SX/SXi/SXi Pro jetting question

sxipro02

sxipro02

Location
Arnold MO.
Im trying to figure out my rich issue, anybody know what a good guess would be for main jets on a big pin dual carb motor bored to 800cc, FP limited pipe, ported, prok filters, high compression head?
Stock was 147.5 800sxr's with a pipe call for 152.5 Zforce suggested 155 mains to start but I think that might be a bit large, Its loading up when you back off the throttle and uses a crap ton of fuel, about 1.5 hours to a 4.5 gallon tank lol.

I found a few other issues that I straightened out last night, havent ridden it yet to see if it hellped.

any input or opinions are greatly appreciated...
 
sxipro02

sxipro02

Location
Arnold MO.
Ok so I pulled the jets to see what I put in it (should have jotted it down). It was 152.5 high and 75 low. That kinda stumped me, The low is the one I though was too big but according to FP's site stock jetting is 147.5/75. My stock jets were 147.5/67.5. Did the pros come with smaller pilots?
 
fastony

fastony

Location
nixa, mo.
sxipro02 said:
Im trying to figure out my rich issue, anybody know what a good guess would be for main jets on a big pin dual carb motor bored to 800cc, FP limited pipe, ported, prok filters, high compression head?
Stock was 147.5 800sxr's with a pipe call for 152.5 Zforce suggested 155 mains to start but I think that might be a bit large, Its loading up when you back off the throttle and uses a crap ton of fuel, about 1.5 hours to a 4.5 gallon tank lol.

I found a few other issues that I straightened out last night, havent ridden it yet to see if it hellped.

any input or opinions are greatly appreciated...
Click to expand...

I have 157.5 main with 80 low speed jets with 25 pop off pressure on my wifes ski and it has the same things that you have. I bet you have a needle valve leaking through is why it is running rich, pull the filters off and see if fuel is trickling in at fast idle to quarter throttle.
 
sxipro02

sxipro02

Location
Arnold MO.
I found one of the carbs loose, the gasket was wet between the carb and manifold. I'm sure that wasnt helping anything lol. I put it back together with the same jets for now. At one point it was running pretty good. Now that I think about it the problem started when I was messing with a factory air box. guess I left the carb bolts a little loose on one carb.
 
sxipro02

sxipro02

Location
Arnold MO.
Just a update, After I bolted the carbs down tight I had it running strong in a matter of minutes, I'm sure there is more power in there if I had time to dial it in. Its running great now though. I test rode a near stock 800sxr and could feel a bit more power out of mine, mainly throttle response was crisper on my ski. If I can get it in the water again before the weekend I'm going to try the stock airbox one more time. I'm still sucking water into the air filters :(
 
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