Hotting Up A MkIII

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I've mentioned before that I have another MkIII being built for me by Baxter's in Iowa but it will be BRG. Don Hoff is the guru Norton builder at Baxter's so I've asked him the question too.

Thoughts and ideas about hotting up a MkIII? I've never heard it discussed. I'm thinking I could have one standard (my red one) and a really wicked hot rocket version (green one). If some prick beats me from the lights during the day, I'll go home and fetch the green one (maybe with 12T sprocket :)) to teach him a lesson or two. Then put it away again for next time.

Has anyone ever hotted up a MkIII? Should be same as any 850 I'd reckon.
I'll send the standing quarter times to 1up3down for inclusion on his data base.

Phil
 
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The same rules should apply an the bills should be just as large :lol:
 
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Hi Phil, I expect they are much the same. Flowed head, bit more compression, 2S cam, big bore exhaust and good air filters all well tuned should be enough depending on how much you want to spend.
 
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I used to have a 2S cam in combination with a flowed RH10 head (by the late Fred Barlow) and standard pistons. OK but not spectacular performance. Not enough compression I guess.
Go for Maney pistons or JS pistons/rods, a good steel US made camshaft (Megacycle/Johnson/Web) and a mild flow job on the head. Try to obtain an RH10 head with 30 mm ports. Big valves not needed for road use. Depending on the camshaft you could get away with .060" oversize Black Diamond inlet valves.
 
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phil yates said:
If some prick beats me from the lights during the day, I'll go home and fetch the green one (maybe with 12T sprocket :)) to teach him a lesson or two. Then put it away again for next time.

Phil
My wifes Suzuki Swift would probably beat a Norton to the next set of lights, :roll: , sorry I looked it up, Mums shopping basket only does a 1/4 mile in 16 secs. :lol: :lol: :lol:
 
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72Combat said:
phil yates said:
If some prick beats me from the lights during the day, I'll go home and fetch the green one (maybe with 12T sprocket :)) to teach him a lesson or two. Then put it away again for next time.

Phil
My wifes Suzuki Swift would probably beat a Norton to the next set of lights, :roll: , sorry I looked it up, Mums shopping basket only does a 1/4 mile in 16 secs. :lol: :lol: :lol:
You can't go a lousy 1/4 mile in NZ without hitting a mountain. Or a kiwi (not protected in NZ).
Mum's shopping basket is nothing but that. A shopping basket.
In NZ, do you all marry your mum's?
 
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Mr.Sparks said:
Hi Phil, I expect they are much the same. Flowed head, bit more compression, 2S cam, big bore exhaust and good air filters all well tuned should be enough depending on how much you want to spend.
What about the 4S cam?
And I'm thinking around 10:1 compression.
The bottom end is strengthened on the MkIII so should handle it fine.
Cost? I don't care. I'm thinking of a serious dragster. Hobot style.
Flowed head sounds good. Maybe even twin discs to stop the mother.

Phil
 
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johntickle said:
I used to have a 2S cam in combination with a flowed RH10 head (by the late Fred Barlow) and standard pistons. OK but not spectacular performance. Not enough compression I guess.
Go for Maney pistons or JS pistons/rods, a good steel US made camshaft (Megacycle/Johnson/Web) and a mild flow job on the head. Try to obtain an RH10 head with 30 mm ports. Big valves not needed for road use. Depending on the camshaft you could get away with .060" oversize Black Diamond inlet valves.
I will be interested to hear what Don Hoff at Baxter's suggests. But all sounds good.
I don't want any bastard beating me off the lights. 12T sprocket is actually feasible.
It will be hard keeping the front wheel on the ground.

Phil
 

SteveA

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phil yates said:
johntickle said:
I used to have a 2S cam in combination with a flowed RH10 head (by the late Fred Barlow) and standard pistons. OK but not spectacular performance. Not enough compression I guess.
Go for Maney pistons or JS pistons/rods, a good steel US made camshaft (Megacycle/Johnson/Web) and a mild flow job on the head. Try to obtain an RH10 head with 30 mm ports. Big valves not needed for road use. Depending on the camshaft you could get away with .060" oversize Black Diamond inlet valves.
I will be interested to hear what Don Hoff at Baxter's suggests. But all sounds good.
I don't want any bastard beating me off the lights. 12T sprocket is actually feasible.
It will be hard keeping the front wheel on the ground.

Phil
Be sure to post the video of you looping it!
 
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SteveA said:
phil yates said:
johntickle said:
I used to have a 2S cam in combination with a flowed RH10 head (by the late Fred Barlow) and standard pistons. OK but not spectacular performance. Not enough compression I guess.
Go for Maney pistons or JS pistons/rods, a good steel US made camshaft (Megacycle/Johnson/Web) and a mild flow job on the head. Try to obtain an RH10 head with 30 mm ports. Big valves not needed for road use. Depending on the camshaft you could get away with .060" oversize Black Diamond inlet valves.
I will be interested to hear what Don Hoff at Baxter's suggests. But all sounds good.
I don't want any bastard beating me off the lights. 12T sprocket is actually feasible.
It will be hard keeping the front wheel on the ground.

Phil
Be sure to post the video of you looping it!
One loop or two?
That will be impressive outside the Mittagong Hotel.
The boys will talk about it for months!!
 
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If money and time and logic over looking enough to think of hobotness, then might pow wow with our Jimmy Hendrix of experimental engines on his path of turbo or driven booster with his EF injection and spend about as much more taking mass off your mind. Ya only live once but done right could make the news papers. With enough lightness and power don't half to worry about Mt's as can hit way over the ton between the close turns so then might reflect on tri-links set up that makes sense of sports bike spanking acceleration.
 
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" Norton MkIII Fastback.
Victa Lawnmower (two stroke). "

Stick ta the Victa . :p :lol: :lol:

One problem in the quater Mile is GEARSHIFTS . Less the Better . Ones Enough . Overdrive lacock de normanville for Trans .

As 24 T give about 135 / 140 mph , 12 T might get you 70 . In TOP , whereas with 24 youd get this in FIRST . :D alternately ,
you could fit a TZ 750 motor . :lol: :lol: :p

There devious secret porting tecniques pioneered by kiwis , unavailable to the General Masses , that would get you there . But
theyre NOT for sale . ! . :lol: 8)

The Factory 4s 36 mm 850 reputedly ran 10s . Ten Fives actually . Which isnt ' tens ' . But you know what drag racers are like .
Into THE Tens , perhaps . The TRACTION wasnt available with a standard rear wheel . Perhaps a SUPERCHARGER or FUEL INJECTION
is required . & / or NITRO , or Nitrous . Or TWO Engines might be simplist . :wink: :)
 

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Assuming you want it naturally aspirated (NA) are you thinking in the 65 HP range, which is certainly not trivial to come by, but is still nicely streetable on good pump gas, or do you seek the full racing entitlement of 75-80 HP on racing fuel? Or are you thinking forced induction and larger numbers yet?

For a NA engine built on this continent, I'd seek the assistance of C^2, i.e., C squared - Canaga and Comstock. In their life times they've built enough, raced enough, and blown-up enough Nortons to know what works as well as the boundaries that shouldn't be exceeded.

The content at the link below always impressed me, as an 11 second vintage Norton is something that I certainly take note of. It's no big deal - a 1974 article describing Bob Trigg making common performance modifications per the factory recommended procedures and design, along with some Jerry Branch head flow work. But 11.8 sec at 114 mph out of a Commando is still very noteworthy to me. At that time few if any street bikes would touch it. In that era I had a 76" (1250 cc) stroked Sportser that ran 11.7 at 117 mph, so the Norton, with much smaller displacement was really boiling at 114 mph.

Follow the link and then scroll down below the large data tables and on the extreme right side of the page there are 4 little images of a Cycle World Article that can be clicked to expand and read.

http://victorylibrary.com/brit/norton-c.htm
 
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Thanks . FINALLY Someones put a LINK to the ORIGINAL ( other than M.C.M but wth ) INFORMATION .
IF the Heads the reangled Dunstall / norvil type finally used with the 4S cam . poore's ' Combat 850 ' ,
regulations forbade . Regulations are for the Guidance of wise men , and the blind obediance of feuls .

EDIT : mutter fume . the Motorcycle Mechainics copy , on the ' continued on Page xxx mentions the Head ,
the 18 in. rear , and the dunlop KR series sticky rubber . IF ANYONE HAS A COPY . :twisted: " STAGE IV " .
http://www.ebay.co.uk/sch/i.html?_odkw= ... &_from=R40
 
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All the hops up listed are worth maybe 25% more power but if really serious then buy Bruce McGergor's proven tested long term Drouin and flat side carb he ran on his stock 850 which could give like 50+% more power if brave enough to load the blower hard enough with throttle snap whiplashes.
 
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hobot said:
If money and time and logic over looking enough to think of hobotness, then might pow wow with our Jimmy Hendrix of experimental engines on his path of turbo or driven booster with his EF injection and spend about as much more taking mass off your mind. Ya only live once but done right could make the news papers. With enough lightness and power don't half to worry about Mt's as can hit way over the ton between the close turns so then might reflect on tri-links set up that makes sense of sports bike spanking acceleration.
Hobot
I've got the money and I've got the time. Just don't have any logic or I wouldn't be doing any of this. At the pub, they don't even ask what I'm doing any more, it scares them. Did I tell you what fine I got for extreme low flying over a farm? One guess who dobbed me in!! But that's an off forum discussion.

No, I'm really keen on this idea of a super hot BRG Fastback, as opposed to my gentle cruisy red one. And now is the time to get all this info together. Baxter's are just finishing off a rebuild and mine is next cab off the rank. So I need to get all this stuff together in my head to tell Don exactly what I want loaded into it. I'm thinking 80hp might be a good target. Maybe more, I really don't know what's possible. This will be low low flying without wings!! But I guess you can get fined for that too!! Just a different regulator.
 

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hobot said:
All the hops up listed are worth maybe 25% more power but if really serious then buy Bruce McGergor's proven tested long term Drouin and flat side carb he ran on his stock 850 which could give like 50+% more power if brave enough to load the blower hard enough with throttle snap whiplashes.
I must be missing something here, as Drouin's data sheet for a Drouin-modified CDO (from the Atlantic Green site) quote 1/4 mi numbers almost identical to the NA numbers from the Cycle World article (Drouin - 11.7 @ 115 mph, vs NA - 11.8 @ 114 mph).

http://atlanticgreen.com/images/AP155r.jpg

http://atlanticgreen.com/ndsc.htm
 
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Matt Spencer said:
" Norton MkIII Fastback.
Victa Lawnmower (two stroke). "

Stick ta the Victa . :p :lol: :lol:

One problem in the quater Mile is GEARSHIFTS . Less the Better . Ones Enough . Overdrive lacock de normanville for Trans .

As 24 T give about 135 / 140 mph , 12 T might get you 70 . In TOP , whereas with 24 youd get this in FIRST . :D alternately ,
you could fit a TZ 750 motor . :lol: :lol: :p

There devious secret porting tecniques pioneered by kiwis , unavailable to the General Masses , that would get you there . But
theyre NOT for sale . ! . :lol: 8)

The Factory 4s 36 mm 850 reputedly ran 10s . Ten Fives actually . Which isnt ' tens ' . But you know what drag racers are like .
Into THE Tens , perhaps . The TRACTION wasnt available with a standard rear wheel . Perhaps a SUPERCHARGER or FUEL INJECTION
is required . & / or NITRO , or Nitrous . Or TWO Engines might be simplist . :wink: :)
I don't like mowing lawns Matt, one of three things I hate in life. The others are making my bed and opening mail. So I don't do any of them. And I get into real trouble for it, another story again.

Yes, 12T might have been getting a bit carried away. I see your point about actual taller gearing relative to horsepower. A balancing issue. If I could get it pulling times in the 10's I'd be real happy. That'd do the job very nicely in Mittagong, or down the magic mile. I'd stick with normal aspiration, don't want big blowers hanging off my Norton. People would think I'd done something to it. This has gotta look pretty normal, until I dump the clutch and disappear miles ahead. I'm looking for the surprise element. I'll screw those kiwis for info on porting. They owe me a few favours from past dealings in the flying world.

Phil
 
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WZ507 said:
Assuming you want it naturally aspirated (NA) are you thinking in the 65 HP range, which is certainly not trivial to come by, but is still nicely streetable on good pump gas, or do you seek the full racing entitlement of 75-80 HP on racing fuel? Or are you thinking forced induction and larger numbers yet?

For a NA engine built on this continent, I'd seek the assistance of C^2, i.e., C squared - Canaga and Comstock. In their life times they've built enough, raced enough, and blown-up enough Nortons to know what works as well as the boundaries that shouldn't be exceeded.

The content at the link below always impressed me, as an 11 second vintage Norton is something that I certainly take note of. It's no big deal - a 1974 article describing Bob Trigg making common performance modifications per the factory recommended procedures and design, along with some Jerry Branch head flow work. But 11.8 sec at 114 mph out of a Commando is still very noteworthy to me. At that time few if any street bikes would touch it. In that era I had a 76" (1250 cc) stroked Sportser that ran 11.7 at 117 mph, so the Norton, with much smaller displacement was really boiling at 114 mph.

Follow the link and then scroll down below the large data tables and on the extreme right side of the page there are 4 little images of a Cycle World Article that can be clicked to expand and read.

http://victorylibrary.com/brit/norton-c.htm
Thanks WZ
This is very good info. 75 to 80hp on racing fuel would be pretty good. NA definitely to keep the machine looking normal and pretty. I can run it on Av Gas with what ever needed to boost the octane rating. I'll find out more about those requirements but I have access to all of that. I'll check out the link you have provided and talk to Canaga and Comstock. Don Hoff the builder has been around Commando's since he bought an S new in 69, so he probably has a few good ideas himself. I'm just waiting on an email back from him.

Thanks
Phil
 
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Matt Spencer said:








Thanks . FINALLY Someones put a LINK to the ORIGINAL ( other than M.C.M but wth ) INFORMATION .
IF the Heads the reangled Dunstall / norvil type finally used with the 4S cam . poore's ' Combat 850 ' ,
regulations forbade . Regulations are for the Guidance of wise men , and the blind obediance of feuls .

EDIT : mutter fume . the Motorcycle Mechainics copy , on the ' continued on Page xxx mentions the Head ,
the 18 in. rear , and the dunlop KR series sticky rubber . IF ANYONE HAS A COPY . :twisted: " STAGE IV " .
http://www.ebay.co.uk/sch/i.html?_odkw= ... &_from=R40
Matt
I can always depend on you to dig up some good information from what must be a huge paper file you have on Nortons. I'm going to discuss all of this with Don Hoff and see what he thinks. I note BTW, a 34mm Mikuni mentioned in there. I'd run with the Mikuni if I can. A hot rod whose idling could still be adjusted whilst sitting at the lights, how good would that be? I'm looking for acceleration rather than top end speed.

Thanks
Phil
 
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