Airbox intake been modified?

[timbo]

Hi all, just looking at my air intake, not having seen any other FJ's I'm not sure how it should be. Its divided into two halves, looks like someone has cut out one half that I assume was previously blocked. Is this a recognised mod to increase air flow?

[Arnie]

Timbo,

The stock '91 airbox intake is a 'horn' on the lid of the airbox which opens to the rear.
I believe that some previous years bikes had airbox inlets on both sides.  Some people put big holes in their airbox to increase airflow.  All these mods (and putting on pods) will add a few hp in some parts of the rev range, if jetted correctly, and will likely add noise and will cost some hp at other rev ranges.

Cheers,
Arnie

[timbo]

Thanks Arnie, I've no idea whether the jets have been changed,do you think I ought block up the hole that's been cut? if the jets havn't been changed will it do any harm leaving it? Cheers.

[Arnie]

Timbo,

Before you go changing anything you need to know what you currentlly have and/or determine how well (or other) its running.

The files section should have some simple procedures (blip test) to help.
Most garages wil have an EGA to 'sniff' the exhaust to tell you if the engine is running rich or lean, at least in no-load situations.  If you can find a dyno shop, they can determine this throughout the range while the bike thinks its on the road.

The FJ engine is pretty tolerant of mixture variations, and is unlikely to be damaged unless your mixture is extremely lean.  If it is that lean, you'll have a very hard time starting it. (is that a safety feature?) :-)

In normal use, you should be getting 'around' 90-110 miles from full to 1/2 full mark on the fuel gauge.

Cheers,
Arnie

[Scooterbob]

In normal use, you should be getting 'around' 90-110 miles from full to 1/2 full mark on the fuel gauge.

Cheers,
Arnie

No Way!  Really?!  I know it has a great deal to do with how a person drives, but I'm lucky to get more than 150 miles before hitting my switch to reserve.  Could I be that far off???  Even with rich mixture, is this possible?  (Mine runs excellent through all rpm ranges)

[rktmanfj]

In normal use, you should be getting 'around' 90-110 miles from full to 1/2 full mark on the fuel gauge.

Cheers,
Arnie

No Way!  Really?!  I know it has a great deal to do with how a person drives, but I'm lucky to get more than 150 miles before hitting my switch to reserve.  Could I be that far off???  Even with rich mixture, is this possible?  (Mine runs excellent through all rpm ranges)

After installing the jet kit (Factory Config 30) and pods, and an inadvertent tweaking of the float during some gas tank work, I was unsure of what the range was on my '89.  While on a ride at the ECSR on Saturday, I was concerned that I would run out of gas on the BRP, and really started to try and conserve fuel during the last 15-20 miles, convinced that I was going to run out.  When we finally did get to a fuel stop, I had gone 212 miles on that tank, but only had burned 4.6 gallons.  Considering that there were several kookaloo moments during the first half of that tank, I was pretty surprised to see that kind of mileage, which is at least as good as it got stock.

Randy T
Indy

[Scooterbob]

After installing the jet kit (Factory Config 30) and pods, and an inadvertent tweaking of the float during some gas tank work, I was unsure of what the range was on my '89.  While on a ride at the ECSR on Saturday, I was concerned that I would run out of gas on the BRP, and really started to try and conserve fuel during the last 15-20 miles, convinced that I was going to run out.  When we finally did get to a fuel stop, I had gone 212 miles on that tank, but only had burned 4.6 gallons.  Considering that there were several kookaloo moments during the first half of that tank, I was pretty surprised to see that kind of mileage, which is at least as good as it got stock.

Randy T
Indy

I suppose it's about right then.  I got 150 on my last tank, before I chickend' out and stopped for fuel. Maybe if I drove a little less "aggressive".  

[rktmanfj]

I suppose it's about right then.  I got 150 on my last tank, before I chickend' out and stopped for fuel. Maybe if I drove a little less "aggressive".  

Not everybody gets that kind of mileage.  Oftentimes at rallies, others need to stop for fuel well before I really need to.

Randy T
Indy

[andyb]

Significantly worse is also possible..

[Scooterbob]

Significantly worse is also possible..

I will count my mileage blessings then.