450r carb!!! HELP!!! NEED HELP ASAP!!

[caseywoods5]

hey guys i finally put on my 450r carb... i put a 52 pilot and 170 main and it barely started but then started idling (a little high), i figured it just needed to run a bit, i walk in for a couple of mins and come back out and see cherry read headers. so it's extremely lean (explains why it would quit if i hit the throttle and it was blowing flames when i tried to give it throttle). considering i need to go a few jet sizes higher (i figure maybe 180-190, i got 180, 185, and 190 from the jet kit) what would you suggest? my mods are in my sig. let me know guys i'm wanting to get this thing closer to right tomorrow. thanks!

[CJM]

Id start at 185 and see where it takes ya. Everyones setup is different and in some cases some people have had to jet dramatically high with the 450r carb b/c they didnt seal the hotstart properly/well enough. Me Id use the stock parts to seal it just to be sure, the rtv method hasnt had good success.

[JOHNDOE83]

the rtv works fine and is the best way, just as good if not better then the actual hot start....its better.

changing your main jet wont change your red headers at idle, my 440 used a 220 main jet and 50 pilot jet 3 turns out on the air/fuel screw with needle on 3rd notch.

This was on my 05 450r carb.

Did you even plug the hotstart? that could be your issue.

[caseywoods5]

yes i plugged my hotstart with rtv as suggested. and why won't jetting change the headers glowing red at idle? that seems a little off to me but i guess you guys would know more than i would about it.

[mxdad423]

The reason is because the main jet does not control idle, the pilot and air screw does, Sounds like you need to go bigger on the pilot jet.

[caseywoods5]

well i got it running mint today but i'm going to need to up the main jet some more. it is at 195 main (the biggest that came in jets r us jet kit), a 52 pilot, and a/f screw out 5 turns (this is why i need to up the main some more). but it runs absolutely perfect, no glowing headers and starts right up and revs fully without trouble. from this info would you guys be able to figure out about what size my main will need to be?

here is a vid of it:

http://www.youtube.com/watch?v=7FgtDT1DXjI&feature=youtu.be

[JOHNDOE83]

with your mods a 195 is close enough to where you need to be for main jet.

BUT 5 turns out! isnt good, I think your hotstart might not be full blocked. Or you may have a leak somewhere, maybe at you adapter. "I dont like those adapters"

My motor is modded a lil more then yours and only uses a 50p 3 turns out.

The main has NO effect on the pilot jet or anything at idle.

This is prob why CJM suggested your hotstart issue, if all you did was plug the hole with a lil rtv its not good enough. theres two holes that need filled with RTv to work properly and mine are FILLED full of RTV.

[JOHNDOE83]

The vid sounds fine? whats up with the vid?

[caseywoods5]

i just took a vid because i finally got it running good. and do you have a pic of the 2 places i need to fill with rtv? i think i got them filled but pics would help to know for sure.

[JOHNDOE83]

if you filled the one in the carb port to the motor side on top of the carb port along with the one on top of the carb "hotstart hole" you got both.

May I ask why 5 turns out is right? maybe 3 would be fine? Im just wondering how you came to that conclusion, maybe I missed something?

do you back fire on decel at all?

[caseywoods5]

at 3 turns it backfired a little occasionally and popped, wouldn't rev the entire range. at 5 it ran great without any pop on decel and revved fully until the rev limiter kicked in. that's how i came to that conclusion. and as for the port on top of the carb (the little back screw in thing with the spring under it), i filled it and put the spring back in place, but the top is plugged. as for the other one, i think that may be my problem because i think i only plugged the top. still not sure where exactly this other place i need to plug is at :/ thanks for the help so far guys!

[JOHNDOE83]

Try adjusting the needle lower on the clip, then try to back down the air screw a lil.

See if that helps?

[caseywoods5]

didn't realize that's what the needle did, thanks! i'll try lowering it tomorrow if i get a chance!

[JOHNDOE83]

just remember, lower the clip on the needle, not lower the needle with the clip.

[caseywoods5]

so you mean move the needle lower or higher? sorry but that just confused me a little haha

[JOHNDOE83]

if you lower the clip on the needle, it will raise the needle making it richer, if you put the clip higher on the needle it will lower it making it more lean.

[caseywoods5]

ok so you mean lower the clip a notch away from the flat end to make it richer? thanks!

[Thumpin440ex]

Man if your using a 52 pilot, still need more pilot, jet that doesn't sound rite.. Mine was really rich with a 52 pilot, the needle at the middle setting.. I have dropped down to a 50 pilot, out 2.5 turns on the AF screw, it is about dead on.. Def see where that needle setting is.. The closer it is to the flat end the leaner it is in the bowl. My mods are very similar to yours.. I just went through all this about a month ago..


John

[caseywoods5]

if i may ask, what is letting you guys know it is my pilot jet? it idles perfect and smooth so i don't understand how my pilot is a problem. even when the main was smaller it would idle but wouldn't take any throttle until i finally upped the main. now it runs mint only thing i see as a problem is the a/f screw out 5 turns but if i could find a way to hold the screw in place to keep it from backing out would i have to change anything? thanks!

[Thumpin440ex]

All your issues seem to do with the idle circuit.. Which the main jet has nothing to do with.. Also I assume it has the stock secondaries( 72 IIRC) And from the tons of reading I have done nobody changes that.. The AF needle should not be that many turns out esp using a pilot jet of a 52. Depending on how long you let it idle also will make the header pipe glow.. Most set ups are still using very similar jetting, but your situation seems to be out alot compared to others.. Are you sure there is no any air leaks between the outlet side of the carb, head/intake? Or leaks in the carb? Only reason I ask is I have just been through a tone of some similar issues, so this is all fresh in my head..


John

[JOHNDOE83]

Originally posted by Thumpin440ex
Man if your using a 52 pilot, still need more pilot, jet that doesn't sound rite.. Mine was really rich with a 52 pilot, the needle at the middle setting.. I have dropped down to a 50 pilot, out 2.5 turns on the AF screw, it is about dead on.. Def see where that needle setting is.. The closer it is to the flat end the leaner it is in the bowl. My mods are very similar to yours.. I just went through all this about a month ago..


John

I agree, Im thinking his needle is set to lean and he made up for it a lil bit with a big pilot jet.

[DnB_racing]

are you sure your running the right series number for your pilot? there are 2 lengths of pilots that can be used...

one is series 21 and its 28mm long and the other is a series 26 and its 23.5mm long...

they both have the same size and type of threads, and have the same type of metering jets... the only difference is how deep the stem goes into the float bowl,

from your symptoms it kinda sounds like your carb is coming out of the pilot circuit too soon,and entering the main, indicating a short series pilot is being used... the one that is preferred for mx or xc racing is the longer series 21(28mm), it allows for a smother throttle response between the pilot and main circuit, the 26 series(23.5mm) is used for a full drag porting were the power is in the main jet (wot)

just a observation and something to check if all else fails

[Thumpin440ex]

??? for you on this.. When I changed jets, it had the longer jet in it.. The one I put back in was the shorter one.. The end with the metering holes was identical lenth to the one that came out.. But the length after the threads is a little diff. I am now using that to the specs of 2.5 turns on the AF and middle setting on the needle.. I have stumbled on some reads that the say''The 28 mm is listed in the Keihin Catalogue for Aftermarket and OEM FCR-MX'' I do not have a FCR carb, just the reg 04-05


OP what carb are you using?

John

[BlasterEaten250]

If you are 5 turns out on the a/f screw you should technically be going to a larger pilot.

[caseywoods5]

the pilot i took out originally from the 450r carb was a shorter one, the ones that jets r us sent me are longer. everything is the same threads and all just the screw end sticks out a little farther. using a 04-05 trx450r carb, same as most people on here i believe, using an adapter from ZRPilot.

[caseywoods5]

Originally posted by Thumpin440ex
All your issues seem to do with the idle circuit.. Which the main jet has nothing to do with.. Also I assume it has the stock secondaries( 72 IIRC) And from the tons of reading I have done nobody changes that.. The AF needle should not be that many turns out esp using a pilot jet of a 52. Depending on how long you let it idle also will make the header pipe glow.. Most set ups are still using very similar jetting, but your situation seems to be out alot compared to others.. Are you sure there is no any air leaks between the outlet side of the carb, head/intake? Or leaks in the carb? Only reason I ask is I have just been through a tone of some similar issues, so this is all fresh in my head..


John

i'm not positive if there are air leaks or not, but i do know that i sealed the black screw in piece that is for the hotstart with black silicone, it is filled full and has no leaks. somebody mentioned another place i need to seal as well though?

[Thumpin440ex]

Have you checked the needle setting?



John

[caseywoods5]

i was going to check the needle and set it richer today but it is cold and rainy outside so it'll probably be tomorrow if i get time. i'll report back with what happens after adjusting the needle!

[caseywoods5]

hey guys i just got a chance to mess with the carb today. i figured i'd try changing the a/f setting in a few different spots before i opened it up to the needle. i think the 450r carb just had to open up some (had sat off of a bike for a while, had cobwebs in it when i bought it) but now it runs perfect on 2.5 turns out. every once in a blue moon it'll pop once or twice but not often at all. i'm glad i finally got it straightened out and it runs so much better than the 400ex carb i can't believe it! it's like night and day difference and off the line it'll nearly rip your arms off!

[TheAwesomehonda]

Wow this helped alot!! so i need to use the same length pilot jet as stock and around a 50 or 52?