Novi and Full specs

[Matt_E]

Full Specs are IMPOSSIBLE to tune*.





*for me

I found that, too.
Then I gave up and called Ed. His jetting was spot on.

 

[waxhead]

Yeah i rung him as well
It didnt help me in the least
some one suggested that its because i had a dry pipe versus a wet pipe and that the carbs were different
thats just meant an excuse for a bad signal in a carb to me

 

[Matt_E]

If his specs don't work, I would give up on it too.

 

[SuperJETT]

A buddy put a set of FS 48's on his SJ back in 2001 or so, never touched a screw, wow, super clean, strong pull, etc. That made me a believer.

I've never ridden a ski with Full Spectrums that didn't run strong/clean.

 

[750SX]

are these on a sj

yep

 

[waxhead]

whats the setup on the sj
you may find its your carbs that are out slightly and you could go quite hard with what you have

 

[750SX]

whats the setup on the sj
you may find its your carbs that are out slightly and you could go quite hard with what you have

62t cases, 61x ported Riva cylinder, protec intake, rad valves, 44 sbn's (22 psi popoff, 137.5 highs screw at 1.25 out, 117.5 lowspeeds screw at 1 out, 2.0 needle and seat), ada girdled head (.033 squish 185 psi cranking), factory b pipe mod chamber, and msd enhancer.

Sorry for the threadjack.

 

[waxhead]

62t cases, 61x ported Riva cylinder, protec intake, rad valves, 44 sbn's (22 psi popoff, 137.5 highs screw at 1.25 out, 117.5 lowspeeds screw at 1 out, 2.0 needle and seat), ada girdled head (.033 squish 185 psi cranking), factory b pipe mod chamber, and msd enhancer.

Sorry for the threadjack.

So a genric sort of yamaha build or close to it
put in a larger low and a smaller high

say a 130 low and a 115 high
it will hit harder down low and rev nicer up top
thats a massive high jet you have in there

 

[Matt_E]

Wow, massive indeed.

I ran 115p, 122.5m, 24psi pop

 

[750SX]

Thanks guys, I will give that a shot when I have some more tuning time. I'm not sure why this motor calls for such a high main, but my plugs look great. I even turned the top screws out a bit this weekend and it ran even better.

Wax, what is the theory about reverse jetting? Maybe we should take this to pm, we are wrecking this guys thread.

 

[waxhead]

Thanks guys, I will give that a shot when I have some more tuning time. I'm not sure why this motor calls for such a high main, but my plugs look great. I even turned the top screws out a bit this weekend and it ran even better.

Wax, what is the theory about reverse jetting? Maybe we should take this to pm, we are wrecking this guys thread.

Reverse jetting works because there is a lag in fuel flow over air flow in a carburator
this is because fuel flow is goverend by air fuel and so it comes after
the extra fuel down low responds quicker and gives you more punch down low
It also helps keep the cases cool and gives you a larger torque hit in the top / midrange

To get the full benefit of reverse jetting you need to use alot of timing as well
but even with stock timing there is gains to be had

 

[750SX]

Reverse jetting works because there is a lag in fuel flow over air flow in a carburator
this is because fuel flow is goverend by air fuel and so it comes after
the extra fuel down low responds quicker and gives you more punch down low
It also helps keep the cases cool and gives you a larger torque hit in the top / midrange

To get the full benefit of reverse jetting you need to use alot of timing as well
but even with stock timing there is gains to be had

nice, that makes sense. Looks like I'm ordering some more jets haha!