Jetting suggestions

[400exrider707]

05 450R

last year I ran an HMF slip-on with stage 1 hotcam and UNI with no lid. Other than that bone stock.

My jetting was as follows: 180 main, 50 pilot, 4th clip down on the stock needle, and 2 1/2 turns out on air screw.

It ran slightly rich this way as my plug was a darker brown, but not black by any means, and it ran excellent with no hesitation from idle to instant full throttle.

I just did complete rebuild from the crank up, with the following changes... HRC cam, Nmotion full exhaust, and JE 11.5:1 std bore piston. I put in a bunch of new stuff like bearings and seals and what not, but the cam, exhaust, and piston would be the only things that could effect how it is running.

On startup it starts , but has a rough idle. If it shuts off it usually takes 5 or 6 starts to kick while warm (this is unusual). I didn't change any jetting as I thought it was rich before so the increase in air flow should be about right with the richer jetting. As I said rough idle, head pipe slightly glows red, played with the air screw by turning up the idle and making small adjustments to the air screw and giving it a few seconds to change, and this seemed to make absolutely no difference. I went from 1 turn out to 3 turns out on the screw and no change in idle at all. Im thinking 52 pilot for that part.

Now when I rev the motor up I get puffs of black smoke... so its rich still. I take it for a drive on a long driveway and it revs up good has good power but nearing top rpm it seems the power falls off and stops pulling. Im thinking possibly leaning to a 175?

It seems to me its lean at idle, rich in the middle, and lean possibly on top? or would it fall on its face from being too rich on top? Can anyone agree or disagree with my diagnosis? I think I will try a 52 pilot 2 1/4 - 2 1/2 turns out, keep it on the 4th clip, 175 main.

Thanks for the help guys and girls.:D

[400exrider707]

Also Im at about 900-1000ft in elevation. Thanks.

[trx250r180]

im running hrc cam ,but lrd full exhast,50 pilot 5th clip from top,182 main but stock piston still and mine runs excellent bottom to the top,i had hrc needle in and it kinda ran like you described,wouldnt idle and glowing pipe,when you changed the cam you didnt get chain off one tooth ? it will still run but not right,id double check the timing,compresion and cam shouldnt throw off that much like a pipe does also my air screw is 2-2 1/2 turns out,i ran at 500 feet and 2000 feet ,ran fine both elevations

[400exrider707]

UPDATE:

I took the carb apart and cleaned out the main and pilot jets, they seemed to have a little build up in them from sitting so long. I ended up putting in the 52 pilot anyway while I had it apart. I now have for jetting:

175 main
4th clip on the needle
2 1/2 turns out
52 pilot.

The bike ran GREAT, but was rather difficult to start. It wouldn't start with the choke at all in 40 degree weather, but it started easier without the choke, and even easier w/ the hotstart. My first thoughts: Rich. However other than the hard starting, it still seemed to have sort of a choppy idle. It ran great from top to bottom with no hesitation and no popping on decel. Im now wondering if the difficult starting and rough idle are just because its a new build?

I went back and swapped the 52 pilot again for the 50. Still seems to have the same starting problems, as well as the choppy idle. However the headpipe is now glowing at idle. This is when sitting still. If I rev it up (sitting still) the red goes away, but puffs a little black smoke. Rich everywhere except idle.

Im so confused because the bike runs great from top to bottom, its just a little more difficult to start than it used to be, and does not idle as smooth as it used to.

Any suggestions?:ermm:

[trx4ever]

try going lower on ur pilot to maybe a 48,

[400exrider707]

Originally posted by trx4ever
try going lower on ur pilot to maybe a 48,

The pipe glows red with a 50 pilot indicating its lean already, going to stock pilot wont help....

[400exrider707]

no suggestions???:confused:

[trx250r180]

are you running stock needle or hrc? and jetting for the n-motion pipe may be the answer since you had stock headpipe,id look at their site or call em for recomended jets,piston and cam shouldnt affect jetting that much,on the hard starting have you rechecked valve adjustment with feeler guage ,could be a little tight if hard to start cold

[d3ktrix]

Sounds like you are taking all the right steps, I would of changed the jetting exactly as you did.

If you tried both a 50 and a 52 pilot and still have an erratic idle it makes me think your valves could be tight. But you just installed the HRC cam so I'm sure you have those in spec.
I would stick the 48 in to see what kind of results you get, even if the 50 makes the header glow at idle.
Just to see what kind of results you get.

And you should have some SLIGHT popping on decel if you go from full throttle to closed throttle in 4th and 5th gear.
Does it pop on decel at all with the 50?

[400exrider707]

Originally posted by d3ktrix
Sounds like you are taking all the right steps, I would of changed the jetting exactly as you did.

If you tried both a 50 and a 52 pilot and still have an erratic idle it makes me think your valves could be tight. But you just installed the HRC cam so I'm sure you have those in spec.
I would stick the 48 in to see what kind of results you get, even if the 50 makes the header glow at idle.
Just to see what kind of results you get.

And you should have some SLIGHT popping on decel if you go from full throttle to closed throttle in 4th and 5th gear.
Does it pop on decel at all with the 50?

I was in say second gear coasting down hill, it wasn't exactly a full throttle to full closed throttle situation. I let it engine brake down the hill to test for popping, so that should be good. Both the 52 and the 50 ran good, just the crummy idle and hard starting.

I think I am going to try another valve adjustment, I dont know why that never dawned on me, but that is probably my problem, I shall try that and go from there. Thanks guys.