Mountain RX-1 jetting

[zross1]

03 RX-1 Boondocker turbo w/gt2871, head shim static compression around 9:1 riding 8-10000 ft. Will be running 15-18 psi.

Could someone please tell me where I should start for jetting. I bought the sled with a gt25r and it had 127.5 mains and he ran it up to 15 psi with good a/f's but I know that won't be enough with the 2871. I was thinking starting around 137 mains or so.

 

[argoman]

Stock 135 works for me

 

[zross1]

thanks, what turbo are you running and how much boost?

 

[Climbmax]

When we went up in boost we stuck with the same main jets. Fuel pressure came up with boost via regulator. I would almost think it won't run very well with 137.5's.
I always ran 127.5 on my RX1.......small front mount, big rear mount and big front mount.
Best of luck.
RS

 

[thinksnow]

Jetting

Does anyone have a set of 127.5 that they aren't using anymore? I am at 130 right now and it is still rich. If you have some, let me know.

Thanks,
Lance

 

[mulot30th]

03 RX-1 Boondocker turbo w/gt2871, head shim static compression around 9:1 riding 8-10000 ft. Will be running 15-18 psi.

Could someone please tell me where I should start for jetting. I bought the sled with a gt25r and it had 127.5 mains and he ran it up to 15 psi with good a/f's but I know that won't be enough with the 2871. I was thinking starting around 137 mains or so.

maybe an off topic question, but why did you go 2871 only to run 15-18# of boost?

2860 would get you there easily

 

[zross1]

When we went up in boost we stuck with the same main jets. Fuel pressure came up with boost via regulator. I would almost think it won't run very well with 137.5's.
I always ran 127.5 on my RX1.......small front mount, big rear mount and big front mount.
Best of luck.
RS

Thanks, I guess I'll just keep in my 127.5 and see what my a/f's will be and if I need more fuel I'll go bigger.

 

[zross1]

03 RX-1 Boondocker turbo w/gt2871, head shim static compression around 9:1 riding 8-10000 ft. Will be running 15-18 psi.

Could someone please tell me where I should start for jetting. I bought the sled with a gt25r and it had 127.5 mains and he ran it up to 15 psi with good a/f's but I know that won't be enough with the 2871. I was thinking starting around 137 mains or so.

maybe an off topic question, but why did you go 2871 only to run 15-18# of boost?

2860 would get you there easily

I'm just starting out at 15-18 psi because I just got the sled and it had a gt25r on it and I put the 2871 on. I got it this summer and never rode it so I'm going to start out somewhat conservative. Trust me, it the sled will be well above 18 psi when it's all said and done

 

[Rx1M5]

My sled with the 127.5's was real lean A/F's were hitting 16. I'm running 132.5's with a mesh hood and my a/f's at WOT are right around 12 -13. I think air flow to the filter will affect what you end up using for jets. If your intake is under your hood you'll use slightly smaller jets. Just a guess on my part though as I'm no expert.

Rx1M5

 

[zross1]

Thanks for the info. I do have a external air intake so maybe I'll play it on the safe side. At what boost level and what turbo did you see the 16's with your a/f ratio?

 

[wheeline]

My sled with the 127.5's was real lean A/F's were hitting 16. I'm running 132.5's with a mesh hood and my a/f's at WOT are right around 12 -13. I think air flow to the filter will affect what you end up using for jets. If your intake is under your hood you'll use slightly smaller jets. Just a guess on my part though as I'm no expert.

Rx1M5

I agree, my air intake is outside and also run a boondocker 2871. I am running 135 mains for 20-24lbs of boost. Lots of guys recommend 127.5 mains but I tried it and was way too lean.

 

[zross1]

Thanks, I have a 2871 and a boondocker kit, and intake outside as well. Sounds like I'm a little closer to your setup.