Effects of Air Intake in carbs....

[BroHay]

well, I've been pickin' individual brains over the past few weeks and now I guess I'm going to make it public and get more insight on the matter.

'01 that I'm looking at doing the work on as far as carbs are concerned.

jet kit/airbox mod/K&N/port boots/timing advance/muzzy exhaust--

I started to disassemble the bike to put the new body and decided to crack open the airbox to see how bad I was looking. to my suprise, I already had a K&N filter installed w/o any of the mentioned mods.

I looked on rt/lt side of the carbs and I still have the plug inserted where the mixture screws are located -- so I'm assuming that nothing has been done in terms of a slip-on jet kit.

Elevation is about 5200ft for day to day riding but I can get up to 7k+. Here where my query starts.....

since I'm at a higher elevation, what are the affects of having the K&N filter installed without any of the other mods? I know that if I were at a lower elevation, I'd probably be feeling the effects.

I'm slowly learning my way around the machine, and looking for some of the basic principles as why increased airflow at different elevations impacts the performance of the bike.

I'll start here and let the topic grow as I have a better understanding, or as others chime in....

.....plus it'll benefit other who might have similar questions....

Thanks,
Adam

 

[Lonerider59]

Good Morning Adam.
If you are still running the stock jets and only the K&N and pipes have changed, you may be running a bit on the lean side if you were at my elevation (about 1300'). You are quite a bit higher and if you were in Flag or equivalent you'd be nother 1500-2000' higher where the air is even less dense. If you remember the A/F meter I had on my bike to track my mixture, I noticed that I was running richer around your area than when I was at or close to the desert floor. In Albaquerque I was running right around 12.5:1 at most cruising speeds here at home I'm running about 13.1-13.7 at the same speeds. At higher elevations the air gets "thin" in other words, there are less oxygen molecules per given quantity of air but as elevation decreases and pressure increases, there are more oygen molecules per the same given quantity of air. So... to keep the A/F ratio about the same, as the air thins, or has less oxygen, the fuel intake system also needs less fuel and as the elevation decreases so the air gets thicker or has more oxygen molecules, you need more fuel to keep the same ratio between oxygen and fuel. One of the things an A/F sensor does on a stock bike like mine is to try to keep the A/F ratio at the correct ratio when it detects unburned fuel in the exhaust. Mine has been eliminated because of my MIVV and I have replaced it with another unit so I can monitor the ratio, so it's not getting to the computer to have any effect. One of the best aspects of a good EFI system is it's ability to modify the A/F ratio all by itself without the rider/driver having to do anything. With a carbed setup like you have, modifying the jetting is about all you can do (easily). Any modification of the intake track will have some affect on the flow and consequently the ratio of fuel to air because of the venturi effect in the carb body. I'm not even close enough on experience with the FZ1 carbed intakes to advise on the right jets for you elevation but there must be somebody on here who has already done it and got it right. Remember though, if you move to a location that is a lot lower or higher, you will more than likely be re-jetting.
Aren't you glad you asked?

Don

 

[NJFZ1]

With everything else being stock I doubt that a K&N filter will make much of a difference on your bike. Once you start opening up the intake and exhaust then it's a different story since it will have the ability to flow more air than stock.