Air Box Mod Consensus

[MUSKOKA APEX RTX 07]

I think me and Rockerdan can probabley count on both hands the amount of times we have not been wide open LOL but yes its usaully lake to lake have had no issues here!!! JMO

 

[1xr]

Here's what I did last season and drove 4000 miles with it. Works great and not alot if any extra noise.

 

[Hinkman]

1xr,
I like that idea, what did you use for the rubber insert?? It looks familiar...


I did some testing behind the house. Throttle response after the mod was a little sluggish and it had a numb spot off idle when I blipped the throttle. I had to set my CO values to +13 to get rid of the numb spot. It now has a nice little cackle from the Air Box. I haven't had a chance to run it flat out yet. I won't know how it will perform until I put against my buddies 06 GT.

 

[1xr]

1xr,
I like that idea, what did you use for the rubber insert?? It looks familiar...


I did some testing behind the house. Throttle response after the mod was a little sluggish and it had a numb spot off idle when I blipped the throttle. I had to set my CO values to +13 to get rid of the numb spot. It now has a nice little cackle from the Air Box. I haven't had a chance to run it flat out yet. I won't know how it will perform until I put against my buddies 06 GT.

I used the rubber out of a rx1 air box. I had to trim a little off of the inside rubber. I had to also had to tape a piece of fine nylon cloth to the opening to keep powder out.

 

[RTX Rox]

Is this CO mod only done when you modify the lid? Do any ajustments need to be made if you use the Ulmers Stealth?

 

[SledFreak]

If you have a stumble then add about 10-20 through the pod, which means you are adding fuel pressure throught the instrument pod. It only effects the bottom end.

 

[Hinkman]

RTX Rox,

This was copied from www.ulmerracing.com, INSTRUCTIONS, STEALTH AIR BOX (Moderators, delete it if unappropriate)

Ulmer Racing
43230 290th St, Menno SD 57045
Phone: 605-387-2833 Fax: 605-387-2883 Email: Srxspec@Gwtc.net
www.ulmerracing.com

Stealth MOD Air Box

The Yamaha Genesis 150FI motor is the first fuel injected Yamaha snowmobile. With this technology is very little adjustability for air box modifications, etc. If you experience a hesitation in the low end RPM range with the MOD air box installed these are the steps you will want to take to richen the low speed fuel curve. Always make sure the snowmobile is fully warmed up before adjusting any settings. A cold engine will also result in a hesitation!

This will change your low speed fuel mixture much like the pilot circuit on a carbureted model. It does not effect on high speed fuel mixture. The engine will start and run normally in C0 mode so you can change settings with the engine running or on the trail. To return to the normal gauge functions simply turn the key or kill switch off and the gauge display will return normal functions.

Apex C0 Fuel Adjust:
- Install a wire (or paperclip) from ground to the pale green wire in the connector on the left of the delta box. This wire has no mating wire in the male connector and only needs to be grounded to the Delta Box.

Enter Diagnostic mode:
- With the key and kill switch off, press and hold both "Select and Reset" buttons then power up the gauge by turning both the key and kill switch on.
- Wait 8 seconds and the gauge will go blank except for "DI" in the display.
- Press "Select" to toggle between "DI" and "C0", Select "C0".
- Press and hold both "Select and Reset" 3 seconds
- Gauge will display "C:01", (this is where you select which cylinder you want to adjust)
- Press and hold "Select and Reset" 3 seconds and 0 should appear in the odometer section
- Press "Select" to increase the number (richer), "Reset" to decrease the number (leaner)
- Example: (10 would be richer) (-10 would be leaner)
- Press both "Select and reset" to chose C:02 and adjust the same as above (must do this for each cylinder)

You will want to go RICHER (positive numbers). Generally up 10 will be enough to get past any hesitation or stumble you may run into.

 

[stoutner]

I always leave her stock when running long wide open runs.
Some of my runs at WOT are over 20miles strait.....that's noting to mess around with.

Did you replace your belt with a chain? I have never seen a sled run 20 miles at WOT and not blow a belt???

 

[tttario]

I always leave her stock when running long wide open runs.
Some of my runs at WOT are over 20miles strait.....that's noting to mess around with.

Did you replace your belt with a chain? I have never seen a sled run 20 miles at WOT and not blow a belt???

I had a problem with blowing belts on my last sled. WOT down the lake and pow. Clutches were out of alignment. Properly aligned and I could hold it down the lake all day long, stop on the lake lift the cab and the belt and clutches weren't even hot. I couldn't touch them they were so hot before the alignment.

As long as the clutches are properly aligned and balanced there should be no problem.

P.S. gained 4-5 MPH on top end after alignment! i still think a clutch alignment tool is one of the cheapest tools to have for tweaking for the DIY'er.

My $0.02.

 

[snoman]

Here's what I did last season and drove 4000 miles with it. Works great and not alot if any extra noise.

where you get your rubber piece ?

 

[170plus]

we set my air fuel ratio using an exhaust gas analyzer tapped into each exhaust header tube 1 at a time,to get the engine to run the exact same on each cylinder,this is the only way to achieve it,just setting your co number up a set amount might have 1 cylinder running way too rich and 1 running just right,every injector has a different flow rate and usually the co number are all different from the factory,yamaha sets all the cylinders at whatever number allows each cylinder to run at the ratio they want,set too hi and your wasting gas,its a pain to do this process but them you'll know its perfect,this is why some people try it with good results and other not so good,this is a pic of my air box mod,similar to the rubber tube the other guy used ,i used 1 inch plastic water pipe,air inters box below the foam so its filtered

 

[Genesis Extreme]

Some of my runs at WOT are over 20miles strait.....that's noting to mess around with.

Damn!!! Did the sled ever get to top speed??

When I put mine to the bar on a hard packed road.........it just kept going.....and going...and going..........until I let off!! I hit 124 on the dream meter.......but it was still climbing!!!!

These motors are fun!!!

GE

 

[1xr]

Here's what I did last season and drove 4000 miles with it. Works great and not alot if any extra noise.

where you get your rubber piece ?

I took a rubber piece from an old rx1 airbox.

 

[RTX Rox]

Hey Hinkman,


I read the same thing on Ulmers website on the instruction page. But if you look under engine performance and click on the Mod Airbox it says you install the Stealth Airbox with NO ADJUSTMENTS.

It's in capitals to. With everyone saying how they set these things up so they don't burn down it's a little scary. I just got this sled and it doesn't even have 2000km on it and I'm trying to buy a house before the spring. If it blows, bye bye sleding for a while. This is suposed to be my last sled for hopefully a couple of years.

 

[Srxspec]

The CO adjustment will be a sled to sled adjustment. Some may need it and some won't. You will not know until you drive it. I have done 20 of the MOD air boxes and only 1 has needed a CO adjustment, otherwise all others have been fine stock. If you have a stumble down low when initially hitting the throttle adjust the CO +10 to start and try it again (after making sure the sled is completely warmed up).