Inlet upgrade?

[City Garage]

And finally this with the black 30 deg silicone elbow :


The aluminum intake runners match the intake ports almost perfectly now .

I don't recall if I asked. All your tuning was done in this configuration not with the airbox, correct?

 

[TonyA]

I don't recall if I asked. All your tuning was done in this configuration not with the airbox, correct?

Hi Lance , Yes , When I brought it to get tuned with the DynoJet PCV it was like this.

 

[TonyA]

Hi Lance , Yes , When I brought it to get tuned with the DynoJet PCV it was like this.

Has anyone ever tried a throttle body porting service. ? I have been looking into doing this for the Norton 961. I am hoping to achieve 40mm at the throttle valves and 48mm at the air filter entry . Then tapering down to the intake port which is 36mm on the Jenvey throttle body/head . I will eventually be porting the head using the technique I have been reading about. Nothing drastic just well thought out improvements.

 

[City Garage]

Hey Tony,

We had someone look at this for a customer, and the feeling was removing the airbox was the best "improvement" that could be done besides ECU tuning because the Jenvey is straight/tapered and gets smooth air behind the cylinder, unlike a Harley (side sucking)

One thing to keep in mind is that a larger on enlarging TB means a lower velocity, which affects lower rpm cylinder fill

The issue that also came up was the exhaust-to-intake ratio.(Not air/fuel) The percentage was really low, as designed, so adding more air was detrimental, but smoothing it out was beneficial. Also, as a side note, there was some power improvement with the restriction of the exhaust versus an open exhaust when we conducted testing on a Cone Engineering pipe we were also considering making

Also, the casting on Jenvey is really rough, so that was also thought of as an area of improvement, but then it was discussed that having it rough helped hold the air concentric and allowed it to move more efficiently. who knew...

If I recall, you already removed your box and are running K&N so you are ahead of the game.

The guy you want to talk to about porting would be Hammer Performance, or reach out to Jim Schmidt here on the Commando side, to talk theory with, as he is really a guru about porting. I would reach out to him as well.

Also, if you need an extra body to mess with, I'll make you a good deal on one!

 

[NorTriDuc]

If you’re looking for power gains, the TB isn’t the place to start.

 

[TonyA]

If you’re looking for power gains, the TB isn’t the place to start.

Thanks for the advice guys.

 

[Gojuu]

Hey Tony,

We had someone look at this for a customer, and the feeling was removing the airbox was the best "improvement" that could be done besides ECU tuning because the Jenvey is straight/tapered and gets smooth air behind the cylinder, unlike a Harley (side sucking)

One thing to keep in mind is that a larger on enlarging TB means a lower velocity, which affects lower rpm cylinder fill

The issue that also came up was the exhaust-to-intake ratio.(Not air/fuel) The percentage was really low, as designed, so adding more air was detrimental, but smoothing it out was beneficial. Also, as a side note, there was some power improvement with the restriction of the exhaust versus an open exhaust when we conducted testing on a Cone Engineering pipe we were also considering making

Also, the casting on Jenvey is really rough, so that was also thought of as an area of improvement, but then it was discussed that having it rough helped hold the air concentric and allowed it to move more efficiently. who knew...

If I recall, you already removed your box and are running K&N so you are ahead of the game.

The guy you want to talk to about porting would be Hammer Performance, or reach out to Jim Schmidt here on the Commando side, to talk theory with, as he is really a guru about porting. I would reach out to him as well.

Also, if you need an extra body to mess with, I'll make you a good deal on one!

interesting that, by comparison, the AT Power unit is actually very smooth, and shaftless.

 

[TonyA]

interesting that, by comparison, the AT Power unit is actually very smooth, and shaftless.

Can you describe the shaftless design or image of this. ? Thanks

 

[lcrken]

Can you describe the shaftless design or image of this. ? Thanks

Info on AT shaftless throttle bodies here:

https://www.atpower.com/products/ida-2-cylinder-electronic-fuel-injection-efi-throttle-bodies-itb-s

Ken

 

[NorTriDuc]

Someone needs to either CNC, hand or extrude hone a cylinder head. I’d like to see a stock heads CFM and CC numbers. Does anyone have this info and what specs the stock cams are?

 

[TonyA]

Someone needs to either CNC, hand or extrude hone a cylinder head. I’d like to see a stock heads CFM and CC numbers. Does anyone have this info and what specs the stock cams are?

I thought the opening and closing degrees were in the service manual. I may be wrong.

 

[TonyA]

Info on AT shaftless throttle bodies here:

https://www.atpower.com/products/ida-2-cylinder-electronic-fuel-injection-efi-throttle-bodies-itb-s

Ken

Thanks for sharing this . It looks like the shaft doesn't run straight through making the throttle plates a slimer profile ?

 

[Gojuu]

Thanks for sharing this . It looks like the shaft doesn't run straight through making the throttle plates a slimer profile ?

Probably explains it the easiest Tony.

 

[cliffa]

View attachment 121523

Probably explains it the easiest Tony.

How the heck do they assemble those?

 

[TonyA]

View attachment 121523

Probably explains it the easiest Tony.

Very nice , thanks again.

 

[City Garage]

Smooth ports are great for wide-open throttle applications. On something like the 961, there are no real benefits. I would fix the oil system on the bike before doing anything else. A 2mm check ball still baffles me

 

[TonyA]

Finally got the throttle body back . 40mm at the throttle valves now and 48mm at the air intake . I love looking at them and runs great !

 

[peebee]

Finally got the throttle body back . 40mm at the throttle valves now and 48mm at the air intake . I love looking at them and runs great !

What are you going to do about filters.?

 

[cliffa]

Finally got the throttle body back . 40mm at the throttle valves now and 48mm at the air intake . I love looking at them and runs great !

Nice Tony!, who did the work for you? Any change in performance?

 

[TonyA]

What are you going to do about filters.?

I am using the K&N filter setup I had before.