2006 450r carb flat spot HELP

[moogie66]

Can someone out there share some tech help
I have 2006 450r that we have just had engine modified with
JE piston web cam
The carb has a flat spot from idle to accelaration
i was always led to believe if this occurs then the pilot circuit needs more fuel and increasing pilot jet fixes this
In this instance after we did this the flat spot still there but i feel it is more of a too much fuel splutter than lack of fuel
We have a 180 main with HRC needle on 3rd clip from bottom of needle...The pilot jet is 45

Anyone out there had some experience or a simular problem that could point me in the right direction
Otherwise i was going to put pilot back to 42, and move needle clip up 3-4 or even try std needle

I havent had much time on the FCR carb

Thanks

it is a carb issue. there is a product called the boyeson quickshot that take scare of this. i have not tried one yet, but i did turn up my idle just a hair and the bog is lessened. this is on a stock motor. it may be more pronounced on a built motor.

[moogie66]

What is a Quickshot ?????

quickshot (http://www.boyesen.com/article/articleview/99/1/32)

[Quadster450]

moogie - i just pm'd you. If you do change your clip position and it helps, post the results, i'd be curious. Can you tell if you're running rich? Is your plug good?

[440xcex]

Might try a 55 leak jet,gives the accelerator pump more fuel.Its only$10 instead of $80.

[redriderex]

hey 440xcex
what a 55 leak jet??

[440xcex]

its a small jet inside the bottom of the fuel bowl which feeds the acc. pump.

[moogie66]

OK, just an update in the hope someone else out there may have more exact idea or know someone
On the weekend i have tried the following
We installed #55 leak jet ( this was in the HRC 2006 kit)
We have HRC needle
I tried diffrent combo each time which was
position of clip on needle from top to bottom...no change
We tried #45 pilot or slow then #50, we screwed fuel screw all the way in then all the way out ( 1/2 out to 3 1/2 out )
No diffrent
The HRC install manual says screw out accel pump lever screw to give max stroke on shaft and for the sake screwed back in 3 turns to reduce stroke...no real diffrence
The only thing yet to try is the Quickshot cover, As i am in Australia no one has one local and have to get from USA 6-8 days,
so i was trying to fix without or if someone could give me a definate that will fix as per what you are saying you have done
On the engine we have 13.1 JE web cam, ported head work and bills pipe, remapped vortex ignition
I am not clear or convinced that problem is lack off or too much fuel on accelleration of throttle
If engine is say 2500 rpm then stab at throttle, cant notice flat spot, but from low idle and quick stab it will flat spot or when warm die in the engine...When this happens it takes longer to restart and i cant touch the throttle a bit. You can here engine trying to start then after a 5 sec it starts, but throttle must not be touched. Also at this restart when engine is trying to start a flame comes out of exhaust
This confuses me as i though flame meant unburnt fuel
Anyone out there with any help or has a friend or engine guy please help
You can email scarab@emerge.net.au

[bwilson624]

Ok first of all the flame coming out is unburnt fuel. When you nail the throttle from low rpms and it dies, there is still fuel being sprayed, so when it does fire, it burns it out. Next, get the quickshot. It should really eliminate your problem. I hope this helps. Let us know how it goes.

[eagertorace]

Originally posted by bwilson624
Ok first of all the flame coming out is unburnt fuel. When you nail the throttle from low rpms and it dies, there is still fuel being sprayed, so when it does fire, it burns it out. Next, get the quickshot. It should really eliminate your problem. I hope this helps. Let us know how it goes.

the quickshot will not fix his problem, been there done that!
Just go by the hrc manual for ALL settings, especially on the acc. pump adjustment.
try that out

[305400ex]

I would try going down in the main jet also. Try a 170main.