I just installed 35mm bored carbs on my 780 SRX. I had a racepak on the sled before with stock carbs and was running temps within 20 degrees of each other while on the stand. With the bored carbs the pto and middle are running the same temp's. the mag side is 40 to 50 degrees hotter. I am running the same mains straight across as I was in the stock carbs. 47.5 pilots and fuel screws out 2 1/2 turns. If i turn out the mag fuel screw to over 3 turns it will bring temps down . No snow to check out midrange or topend jetting yet. Should I have to adjust the mag fuel screw different than the rest or is there something else I should be checking out. Any help would be appreciated. Thanks
Help with bored carbs
- Thread starter nysrx
- Start date
first things first, if your over 2 turns out and you are lean or having idle hang up problems you need the next size up pilot jet! Running the screw over 2 1/2 turns out is risky as your barely on the spring tension and can lose the screw due to vibration. It wouldnt be uncommon to use use 50-52.5 pilots in bored carbs, it also will require the raising of the needles!! The mains will be somewhere in the neighborhood of 157.5-160's depending on your engine and its state of tune.
I would definitely tune each circuit to the plug color and piston wash, then you have a number to go off of on your EGT. If you were here tuning them in I would place a peice of black duct tape over your display and make you tune them reading the plugs and pistons, dont tune them by the numbers you show on a EGT, youll be chasing your tail like a dog.
I would definitely tune each circuit to the plug color and piston wash, then you have a number to go off of on your EGT. If you were here tuning them in I would place a peice of black duct tape over your display and make you tune them reading the plugs and pistons, dont tune them by the numbers you show on a EGT, youll be chasing your tail like a dog.
bored carbs
Thanks alot Mr. Viper 700. I will try going to 50 pilots. I believe I have 155 straight across now. I have also raised the needles already. I just need some snow to go play in to tune everything in. I was kind of wondering why with the stock carbs all 3 temps ran closer to each other than when I installed the bored carbs. Each of the stock carbs were set up alike. I set up each of the bored carbs alike. I was wondering if maybe one carb could be bored a little different to make up the temp difference.
Thanks alot Mr. Viper 700. I will try going to 50 pilots. I believe I have 155 straight across now. I have also raised the needles already. I just need some snow to go play in to tune everything in. I was kind of wondering why with the stock carbs all 3 temps ran closer to each other than when I installed the bored carbs. Each of the stock carbs were set up alike. I set up each of the bored carbs alike. I was wondering if maybe one carb could be bored a little different to make up the temp difference.