Koso EGT
- Thread starter CMB70
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shoppingcart111
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There's lots of threads on proper operating temps but your temp will vary based upon where you placed your probes.
Nice install. As stated your readings will vary depending on probe placement but you should be in the neighbourhood of 1250-1300 ish on the high end from what I found on my BB. The biggest thing I found was you really have to watch your temps on the trail as most BB set-ups have a lean spot in the midrange.
pfi572
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I believe if probe is 2.5 inchs from piston skirt you should not exceed much more than 1300 for extended pulls. Good rule of thumb is to check plug color and possible wash on piston.
As stated it is the mid range that will most likely be warm.
As stated it is the mid range that will most likely be warm.
oler1234
Active VIP Member
mmmm.... if i remember correctly it is 4" fromt pistoin skirt and 2ish from the flange. CMB last time i heard you where running the twins, if so add a additional 2" as the flame front is typically longer on twins. Set it where you feel you make the most power.
pfi572
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Older 1234 is right at 4 inch's as looked it up and race book says 100mm (4 inchs) from piston skirt .
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oler1234
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Pto is typically the hotter one. Due note the above temps are correct, but we always found the sweet spot is around 10-1100 degrees. Not sure why but u can feel it pull harder in these temp ranges. Just out groups observations with big bores
pfi572
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Have found the same on BB also . Ran a RKT 860 and now the 880 BMP and both seemed to be the same. They need fuel and good fuel.
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pfi572
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I have 480 but have alot of things done. With a RKT 860 i ran 470 with 14:1 head and his ecm update with couple gallons VP 110. Went down in jet sizes as builder requested but motor was running out of fuel and to lean.
oler1234
Active VIP Member
currently i am running a 560 jet with .030 shim in the needles. running a 13.5 head and a shot of nos
One single pipe version in the group is running a 540 with a 0.020 shim in the needles. this is a 13.5 head and a shot of nos.
The other with the most similar setup is running a 500 with .020 shim in the needle, 13.5 head no nos
Start rich and go lean, you will find the sweet spot as you go down if you need to. These types of setups are good for 5-7500ft. Doo motors love gas, plus 480 is the stock jet, yes it may be rich for the stock power but not that rich.
One single pipe version in the group is running a 540 with a 0.020 shim in the needles. this is a 13.5 head and a shot of nos.
The other with the most similar setup is running a 500 with .020 shim in the needle, 13.5 head no nos
Start rich and go lean, you will find the sweet spot as you go down if you need to. These types of setups are good for 5-7500ft. Doo motors love gas, plus 480 is the stock jet, yes it may be rich for the stock power but not that rich.
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- #13
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