T-Rx1 Jetting

[BrandX]

I have been struggling with my jetting, Need some insight from someone with Knowledge.
Elevation: 6 to 9
Fuel: 110/91 50/50
boost: 9 to 11
Pito: 700
Mains: Started with 135's, A/f meter was going to 10, sled would only run half throttle.
Changed to 140's, This made it worse, A/F bottomed at 10
Changed to 125's, This seemed to help but still won't run at WOT. A/F at 11.5 to 12.5 blubbering.
Changed pito to 300, A/F at 11 to 12.5 still but ran worse at WOT
took pito clear out, sled quit at half throttle, could not read A/F
Changed pito to 140, Ran worse
Changed pito back to 700, Now I'm stuck on what to do.

If I change my main to a leaner jet, I,m afraid I will toast something

By the Way it is an 03 rx1 with a Bender rear mount, purchased last spring, and the only thing I changed was the pito, new vaccum tubes, tees, clamps, and inspected hoses and turbo. It had a 200 pito when purchased and would hardly run at cooke city until we put in the 700 pito.

Any help would be apreciated, Pray for SNOW!!!!!

 

[Turbo Tim]

I take it you're running a bender rear mount . I found that blocking the pitot tube completely off was the best way to go . I ran 127.5 jets and I leaned down the idle mixture some . ran pretty good that way in Alaska at around 3000 ft .

 

[M5-]

I asked the same question a few years ago when my buddy picked up a Bender Rx. Tim answered the same thing then as he did here and we did it. The sled is still running perfect. So try what he says.

M5

 

[air4ce1]

I take it you're running a bender rear mount . I found that blocking the pitot tube completely off was the best way to go . I ran 127.5 jets and I leaned down the idle mixture some . ran pretty good that way in Alaska at around 3000 ft .

Would that apply at all elevations? I run 7-10K.
Thanks

 

[zebiraross]

I ran 127.5's on my old rx1 as well with a boondocker 2871r. 12.0-12.4 a/f at 9-10K ft.

 

[TTE]

Are you make any boost before sled is staring to act up?

Start of getting aluminium Ts for the carbs if you don't have it. This is the best way to be 100% sure that you float bowls get the right pressure signal.

Do a pressure test on the intake side and make 100% sure you don't have any air leaks. Fix all air leaks before you start rejetting

Also make sure you don't have any cracked exhaust parts (flex pipes up front, Bender Y-pipe etc.)

Pull the air filter out back. It will clog very easy in powder if located under the seat, and you will go pig rich on your AF readings

Make sure fuel pressure is around 4,5-5 psi at idle.

Make sure that the rubber o-ring unders the carb caps are in good condition.

If you bought the sled used - look into what carb sprigs your have. Alot of people would tried to cure a the lean midrange with softer springs. Try to install OEM yamaha springs. Not all sleds with Bender turbos worked good with other carb springs.

What chargetube do you have - stainless og titanium? My titanium charge tube required BIG main jets. Turbo Tim set me up with his old stainless so I am leaning out with smaller mains this year. Remeber all Bender charge tubes seems to jet a little different.

After that listen Turbo Tim's directions - if you plan on running just one boost level. If you are going to run different boost levels - I would dial in main jets with a 600 in the pitot on low boost. This way you can still go with a smaller jet in the pitot when going to higher boost levels.

Hope this helps

 

[BrandX]

I take it you're running a bender rear mount . I found that blocking the pitot tube completely off was the best way to go . I ran 127.5 jets and I leaned down the idle mixture some . ran pretty good that way in Alaska at around 3000 ft .

Tried blocking the pitot, it still blubbers at WOT, Drilled out a main jet with 1/8 drill bit and it seems to run a little better,
What is the best method for leak detection on the intake?

 

[TTE]

Build your own pressure tester:

1 piece silicone hose (same sizes as turbo inlet)
2 clamps for hose
1 plug drilled to accept air line fitting


Remove the airfilter and clamp the presssure tester on and air it up to 20 PSI on your boost guage, 1% dish soap solution and start washing your engine. I block off the pitot so air doesn't leak out. Listen for air leaks and look for bubbles. Fix what ever leaks you find. You should have no air leaks what so ever, it should be tight. It tests the whole system precooler, charge tube, intercooler, plenum, carbs, hoses, float bowls vents, everything.

Good luck!

 

[BrandX]

Thanks, I will try that next.

Brandx

 

[BigFish BC]

one other thing to check is make sure your bov is closing too.

 

[TTE]

Are you making boost before sled is starting to act up? Did you check your exhaust systems for cracks?

If you have a BOV (not working correct) or bypass valve after the pitot/float bowl pressure signal pick up this could screw up your jetting big time.


If you can't figure this out give Justin Fuller at Full power performance a call.