What should I be starting with for jets and neddle settings? I have stock bore with new piston and rings with a fresh hone. Cylinder was ported per the DIY links from Oconnor racing on here.The head was milled .020 and the combustion chamber was polished. Its running a FMF fatty with a turbine core silencer.Boyseen power reeds with stock box and stops in place.TORS has been removed and at present there is a 310 main jet in the stock carb. We have ran the the bike through the break in like this.Brought it up to operating temp, and let it cool three times.And now its time to ride. But I cant do a plug chop ,cause no wide open throttle for a tank full of fuel.It seems to run decent, but it starts without using the choke.It has an aftermarket air filter with 8 1" holes drilled through the stock box cover.Let me know what you guys think I should be at with the needle and jet settings.Thanks
Jets and neddle settings
- Thread starter blowncash
- Start date
i would start in the area of a 260...270 mabe a 280 main..310 seems a tiny bit big for such mild mods, leave the stock pilot and the needle clip in the middle
You are not going to do any harm running a #310 main if you are not going to go WOT, you will only be running on the needle at 3/4 throttle.
You are prolly going to go back to the region of #290 main, but only plug chops will tell.
You are prolly going to go back to the region of #290 main, but only plug chops will tell.
maybe for reference or whatever I ran a stock carb on bbk and changed the main jet to 340 and left the pilot stock
Sounds good! Im gonna knock it down a little on the jet. I started at the 310 based on my reading on here. I was looking at jetting for a stock bike with just the exhaust system and came up with 270-280,so figured I would start at 300,but all I had was a 310,so I used that,I did not want to run lean.Also my head Temp was at the 225-230 range with the infrared gun,is that ok?The head and cylinder were painted with engine enamel prior to assembly. Gloss black if it matters.Just a few light coats.
What are the air temps where you're at?? I would leave the 310. Plugs are cheaper than pistons. Unless it blubbers like an idiot I'd leave it. Until you're uber confident in your jetting skills it's safer to run fat. You'll never miss the bit of power but you will miss your piston. I have DIY port, Vito's reeds, Fat Bastard pipe and ran 310 in the summer, so I'd have to run 330-340 now.
How does the plug look? Next time you're out, in the highest gear possible at WOT, pull choke out halfway. If it runs better you need bigger main, if not it's good to go.
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