More Power Vicker!

I know, I know, it’s not about the numbers, it’s powerful enough, that’s not what the bike is all about!

Just wondering, dare I start a thread about the possibility of extracting more power from the Norton 961 parrallel twin push rod motor!? I am yet to go down a tooth on the front sprocket which I understand will give me greater acceleration.

Don’t tell me you have’nt thought about it!

Steve
Sunshine Coast

The sprockets are available from CNW (made by John Snead Co.). They were available last I looked. Do you have another source ? You can also play with the rear size a bit. I went the other way and have a 47T on the rear which works well for highway touring use. 47T is smallest without shortening the chain by 1 link. Also 47T seems to be about as tall as I would go without affecting low speed drivability . (47T rear = 19.1T front ) . Another benefit of the 47T rear gearing is my speedo reads spot on.

We should ask Raphi what he thinks of the change , when he went down 1T in the front sprocket . ? Also , the Coote's have done this when the front sprockets were being developed with John.

I’m waiting for someone to market a small, lightweight, efficient supercharger...

No way I can ignore this thread.
Everything is better with more power!

https://www.1000ps.at/modellnews-3002501-triumph-thruxton-r-kompressor

A German company makes a cute little supercharger for the new Triumph 1200 Thruxton.
Of course the kit installed does severely ugl-ify the bike.
It creates 140 horsepower from the stock mill that makes 97 normally.
Not bad at all.

Like to see some enterprising individual build a similar kit for the 961.
The Triumph is liquid cooled so is able to deal with the extra heat better than a 961 can.

I recall hearing that Matt Capri (South Bay Norton) had developed a big bore kit for the 961, but have heard no more since he folded his shop and silently stole away. The engine is already 10.1 compression ratio, so I don't imagine there's much point in trying to go higher on a street bike. Doesn't look like there's a lot of room for larger valves, but I suspect some hand work on the ports and seats would produce at least some gain. Definitely some HP to be gained with aftermarket exhausts and ditching the cats. About all that's left are higher performance camshafts, and I don't know of anyone who has developed them yet. To really make use of them might require somehow hacking the rev limiter software, and that might not contribute to engine longevity. One of the problems with any of these mods is being able to tune the engine management properly for them. At the moment, the only options appear to be either hacking the ECU to change the fueling map, or fitting a Power Commander.

The other thing that would improve performance is dropping some weight. It's a bit of a pig in that area, but loosing a significant amount of weight could get really expensive. Think titanium and carbon fiber.

And then there's the over-the-top stuff, like superchargers and nitrous oxide injection.

Ken

TonyA said:

We should ask Raphi what he thinks of the change , when he went down 1T in the front sprocket . ? Also , the Coote's have done this when the front sprockets were being developed with John.

Click to expand...

It is great for torque! If for long distance I would go back to OEM or even up 1T...
Speedo reading is 10% too high with 1T down at front sprocket.

lcrken said:

I recall hearing that Matt Capri (South Bay Norton) had developed a big bore kit for the 961, but have heard no more since he folded his shop and silently stole away. The engine is already 10.1 compression ratio, so I don't imagine there's much point in trying to go higher on a street bike. Doesn't look like there's a lot of room for larger valves, but I suspect some hand work on the ports and seats would produce at least some gain. Definitely some HP to be gained with aftermarket exhausts and ditching the cats. About all that's left are higher performance camshafts, and I don't know of anyone who has developed them yet. To really make use of them might require somehow hacking the rev limiter software, and that might not contribute to engine longevity. One of the problems with any of these mods is being able to tune the engine management properly for them. At the moment, the only options appear to be either hacking the ECU to change the fueling map, or fitting a Power Commander.

The other thing that would improve performance is dropping some weight. It's a bit of a pig in that area, but loosing a significant amount of weight could get really expensive. Think titanium and carbon fiber.

And then there's the over-the-top stuff, like superchargers and nitrous oxide injection.

Ken

Click to expand...

Back in 2013 Matt Capri was preparing a few performance items for the 961. When my 961 arrived in the US in December 2013 I had my dealer call Matt to get one of his first SBN decat-ed exhausts. He told us about some of the performance components he was working on like, 1003cc high compression pistons, big valve ported head, and a split lobe roller cam. The basic 961 design has some limitations though. Matt said that the stock cylinder liners were too thin to go larger than 1005cc (90mm). He was designing a billet cylinder block to go 1100+cc that required boring the crankcase cylinder spigots. Then the pushrod tunnels are the limitation. Before Kenny Dreer sold-out to Garner, Kenny had Doug Lofgren involved in planning performance upgradws for the original 961. So there is certainly some additional performance lurking in the 961. Just too bad that Matt's business went belly-up before he could bring the components to market.

Rather than tearing the motor apart and building it up, I think a supercharger would be a much better idea. Nothing crazy, just something like modern version of the old Drouin units. Modern components, and technology, with an intercooler like the Triumph 1200 units.

Not for everyone for sure, but would be a neat little toy for some of us.

There are a couple of unscrupulous dealers here in the UK advertising used Dommi's with a claim that they have the factory 100hp power upgrades. I asked Olivia the other day if such kits exist and if the Dommi is any different to the Commando and she said no.

This 'used car' dealer is local (ish) to me... https://www.woldsideclassics.co.uk/norton-dominator-dominator-961-with-extras-in-louth-6233762

It sounds like the individual in the video says: "the bike has a decatted exhaust and has been remapped by the factory to make 100 horsepower."
That must be one hell of a factory remap. Where do I get one?
Completely ridiculous!

In fairness to that trader, he’s obviously not a bike guy. I’ll bet he’s simply passing on the BS given to him by the PO !

Thanks for posting the info on Matt's efforts, Fred. I wondered if he was just doing bigger pistons, or if he had sleeved the block out larger. It would be pretty easy to have larger pistons made with the same configuration as the stock ones. If I ever tear mine down, I'll see about having some made by JE, but no plans to do so at the moment. I wondered about the big valve possibilities. The new service manual has really good pictures of the head and the valve seats, and it looks like there is little room for larger intake valves. Might go 1 mm over with the stock seats, but I'm not really sure. I'd have to actually measure them to be sure. I'd still be concerned over valve-to-valve interference with bigger valves and hotter cams. That's one of the issues we have to address with the original Commando engines. There looks to be room for slightly larger intake valve seats, but not much, so you might go even larger, but then I'd really worry about valve interference.

The supercharger idea is appealing, but I'd be a little worried about fitting one with any significant boost with the stock 10.1 compression ratio, unless you want to run race gas all the time. Might also rind that the stock injectors don't have enough capacity for a boosted engine. Still, none of that makes it impossible. And there's also always the option of an alcohol/water injection system to help with knock reduction. I'm thinking a turbo might also be an interesting mod. In either case there is the question of what to do for engine management. The locked ECU prevents us from re-programming it to suit the mods. I'm thinking it might require using a different ECU (megasquirt, Motec, etc.). Always something to keep enquiring minds occupied.

Ken

961 Commando Valves are pretty good size already. Inlet = 44.5 and exhaust = 37mm .

lcrken said:

The supercharger idea is appealing, but I'd be a little worried about fitting one with any significant boost with the stock 10.1 compression ratio, unless you want to run race gas all the time. Might also rind that the stock injectors don't have enough capacity for a boosted engine. Still, none of that makes it impossible. And there's also always the option of an alcohol/water injection system to help with knock reduction. I'm thinking a turbo might also be an interesting mod. In either case there is the question of what to do for engine management. The locked ECU prevents us from re-programming it to suit the mods. I'm thinking it might require using a different ECU (megasquirt, Motec, etc.). Always something to keep enquiring minds occupied.

Ken

Click to expand...

Ken,

TTS Performance who build the Triumph Thruxton R Supercharger use the stock Keihin injectors and install a power commander with custom map for engine management. That's it, and the Thrux is more complex ride-by-wire EFI system. That takes the Thrux from 97HP to 139HP, and a s**tload of extra torque using 8-10 psi boost.
The downside is the kit sells for 4,000 Quid. About $5,300 at the current rate.
If they built a 961 kit it would probably cost a fortune.

TonyA said:

961 Commando Valves are pretty good size already. Inlet = 44.5 and exhaust = 37mm .

Click to expand...

Tony,

If I remember Matt was planning to use 2mm over intakes because of possible interference issues. Even though the performance cam he was developing was only a hot-street cam, not a very high performance one with high lift or long duration.

All those extras with stock mirrors. Oy. Cranked a few too many times. Keeping it off tender.