Jetting RX-1 MCXpress turbo - HURRICANE's turbo springs

[rxrider]

Thank you lakercr

I was out in my garage last night and changed the main jets to 132.5 and I also adjusted down the pilot screws to 2 turns out. I raised my needles from #2 to #3 position resently, midrange got better but not enough apparently.

Thanks Jim for your advice

I have the carb rack on my workbench. I will try changing my needle clip position up one notch today.

 

[Skydog]

Man good luck!! I know what you mean about right on the money! Mine does not pop or anything right now. My AFR are not right where i want them to be but sled runs great so i will let her roll. The one thing about changing the mains, it changes lots of other things too. I think it is best to get you WOT right on. (mains) then work your way back. needles, Pilots and screws.

GOOD LUCK!!!! Skydog

 

[rxrider]

Skydog - you're right on there, that's the proper way of jetting. Mains first for proper WOT AFRs, then spring, needle and jet combo, finally the pilot jets and screws.

I don't think I'm too far off. Going down on the mains will affect the high speed cruising AFRs at 12-14 lbs part throttle. Going up on the needle clip to #4 should fix that, adjusting needles is fairly easy work

Hahaha when searching thru my bike files I found the CV-carb tune how to Just as you said Skydog

I hope I will nail it this time, carb work is becoming second nature to me LOL. Can't say I like breathing gasoline fumes that much. Going out to adjust needle position and install everything this evening.

 

[lakercr]

Good luck!!! Let us know what she does!! No snow here for me to test.

Skydog

You could always put your sled on the bus and send it north to 'winter camp'. We can provide a bunch of activities to keep him well excersized until you have snow again.

 

[Skydog]

ha ha!! Sounds good to me!

 

[rxrider]

Bummer - while installing the last needle in the slide I managed to break one of the 4 holders in the needle seat. The little washer underneat the plastic spacer managed to pinch sideways down in the hole, not laying flat at the bottom, and when pushing the plug into place that washer prevented the plug to seat in place and it broke the plug seat. STUPID ME grrrr.

I were able to make the plug to seat correctly with only 3 of the 4 holders left That would do until I can get a new one ordered. I could always steal one from my stocker LOL

Thank you guys - lakercr and Skydog for your inputs and suggestions during my carb tune project

 

[Skydog]

Man that all ways sucks!

Anytime Skydog

 

[rxrider]

I ordered the slide and the diaphragm today, man they aren't exactly cheep them plastic and rubber parts, like $120 USD. Expensive mishap :-(

 

[rxrider]

I was out riding my sled with the broken slide today, had no problems. Sled ran flawlessly on top and mid, still fat at slow cruising, AFRs went into the high 10s to low 11s going 20-30 MPH cruising. I did not check AFRs today but I will have to lower the needles to stock. Temps were between -10 C to -15 C or between 14 F to 5 F. With the 132.5 main jets the sled ran very well up top at WOT. I had to back off on the boost controller because I reached target boost level at slightly over half throttle . I backed the controller back 2 turns. Now my sled went to 14 lbs WOT. Turned it up 3/4 turn to get target boost pressure back. I will watch the boost pressure more carefully next time out and adjust pressure to target at 16 lbs, if needed that is.

Went out in my garage this evening to change out the broken slide. While at it I lowered the needles to stock position. Jetting is now stock except for mains at 132.5, my riding altitude is 0-600 meters or 0-2000 ft. I will test my current setup on the lake on saturday. And post the final results then, no more changes will be made, stock jetting works.

 

[Skydog]

Cool looks like i will be lower my mains for sure with the injection. My O2 took a crap so i could not tune the sled.

Skydog

 

[rxrider]

Update on jetting, AFR. On the lake February 3.

Idle hot: 15.5
Takeoff rpms: 13.5
Driving slow: 12.8
Cruising 0 lbs of boost: 13.0
Cruising 5 lbs of boost: 13.5
Cruising 10 lbs of boost: 13.5 (1/2 throttle)
Cruising 12-14 lbs of boost: 13.5-14.0 (5/8 throttle cruising at 100-110 MPH)
WOT 16 lbs: 10.9-11.6 (starting at 10.9 giving it WOT ending at 11.6 at speed holding it WOT all the way to top end)

Temps on the lake today were -6C or 21F
Altitude: 100 meter or 300 ft

Jetting:
Main jets = 132.5
Pilot jets = 17.5
Pilot screws = 2.0 turns out
Needle = 3 position
Stock carb springs
STM Billet Carb Caps

- AFR is 13.5 at engagement, perfect.
- Down low is still too fat, but I have found the reason why. The heat insulator material inside the heat shield in the rear had started to desintegrate and the stuff were all over the pre filter and air filter as well. When sucking in moisture from snow melting on the turbo it literally plugged the air filter making it run into the hi 10s and lo 11s when cruising slow.

- Needles is OK up to 10 lbs of boost. At 12-14 lbs of boost cruising stady at 100 MPH I get 14.0 AFR. I may have to raise my needles some.

- WOT was just fine at 10.9-11.6 with the temps that day. On colder days I will be spot on.

I will have to relocate the air filter out the back away from the moisture to cure the fat low end. After cleaning the filter and pre-filter the sled had 12.8 AFRs at slow cruise speed, acceptable. When running in powder the AFRs dropped into the hi 10s to low 11s when running slow, that lead me to believe the filter to be full of moisture blocking off air when the engine is out of boost.

 

[Skydog]

Nice update!!! Thank you !!! For the great info!!!!!!
Skydog

 

[Skydog]

Cool looks like i will be lower my mains for sure with the injection. My O2 took a crap so i could not tune the sled.

Skydog

Well new O2 in sled, ran it with the 135 mains and a BIG jet in the charge tube. Why to rich, like 10.0 WOT so i pulled carbs and put some 128.5 mains in and a 300 jet in the charge tube. Kind of warm here 30 deg to day. (by the way we got HIT big time to day!!!!LIKE 1.5++Feet of snow!!) Ok now were was i, took sled back down the road now she does not miss a beat and running at about 11.2-11.5 so i will wait for it to get colder should be close this was running 15PSI on pump 93!!

Skydog

 

[rxrider]

Looking good Skydog. You're closing in on the jetting.

Last night I took the rear end apart and cleaned the air filter with compressed air, it was full of dust. I installed a plate between the turbo and the air filter to hinder the water vapor from the exhaust turbine to reach the filter, and I changed out the hose clamp for the pressure signal line going to the wastegate bell. I will do some testriding today and monitor my AFRs, maybe my rich low end is cured with a free flowing air filter and moisture kept from entering the filter. Kinda warm here as well, -2C or 28F.

 

[rxrider]

Update on jetting, AFR. On the lake February 7.

Idle hot: 15.5
Takeoff rpms: 13.5
Driving slow: 12.8
Cruising 0 lbs of boost: 13.0
Cruising 5 lbs of boost: 13.5
Cruising 10 lbs of boost: 13.5 (1/2 throttle)
Cruising 14-15 lbs of boost: 14.0-14.7 (3/4 throttle cruising at 100-120 MPH)
WOT 16 lbs: 11.4-11.6
Temps on the lake today were -6C or 21F
Altitude: 100 meter or 300 ft

Jetting:
Main jets = 132.5
Pilot jets = 17.5
Pilot screws = 2.0 turns out
Needle = 3 position
Stock carb springs
STM Billet Carb Caps

AFRs were pretty much the same as last time out except for high boost cruising on 3/4 throttle and low end cruise 1/8 throttle. I went leaner in those areas, it may have something to do with cleaning the pre filter and air filter. Low end is OK, but high boost cruise went scary lean. WOT AFRs was OK at 11.4-11.6

I have installed a set of Holtzman silver carb springs. Will give them a try and see what happens. I figure they will let the slides lift higher at the same throttle position letting in more fuel at high boost cruise at 3/4 throttle. I'll post my results after the next ride.