It's a long way to 920 type(rary)

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Fast Eddie said:
Yves, my dyno testing showed that the velocity stacks make only a VERY small difference. Meaning less than 2bhp, which is basically something you wouldn’t feel.
So my money is on the difference being the main jets...
Click to expand...

You’re probably right although the change from velocity stacks to air filters can make a substantial difference for example when I swapped the fitted flat pancake filters from a double Mikuni kit for velocity stacks.
 
Next week I will put the velocity starcks back on the carbs and keep the same main jets, what I don't understand is why, with my first 0.6mm HG, the one that blow, I was using 145 main jet if I remember well, and the bike was very fast and after the dyno run it show even to ritch, and to day the bike was maybe faster with 170 main jet.
I am using a 0.5 mm HG now, can this explain that I have to ritchen the main jet so mutch?
At the moment I feel happy with the setting, but I always wish to understand why?? feel free to give me your well estimated opinion
Hope to have a good ride to the classic races at Chimay this WE
Thanks
yves
 
Yves, I get the impression that whilst you are also changing the compression, albeit not much, you are close to an area where you are also potentially changing the squish effect? If so that may be the major effect.

Though we should not forget the changing season and the changing humidity Belgium can be famous for, which may be even more significant!

For road use, especially on gritty Belgian roads, if it can be made to run well with filters, surely that is also important.

Also on the road, how much of the time are you really running directly on the main jet? are you content with the needle and needle jet at 3/4 throttle?

I am not running on the main jet only for very long on tight French circuits. Just enough to confirm, as at Carole, when closing the throttle a little increases performance.

Enjoy Chimay, hope to see you at Gedinne.

Steve
 
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Steve, that is certainly true...yesterday evening I took the Norton around 7pm to go for a drink with friends, temperature was still around 28c° and the bike was going absolutely fine. At around 10pm, the temperature had dropped down to about 18c° when I left and went home through the Bois de la Cambre twisty road, the old girl was roarring like a tigress in heat! The difference felt amazing!!!
 
Yves, in theory at least, your slightly tighter squish should want a slightly weaker mixture!

Out of interest, what needles are you running? I discovered mine was weak on the needle, something which is not easy to discover when you have accelerated pumps dumping load speed of fuel in on acceleration !

But, the 2:1 pipe is very different, that requires a much leaner needle.

But both set ups a fine with the same main jet.
 
Fast Eddie said:
Yves, in theory at least, your slightly tighter squish should want a slightly weaker mixture!

Out of interest, what needles are you running? I discovered mine was weak on the needle, something which is not easy to discover when you have accelerated pumps dumping load speed of fuel in on acceleration !

But, the 2:1 pipe is very different, that requires a much leaner needle.

But both set ups a fine with the same main jet.
Click to expand...
HI Nigel,
I use a EMR needle, this one is leaner as the EMT original. To day I put the velocity starks back on the carbs but keep the 170 main jets, did a test ride and believe it or not
I have the same problem, maybe I should go for even more bigger main jets, but the biggest I have are 175. So I will go back to the K&N filters like yesterday, this was top!!
The fact that the bike was runing leaner with the velocity starcks, let me think that more air are comming in the engine, so, if I can adapt the main jets the bike will go faster no?
Tomorow I will put the Keihin's back and test ride it again.
Something you must know: On Keihin FCR the main jet start acting from 1/8 trotel opening...
Keep you posted
Yves
 
SteveA said:
Yves, I get the impression that whilst you are also changing the compression, albeit not much, you are close to an area where you are also potentially changing the squish effect? If so that may be the major effect.

Though we should not forget the changing season and the changing humidity Belgium can be famous for, which may be even more significant!

For road use, especially on gritty Belgian roads, if it can be made to run well with filters, surely that is also important.

Also on the road, how much of the time are you really running directly on the main jet? are you content with the needle and needle jet at 3/4 throttle?

I am not running on the main jet only for very long on tight French circuits. Just enough to confirm, as at Carole, when closing the throttle a little increases performance.

Enjoy Chimay, hope to see you at Gedinne.

Steve
Click to expand...
Hi Steve, Inever use the velocity starcks w/o filters, I use Pipercross dual socket air filters over the starcks
See you at Gedinne
Yves
 
marinatlas said:
Hello Bruno, after few beers , evry norton is roaring like a tiger........see you at Nogaro ??
Click to expand...

Well, I (almost) never drink alcool, and absolutely never when I ride a bike. No Nogaro, but I will be in Chimay this WE and Gedinne next month.
 
Hello there,
To day I did a test ride with the 175 main jets, the velocity starcks and the Pipercross dual socket, the only change was raising main jet from 170 to 175, the problem stay the same, f..K!!!
So I put the K&N filters back on the carbs with the special adapters for K&N and the bike was going like the hell, even with the 175 main jets, a good reason to be satisfied, but I still wish to understand why the engine was not working with the velocity starcks with the Pipercross over it and I think I find the reason:
On the back from the Keihin FCR you will find two jets, one is a pilot air jet and the other one is the main air jet, with the K&N adapters the jets are inside the adapters but with the velocity starck they are outside, so to me, the Pipercross create a air turbulence arond the two air jets, you must know that the Pipercross let air in every where, this will maybe create turbulence that affect the jetting??
I remember when I was working for the Kawasaki distributor here in Belgium, we tune a Z 900, the bike was runing fine and fast till we put a fairing on it and this made the Z 900 runing bad, the reason: air turbulences!!
Sunday I go to Chimay, msut be around 400 kms from my home, this will be a good test ride.
Keep you posted
Yves
 
Hi there,
Yesterday I did a test trip from 400 kms, going to the classic races at Chimay, the 920 did it perfectly, carbs setting and ignition timing same to be perfect, I did a part of the road on highway at 4800 RPM, sometime a did a push to 6200, after the highway, I was on B roads with a lot of long turns, what a joy, finally I am so happy, not one problem no oil leaks, the 0.5mm don't blow and the engine is amasing powerfull.
At the track of Chimay, I meet Ralph, aka Storm 42, and is lovely wife Georgina, we did a long chat, Ralph was there w/o bike, BTW Ralph says that he never race, only Parade, but he gat a lot of knowledge about Norton.
Always fine to meet a member of Access live
I will not work this week, Belgium is as warm as the Dead Valley over the 30 degrees Celcius
Keep you posted
Yves
 
yves norton seeley said:
............
I will not work this week, Belgium is as warm as the Dead Valley over the 30 degrees Celcius
Keep you posted
Yves
Click to expand...

Probably not as hot as Albi this weekend, it was showing 36C at times on the camper thermometer read out! High humidity too,

I am so glad we took the gazebo to hide under!

I can also tell you the downside of sitting on a oil in frame bike for 14 laps of a 2.2 mile circuit! 25 minutes of racing gets that oil pretty warm! I made some jetting changes as well, should be even closer for Gedinne! Though being Belgium....maybe it will rain!

I have been learning a little more about Mikuni air jets and main jet interaction, but also went to a leaner needle which gave the biggest benefit!
 
Last edited:
yves norton seeley said:
Hi there,
Yesterday I did a test trip from 400 kms, going to the classic races at Chimay, the 920 did it perfectly, carbs setting and ignition timing same to be perfect, I did a part of the road on highway at 4800 RPM, sometime a did a push to 6200, after the highway, I was on B roads with a lot of long turns, what a joy, finally I am so happy, not one problem no oil leaks, the 0.5mm don't blow and the engine is amasing powerfull.
At the track of Chimay, I meet Ralph, aka Storm 42, and is lovely wife Georgina, we did a long chat, Ralph was there w/o bike, BTW Ralph says that he never race, only Parade, but he gat a lot of knowledge about Norton.
Always fine to meet a member of Access live
I will not work this week, Belgium is as warm as the Dead Valley over the 30 degrees Celcius
Keep you posted
Yves
Click to expand...

That’s good to hear Yves!

Can you tell us you final carb settings please?
 
Fast Eddie said:
That’s good to hear Yves!

Can you tell us you final carb settings please?
Click to expand...
Here you go:
Pilot jet: 58
Pilot fuel screw: 1.5 turn out
Pilot air screw: 1 turn out
Needel: EMR notch 5 from top
Main air jet: 200
Main fuel jet: 175
Note: I change the setting from the accelerator pump also: they start later and the duration of the injection is shorter
Keep you poste
SteveA said:
Probably not as hot as Albi this weekend, it was showing 36C at times on the camper thermometer read out! High humidity too,

I am so glad we took the gazebo to hide under!

I can also tell you the downside of sitting on a oil in frame bike for 14 laps of a 2.2 mile circuit! 25 minutes of racing gets that oil pretty warm! I made some jetting changes as well, should be even closer for Gedinne! Though being Belgium....maybe it will rain!

I have been learning a little more about Mikuni air jets and main jet interaction, but also went to a leaner needle which gave the biggest benefit!
Click to expand...
It's only raining once the year here in Belgium, mostly 355 days on a row
Yves
 
yves norton seeley said:
Here you go:
Pilot jet: 58
Pilot fuel screw: 1.5 turn out
Pilot air screw: 1 turn out
Needel: EMR notch 5 from top
Main air jet: 200
Main fuel jet: 175
Note: I change the setting from the accelerator pump also: they start later and the duration of the injection is shorter
Keep you poste

It's only raining once the year here in Belgium, mostly 355 days on a row
Yves
Click to expand...

Thanks Yves,

When you say “one notch from top” I assume you mean one notch from leanest setting (ie you’re referring to the clip, not the needle)?

What about the stacks, is this with the stock stubs and K&N filters?
 
Fast Eddie said:
Thanks Yves,

When you say “one notch from top” I assume you mean one notch from leanest setting (ie you’re referring to the clip, not the needle)?

What about the stacks, is this with the stock stubs and K&N filters?
Click to expand...
I put the clip on grove 4 starting from the top of the needle
The velocity stacks are they provided by CNW, also the K&N adapters are from CNW to
Billet intake manifold are also CNW
Yves
 
Ok Yves, I understood the wrong way around! So you have them on almost the richest setting?

And your current set up that you are so happy with is with the K&Ns and cNw adapters?

Your engine is very similar to my ‘work in progress’ 920, hence my interest!
 
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