143MPH 850 MK1 Commando?

Hobot · Jan 13, 2012

I've chased a predisscussed ride with a carfe'd hopped up R/90 and it was a terrror that sounded great to keep up with no my '00 Sv650. But was low like cafe's so lean limited. Gosh how I'd love a Cdo that goes 160 before the strong pull lets off.

72Combat · Feb 6, 2012

Just reviving an old thread...
I have built up a BMW racer as a budget alternative to thrashing my Commando or Ducati....
After 5 years got it finished last week and raced it over the weekend here at the Pukekohe Festival.
There are lots and lots of Nortons there...Manx's and Commandos.
My group was open post classic and I was happy for my first ever time on a race track racing just to circulate and take in the atmosphere.
I have done 2 levels of the California Superbike school and 3 track days in prep.
I was pulling 6500 down the back straight and the three Commando blitzed past along with the 900SS ( the 900 SS was doing 1.10m ,160 kmph laps on the 2.84 km circuit)
I estimate they were doing 130 plus MPH....awesome.
I was able by the end of the day to do a 140 kmph lap.... managed to beat a BSA Gold Star and Rob North Dunstal Commando..won the race did a 1.23 fasted lap..made my day...week...year....
I know this is a Norton forum but heres a pic of my entry... ( it has a Norvil fairing) I doubt it has much over 55 HP....its faster than my Triumph Thruxton ( handles about the same.suspension is better..and is lighter)

209 finished 2 seconds ahead of me.

sorry for posting a BMW...I'll never do it again. :roll:
Anyone here in NZ wanna buy a Thruxton NZ $7700 and its yours.

Matt Spencer · Feb 6, 2012

You seen the old ' Two wheels ' artical on the Pridmore R90S & F 750 BM' s ? .Titanium Conrods ! .
We'll let you off , But Next Time ' Anything Else' motorcycle related unless ' Other Classic ' etc .

GEES Classic Bike is full of the Jap Stuff that was current , when It first Came Out . :shock: :lol:

72Combat · Feb 6, 2012

Matt Spencer said:
You seen the old ' Two wheels ' artical on the Pridmore R90S & F 750 BM' s ? .Titanium Conrods ! .
We'll let you off , But Next Time ' Anything Else' motorcycle related unless ' Other Classic ' etc .

GEES Classic Bike is full of the Jap Stuff that was current , when It first Came Out . :shock: :lol:

I have read some of the stuff that the US guys did to the airheads...pretty trick stuff.
All I have done is raised the motor, sports cam and dells...original 1973 pistons, rods etc. Many of the Commandos entered had DNF next to them....fast but fragile.
There was one Norton that had the crank out....and more than one Triumph all in bits.....next time I'll sprinkle some tools, parts and oil around to try and fit in... :wink:

Classic Bike is $16.00 here.... stuffed if I want to read a SR500 Vs BSA Goldstar test.....I'd rather read the posts here....way more amusing and helpful.

Matt Spencer · Feb 6, 2012

Sounds like they need a good mechanic ! With a Big Stick to Whack them if they overrev them !

8)

These old cows , the 72 F 750 Longstrokes , were timed around 150 / 155 .Getting back somewhere near the original subject

Apparently williams never went past 7.600 on the long strokes , So tell them , Its the Gallows , for those that do . :lol:

grandpaul · Feb 6, 2012

Nice 'Toaster'.

Well done.

Matt Spencer · Aug 21, 2012

155.17 mph Qualifying and Fourth Place Finish . Daytona 1972 .

If Brooklands hadnt been trashed , they could have tested the swing arm fuel pump , 74 , before the race .

Matt Spencer · Aug 21, 2012

http://commando.yolasite.com/performance-mods.php

P.S. heres the drawings from the service bulitens . Also in the rear of the ' Clymer ' Commando manual .UNFORTUNATELY they have NOT shown the
correct drawing for the 27 1/2 degree intake valve ' full hemi ' head . As per Norvil / Dunstall . Which I believe was included and fitted to the ' 850 '
as the " stage 3 " .AS both drawings appear identical , bar caption .

acotrel · Aug 21, 2012

'To go that fast the bike would have needed at least 80bhp at the rear wheel, and or a very effective lay down streamliner type chassis. '

To go that fast in what time and on what circuit ? Everything is not about horsepower. Using a lot of gears and a torquey motor with a good fairing can give a similar result.

beng · Aug 21, 2012

Cycle World tested the first series of Commando 750 Production racer I think at Riverside and got it a hair over 130mph. I recently read that the 140+mph 850 Commando had some sort of abbreviated fairing on it, which would help out.

The Manx Nortons that were timed on a section of the IOM at over 130mph had full dolphin fairings and were ones prepared by great tuners like Joe Potts or Beart.

It is noteworthy that when the 500cc twin Domiracer placed 3rd and did it's 100mph lap of the IOM, it must have been capable of 130+mph.

With all that taken into consideration, using some sort of production/bikini fairing and a serious 850 engine I don't think that 140+ would be out of reach under some conditions.

Ken Canaga has gone about 143 with a 750 at speed trials before, but I do not remember what sort of fairing he used.

Matt Spencer · Aug 21, 2012

walked into a ' motorcycle ' store the other day . My , how shiney . They ALL looked the same . BM & 675 had almost identical pattern windscreens on the race reps . Definately optimised minimal frontal area . Past the point of Williams endevours , but looked as if you moved your head , youd disrupt the airflow .

Definately say their over developed aerodynamics , and no doubt ' ramcharger ' intakes contribute to their 160 + mph top end capeability .

Phil Read 1972 John Player Norton . 155.7 mph. Daytona Speedway .

Seeing ' our ' 143 mph 850 would be essentially the same spec engine , + 4 mm on the carbs ( 36 mm ) and a wee bit on the bore , the speeds not really off .
Even Nasty BMW ' S ' es had head fairings at that stage of the proceedings . Standard even . :shock:

Then Theres slipstreaming .

Id presumed the later tuned 30M were 60 crankshaft horsepower and in the vacinity of 135 mph on the iom . ( Downhill ) .

J.A.W. · Aug 21, 2012

About 20 years ago Kawasaki sold a roadbike 250 [KR1-S] that from memory [google bot can reference it] was timed on test at `bout 140mph, from ~60hp..