BritTwit
VIP MEMBER
This is my fantasy.
Love to see someone develop this into reality.
Ollie was supposed to be working on it, Dave Coote too.
I dream about it frequently.
Inlet upgrade?
- Thread starter Al's#5
- Start date
Love to see someone develop this into reality.
Ollie was supposed to be working on it, Dave Coote too.
I dream about it frequently.
lcrken
VIP MEMBER
I also had fantasies about fitting FCRs, but now that I've got the EFI sorted out, it works so well that I've lost my motivation to change to carbs. But I do like the idea of trying to get some more power out of the engine, if I could ever get around to it 
. In that case, larger throttle bodies might be worthwhile to go along with more displacement and a cam update. But that's pretty low on my priority list at the moment.
Ken
. In that case, larger throttle bodies might be worthwhile to go along with more displacement and a cam update. But that's pretty low on my priority list at the moment.Ken
BritTwit
VIP MEMBER
On the Triumphrat forum a member actually adapted 2 Keihin throttle bodies from a Street Triple and cut down the linkages to work on a Bonneville 903. He also went the Hi Compression piston, and cam route and the results were tremendous. The intake manifolds were port matched with the head, but no major porting work was done. I think the TBs were 44mm, or 46, can't remember.
I'm sure the Keihin TBs and injectors can be controlled by the SC Delta ECU, and TBs can be sourced off ebay.
Nice project for a bored 961 owner, no?
I'm sure the Keihin TBs and injectors can be controlled by the SC Delta ECU, and TBs can be sourced off ebay.
Nice project for a bored 961 owner, no?
Time Warp
.......back to the 70's.
One reason I machined new manifolds to fit 54 mm (iirc) SP-1 TB's to one of my TL1000S's.
Later getting 61 mm SP-2 TB's.
Prior to that I had cut down and over bored stock TB's with custom titanium butterflies with an altered seated angle.
Anything would be possible with the Norton 961 if you were so inclined.
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I bought one of these. I will post when it come in.There is somebody selling new 961 Jenvey bodies and injectors complete for £225 (or offers)
Jenvey 38mm Throttle Body / Bodies - MCT Norton 961 - New Old Stock - NOS | eBay
<p>Jenvey 38mm Throttle Body / Bodies - MCT Norton 961 - NOS. Condition is "New". Dispatched with Royal Mail 2nd Class </p><p>Brand new / new old stock throttle bodies built by Jenvey for norton bit suitable for any bike or car that requires 38mm tb’s.</p><p>Will post better pictures soon.</p>www.ebay.co.uk
Here we go finally ! After having found air filters that fit and can flow enough air for a 961 , I have the beginnings of a plan :
After approximating the head angle in the frame , it is obvious that a straight shot is not possible . So , as others have shown a curved intake is necessary : More like this , Naturally , some trimming is in order .
There is also the Harley Davidson curved into the wind approach like Free Spirits of Italy does for the XR1200 or the Triumph Thruxton Intake :
Again some trimming is in order :
I think there really needs to be a Thread dedicated to the Norton 961 performance upgrades.
From the Free Spirits Italy Website :
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BritTwit
VIP MEMBER
Tony,Here we go finally ! After having found air filters that fit and can flow enough air for a 961 , I have the beginnings of a plan :
From the Free Spirits Italy Website :
Are you telling us you're buying a SpeedTwin?
Positioning wrt getting wet needs to be considered, especially if ditching the airbox.Here we go finally ! After having found air filters that fit and can flow enough air for a 961 , I have the beginnings of a plan :
After approximating the head angle in the frame , it is obvious that a straight shot is not possible . So , as others have shown a curved intake is necessary : More like this , Naturally , some trimming is in order .
There is also the Harley Davidson curved into the wind approach like Free Spirits of Italy does for the XR1200 or the Triumph Thruxton Intake :
Again some trimming is in order :
I think there really needs to be a Thread dedicated to the Norton 961 performance upgrades.
From the Free Spirits Italy Website :
I would never say you couldn't give me one ! BUT , I had a chance to buy one and you guys saw what I bought didn't you ? Not a Speed Twin .Tony,
Are you telling us you're buying a SpeedTwin?
In a few quick hours , Intake upgrades like this one from Free Spirits Italy can be installed :
BritTwit
VIP MEMBER
Hot Rod Norton 961 : PHASE 1 , not finished , more trimming and fitting needed.
So far so good. I was trying to form an intake runner with the black hose . I think this is going to work good ! Making it look nice will come later , once I know its worth the effort .
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V
Voodooo
Guest
Tony
Please don’t be offended by me asking this.
but what’s the reasoning?
looks?
performance?
both?
Please don’t be offended by me asking this.
but what’s the reasoning?
looks?
performance?
both?
I did this three years ago when I was fixing the idle issues. Ran fine, although was just a temporary setup at the time with sensors dangling in thin air.
On the subject of increasing the throttle body size it's doubtful there are any gains to be made. If you increase the throttle body size you lose part throttle control as well as reducing the velocity of the air which leads to a loss of mid range torque where the engine spends most of its time. Also if any part of the inlet tract is smaller like the ports then it's a waste of time. But I'd be very interested to see the results of any experiments esp. with before and after dyno runs.
On a side note I got rid of that awful oil/air separator years ago, absolutely no issues now. My little pot only seems to collect water with a smudge of oil.
www.accessnorton.com
On the subject of increasing the throttle body size it's doubtful there are any gains to be made. If you increase the throttle body size you lose part throttle control as well as reducing the velocity of the air which leads to a loss of mid range torque where the engine spends most of its time. Also if any part of the inlet tract is smaller like the ports then it's a waste of time. But I'd be very interested to see the results of any experiments esp. with before and after dyno runs.
On a side note I got rid of that awful oil/air separator years ago, absolutely no issues now. My little pot only seems to collect water with a smudge of oil.
Unraveling the 961 part two (oil in the air box)
There are two shortcomings with the 961 that have annoyed me the most. One is the idle which I've been investigating HERE The other is oil in places it shouldn't be! Neither unfortunately can be fixed with a cable tie! So this thread is going to deal with understanding the oil in the airbox...
www.accessnorton.com
Looking good! Something to watch......now there's a clear path for water from the back wheel, above the hugger, in the wet the filters get soaked. Had to fit additional guard to stop this on one of mine.Hot Rod Norton 961 : PHASE 1 , not finished , more trimming and fitting needed.
So far so good. I was trying to form an intake runner with the black hose . I think this is going to work good ! Making it look nice will come later , once I know its worth the effort .
Fast Eddie
VIP MEMBER
Very interested to see how this performs Tony. The fact that you have long hoses between the injectors and filters is likely to effect things I suspect, and personally I’d be surprised if it was for the better. You have effectively increased the length of the inlet tract, doing this on a carbureted engine definitely effects things, sometimes for the better, sometimes not.
I am working on a plate to cover this area , coming soon.
I did this three years ago when I was fixing the idle issues. Ran fine, although was just a temporary setup at the time with sensors dangling in thin air.
On the subject of increasing the throttle body size it's doubtful there are any gains to be made. If you increase the throttle body size you lose part throttle control as well as reducing the velocity of the air which leads to a loss of mid range torque where the engine spends most of its time. Also if any part of the inlet tract is smaller like the ports then it's a waste of time. But I'd be very interested to see the results of any experiments esp. with before and after dyno runs.
On a side note I got rid of that awful oil/air separator years ago, absolutely no issues now. My little pot only seems to collect water with a smudge of oil.
Unraveling the 961 part two (oil in the air box)
There are two shortcomings with the 961 that have annoyed me the most. One is the idle which I've been investigating HERE The other is oil in places it shouldn't be! Neither unfortunately can be fixed with a cable tie! So this thread is going to deal with understanding the oil in the airbox...
Hello Iwilson , Your work inspired me so to speak. I have ordered a oil breather like the one you fitted and will give it a try.
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