I live in Salt Lake. I have two raptors with dyno jet kits in them. I run a 146/148 mains, with a 25 pilot jet. They run a tad rich a the dunes. If your running 142 mains, I would say you are running a little lean. I would jet up and make it rich, then work your way down until it runs good.

 

Firefly: Are those Rappys stock?

 

yeah im curious on that also.

 

Bigbubba, Im running 170/175 Dynojets with Dynojet needles too.


Caliraptor, I wouldnt say Im "WAY wrong" ?! For my build, Bob
specifically says 190/195 Mikuni mains on stock Mikuni needles. This is the
correct jetting area for a ported 686, ported intakes and open airbox, 11:1 with
stage 1 cam, at or around sealevel.

Im running DynoJet needles. They are way thinner than stock Mikuni needles. Therefore,
my jet sizes are not going to be as big as they would be with stock needles. Add to that
that Im using Dynojet jets too, not Mikuni, which are numbered differently.

If a piped Raptor with semi-modded airbox requires 146/148 Dynojet mains on Dynojet needles,
and the same piped Raptor using Mikuni mains with stock needles, requires 155/160 or 160/165,
then that gives you the ratio basically.

Using that ratio, if I needed 190/195 mikuni mains on stock needles... then where would the Dynojet
mains be using Dynojet needles ??? in the 170 range, + or - a size. The ratio doesnt change, so
thats all I did to get close, and Bob said it sounded like a good starting spot as well. So far, its great.

Like I said, I wasnt saying you were wrong at all, just discussing. Just seems to me you would be rich,
unless the no airbox makes that much a difference. But in any case, you are still running fatter jetting
than me, and I cant understand why yours would require fatter jetting... thats all. Im about 500ft above
sea level.

In any case, Im still confused on where I was "way wrong" ? If I ran 180+ Dynojets on Dynojet needles,
that would be using nearly the same size as recommended Mikunis, but with much thinner needles, which
would be way rich.

In all seriousness, comparing your motor to mine, I should be running fatter jetting than you I would think...
However, your with no box, and whatever spark plug wire thing you mentioned... maybe that is upping your
fuel needs ? I just cant see that making fuel needs "more" than a fully ported Craycraft head. Another guy on
the forums here also runs DJ needles and mains really really high too, like 185/190 area. That also baffles me.

/shrug - Ill report tomorrow after I do a few plug chops.

 

As you can see by my sig, their not stock. They are pretty much identical except one is 12-1 and the other is 11-1. Other than looking different thats the only difference.