Needle postion or jets?

[zr2highrider]

I just got done with my top end and was wondering what position I should have me needle in. I cant remeber what clip it was at the last time I cleaned my carbs and was just wanting to get in the ballpark.

My mods:

.40 overbore w/ wiseco's, ported cylinders, VF 2 reeds, T-5's, K&N pods, 310 mains with 27.5 pilots (1.5 turns out) on stock carbs. Rest of motor is stock.

Blows a little smoke out at idle and when first starts up. Plugs look about right but there is a little hesitation right of idle. So my question is do i need to move the needle or are my jets off?

[SD1026]

Depending on ypur elevation you might wanna try a 25 piolet have you messed with the air screw.did you try 2.5 turns out to see if it got better or worse. If it gets better 2.5turns out drop the piolet if it get better at a half turn out bump the piolet to a 30 but check to see if your needle clip is in the middlle. Needle clip should be in the middle.

Edited April 29, 2010 by SD1026

[dirtydownunder]

the clip doesnt have to be in the middle, you start from the middle and either go up or down if needed.

 

so when you say you just got your top end, does that mean you just had them ported aswell ? because 310 is pretty lean for a ported engine with pods or open airbox.

 

if you have a bit of hesitation off idle , try needle hights.

 

 

list all of your mods and elevation.

[zr2highrider]

Ok here my bolt ons/mods.

 

T-5's, K&N clamp on pods, .40 overbore w/ wiseco pistons, ported cylinders, VForce 2 reeds. 310 mains w/ 27.5 pilots. 1.5 turns out on the air screw. Everything else is stock. (no timing plate...yet)

 

As for my porting....well, it doesnt look the best. Looks like a 2 year old did it. Didnt even polish it. It was there when I got the quad.

 

Elevation in LV, KS is 840 ft. above sea level.

 

So is 310's to low?

 

Just some stuff I was reading up on...

My pipes are discolored in the front of the headpipe right out the exhaust. Its not a blue color either. Its like a brown. Is this from running it to lean or to rich? They were like this when I got the quad as well.

Also, it smokes at idle but more on my choke side. Is this normal?

Edited April 29, 2010 by zr2highrider

[dirtydownunder]

for a ported motor 310 does sound lean, how does it go ?.

depending on the porting it could be in the 320-340 range.

 

golden brown is normal, you can get some 4x steel wool and see if you can polish some of that brown off.

[zr2highrider]

When I was out riding today i did notice a slight sputter when i hit wot. It was right before I hit the powerband. Basicly I would be going as a decent clip in 3rd and just punch it. It would have just a slight hesitation before the band and then once I got into the powerband, it just takes off like it should (if I ever got decent tires to hook up).

 

So I should be stepping up the mains. 320 as a good start?

[dirtydownunder]

worn spark plug caps can have a similar effect.

if it needs more fuel, you would think it would need it in the upper revs as well, instead of getting to a spot and revving clean after that.

you could try needle hights or throw a 320 in because 310 does sound lean if its ported.

 

if you take off your plug cap boots, and check the resistance on them, they should be no more than 5k.

 

 

 

 

i thought you had stock pilots, 25pilots is all you should need with those mains, tho some people run 27.5 without a problem.

[AKheathen]

generally, a hesitation like that pinned is a lean main jet, although plug caps can mymic it sometimes. that's pretty rpm specific, usually