Thread: Pro 785 carb questions
06-12-2013, 10:32 AM #1
Pro 785 carb questions
I had some problems at the race this weeked with the Pro785,
It ran great for 30 minutes for practice, then it would not go above 6000 rpms,
we checked the mechanical valves- they were opening, changed spark plugs, nipped back 1/2" on the plug wires, checked the V-force reeds/good,
all the usuall places and still 6000 rpms,
The guy that races it for me, took the carbs off and found a little bit of goo in the pump side of the Mag carb, and all the filters had some crud in them, Hyoctaine suggested that it was my old Tempo fuel lines, so I will change them out this week,
the next question is the Jetting, I have always had some top end problems with this motor as it would not go above 7600 rpms,
after pulling the jets here is what I found,
(B) Low jets are 120 across all three,
(A) High jets are 117.5 across all three,
with a 2.0 needle and seat on all,
I was told to go with 122.5 on the lows and 135/130/135 on the highs by Polaris racer 166
Bob suggested I go with 155/15/155 on the highs
06-12-2013, 10:46 AM #2
Ronnie, there seeems to be some inconsistancies here with the jetting. Here is a thread you made back in 2011 about the jetting on those Redtops. Did you change the jetting since then?
06-12-2013, 11:03 AM #3
NO I never changed any jetting, I had done the Randy tuning tips and it ran pretty good, but still would not go over 7600 rpms, Matt at Gene's says it was the stator, I have pressure tested the pipes, I have checked the crank, but this time is the first time I have checked the actual jets,
I had 2 different jettings suggested by Polarisracer166
Are these carbs the 97 or 98 up models?
06-12-2013, 01:20 PM #4
I forgot to mention these are RED Top carbs and not the stock ones,
does anyone know what year design these are? 97 or 98 and above??
I found this old post from polarisracer166
Stock 98-2000 Jetting.
“3 hole carbs”
Mag Center Pto
Low 122.5 122.5 122.5 3/4
High 135 130 135 1/16 turn
2.0 Float valves 80 Gram springs
15 degree throttle plates. High entry jet blocks No choke plates
97 Red Top 44mm (Red-Top carbs).
Mag Center PTO
Low. #125 #125 #125
High. #125 #125 #125
Low speeds @ 1.5 turn. High speeds @ 1turn.
OEM throttle plates 2.3 float valves 95 Gram springs Stock single fuel pick-up,
06-12-2013, 01:33 PM #5
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