440 w/450R carb jetting issues

[400Trooper]

Here's one for you to contemplate.
440 w 450R carb (zrpilot adt)
Full FMF exhaust
stock head (w kibble valves, stock sizes)

test 1:
190 main
48 pilot
2.5 turns A/F
clip @ #2 slot
- start fine
- idle fine
-slow throttle roll, good to 1/2 plus throttle then stumble

changed main jets from 190 all the way down to 168 using sizes in between. same results as beginning.

Test 2:
185 main
50 pilot
2.5 A/F
clip @ #3 pos. (center)

Changed jets all the way down AGAIN to 168
- same results!!!!!!???????

Called zrpilot, (great dude btw!)
After talking to him and explaining all the checks, he suggested removing the air box!!
Test #3:
185 main
50 pilot
20.5 A.F
clip @#3
(No airbox)
-ran GREAT, no stumble, hit rev limiter REAL quick!!

Recalled Z, he suggested replace air box.
- replaced it and
-started
-idled
-stumbled at throttle. 1/2 to WOT!!

We are thinking this one out! Interesting huh!

Suggestions are welcome!!! Will post more info later, off to garage!!

[JOHNDOE83]

The stumble generally means its running rich, although it is very odd that you can go all the way down to 168 and still stumble.

Is it possible that your snorkel is clogged? My friend ran his ex everyday, let it sit for 1 week and a rat built a nest in his snorkel.

It wouldnt start wouldnt run, after he noticed the nest while trying to clean his filter, it ran great once it was removed...lol.

Just a thought.

[CJM]

Tried removing just the airbox lid?

I also run no snorkel, put a spraypaint can lid in its place.

[400Trooper]

Originally posted by JOHNDOE83
The stumble generally means its running rich, although it is very odd that you can go all the way down to 168 and still stumble.

Is it possible that your snorkel is clogged? My friend ran his ex everyday, let it sit for 1 week and a rat built a nest in his snorkel.

It wouldnt start wouldnt run, after he noticed the nest while trying to clean his filter, it ran great once it was removed...lol.

Just a thought.

I don't run the air box lid or snorkel, and air box and air horn are completely clear and clean! Did you read the part about it running great without the air box attached? But would stumble bad with just the box and no filter in place!!! very perplexing huh!! Thx

[06440ex]

First I'll list my mods then my current problem . 440 big bore kit stage two hot can port and polish full white bros exhaust kibble white valves and springs. I'm used to my bike being a torque monster but lacking some high end power so I decided to get a 450r carb in doing this I figured more air needs more fuel in order not to lean out.. So my bike running a 44 pilot and a 175 main on a stock carb 1st gear threw 3rd on the back tire petty much dragging rear bar now I did the swap and I put a 44 pilot and a 210 main ( obviously very rich) and needle 3rd from top but the bike at WOT is running like a raped ape but take off is lacking power .. Not really stumbling or spitting just not strong should I leave all a/f alone and just go with a 195-185??

[400Trooper]

Originally posted by 06440ex
First I'll list my mods then my current problem . 440 big bore kit stage two hot can port and polish full white bros exhaust kibble white valves and springs. I'm used to my bike being a torque monster but lacking some high end power so I decided to get a 450r carb in doing this I figured more air needs more fuel in order not to lean out.. So my bike running a 44 pilot and a 175 main on a stock carb 1st gear threw 3rd on the back tire petty much dragging rear bar now I did the swap and I put a 44 pilot and a 210 main ( obviously very rich) and needle 3rd from top but the bike at WOT is running like a raped ape but take off is lacking power .. Not really stumbling or spitting just not strong should I leave all a/f alone and just go with a 195-185??

Man I feel your pain! I'm dealing with an issue similar and it's pissing me off! My quad will run like a raped ape without the air box, but put the air box back in and stumble badly from 1/2 throttle to WOT!

[400Trooper]

Well after much digging and research into my 450R carb I found a few things that are contributing to my problems.

#1. Wrong needle!!!
#2. Wrong needle jet!!

So off to order the correct ones from service Honda!

Lesson to all: When buying a 450R carb, make sure it has ALL the CORRECT ORIGINAL parts inside. It is utterly impossible to tune the carb without them!!

Thanks again to zrpilot, this man is a GENIUS and knows his ****!!!

[JOHNDOE83]

Originally posted by 06440ex
First I'll list my mods then my current problem . 440 big bore kit stage two hot can port and polish full white bros exhaust kibble white valves and springs. I'm used to my bike being a torque monster but lacking some high end power so I decided to get a 450r carb in doing this I figured more air needs more fuel in order not to lean out.. So my bike running a 44 pilot and a 175 main on a stock carb 1st gear threw 3rd on the back tire petty much dragging rear bar now I did the swap and I put a 44 pilot and a 210 main ( obviously very rich) and needle 3rd from top but the bike at WOT is running like a raped ape but take off is lacking power .. Not really stumbling or spitting just not strong should I leave all a/f alone and just go with a 195-185??

Main jet has nothing to do with your lowend, main jet is only topend.

If it runs like a ape at wot then its not to rich, in fact you could possibly go even richer and make it even better.

I used a 220 mainjet, 50 pilot on my 440 and it was a super beast.

You might be hesitating from being to lean on your pilot jett.

[JOHNDOE83]

Originally posted by 400Trooper
I don't run the air box lid or snorkel, and air box and air horn are completely clear and clean! Did you read the part about it running great without the air box attached? But would stumble bad with just the box and no filter in place!!! very perplexing huh!! Thx

Yes I read it.

Thats why I suggested a block in the snorkel, but if you have removed the snorkel and dont run a airbox lid, then I guess it doesnt really matter.

[06440ex]

o i just figured that the main jet was dumping too much fuel and what makes the enormous amount of popping on decell? its never done this before i put this carb on..

[JOHNDOE83]

Popping on decel is deffinetly to lean on the pilot jet.

I suggest the 50 pilot and 2.5 out on the a/f screw.

Check out the FAQ section at www.jetsrus.com for detailed jetting info.

[06440ex]

ok great so ill swap out the pilot i have a 52 on order that should be in tommorow am and by the weekend i should have some more info for you guys do you think the 210 is too rich i mean i rode this bike hard for 6 years with a stock carb 44 pilot and 165 main pulled the piston to overhaul after head gasket went and i was honey golden brown now i dont know about this carb too much but a 40+ jump on the jet was just a shot in the dark to give me a baseline should i put in a 185-195 with the 52 pilot needle is third from top and a/f screw 2.5 turns out

[JOHNDOE83]

The way your supposed to jett for a main jet is to start off really big, if you have a 210 now, I would buy a 215 and a 220. Start at 220 if it doesnt fully rev out and stumbles instead of rev out fully, its to rich and I would back down to the 215.

If it stops stumbling and fully revs out with a 215, then your jetting is close to perfect for the main jet.

Its NEVER to rich on main jet unless you get that stumble at WOT.

If 215 stumbles slightly, go back to 210.

Or you could leave it like it is now 210 and Im sure you'll be ok

[06440ex]

thanks for the info and no im definately not stumbling on WOT but the Accelaration is just not there this is def not the monster it was with the stock carb thats why i was thinking it was being choked with gas because im 240 lbs and 1-3 and occasionally 4th was scary on the back tire with the stock sprocket and i dropped a tooth in the front and things got really fun. then i put on this damn carb and i lost it all.. its def not to potential

[JOHNDOE83]

Judging by the mods in your sig I would think your jetting should be close to mine.

Deffinetly try a bigger pilot jet.

Possibly try a 220 or 215 main jet.

I have a 440, with kibble white + size valves, stage 2 cam, custom exhaust, custom "no box" intake, whitebros CDI and stock porting with 450r carb jetted @ 220main, 3rd notch on needle, 50 pilot.

That was for my 400ex drag quad.

[06440ex]

Ok went riding today 185 main 44 pilot needle 3rd notch ran great but had some popping on let off around mid rpm range after letting off from 1/2 to full throttle but not much hesitation in the accel still feels like it needs a little more pep to be as efficient as it was with the stock carb should I increase pilot ?? Would this bring the low end pep back and reduce popping on decel??

[JOHNDOE83]

If your only at 2-2.5 turns on your a/f screw try turning it out to 3-3.5 and see if it still pops, if it still does maybe your needle should be richend up a lil bit.