Simplifying the 961

robs ss

robs ss

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I don't own a 961 but know of a couple of friends that have problems with their temperamental beasts.
I have asked the question before without getting any real answer, so...

Why has no-one got rid of the ECU and other "troublesome" bits and simply put on a decent pair of carbs and electronic ignition and go?

It's not as if it's some sort of high performance modern engine, is it?

I know you couldn't put carbs on these modern, fire-breathing 200hp engines - the carbs simply could not deal with the level of "smart" alterations that fuel injection gives these technical marvels.

Without wishing to be too disparaging, a technical marvel the 961 is not.

It's a warmed up - still pushrod - version (yes 270 degrees) of the Norton heavy twin of the late 60's. It's got a split-gear balancing shaft, which together with the 270 degree crank, obviates the real need for isolastics. Other than that - plain 60's.

It's Achilles' heel, other than being extremely noisy, mechanically, seems to be the fragility of the ECU and all that surrounds it.
Why not get rid of it? It isn't required for high performance - or is it?

I realise what I have said may upset some (a lot?) but I feel it is pointing at the elephant in the 961's changing room

Cheers
 
Last edited:
I just replace all the shoddy relays etc for Bosch, pretty reliable then. Dont actually see many ecu faults.
But yeah, a pair of flat sides would be awesome. Im pretty sure I remember Col at Thor telling me he put some flatsides on a hill sprint climbing 961 of his.
 
Thanks Stu - I think the carb side might be simple - pair of FCR 36-37 and a jetting exercise.
The electronic ignition (and I'm ignorant of the 961 system) might require working with someone (like Trispark?) to develop a system to suit. It's probably more about the physical constraints of how to house the system. The existing system must have a crank/cam based sensor. Just maybe plug this sensor into a "new" EI box - without all of the "other" gear (O2 sensors, etc)
I wonder if someone were to come up with a complete carb-based kit - what the uptake might be?
 
Relays and a few sensors have been replaced but apart from when the dodgy starter motor drops the bus voltage and the ECU gets upset my Euro4 961 runs absolutely fine with a stock omex ECU. This proves that the setup is basically sound IF the relays and sensors are all working as they should. And I get 55mpg which I am more than happy about. I work in IT and qualified in electronics so my personal take on it is; why mess around getting your hands dirty swapping carbs and jets and sacrificing the odd chicken and whatever the carburettor setup shamans do to get the horrid things balanced and set up when I can press a few keys and move a few fueling map points sitting in my underpants in a nice warm living room? To me it's the easier option: just kinda what you're used to isn't it?
 
robs ss said:
Thanks Stu - I think the carb side might be simple - pair of FCR 36-37 and a jetting exercise.
The electronic ignition (and I'm ignorant of the 961 system) might require working with someone (like Trispark?) to develop a system to suit. It's probably more about the physical constraints of how to house the system. The existing system must have a crank/cam based sensor. Just maybe plug this sensor into a "new" EI box - without all of the "other" gear (O2 sensors, etc)
I wonder if someone were to come up with a complete carb-based kit - what the uptake might be?
Click to expand...
Unfortunately most companies are not willing to develop bike specific parts for the 961 because of such low production, there simply is not enough money in it for them.
 
Clive said:
Relays and a few sensors have been replaced but apart from when the dodgy starter motor drops the bus voltage and the ECU gets upset my Euro4 961 runs absolutely fine with a stock omex ECU. This proves that the setup is basically sound IF the relays and sensors are all working as they should. And I get 55mpg which I am more than happy about. I work in IT and qualified in electronics so my personal take on it is; why mess around getting your hands dirty swapping carbs and jets and sacrificing the odd chicken and whatever the carburettor setup shamans do to get the horrid things balanced and set up when I can press a few keys and move a few fueling map points sitting in my underpants in a nice warm living room? To me it's the easier option: just kinda what you're used to isn't it?
Click to expand...
Because flat sides sound and look cool :D haha
 
robs ss said:
Why has no-one got rid of the ECU and other "troublesome" bits and simply put on a decent pair of carbs and electronic ignition and go?
Click to expand...
Thank you.
I have suggested just such a conversion before.
Should be a pretty easy work for those with the talent and time on their hands.

1. Ditch the throttle bodies, for a set of port matched, rubber insulated intake manifolds, and a set of 41mm FCR's
Replace the EFI pump assembly in tank with an orifice plate which has a petcock to feed carbs
Enterprising individual can connect a micro switch to petcock to send signal to low fuel indicator light when RESERVE position is selected on the petcock.

2. Ditch the EFI ECU ignition, replace with a Triumph igniter box from a pre-2009 Scrambler (carbed - 270 degree engine.)
The Triumph igniter box has inputs for ignition switch, crankshaft position sensor, neutral switch, clutch lever switch, kill switch, TPS.
The box has outputs to coils, and tach.

2. And of course, a supercharger.
 
The engine was designed for use with FCR 39s. That’s how Kenny original conceived the engine and that’s how the first engines were tested and run and fitted into the pre production bikes.

The complex electronics were added in order to make them compliant with the emissions laws I believe.

Looking around at other bikes, it is quite obvious IMHO that fuel injection and the associated electronics could work. If HD can do it on 2.0L plus twins then there’s no reason it couldn’t be done on the 961. BUT the whole system would need a re-design I believe.

And that’s a heck of a job. And if FCRs work so well on ‘old’ Nortons, even big uns, and they do, then I would suggest they’d work just fine properly dialled in to a 961.

I bought a pair of FCR 39s off of Kenny Dreer when I had mine. But I sold the bike. So I sold the carbs. Ollie Theil bought them, so I suspect he has it all worked out how to make them work well.
 
Stu Bodycote said:
Because flat sides sound and look cool :D haha
Click to expand...
I will admit that having flatsides is good for a bit of willy-waving down the biker's pub but I'm sure Triumph could fashion some convincing smart flatside imitation throttle bodies.....
 
Some pics from Kenny showing the FCRs ...


EOJK5164.JPEG
GHUX2567.JPEG
HOML8115.JPEG
 
Fast Eddie said:
Some pics from Kenny showing the FCRs ...


View attachment 85766View attachment 85767View attachment 85768
Click to expand...
Kenny had the right idea............said this carb guy.
I like the FCR idea, but have to admit that the last 2 years or so I've learned quit a bit about EFI.
I can see the superiority of EFI for sure, if done right, not like the 961 was done.
The Japanese have separate idle air lines to each throttle body, unlike the Jenvey TBs on the 961.
If I were Jinland, and intended to produce 961's, I would buy Keihin EFI systems.
End of EFI issues!
 
Clive said:
I will admit that having flatsides is good for a bit of willy-waving down the biker's pub but I'm sure Triumph could fashion some convincing smart flatside imitation throttle bodies.....
Click to expand...
I still remember laughing at the plastic throttle-body covers on a new Triumph 3 or 4 years ago.
They had been made to look like monoblocs - even had the fake brass coloured tops.
How low can you go?;)
 
robs ss said:
I still remember laughing at the plastic throttle-body covers on a new Triumph 3 or 4 years ago.
They had been made to look like monoblocs - even had the fake brass coloured tops.
How low can you go?;)
Click to expand...
If you want to give an engine a vintage appearance, dress it up with faux Amals.
Imitation is the sincerest form of flattery.
 
Britfan60 said:
Unfortunately most companies are not willing to develop bike specific parts for the 961 because of such low production, there simply is not enough money in it for them.
Click to expand...
I don't think it would be an enormous job to make manifolds and jet a suitable carb. Maybe modify an EFI throttle-body to become simply a manifold to accept a flexible boot. I think that would be quite do-able for most owners in their shed/workshop.
A bit more effort would, I think, be required to come up with suitable EI - but maybe if you got someone like Trispark interested in making something for the 961, it might work.
 
robs ss said:
I don't own a 961 but know of a couple of friends that have problems with their temperamental beasts.
I have asked the question before without getting any real answer, so...

Why has no-one got rid of the ECU and other "troublesome" bits and simply put on a decent pair of carbs and electronic ignition and go?

It's not as if it's some sort of high performance modern engine, is it?

I know you couldn't put carbs on these modern, fire-breathing 200hp engines - the carbs simply could not deal with the level of "smart" alterations that fuel injection gives these technical marvels.

Without wishing to be too disparaging, a technical marvel the 961 is not.

It's a warmed up - still pushrod - version (yes 270 degrees) of the Norton heavy twin of the late 60's. It's got a split-gear balancing shaft, which together with the 270 degree crank, obviates the real need for isolastics. Other than that - plain 60's.

It's Achilles' heel, other than being extremely noisy, mechanically, seems to be the fragility of the ECU and all that surrounds it.
Why not get rid of it? It isn't required for high performance - or is it?

I realise what I have said may upset some (a lot?) but I feel it is pointing at the elephant in the 961's changing room

Cheers
Click to expand...
Block the balance tube, get a Delta ECU. It will probably be cheaper than the carbs, its easier, and it will work better.

Honestly, its a very simple efi system let down by a poor throttle body.
 

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