Sx700 jetting?

G

Greaser

New member
Joined
Dec 18, 2007
Messages
4
Location
SK, Canada
Recently bought a 97 Sx700 with Bender triple pipes. Compression tested good 150+ on all three. Its been fouling plugs. Boggy and backfiring around 6000 rpm. Cleaned carbs and this is whats in it.
Mains 147.5
Pilots 55
Fuel screw out 1.25 was 1.5 (i don't know what I'm doing)
Needles 343
Im new with jetting does anyone know what jet sizes Id need and fuel screws out. Im lost don't know what to do next?
Im thinking of buying different size jets what you guys recommend for sizes?
 
I’m at 1700 elevation, and I use 147.5 mains, all needles at 3, and 45 pilots.
Your pilots are way rich unless your at higher elevation. Would also changes all needles to pos. 3
 
Greaser said:
Recently bought a 97 Sx700 with Bender triple pipes. Compression tested good 150+ on all three. Its been fouling plugs. Boggy and backfiring around 6000 rpm. Cleaned carbs and this is whats in it.
Mains 147.5
Pilots 55
Fuel screw out 1.25 was 1.5 (i don't know what I'm doing)
Needles 343
Im new with jetting does anyone know what jet sizes Id need and fuel screws out. Im lost don't know what to do next?
Im thinking of buying different size jets what you guys recommend for sizes?
Click to expand...
How do the main nozzles look at the top. Probably best to replace all three if you can still get them.
 
Im running at 2000 elevation. Yes it is running rich. Murder Yamaha do you recall how many turns out on fuel screws? Do you run premium?
 
As you have tripple pipes on your sled and 150psi is high cranking compression on a Red Head 700 definitely run premium.
A common problem on the older Yamaha triples is the the spark plug caps resistor breaking down and causing too much resistance and creating spark plug fouling problems.
Also make sure the right plugs are installed.
45 or 47.5 pilot jets is more normal at your elevation with fuel screws around 1.5 turns out.
 
I run 91 octane. Also usually a splash of Torco octane booster if it gets real cold.
That needle on pos 4 is gonna make it run poorly, along with the too rich pilots.
You should be able to run the same stuff I am. BR9ES plugs.
 
Hey guys, new here and I acquired a set of Bender triple pipes from a used sled lot here in MI and I do not believe I got the correct header pipes for them? I pretty much know what I need to try for jets right off the rip, but I need to get the dang things on there first. Wondering if anyone could provide any pictures of their engine compartment? I did not get any springs with them either in which they told me "all" hardware was included. The pipes themselves look correct based on youtube videos I have found so I think thats a good start. Hoping you guys can help and I can get this thing going! Thank you
 
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