sorted Commando and it is quite different from a well sorted Featherbed. One of the main attributes I see with a race Commando is reduction to rider fatigue. Nobody performs better when being shaken and buzzed by the bike. Have a read of the recent blog from our Kenny C. on NYCNorton.com regarding racing an electric road racer.

See: http://www.nycnorton.com

I like your thinking on cam timing and cam choice. The Norton Commando head has such great breathing attributes and I believe the port to chamber attitude promotes fast burn, all good stuff. Once you start speeding things up you literally run out of time to take care of the breathing and combustion processes, that is where the increased duration comes in. This is something Herb Becker had begun to recognize for performance from a Norton big twin.

I use 34mm Mk2 Amal carburettors, with the ports tapered back to standard just before they open out in front of the valve. I would never open them out right down to the valve, and fit bigger valves. I think that when you do that you drop the gas speeds too much at low revs, and low revs is what commandos are about. I believe that when you build any racing motor you must choose between top end and torque. If your breathing suits top end better, you are comitted to reving the tits off the motor, and I've looked long and hard at the crankshaft and the cases in the Commando engine. They just won't cop it. A pre-unit Triumph engine, is not a better engine than the commando. If you are going to develop the commando to behave in the same way, better to start with a Nourish Weslake engine. It would be cheaper !
I get a bit of a laugh when I think about the compression ratio I am using with the methanol fuel. It is standard about 8.5 to one. However you don't need to run sky high comp ratios to get benefit, it works on latent heat of vaporisation and even at low comps, it is great. I am really impressed with the way my 2 into one exhaust works. When I made it I made a bit of judgement based on past experience with my old Triumph, the header pipe and tail pipe lengths are pretty much a fluke towards being right, but I believe the diameters are critical.

I've seen Herb Becker with Doug Mcrae's bike on Youtube. He looks like a wise old snoozer. I'm glad my thoughts on road racing might help you guys to go a bit faster. I've had a really bad upbringing, and I raced an uncompetitive four stroke twin for far too long. You don't become a good rider by riding a bad bike, and I've never subscribed to the idea that 'big is better'.