Fro
New member
Why are there 2 different jet sizes on a '99 SRX(mains). Which one is different...PTO, Center or Mag side.
I cleaned & adjusted my carbs & have a few hundred miles on it so far. Runs great. I caught a thread about different sizes & now I'm worrying about it. I did one at a time, so they are in the same carb as before. This doesn't mean they are right tho. I bought it used last year. What can happen if mixed???...I know I'll end up pulling them to check tho.
I cleaned & adjusted my carbs & have a few hundred miles on it so far. Runs great. I caught a thread about different sizes & now I'm worrying about it. I did one at a time, so they are in the same carb as before. This doesn't mean they are right tho. I bought it used last year. What can happen if mixed???...I know I'll end up pulling them to check tho.
PTO cylinder gets the bigger jet.
YAMMIEGOD3:16
Active member
USUALLY, THE PTO (closest to clutch gets larger main ) BUT NOT ALWAYS THE CASE. THE 99 SRX 700 SPEC WAS.
#1 & #2 146.3
#3 148.8 ! 3:16 (yammie tony)
#1 & #2 146.3
#3 148.8 ! 3:16 (yammie tony)
A K MtnViper
New member
My PTO runs too rich so I'm stepped down one size. You have just got to check each cylinder for your self.
Here is what I'm running. I ride at 8,500 to 11,000 with this set up and get about 8-9 MPG. I'm a hair lean at 8,500 and a hair rich at 10,500. Carb heaters off.
PTO 145, CENTER 147.5, MAG 147.5, Pilots 45, Needles 2.0, Air screws 1 7/8.
Torsion spring silver, Torsion cam 43 degrees, 100 degree twist on secondary.
13.3 steel outer rivet, 13.3 Alum inner, 8DN 10 weights, Green-White-Green spring
I engage at 4,050 rpm and max out at 9,100 out of the hole and settles to 9,000
21 x 40 gearing. I forgot to mention I'm jetted for 20 to 0 degrees air temp. If its colder out I my sled runs a little lean, warmer is richer of course.
Here is what I'm running. I ride at 8,500 to 11,000 with this set up and get about 8-9 MPG. I'm a hair lean at 8,500 and a hair rich at 10,500. Carb heaters off.
PTO 145, CENTER 147.5, MAG 147.5, Pilots 45, Needles 2.0, Air screws 1 7/8.
Torsion spring silver, Torsion cam 43 degrees, 100 degree twist on secondary.
13.3 steel outer rivet, 13.3 Alum inner, 8DN 10 weights, Green-White-Green spring
I engage at 4,050 rpm and max out at 9,100 out of the hole and settles to 9,000
21 x 40 gearing. I forgot to mention I'm jetted for 20 to 0 degrees air temp. If its colder out I my sled runs a little lean, warmer is richer of course.
oops! Thats right. guess i was thinking of the sx,sorry.
Fro
New member
YAMMIEGOD3:16 said:
Thanks Tony. I'm gonna pull them to make sure. Just curious as to why they are different too, what's the theory...longer fuel line & a little less pressure??? Just guessing.
So #1 is the PTO side & #3 is the Mag side right?
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YAMMIEGOD3:16
Active member
FRO, I SEEN THAT ALOT OVER THE YEARS ON TRIPLES. THAT STAGER JETTING, IT ALWAYS SEEMS IT WAS THE PTO THAT WAS LARGER SIZE. AND THATS THE CASE ON THE 00-01-02 SRX. FOR SOME REASON YAMAHA UP JETTING ON MAG. YOUR ORDER IS CORRECT. I ACTUALLY WENT TO THE 99 TECH MANUAL FOR THIS BECAUSE I DID NOT REMEMBER. 3:16 (yammie tony)
Fro,
yamaha increases the jet size on the PTO cylinder because it supposedly takes on higher loads than the others due to the fact the the clutch is right next to it. With the higher load comes higher temperatures, with higher temps comes leaner burn conditions in the cylinder so they are trying to use the jetting to compensate and bring the burn conditions within the cylinder back to the desired lean/rich conditions.
Mills
yamaha increases the jet size on the PTO cylinder because it supposedly takes on higher loads than the others due to the fact the the clutch is right next to it. With the higher load comes higher temperatures, with higher temps comes leaner burn conditions in the cylinder so they are trying to use the jetting to compensate and bring the burn conditions within the cylinder back to the desired lean/rich conditions.
Mills
YAMMIEGOD3:16
Active member
CORRECT, BUT THIS IS MAG SIDE WITH LARGER SIZE. 3:16 (yammie tony)
I'm out - I don't have any idea why that would be.
Fro
New member
I'm going to make sure it's like the manual as Tony said...larger on the Mag side. Seems to be opposite of the "Norm" as others have said, but there must be a reason if it's straight from the manufacturer.
the 98-99 srx used the larger mag side jet because they had the old ignition system, was thought that the mag cylinder recieved the most power closest to the power source, the 2000-02 used it on the pto for the added heat from the clutch, the ign. system is the 3d one and doesnt fire all the plugs at 1 time like the earlier 98-99 system.