[giancarlo]

hello
Yesterday I removed the air filter to replace it, looking in the 'air box I saw the two intake valves and I noticed that there a bottleneck in the cones of aspiration ...
why? in all other bikes I've never noticed a thing ...
could be a way to limit the intake air amount to the maximum accelerator? I am attaching a picture thanks

 

[SeriousGarry]

I shall reply so you don't get too disheartened by your first post. But to be honest I haven't played with the air box much. Maybe check out the threads to do with the "air box mod". I personally didn't bother even looking at them because I have a TBR exhaust which to be honest is loud enough, but they may be talking about the same parts. ^^^ search bar.
Good luck

 

[bones33]

From that picture it does look like a restrictor. Remove it, ride it and report back. This may be the easy power mod that many people are seeking.

 

[tizzy23]

I cant get a pic on here right now but if anyone else has the service manual this part is on page 7-14. They call it an air funnel. It is held into the throttle body with three screws and there is a rubber seal between them. It doesn't look as restrictive as it does in your picture because it doesn't show the inward angle that yours shows. I guess the question is how much does that taper change the diameter. If it is a significant change and not just a slight change of direction then this part should be relatively easy to pull out.

 

[Xch]

It will be interesting to hear what happens if you remove the funnel as they are usually used to improve low down torque and high end performance by creating a vortex or directing the airflow into the intake properly.

If it is being used as just a restriction then it is likely that you would need to use a map programming device to correct the air fuel ratios from running lean.

 

[tizzy23]

Bump.

 

[Blackfin]

My guess is that Honda put that there as a tumble-generator (i.e. to impart turbulence in the air to get better A/F mixing downstream.

It sure looks like it could be a restriction though. Somebody get in there with a Dremel already (take them off first of course...) :spin

 

[Wavefront]

Hmmm, I did the airbox snorkel mod a while back and don't remember seeing this when I was looking around. Here's a similar photo from my bike. There doesn't appear to be any restrictor like in the OP from what I can tell.

https://www.dropbox.com/s/v3h8pkdxo7ka1th/2014-06-05 12.04.30.jpg

Maybe this is a regional thing?

 

[tothezenith]

Well this is interesting... When I was installing the K&N filter and blanking the PAIR system, I also had a look at my throttle bodies and inlet runners to see if they could do with some massaging. However unlike the OPs image and similar to Wavefront, my throttle body trumpets have no piece of plastic impeding flow (as pictured); actually I was quite impressed with the quality of finish for both the trumpets and runners straight from factory that I couldn't see much gains to be had from a bit of porting and polishing.
I wonder too if this is a regional thing...

 

[Blackfin]

The plot thickens...

 

[Blackfin]

The plot thickens...

A few minutes ago I posted a link to a PDF with all CBR500R part numbers in it. One thing I found curious was that the air cleaner page (see page 90) shows different part numbers for the left and right funnels depending on the market.

Left-side funnel:
- part number is 17251-MGZ-D00 for England, France and "European Direct Sales"
- part number is 17251-MGZ-A00 for Australia

Right-side funnel:
- part number is 17252-MGZ-D00 for England, France and "European Direct Sales"
- part number is 17252-MGZ-A00 for Australia

Unfortunately, that resource does not show the part numbers for bikes sold into North America.

Looks like Wavefront is correct: It's a regional thing. Would be interesting to see if one P/N has the "restriction" and the others don't.

 

[tizzy23]

A few minutes ago I posted a link to a PDF with all CBR500R part numbers in it. One thing I found curious was that the air cleaner page (see page 90) shows different part numbers for the left and right funnels depending on the market.

Left-side funnel:
- part number is 17251-MGZ-D00 for England, France and "European Direct Sales"
- part number is 17251-MGZ-A00 for Australia

Right-side funnel:
- part number is 17252-MGZ-D00 for England, France and "European Direct Sales"
- part number is 17252-MGZ-A00 for Australia

Unfortunately, that resource does not show the part numbers for bikes sold into North America.

Looks like Wavefront is correct: It's a regional thing. Would be interesting to see if one P/N has the "restriction" and the others don't.

I found a parts list from a North American site. the left and right side funnel part numbers end with A00.
All other air intake related parts end with D00.
Except for one.
I found this interesting.
The intake elbow that some people have removed as a mod, also ends with A00.

 

[julman99]

Hello

Reading another post I learned that there seems to be two versions of the inlet funnels. One with a "flap", and another without it.

In specific
17251-MGZ-A00
17251-MGZ-D00

By doing a google search I got to this thread. Did anyone ever swap the flapped intake for the unrestricted one?

I have a CB500X 2015 (US) and according to bikebandit and babbitsonline it comes with 17251-MGZ-A00 , I don't know if that is the restricted version or not.

Thanks!

 

[_Yamato]

@julman99 not yet as far as i know, it's EU countries restriction

i have a pair of unrestricted sitting at home at my window, but before i swap them i want to make a dyno run with the original ones with a modified airbox inlet and filter ... after i swap them i will do the same, the problem is to get the time for that dyno run ...

 

[Kida Lee]

I cant get a pic on here right now but if anyone else has the service manual this part is on page 7-14. They call it an air funnel. It is held into the throttle body with three screws and there is a rubber seal between them. It doesn't look as restrictive as it does in your picture because it doesn't show the inward angle that yours shows. I guess the question is how much does that taper change the diameter. If it is a significant change and not just a slight change of direction then this part should be relatively easy to pull out.

hello
Yesterday I removed the air filter to replace it, looking in the 'air box I saw the two intake valves and I noticed that there a bottleneck in the cones of aspiration ...
why? in all other bikes I've never noticed a thing ...
could be a way to limit the intake air amount to the maximum accelerator? I am attaching a picture thanks

View attachment 16769

Have a look at this, I've heard that the engine produces more power and was capped using air intake restriction.

hello
Yesterday I removed the air filter to replace it, looking in the 'air box I saw the two intake valves and I noticed that there a bottleneck in the cones of aspiration ...
why? in all other bikes I've never noticed a thing ...
could be a way to limit the intake air amount to the maximum accelerator? I am attaching a picture thanks

View attachment 16769

I heard that Honda restricted the CBR500R for the European market by restricting the throttle bodies. I've just watched this video looks interesting also note that they restrict the CBR650R using airflow restrictions (in part remap etc) as well as to make that A2 compatible. The person who posted the video stated he can notice s differance and claimed approx 5bhp increase however how accurate that is reliant on a proper test but it caught my attention.

 

[eds]

This was discussed before.
Most EU countries have the restricted Air Funnel to reduce power for A2 compliance.
AU, US, etc. countries have the normal full-flow Air Funnel.

 

[airhead83]

In your opinions, would these new air funnels alone be enough to require an ECU tune or a fuel controller? Or funnels and a free-flow air filter?

 

[ADIOS600]

Am I right in saying the man said in the video no noticeable change with the alloy trumpets. It sure would be a cheap mod for us euro boys to use the standard us type open trumpets.