1972 Norton 750 Short Stroke Racing Superbike class at CTMP

Racing my Herb Becker built 1972 Norton 750 short stroke in the Period 3 Superbike Middleweight class at the 2017 VRRA race weekend at Canadian Tire Motorsports Park (Mosport). In the heat race on the Saturday, my engine pulley came loose on the start grid and I had to pull off and start the final race here from the back.
Still photo in the video by Dreamcatcher Imaging.
Big thanks to Herb Becker, Fullauto Technologies for their excellent new Commando head, JS Motorsport and Walridge Motors.

[@rcnelson]

Terrific footage and sound. And racing in the rain takes a special kind of skill and courage.

[@winonabigbrownbeavereater2218]

That music coming out of those two lungs is absolutely beautiful !

[@DouglasLMacRae]

Thanks!!

[@winonabigbrownbeavereater2218]

Douglas MacRae You're Welcome 👍 👍 I'd love to mount that two lung iron beast and spin 'er around that track! 😊

[@DouglasLMacRae]

@@winonabigbrownbeavereater2218 You would love it!

[@JohnSmith-de2mz]

@@DouglasLMacRae What is the bore and stroke? Is it larger bore than stroke?

[@DouglasLMacRae]

@@JohnSmith-de2mz Stock is 73X89, I believe mine is 78X81 but I would have to ask Herb, I forget.

[@Zerobullshit.garage]

Fantastic racing. You had the FLOW !!! GREAT !!!!!!!!!!!

[@DouglasLMacRae]

Yeah! Thanks Ulrich!

[@davidmarshall1259]

wow, that motor sounds in fine fettle. absolutely fantastic sound, and you're not exactly hanging around. nice to see the old Brit iron still kickin ass.

[@DouglasLMacRae]

Thanks David!

[@martinburke362]

@@DouglasLMacRae what kind of horse power the old girl putting out the best of the factory racer put out about 78bhp at the crank

[@DouglasLMacRae]

@@martinburke362 We got a e best of 78 hp at the rear wheel on the dyno from the short stroke

[@martinburke362]

@@DouglasLMacRae mick grant would be proud of you read a big article about his races with cal rayborn he had against the xr harley he said the harley always had it down the straights but the Norton done it through the twisties

[@DouglasLMacRae]

@@martinburke362 Thanks Martin! the Norton is always lighter and more agile...! While shooting it, I rolled an ex-Cal XR Harley around, I have no idea how he went so well on it- it's a beast!

[@pinslayer4579]

Smooth great entry and mid corner momentum old girl seems to get even longer legs when she huffs a little blue. Great ride you're definitely one with your bike it was true art watchin you reel the front runners in.

[@jimstrainsandstuff9539]

Those Norton twins just purr when they're set up right. This bike is one of them. Just love em. My Dad and his brother both rode Nortons way back in the late 1940s. I think it's in my blood! Thanks so much for sharing the 'cab ride'.

[@DouglasLMacRae]

That's cool! Glad you enjoyed the video...!

[@ronniesutherland108]

Excellent video 👍 , straight into the racing, no messing about, very enjoyable

[@DouglasLMacRae]

thanks Ronnie!

[@MrPnew1]

Great Doug, you just tore through that pack like they were standing still. Fantastic.

[@DouglasLMacRae]

Thanks Pedro!

[@cecilwilson5442]

Great to hear and see giving the big 4s a good run for their money,, sees like a great race series you Canadians have going on for era motorcycles,, bloody brilliant viewing,, from Northern Ireland greatly appreciated ☘️☘️☘️☘️☘️👍👍

[@DouglasLMacRae]

Thanks Cecil! The VRRA run a pretty good vintage race series here

[@RE650NZGraeme]

Great vid to watch - that's two now!! Really enjoying you coming from the back and catching the front guys! Even in that class, and you are a biggish guy on a Norton kicking ass! Loved the sounds. Due for a track day shortly myself in our summer in NZ.

[@seandunn3116]

Great riding, surprising top end from the twin compared to the 4s, great racing video

[@DouglasLMacRae]

Thanks! It is all in the power to weight ratio, it makes good power and is very light

[@seandunn3116]

@@DouglasLMacRae so what are the specs Douglas, I'm thinking 350 lbs, 75 hp??

[@DouglasLMacRae]

@@seandunn3116 I weighed it with no fuel and it was exactly 320 lbs. The last time I had it on the dyno it did a best pull of 78 hp at the rear wheel with a great torque range as well

[@seandunn3116]

@@DouglasLMacRae Good figures Douglas, but nothing without a skilled rider, I'm enjoying your video's, it would be great to see some shot's of you and the bike racing not from on bike cam, hard I know but just a wish!

[@DouglasLMacRae]

@@seandunn3116 So would I! Problem is I always am at the track on my own and all my fellow racer buddies are busy with their own racing...

[@arnoldmosk494]

What a brave fantastic bike , sounds like a dream and still kickin' ass!! stay save !!

[@DouglasLMacRae]

Thanks Arnold!

[@michaelegan6092]

Wonderful stuff, I used to use a local motorcycle shop which wasn't far from the Norton factory and they had some interesting stuff. A monocoque Norton was sometimes there until the stupid owner filled it with fuel while smoking a cigarette-- Exit one bike. For reasons that I won't go into, the Norton storeman was very generous to them, they ended up with works forks etc. but the one thing that intrigued me most was the short stroke crankshaft that they had. It was one piece with the middle of the crank consisting of a machined high tensile tube, with the mainshafts and discs that were welded into the tube being one piece. Instead of having a splined shaft for the primary take off it had a ground taper. All very unusual but extremely stiff. I was told that the engines gained 2 bhp by using steel pushrods to avoid flexture and another 2 bhp by using cast iron camshafts instead of steel for the same reason. Happy days.

[@jesseshepherd10]

Puff of smoke on the overrun. Valve guides going. I raced a 73 production Norton. Great bikes.

[@DouglasLMacRae]

It always puffs on the overrun, even with a brand new rebuild, we don't use valve seals as they get in the way with big valve conversions and they melt down with high revs. That's very cool you raced a production racer!

[@marlecmarine5393]

Really great ride !! If the two guys in front had not held you up you would have won from the back of the grid........:-) fantastic camera footage. I used to club race a 750 Norton Commando in a Rickman frame back in the mid 1970's and 1980's. It was prepared by Gus Khun Motorcycle dealership in south London where i worked for a few years, I 'd blast past the BMW's on the shorter circuits, they were more suited to endurance racing where they did well.

[@DouglasLMacRae]

Very cool! That would have been a nice ride! I have raced against some fast BMW's but usually I beat them...

[@bigred8438]

Great ride and wonder full video. You did well. I think in my country, if this is historic racing, your bike would be put in period 4. Period 3 is for bikes between 1946 to 1962.

[@jonpage4029]

That was an amazing ride sir

[@chrismoody1342]

Dude rides like he stole it. Very commendable job.

[@DouglasLMacRae]

Thanks Chris!

[@threepot]

Fast Norton,and well ridden!

[@DouglasLMacRae]

threepot Hey! Thanks a lot!!

[@MervandtheMagicTones]

@6:41 Nice little battle there with the 182 bike!

[@DouglasLMacRae]

Yea, that was good fun...!

[@sup3rbird]

I could listen to this bike ALL DAY! (Please excuse the shouting, I had the volume right up)

[@DouglasLMacRae]

Harry Irvine Thanks Harry!!

[@briancritchley5295]

SPECK UP i CANT HEAR YOU..

[@ToddSloanIAAN]

Pow! I gave the 400th thumbs up!! That Norton sounds so good what are Rush

[@DouglasLMacRae]

Thanks Todd!! Good to see this video still doing well!

[@martinsinclair55]

Can u tell us the details of your motor build😢?

[@grantsnell6782]

You have good top end on that bike!

[@DouglasLMacRae]

The Herb Becker motor rocks!

[@Team-fabulous]

Fantastic

[@DouglasLMacRae]

Thanks!

[@graemebrumfitt6668]

Shiiiit she sound Beautiful :) thanks for sharing 'TFS' GB :)

[@DouglasLMacRae]

thanks a lot!

[@jagitmax]

What does it mean by short stroke racing ?

[@lubricantrc3244]

GO Norton

[@tamasgocza7444]

Hi, Very good race! The Norton power is british horse power! Are You use outrigger bearing the Nourish/Triumph gearbox? Thank You!

[@DouglasLMacRae]

Hey Tamas! Thanks! I don't use the outrigger but it is probably a good idea, I know a Norton sidecar racing outfit that uses it. That is indeed the Nourish/ Triumph gearbox I use, it works OK for a 5 speed, I have had some downshift issues with it- I would much prefer a TT box but I can't afford it...

[@tamasgocza7444]

+Douglas MacRae ThankYou Douglas the answer! I read earlier lot of books,that big Triumph (850, 900) used outrigger. I am making the 910 ccm Nourish Weslake and to reflect on useing the outrigger. The high gear bearing and the clutch far apart.... Congratulation this Norton, its very quick and good sound engine.

[@Unime69]

I was trying to get some shot at the hairpin. Holy rain!!

[@DouglasLMacRae]

Unime69 Yes, that was some hardcore rain when it came down...!!

[@doucemaniac]

Is this a stock frame with stock isolastic mounting?

[@DouglasLMacRae]

Hi Tom. This is a stock frame with stock isolastics but there have been a number of modifications- for a detailed description, I did a post on the Access Norton page a few years ago, you can do a search on it, I called it something like 'Norton Commando handling secrets revealed' I think. In brief, there is a frame member added and a aluminum block added under the trans with teflon sliders to eliminate all side to side movement- also eccentric steering head bearing inserts sharpen the rake 2 degrees, custom reduced offset triple trees, some frame bracing here and there and a custom made interference fit headsteady help. Also we welded a plate to the back of the trans cradle and made an adjustable mounting point for the swingarm pivot and we have it slightly higher, 3/8" or something like that, I forget- when we got it working good, we never changed it.

[@DouglasLMacRae]

It is a stock frame with normal Isolastics but some trick modifications have been done including an aluminum block under the transmission cradle which has teflon embedded in it- this fits up inside the cradle from below and allows the cradle tomove freely back to front but not side to side at all; I can lays this bike on its side through a corner at 100+ mph without a wiggle... I did a whole write up on all the handling mods we did to it with photos on the Access Norton blog, do a search there if you want a more detailed explanation. Thanks!

[@toniaharrison8978]

Was that a Hailwood replica Ducati in there ?

[@DouglasLMacRae]

That was Mike Heggarty on his Ducati, not a MHR but I believe was a TT 650/750 (better for racing)

[@superbikebox]

Top !!!!!

[@critchley3819]

Could someone explain to me the Norton 750 short stroke...

[@DouglasLMacRae]

brian critchley Hi Brian- a 750 short stroke is when you take a regular 750cc motor, 73mm bore (width of the hole) and 89mm stroke (up and down) and using a custom crank, barrels and rods you change the bore up to say 80mm and the stroke shortened down to say 81mm(these are not the correct numbers, I would have to look up what mine are, just for example) - now you will have the same displacement, 750cc but with a larger bore and much shorter stroke; with a shorter stroke you get more revs, and with more revs you get more power and you go faster.

[@critchley3819]

Who first developed this, was it factory? know all about long & short stroke engine design, so I don't need lessons, just an answer to my first two questions,, Thank you..

[@DouglasLMacRae]

The Norton factory did a short stroke Commando racer but privateers were doing their own at the same time, there were also a number of Commando short stroke dirt track racers done by privateers like the Ron Wood and Axtell Nortons

[@darkdestroyer6634]

If memory serves (it's a bit hazy and a lot of beer has flowed under the bridge since my Brit-biking days) you could order a short stroke proddie racer from the Norton catalogue for a brief time. But I was always led to believe they were few and far between.

[@DouglasLMacRae]

Yes, if someone has an original factory short stroke, they are worth big bucks as they are rare...!

[@martinburke362]

My Bsa Bantam turbo would blow this thing into the weeds🏍️🏍️🏍️

[@DouglasLMacRae]

Well all right!

[@derekheuring2984]

I'm interested on what the top end (speed) of your bike is. I had a 1968 P11A that I bought used as a teen ager and was surprised how much faster it was than my friends' motorcycles. I believe the motor was stock although it had Dunstall mufflers installed. If the speedometer read correctly, it was still pulling at 105 mph and that was with a friend on the seat behind me. I grew up in West Vancouver, British Columbia and we would race from there to Squamish at night. If you're familiar with the 'Sea to Sky' highway you know how twisty it was but my Norton with the featherbed frame left everyone else in my dust.

[@azuwarizzorizzo318]

Liyf ironman lyfe

[@tonioruben]

6 gears

[@amelierenoncule]

Do you find that the power-plant is down on torque, mon amour...'cause of the short stroke? What red line does it employ? imgur.com/w24PGkx

[@DouglasLMacRae]

I am not revving it over 7200 here, it will rev up to 8500 but no need. Much to my surprise when we built this motor is that it is a torque beast, pulls like a train. We could sacrifice some of that torque for some more revs though, need to play on the dyno a bit more still.

[@tonioruben]

sorry 5

[@DouglasLMacRae]

Yep, 5 gears make it much easier to go fast...!

[@charliebrown4624]

Good bike, crap rider.

[@MrPnew1]

Funny that, I go to your channel and it says "This channel doesn't have any content" UR a real loser