Blue shadow
TY 4 Stroke Guru
If you are going to put up the boost some more would it be more safe to leave the 135 mains in?
rxrider
Jan-Ove Pedersen
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Yes I would think so, but I will not go higher than 16 lbs on pump fuel. The MCXpress turbo kits doesn't seem to run leaner when going up in boost. The fuel pressure regulator feeds fuel to the carbs very linear to the rise in boost. I get the same AFRs at 12 lbs as I get at 16 lbs, that's how she runs 
I will leave the 135 mains in for now as I may upgrade to a MCX400 in a few weeks time. I have a few dependencies going my way to have the MCX400 upgrade this winter, or else it will have to wait till late autumn. If the upgrade goes down south, I will fine tune what I have and run it for the remainder of this season.
I will leave the 135 mains in for now as I may upgrade to a MCX400 in a few weeks time. I have a few dependencies going my way to have the MCX400 upgrade this winter, or else it will have to wait till late autumn. If the upgrade goes down south, I will fine tune what I have and run it for the remainder of this season.
Blue shadow
TY 4 Stroke Guru
what oct is your pump fuel,wow ,you realy have it tune in on pump gas
rxrider
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Blue shadow said:
Our pump fuel is 98 octane RON, it should equal or better than your 93 octane premium. Our 98 octane pumpgas is of a very high quality, actually I keep my boost level a bit lower than MCXpress recommends for max boost on pumpgas. I run 10:1 pistons and 2 stacked head gaskets for a CR or 9.13:1, that's the reason I can get away with running it on pumpgas.
Blue shadow
TY 4 Stroke Guru
Your a smart man,keep up the good work
rxrider
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Thank you 
Skydog
TY 4 Stroke God
Right on buddy!! I would put the needles back to stock then you will be right on.
Skydog
Skydog
rxrider
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Thanks Skydog
AFRs at 13.5-14.0 at half throttle stedy cruise making 10 lbs scared me a bit, only held it long enough to get the 10 lbs cruise readings. Will raise the needles back to stock. I had a feeling .... thath I would have to LOL.
I will adjust the needles back to stock #3 position and run her.
Got the 132.5 mains today. Will test how the sled runs with the stock needle settings before going down on mains. Will be doing plug readings after running it WOT on the lake before jetting down on the mains to see if plug readings does correlate with the AFR readings. Before riding it jetted down on the mains I will also go down on boost to 11 lbs and start from there going up again in boost while verifying AFR levels. One cannot be careful enough.
AFRs at 13.5-14.0 at half throttle stedy cruise making 10 lbs scared me a bit, only held it long enough to get the 10 lbs cruise readings. Will raise the needles back to stock. I had a feeling .... thath I would have to
LOL.I will adjust the needles back to stock #3 position and run her.
Got the 132.5 mains today. Will test how the sled runs with the stock needle settings before going down on mains. Will be doing plug readings after running it WOT on the lake before jetting down on the mains to see if plug readings does correlate with the AFR readings. Before riding it jetted down on the mains I will also go down on boost to 11 lbs and start from there going up again in boost while verifying AFR levels. One cannot be careful enough.
Skydog
TY 4 Stroke God
Good luck!!! Let us know what she does!! No snow here for me to test.
Skydog
Skydog
rxrider
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Needles are now in the stock position. I'm going out riding tomorrow if weather allows
Skydog
TY 4 Stroke God
Cool, good luck BE SAFE!!
Skydog
Skydog
rxrider
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HAHA I'm right on up mid, but now I'm fat down low at 2.25 pilot screws, I better go stock on them pilot screws too LOL, it never ends. Riding slow like 20-30 mph at 6000 rpms on less than 1/8 throttle, AFR goes low 11s
I will have to go out on the lake when it gets colder to get proper readings. Warm weather kicked in yesterday afternoon with +4C or 39F temps. The warm weather most likely made my readings go fat by a lot. I want to tune it for down to -10C or 14 F give or take some. I won't change anything before I find test conditions more like the condition I ride in the most.
I will have to go out on the lake when it gets colder to get proper readings. Warm weather kicked in yesterday afternoon with +4C or 39F temps. The warm weather most likely made my readings go fat by a lot. I want to tune it for down to -10C or 14 F give or take some. I won't change anything before I find test conditions more like the condition I ride in the most.
Skydog
TY 4 Stroke God
For sure 39F will make her richer for sure!!
Skydog
Skydog
rxrider
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Update on jetting, AFR. On the lake January 19.
Idle hot: 14.3-14.5
Takeoff rpms: 13.5
Driving slow: 11.5 (not good)
Cruising 0 lbs of boost: 13.0
Cruising 5 lbs of boost: 13.0
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: 10.5-10.9 (starting at 10.5 giving it WOT ending at 10.9 at speed holding all the way to top end)
Temps on the lake today were -2C or 28F
Altitude: 100 meter or 300 ft
Jetting:
Main jets = 135
Pilot jets = 17.5
Pilot screws = 2.25 turns out
Needle = 3 position
Stock carb springs
STM Billet Carb Caps
AFR is 13.5 at engagement, perfect. It does not die when letting off throttle from WOT 16 lbs to no throttle. It does run pour when riding slow for a mile. It sputters some and clears up when giving it WOT after slow riding for a while.
- Down low is now too fat, I will go down on pilot screws to 2 turns out.
- Needles is OK up to 10. At 12-14 lbs of boost cruising stady at 100 MPH I get 14.0 AFR. What do you guys think? Should I raise my needles?
- WOT was 10.5-10.9. I have a set of 132.5 on the shelf to help cure the fat WOT.
I would like to jet it so that 0 boost is 13.0 AFR, 5 lbs is 12.5 AFR, 10 lbs is 12.0, over 10 lbs should be 11.5-12.0. It seems like this is very difficult to achieve. Any info on jetting would be much appreciated.
Idle hot: 14.3-14.5
Takeoff rpms: 13.5
Driving slow: 11.5 (not good)
Cruising 0 lbs of boost: 13.0
Cruising 5 lbs of boost: 13.0
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: 10.5-10.9 (starting at 10.5 giving it WOT ending at 10.9 at speed holding all the way to top end)
Temps on the lake today were -2C or 28F
Altitude: 100 meter or 300 ft
Jetting:
Main jets = 135
Pilot jets = 17.5
Pilot screws = 2.25 turns out
Needle = 3 position
Stock carb springs
STM Billet Carb Caps
AFR is 13.5 at engagement, perfect. It does not die when letting off throttle from WOT 16 lbs to no throttle. It does run pour when riding slow for a mile. It sputters some and clears up when giving it WOT after slow riding for a while.
- Down low is now too fat, I will go down on pilot screws to 2 turns out.
- Needles is OK up to 10. At 12-14 lbs of boost cruising stady at 100 MPH I get 14.0 AFR. What do you guys think? Should I raise my needles?
- WOT was 10.5-10.9. I have a set of 132.5 on the shelf to help cure the fat WOT.
I would like to jet it so that 0 boost is 13.0 AFR, 5 lbs is 12.5 AFR, 10 lbs is 12.0, over 10 lbs should be 11.5-12.0. It seems like this is very difficult to achieve. Any info on jetting would be much appreciated.
Take away a bit of fuel on your screws and try one clip richer on the needle. You could also try a 1/2 clip position by putting an extra plastic washer under the C clip. Go down one size on the mains.
