416 jetting?

[infantry317]

Hey guys,
I was wondering what I should run for jetting on my 416ex. It is a JE 416 10.8:1 piston, stock cam with K&N/Outerwear and I don't run an airbox lid, also the needle clip has been raised one position from stock. It ran great during the summer with 155-40 jetting but once it started to cool off it seemed like the engine wanted to backfire. I'm not an engine guy so any positive input is appreciated.

Thanks,
Scott

[speedy400]

I also had a problem with that, I uped the pilot and I think I turned out the fuel screw, mess with the fuel screw 1st, good luck-darren

also, when is it backfiring? when your high revving on deceleration?, if so fuel screw should be right

[infantry317]

It hasn't fully backfired, but it is when you let off the gas.

[cals400ex]

if you don't like the popping on decleration, turn the fuel skrew out a bit. personally, on my bike, the air/fuel ratio seems to be close to where it needs to be when it pops. if i richen up the fuel skrew so it doesn't pop on deceleration, my bike runs a little rich at idle. also, with my stage 2 cam, if i am rich at all on the pilot jet/fuel skrew, my bike doesn't want to idle that great. however, turning the fuel skrew out a little will probally fix the popping in your case. you could also put in a 158 keihin main for the winter months if you want.

[infantry317]

I'll give it a try, thanks guys.:D

[Glamis400ex]

Just curious why you went thru ALL the trouble of a 416, and kept the stock cam??:huh

Glamis

[speedy400]

Originally posted by infantry317
I'll give it a try, thanks guys.:D
just to let you know I rejetted mine for winter today, mine is diffrent than yours but I thought I's tell you anyways.
Dynojet needle- 3rd from top with washer under it.
Dynojet 175Mainjet(from my dad's ds650 dynojet kit)
45 pilot
3 1/2 turns out on fuel screw
it seems to be just perfect, maybe a bit rich, but by the time our "winter" comes it should be about perfect
-darren

[infantry317]

Originally posted by Glamis400ex
Just curious why you went thru ALL the trouble of a 416, and kept the stock cam??:huh

Glamis

It was time for a rebuild and I got the machining and JE piston for 135 bucks. It seemed to give it more low/mid end. I may do a cam, but it seems like the race cams really tear up guys' engines quick just from what you hear.

[Glamis400ex]

That's why we all seem to like the Hotcams. They are billet which means they're nice to all the other stock parts in the valve train. I put a new Hotcam stg. 2 in with my 4 year old rockers and springs and don't have one bit of problem. If you get one, and I suggest you do, you'll notice a marked improvement. Best cam for the money, hands down.

Glamis

[infantry317]

Good info, thanks Glamis.

[cals400ex]

yes glamis is correct. you think you noticed some low to midrange power with the piston. well put a hotcam in and you will definately feel much more power, mainly in the midrange on up. the cam won't trash your motor quickly. it is a drop in cam, which is nice if you don't have the cash to spend on new rockers and springs.

speedy, i bet your plenty big on the main.