Freeride 760 Setup (with dual 44's)

[Seb62T]

Hi,
I need some advices to finish tuning my 760 engine.
Here is the setup :
-760 (84.25mm) 62 Cylinder
-Ported 62T cases (lightly ported)
-Factory B pipe (MOD chamber) : dual cooling line
-ADA Head with 38cc domes
-R&D intake (high ported)
-VFORCE 2 Reeds
-Dual 44's XL 760 carbs (dual signal fittings) with two 650 f/a (2 screens installed), dual fuel lines
-3° Static advance
-Solas 13/17 Swirl Wamilton's modified impeller
-Wetwolf pump cone

I am searching for the right setting for my carbs.
I am actually using :
Needle : 2.0
Arm spring : 95g
Pilot : 110
Main : 135
LS : 2 turns out
HS : 1.25 out

It runs great in the whater, no hesitations, good response...
But out of the water, it sounds really lean !! If I just slightly touvh the throttle, it revs immediatly high and don't slow black to the idle...

I think that some people use the same setup. So let me know what do you use.
I am thinking goning on 125 pilot 115 main ??

My plugs are actually dark and dry !

Waiting for your help.

Regards,

Seb

 

[Mark44]

Could it be an air leak?

Mark44

 

[SuperJETT]

I would flip-flop your jetting.
http://www.x-h2o.com/showpost.php?p=122348&postcount=232

This is what I ran at one point with my old carbs, and almost an identical setup to your's:

Lehr Performance 760, ADA head with pump gas domes
B mod
oem 44's
Riva spacer plate
oem reed cages with Boyesen pro dual stage
MSD enhancer
mild case porting

My current jetting is 2.5/80, 115L/100H, low screws around 7/8, high screws around 1/2.

 

[Seb62T]

Could it be an air leak?

Mark44

No that's not an air leak.
The sum of the jets that give me a good plug colour is 110+130 =240.
I just need to equilibrate the jets.
So what do you think of 125 for the pilot and 115 main ??

Superjett, that correspond to what you told me, considering I have a higher popoff then you.

 

[DAG]

read my carb set up, in myski section.. somewhat simuler w/o the timing advance. but how its listed in the thread is very lean.

i'm going to:
122.5p
125m
2.0 95g

 

[#ZERO]

You're too lean on the pilots and to rich on the mains.

117.5 Pilot Jets
122.5 Main Jets
2.0 Needle & Seat
95 Gram Spring
2-1/4 Turn LS
1-Turn HS

 

[Matt_E]

You're too lean on the pilots and to rich on the mains.

117.5 Pilot Jets
122.5 Main Jets
2.0 Needle & Seat
95 Gram Spring
2-1/4 Turn LS
1-Turn HS

That's a good setup...ran it for a year.

 

[crammit442]

Hi,
I need some advices to finish tuning my 760 engine.
Here is the setup :
-760 (84.25mm) 62 Cylinder
-Ported 62T cases (lightly ported)
-Factory B pipe (MOD chamber) : dual cooling line
-ADA Head with 38cc domes
-R&D intake (high ported)
-VFORCE 2 Reeds
-Dual 44's XL 760 carbs (dual signal fittings) with two 650 f/a (2 screens installed), dual fuel lines
-3° Static advance
-Solas 13/17 Swirl Wamilton's modified impeller
-Wetwolf pump cone

I am searching for the right setting for my carbs.
I am actually using :
Needle : 2.0
Arm spring : 95g
Pilot : 110
Main : 135
LS : 2 turns out
HS : 1.25 out

It runs great in the whater, no hesitations, good response...
But out of the water, it sounds really lean !! If I just slightly touvh the throttle, it revs immediatly high and don't slow black to the idle...

If it runs great on the water, you may not have a jetting problem at all. You may want to check your throttle cable for kinks and binding. It doesn't take much to cause the throttle to stay open enough to sound like it's running away. Before you go to the trouble to rejet, try pushing the throttle closed at the carbs and see if that is the problem.

Charles

 

[Seb62T]

Hi,
I need some advices to finish tuning my 760 engine.
Here is the setup :
-760 (84.25mm) 62 Cylinder
-Ported 62T cases (lightly ported)
-Factory B pipe (MOD chamber) : dual cooling line
-ADA Head with 38cc domes
-R&D intake (high ported)
-VFORCE 2 Reeds
-Dual 44's XL 760 carbs (dual signal fittings) with two 650 f/a (2 screens installed), dual fuel lines
-3° Static advance
-Solas 13/17 Swirl Wamilton's modified impeller
-Wetwolf pump cone

I am searching for the right setting for my carbs.
I am actually using :
Needle : 2.0
Arm spring : 95g
Pilot : 110
Main : 135
LS : 2 turns out
HS : 1.25 out

It runs great in the whater, no hesitations, good response...
But out of the water, it sounds really lean !! If I just slightly touvh the throttle, it revs immediatly high and don't slow black to the idle...

If it runs great on the water, you may not have a jetting problem at all. You may want to check your throttle cable for kinks and binding. It doesn't take much to cause the throttle to stay open enough to sound like it's running away. Before you go to the trouble to rejet, try pushing the throttle closed at the carbs and see if that is the problem.

Charles

Hi Charles and thanks to everybody for your answers.
The carbs works perferctly. that's not a cable or a throttle problem.
I am too lean in the low RPM.
Next setup will be with 125 low and 120 high. I don't have other jets in stock for now. I'll told you how it pulls !!
If this rich setup works, I'll slowly decrease the jets (122.5 / 117.5).

Seb

 

[sjetrider]

2.25 turns out on low screw and still lean reving out of the water WOW, that would be way to lean on low jet. Why would he not have a lean hesitation when it water?

 

[Matt_E]

Because it's not lean.

 

[D-Roc]

did you try to lower the pop off?

 

[Seb62T]

Hi,
I let the ski to the garage for 4 days... Today, i started it and it worked perfectly out of the water (I just reset the low speed screws to 1.5 turns).
That was also great in the water... everywhere.
I think I am close to the right setup. i'll try 115 / 130 next time in order to have 1 turn on the low speed adjusters.

I notice a big vibration problem... The engine seens to be in line with the pump... The vibration is only in the lows RPM... but it's quite amazing.

One more thing, how many time to get the carbon layer on the top of the pistons (the engine have two tanks since the last pistons washing, when I opened it).

Seb

 

[Seb62T]

Hi,
I tryed several setups : all with the same popoff :
110/130, 110/135, 125/120 (too rich !!!)
I finally come back to :
pilot : 110 / 1.5 turns (Works great at 1.5, this is really better than 1.25 or 1 turn)
Main : 130 / 1.25 turns (1 turn : Brown plugs 1.25 turns : brown to black plugs). So I'm actually running 1.25 (I prefer to be rich !).

The response is linear, it pulls hard from the idle... it also pulls harder in mid/high RPM !!

The only problem is if I let the engine idling for 1-2 minutes, il I pull the throttle crisply, it dies...

Considering that we never use the engine in these conditions, i am using this setup.

With this setup : 1 full tank = 1h30 (Freeride + some straight lines full throttle)
Fuel mixture (2.5%): Unleaded 98 gas + MOTUL 600 DI Jet + Mecacyl AER

Could you tell me what you are using as flame arrestors ??
I actually use two cutted 650SJ F/A but it take some water sometimes.
I'll try to put the 38's stock airbox on the 44's (I'll machine the metal plate)

Thanks for your help

Seb