Help jetting blaster mod chamber in 61x/62t superjet

[adet16v]

Looking for some help with this.

62t case
61x rec ported cyl
dual oem 38's
stock flame arrestor
stock head


When I looked on factory pipe's web site they recommend the following for the blaster 701 mod pipe...

140 Main 1 1/8
70 Pilot 7/8
Needle/seat/spring - stock (55 psi)

This is what I tried and it was WAAY rich. I got down to having the top screws all the way closed and bottom screw at 3/4 turn out. And it was still running rich.

Am I missing something? Is the blaster a 62t cyl?? or 61x?

Anyone else running blaster mod pipe in a sj with oem 38's??

 

[Matt_E]

It's way too rich because it's for a sitdown.

Run the limited SJ pipe specs. something like 72,5/135 with 95 g spring or so.

 

[adet16v]

Yeah I am going to give it a go again and drop the main jets to 135's.

What does it being a sit down have to do with it?

Is the 701 blaster a 62T(case)/61x(cyl) or a 62T/62T??

 

[adet16v]

It's way too rich because it's for a sitdown.

Run the limited SJ pipe specs. something like 72,5/135 with 95 g spring or so.

When I had the same pipe on my 61x/61x motor I used factory pipe's jetting recommendations for the 61x case single carb waveblaster and it was almost spot on....

That was -

145 Main 1 turn out
120 Pilot 1 1/4 turn out
Stock needle/seat/spring 55 psi

This is why I was so surprised that the dual carb specs were so far off...

 

[yamahammer]

i had similar experience when i switched from a sjmod to b1mod chamber-- had to lean out boat a lot-- always seemed a little rich after swap regardless of tuning and always had a ton of exhaust sludge-- engine was maybe a little more grunty at low rpms--but i thought it signed off earlier-- if you invert youll get real tired of that POS chamber coming loose off the headpipe when pancaking-- i swapped back to sjmod and am much happier-- best of luck to you