TurboJamie
TY 4 Stroke God
I have all the issues fixed on my stage 1 SC nytro now with the MPI kit on it.
Sled run down;
29/26 pulleys makes 8 psi at WOT at 8800 rpm
MPI regulator kit upgrade
24/39 gearing in the chaincase
Dalton dypr 65g base weights with 1 heavy yamaha rivet mid and 1 heavy yamaha rivet tip.
OPO primary spring
50/42 cam with Dalton RED secondary spring.
Works really good for trail riding I still need to get a touch more back shift, I am working on this and I may or may not go a touch stiffer on primary spring in the start. Its very good in the trails though.
Riding pretty hard 40-70 mph I am within 3 liters of the stock apex at fuel up.
I havent been on the radar gun yet but racing the apex I am putting at least 2 large school bus lenghts on it in less then 1500'.
My fuel box #'s are as follows
Green is 1.5
Yellow is 4
Red is #6.5
Yellow/Blue is #2.5
Green/Blue is #5.5
Red/Blue is #8
Hope this helps anyone struggling at sea level.
Sled run down;
29/26 pulleys makes 8 psi at WOT at 8800 rpm
MPI regulator kit upgrade
24/39 gearing in the chaincase
Dalton dypr 65g base weights with 1 heavy yamaha rivet mid and 1 heavy yamaha rivet tip.
OPO primary spring
50/42 cam with Dalton RED secondary spring.
Works really good for trail riding I still need to get a touch more back shift, I am working on this and I may or may not go a touch stiffer on primary spring in the start. Its very good in the trails though.
Riding pretty hard 40-70 mph I am within 3 liters of the stock apex at fuel up.
I havent been on the radar gun yet but racing the apex I am putting at least 2 large school bus lenghts on it in less then 1500'.
My fuel box #'s are as follows
Green is 1.5
Yellow is 4
Red is #6.5
Yellow/Blue is #2.5
Green/Blue is #5.5
Red/Blue is #8
Hope this helps anyone struggling at sea level.
Skydog
TY 4 Stroke God
WOW COOL!!
doo_man
Expert
Are they working at elevation well, I want a mpi sc on my mtx but somewhat reluctant until next year. I rode with an apex sc and he was constantly messing with the fuel controller, my rx-1 sc was great other than at fuel delivery with steep hills.
Skydog
TY 4 Stroke God
TurboJamie
What is your alt?
Skydog
What is your alt?
Skydog
TurboJamie
TY 4 Stroke God
800'
woodsrider
TY 4 Stroke Junkie
- Joined
- Feb 17, 2005
- Messages
- 669
- Reaction score
- 11
- Points
- 893
- Location
- Lewiston, ID
- Country
- USA
- Snowmobile
- 2017 YZ450FX1 Moto-Trax 137 Mountain Kit
IMO, go to a straight helix (47-deg) or a shockwave i don't feel you will ever get the clutch to perform quite the way you want. I spent a whole season (and alot of $) changing helixes trying to get a multi angle helix to work on a boosted sled.
Skydog
TY 4 Stroke God
TurboJamie said:800'
Thank you boy that is right on with me!!

Skydog
Skydog
TY 4 Stroke God
One more thing when you killed yours can you tell me what you were doing? Was it kind of a long pull? Back to back pulls? (heat soaked)What was your AFRS? I feel that incooler gets warm fast! Then the filter is sucking in hot air.... not good....
Skydog
Skydog
TurboJamie
TY 4 Stroke God
The filter sucking hot air is definately not good. I don't know exactly when mine went, my buddy said he could smell sweet antifreeze burning on our ride about 1/2 way though it I had done some 5 second WOT pulls with it, AFR in the high 12's No fuel pump yet. I am sure at 6-7 psi with a 12:1 aft you will be fine for 2000'
Skydog
TY 4 Stroke God
Well the upgrade went very well!! Boy that is a BIG upgrade! That stock pump is a joke for boost! I have a questions the new fuel line that come off the new pump and goes to the fuel rail. I just have a hose clamp on it and could not push the fuel line over that rib on the metal line. Is this ok?? I DO not want that line to come off!! FIRE//LEAN////. I know that pump is going to be pushing some big psi.
THank you Skydog
THank you Skydog
You know why that rib's there right?
Skydog
TY 4 Stroke God
It is where the stock hard line clips on. That high psi rubber fuel line will not streatch over it. It is on about 1" It is not a barb for rubber line.
Skydog
Skydog
Skydog
TY 4 Stroke God
Well MPI says thats fine........
Skydog
Skydog
woodsrider
TY 4 Stroke Junkie
- Joined
- Feb 17, 2005
- Messages
- 669
- Reaction score
- 11
- Points
- 893
- Location
- Lewiston, ID
- Country
- USA
- Snowmobile
- 2017 YZ450FX1 Moto-Trax 137 Mountain Kit
Take the female connector off your old line and cut the hard line off hose clamp your fuel hose to this connector and use this as the adaptor to connect your hose the to the stock fuel rail. That's what I did and it works fine. Hope that made sense. 

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