started my 450 carb swap. some results, some pics and a few questions [Archive]

uchi

04-27-2009, 05:02 PM

i decided to document this and perhaps help out others who like me are somewhat not handy when it comes to carbs. ive done my reading on here and i felt confident enough to tackle this. im not sure what year the carb is but when i bought it last year im pretty sure i followed the guidelines for the specific years that work on the 400. anyways, onto the pics

first a few questions

there are some electrical connectors that come off of the carb, do i simply just cut them off at the carb and call it a day?

also the screw thats right beside where this connector comes out is the fuel screw i use for fine tuning correct?

http://img.photobucket.com/albums/v96/turbocav/carb/DSCN3111.jpg

http://img.photobucket.com/albums/v96/turbocav/carb/DSCN3112.jpg

i started off by popping off the back plate so that i could drill the new hole for the vent line.

turns otu 2 of the screws didnt want to come out and one was pre stripped.

this was the worst of the 2 bad ones. luckily i had the stripped screw removal tools and after some pressure and using all 3 different sizes the bit finally grabbed and i was able to remove the dirty little *******

http://img.photobucket.com/albums/v96/turbocav/carb/DSCN3115.jpg

the tool and the result
http://img.photobucket.com/albums/v96/turbocav/carb/DSCN3116.jpg

after that i clamped the plate into the vice
http://img.photobucket.com/albums/v96/turbocav/carb/DSCN3121.jpg

then i went to town with the drill
http://img.photobucket.com/albums/v96/turbocav/carb/DSCN3122.jpg

originally i had cut a short piece of vac line and filled half of it with black rtv, but then changed my mind and instead decided to fill the hole with the rtv
http://img.photobucket.com/albums/v96/turbocav/carb/DSCN3123.jpg

shot from the inside
http://img.photobucket.com/albums/v96/turbocav/carb/DSCN3124.jpg

then i took out the hot start plug. and with it came a bunch of dirt. maybe its normal, maybe not. the kdi i got the carb from said he cooked the motor by running it low on oil. maybe he swallowed dirt, who knows
http://img.photobucket.com/albums/v96/turbocav/carb/DSCN3118.jpg

http://img.photobucket.com/albums/v96/turbocav/carb/DSCN3119.jpg

and what i was able to tap out. this is literally half of what was left dirt wise, the other half fell out when i pulled out the plug

http://img.photobucket.com/albums/v96/turbocav/carb/DSCN3120.jpg

i dont have a pic but i cut the cable from the plug and then filled the open end of the plug with some black rtv.

after that i popped off the other cover to check the jets. im guessing this guy is the pilot. its labelled as 48 S.

http://img.photobucket.com/albums/v96/turbocav/carb/DSCN3127.jpg

and the surprise is the main, its a 175. i thought they were 180 or 185 from factory?
http://img.photobucket.com/albums/v96/turbocav/carb/DSCN3130.jpg

as for the needle, im not sure what it looks like or where to find it so i didnt check its location. but heres anothers shot of the jets
http://img.photobucket.com/albums/v96/turbocav/carb/DSCN3131.jpg

as it is i havent started to dis assemble my atv yet and probably wont till after the weekend. what are these 2 lines for, the big and small one. ?

http://img.photobucket.com/albums/v96/turbocav/carb/DSCN3125.jpg

uchi

04-27-2009, 05:05 PM

oh and what size main should i upgrade to? im gonna order one tonite or tomorrow. basically stock 400 with an fmf slip on, k&n filter drilled air box spark key and 13t sprocket. would i be fine with a 185?

04-27-2009, 05:40 PM

this will be very helpful to alot of people... I'll be doing this mod also. I think, but not sure, you wanna go down on the main jet.

zrpilot

04-27-2009, 06:02 PM

OK,
1) they came stock with a 118 main.
2) I THINK that may be a dyno jet jet. I think this because of the adapter that the jet screws into. The stock Keihen did not have such an adapter.
3) That is the DIRTIEST carb I have EVER seen. YOU REALLY need to do a good job on the cleaning
4) The HOT START NEEDS TO BE REPLACED\
5)Yes just cut wires to the heater and the TPS
6) the two hoses are the gas line and I think the air cut-out valve.... not really clear with the pictures provided.
7) the screw next to the wires is the pilot jet or fuel screw.

Let me ask... what did you pay for this carb?

04-27-2009, 06:16 PM

that is rediculously dirty spray a lot of carb cleaner on that

BassHunter0123

04-27-2009, 06:22 PM

^^^^what this guy said X2!!!!!

uchi

04-27-2009, 06:47 PM

Thanks for the info.

The hot start plug is going back in after the cleaning happens. I think I got it for around 100 cdn so it was a good deal.

I understand that different brand jets are numbered differently. So when ordering a new jet what brand and size should I start with? Ill order a kit or a few jets just to have for tuning if I need to.

Also am I safe to use carb cleaner on everything or should I avoid spraying certain parts down? Ill get her cleaned up tomorrow or wed and ill get pics of it cleaned up.

Thanks again for the help

Snipe

04-27-2009, 08:35 PM

I ended up running the jets in my sig for my 450R carb swap. Ran perfect but what I dont like is season to season there is a huge difference in jetting. In winter I smoked in spring im running good and im guessing by summer I will be lean.

Im actually going back to stock carb, I think my air flow will actually increase due to having to neck the air intake down and the head aches from this job.

Carb will work and will run hard just dont expect to ram the gas hard as it will suck the bowl dry and you loose all power that you spent hours installing IMO not worth the time it took to install so mine is coming off and going back on ebay.

zrpilot

04-27-2009, 09:02 PM

Originally posted by Snipe
I ended up running the jets in my sig for my 450R carb swap. Ran perfect but what I dont like is season to season there is a huge difference in jetting. In winter I smoked in spring im running good and im guessing by summer I will be lean.

Im actually going back to stock carb, I think my air flow will actually increase due to having to neck the air intake down and the head aches from this job.

Carb will work and will run hard just dont expect to ram the gas hard as it will suck the bowl dry and you loose all power that you spent hours installing IMO not worth the time it took to install so mine is coming off and going back on ebay.
You will have to re-jet ANY carb for season changes... stock carb or not.

As far as air flow, your flow will not increase, rather velocity MIGHT increase. The stock carb is a 38MM while the 450R carb is a 42MM. (edited, thanks for the clarification Wheelie)

Most people (myself included) feel the 450R carb is a GREAT upgrade...it is too bad yours did not work out and IMO, you are in the minority on that.

Wheelie

04-27-2009, 09:13 PM

The stock carb is listed as a 35.5mm until 04', I believe. Then it's listed as a 38mm.

GPracer2500

04-28-2009, 01:11 AM

Originally posted by Wheelie
The stock carb is listed as a 35.5mm until 04', I believe. Then it's listed as a 38mm.

Good word choice!

uchi

04-28-2009, 04:57 AM

Good info. I don't ride in the winter though so I'm hoping to be fine with whatever jets I end p running. Another thing. Do. Need to remove the carb to rejet once its on the atv?

Also when I got the crb it came with eveything. Air box hot start throttle cable with thumb throttle fuel line and the pipes for the carb to go to tthe carb so I think I'm gonna try to make those work rather than having to move the stock airbox forward. And if not then ill move it not a big deal.

richards

04-28-2009, 06:47 AM

Originally posted by uchi
there are some electrical connectors that come off of the carb, do i simply just cut them off at the carb and call it a day?

also the screw thats right beside where this connector comes out is the fuel screw i use for fine tuning correct?

Good info above from others, I will add that you can remove the heater instead of cutting the wires. You are correct in identifying the fuel screw and the heater is right next to that. Just unscrew the brass piece that the wires go into. It will leave a threaded recess in your carb but there are no air or fuel passages under it so you can just leave it off.

The other electrical device on the side is the TPS and I recommend you just cut the wires on that as recommended above. I took mine off to see what was underneath and it looks like the throttle shaft will not seal well without the TPS in place. So I cut the wires and reinstalled the TPS.

Another tip - use a small dab of anti-seize on all of the carb screws. That should help prevent the threads from freezing and the corresponding stripping/drilling/etc in the future.

after that i popped off the other cover to check the jets. im guessing this guy is the pilot. its labelled as 48 S.

Yes that is the pilot and it is a Keihin. The "S" means it is a short pilot. Keihin pilots without the "S" are a bit longer but still seem to work fine in this carb. I am running a 50, not a 50S and it works fine. I mention this because the "S" pilots may not be as easy to find.

as for the needle, im not sure what it looks like or where to find it so i didnt check its location.

When you look into the carb there is a large cylinder that moves up and down when you move the throttle mechanism. That cylinder is called the slide. The needle is attached to the bottom of the slide. You will not see it until you move the slide up a bit in the carb. The needles goes down into a tube and that tube is the same one the main jet is attached to. You will have to remove the slide to check/change the needle clip position.

To remove the slide you have to remove the top plate from the carb, remove the linkage that connects to the slide, then you can pull the slide out of the top of the carb. From the looks of your carb you should do this while you are cleaning - I bet there is some dirt in there that will keep the slide from sliding easily.

uchi

04-28-2009, 06:55 AM

Perfect thanks. Looks like it might be another short work day and my gf works midnights. So that means I have an excuse to go and tinker with the carb some more. Gonna get her cleaned up today. Gonna have another update later on with some more pictures of progress. The swap won't happen till after I order and receive jets.

bbender85

04-28-2009, 07:43 AM

Originally posted by zrpilot
...2) I THINK that may be a dyno jet jet. I think this because of the adapter that the jet screws into. The stock Keihen did not have such an adapter.

yep, i noticed that as well.

you might check the needle setting while you have it apart, too.

uchi

04-28-2009, 07:57 AM

I'm not sure where to find the needle or what it looks like. Do you guys have a picture or a description for me to use as a guide

richards

04-28-2009, 08:08 AM

See my response above for a description.

And here (http://partsfinder.onlinemicrofiche.com/servicehonda/Honda_OEM/HondaATV.asp?Type=13&A=200&B=23) is an exploded parts view from Service Honda.

uchi

04-28-2009, 08:17 AM

Crap I didn't notice that. I'm using my blackberry and the last part of that message must not have loaded. Thanks for the description and link. Ill give it a go tonite as long as there's time.

Originally posted by richards
See my response above for a description.

And here (http://partsfinder.onlinemicrofiche.com/servicehonda/Honda_OEM/HondaATV.asp?Type=13&A=200&B=23) is an exploded parts view from Service Honda.

Speedy 400ex

04-28-2009, 10:45 AM

I had the extremely soft screws strip when i was jetting my stock carb. So since i was going to be taking it apart a few times to get at the jets i just decided to replace the screws with hex heads that i got from the local hardware store. Works great.

uchi

04-28-2009, 10:48 AM

Good to know. I was wondering where to get new screws from as 3 of mine are stripped. Looks like home depot is on my list of places to stop this week.

GPracer2500

04-28-2009, 02:18 PM

Originally posted by richards
...Yes that is the pilot and it is a Keihin. The "S" means it is a short pilot. Keihin pilots without the "S" are a bit longer but still seem to work fine in this carb. I am running a 50, not a 50S and it works fine. I mention this because the "S" pilots may not be as easy to find....

Seems logical. But as a friendly FYI (meant to inform, not nitpick), that is not the case. The difference between the short and long pilots is one is a Series 21 and the other is a Series 26--two different styles of pilot jet. The "S" does not distinguish the two--only the length above the threads distinguishes S21 vs S26. They are frequently interchangeable in practice.

The "S" only identifies a jet as being a "stock" jet specifically chosen by the OEM. Check out this pic. The shorter Series 26 style pilot in this picture bears no "S" designation while one of the Series 21's does. That main jet ("hex head" style or Series 357) also carries an "S" label. The two "S" jets in the pic were stock jet sizes in the machines they were pulled from.

left to right: Series 26 size 38, Series 21 size 65 "S", Series 21 size 42, Series 357 "hex head" size 158 "S"
http://i34.photobucket.com/albums/d133/gpracer2500/pilots.jpg

The "S" can mostly be ignored on Keihin jets. Regarding mains, AFAIK they are identical in every way to their non-S counterparts. "S" pilots can be slightly different. The emulsification holes in a Honda spec "S" pilot can be slightly smaller than non-S pilot jet. The primary fuel delivery orifice is the same though. The reason for this is open to speculation. No one seems to know for sure but I suspect it's emissions related. Whatever the case, the difference in fueling between a std and Honda "S" spec pilots are too small to be of any consequence when tuning, IMO.

Also, not all showroom stock jets bear the "S" designation. That S26 size 38 pictured above was the stocker pulled out of a '99 400EX. So if you pull a jet out of a Keihin carb and there's no "S" on it, that doesn't necessarily mean it isn't the stocker. Go figure.

Bottom line: ignore the "S". What the "S" actually means is somewhat mysterious but since the physical differences are (or are nearly) undetectable....

richards

04-28-2009, 02:32 PM

Originally posted by GPracer2500
Seems logical. But as a friendly FYI (meant to inform, not nitpick), that is not the case...

No offense taken at all, I am glad to learn. Thanks for the information.

uchi

04-28-2009, 03:41 PM

heres my update. i went to town on the carb today. its gonna get a second cleaning later today or tomorrow but i wanted to give it an initial cleaning, brushed it with a soft bristle brush and wiped everything clean with a shirt.

i also decided to take off what i could, choke lever, throttle cable, vac lines, stuff like that so that i could give everythign a thorough cleaning inside and out.

now the before pic.

http://img.photobucket.com/albums/v96/turbocav/carb/DSCN3133.jpg

http://img.photobucket.com/albums/v96/turbocav/carb/DSCN3134.jpg

and after

it still ahs a bit of crap on it that i didnt notice because it wasnt fully dry when i took the pics, but in the pics you can see the dirst and the now i can see it too. so ill go and give it another spraying later tonite.

http://img.photobucket.com/albums/v96/turbocav/carb/DSCN3135.jpg

http://img.photobucket.com/albums/v96/turbocav/carb/DSCN3136.jpg

http://img.photobucket.com/albums/v96/turbocav/carb/DSCN3137.jpg

http://img.photobucket.com/albums/v96/turbocav/carb/DSCN3138.jpg

http://img.photobucket.com/albums/v96/turbocav/carb/DSCN3139.jpg

http://img.photobucket.com/albums/v96/turbocav/carb/DSCN3140.jpg

http://img.photobucket.com/albums/v96/turbocav/carb/DSCN3141.jpg

http://img.photobucket.com/albums/v96/turbocav/carb/DSCN3142.jpg

and i managed to find a parts numbder on the carb, somethign that had previously been buried by years or dirt and grime.

http://img.photobucket.com/albums/v96/turbocav/carb/DSCN3143.jpg

i pulled the needle out and found its on the third notch from the top.

http://img.photobucket.com/albums/v96/turbocav/carb/DSCN3149.jpg

judging by how tight every screw is im gonna assume this thing has probably never been apart, and if it has it was taken apart once and thats it.

also another question with the main jet. i noticed the top unscrewed from the shaft

http://img.photobucket.com/albums/v96/turbocav/carb/DSCN3132.jpg

is the top the actual jet in this case or hows that work?

anyways, thats todays update. oh last thing, is there a rebuild kit for this thing? i figure since its half apart i might aswell rebuild it and call it a day. also is that the factory needle position? id like to find out what size jets and what needle position is stock for this thing so i can adjust things from there for my setup. thanks for looking

uchi

04-28-2009, 03:44 PM

Originally posted by GPracer2500
Seems logical. But as a friendly FYI (meant to inform, not nitpick), that is not the case. The difference between the short and long pilots is one is a Series 21 and the other is a Series 26--two different styles of pilot jet. The "S" does not distinguish the two--only the length above the threads distinguishes S21 vs S26. They are frequently interchangeable in practice.

The "S" only identifies a jet as being a "stock" jet specifically chosen by the OEM. Check out this pic. The shorter Series 26 style pilot in this picture bears no "S" designation while one of the Series 21's does. That main jet ("hex head" style or Series 357) also carries an "S" label. The two "S" jets in the pic were stock jet sizes in the machines they were pulled from.

left to right: Series 26 size 38, Series 21 size 65 "S", Series 21 size 42, Series 357 "hex head" size 158 "S"
http://i34.photobucket.com/albums/d133/gpracer2500/pilots.jpg

The "S" can mostly be ignored on Keihin jets. Regarding mains, AFAIK they are identical in every way to their non-S counterparts. "S" pilots can be slightly different. The emulsification holes in a Keihin pilot can be slightly smaller on a Honda spec "S" pilot jet. The primary fuel delivery orifice is the same though. The reason for this is open to speculation. No one seems to know for sure but I suspect it's emissions related. Whatever the case, the difference in fueling between a std and Honda "S" spec pilots are too small to be of any consequence when tuning, IMO.

Also, not all showroom stock jets bear the "S" designation. That S26 size 38 pictured above was the stocker pulled out of a '99 400EX. So if you pull a jet out of a Keihin carb and there's no "S" on it, that doesn't necessarily mean it isn't the stocker. Go figure.

Bottom line: ignore the "S". What the "S" actually means is somewhat mysterious but since the physical differences are (or are nearly) undetectable....

some great info there. this stuff makes me wish i was born 15 years earlier and that i would have grown up with carbs and not fuel injection. but im learning and this place is full of information. although im sure my heads either gonna pop soon or ill eventually forget how to get home, lol

richards

04-28-2009, 04:10 PM

Originally posted by uchi
also another question with the main jet. i noticed the top unscrewed from the shaft

is the top the actual jet in this case or hows that work?

Yes the small part is the main jet. The large part is the tube that the needle slides in/out of. The main jet screws onto the end and limits the max amount of fuel that can be drawn from the float bowl through the tube and into the carb throat.

uchi

04-28-2009, 04:19 PM

Originally posted by richards
Yes the small part is the main jet. The large part is the tube that the needle slides in/out of. The main jet screws onto the end and limits the max amount of fuel that can be drawn from the float bowl through the tube and into the carb throat.

gotcha thanks. is the third notch the stock location for the needle? also theres a littla black cap

http://img.photobucket.com/albums/v96/turbocav/carb/DSCN3142.jpg

whats inside of it? i pulled off the cap and nothing comes out but theres something brass inside

Snipe

04-28-2009, 05:30 PM

The 450R carb can be a good upgrade and on some bikes it might work. As for my quad in my area im running the stocker again spent all day rejetting and guess what its running the exact same jetting as before and get this it runs 10X cleaner than before no lugging no skipping when throttling and no distortion in power or loss there of.

Guess my quad is ment to do better with the stock now I have a 450R carb goin on ebay lol.

uchi

04-28-2009, 05:33 PM

Weird. Maybe your 450r carb needs a cleaning or has something wrong with it

richards

04-28-2009, 05:49 PM

Originally posted by uchi
gotcha thanks. is the third notch the stock location for the needle? also theres a littla black cap

http://img.photobucket.com/albums/v96/turbocav/carb/DSCN3142.jpg

whats inside of it? i pulled off the cap and nothing comes out but theres something brass inside

I dunno on either question. Stock clip position will not matter though at that would be stock for a completely different engine (the 450R.) When I looked through the jetting thread most seemed to be happy in 3rd or 4th notch from the top with this carb on the 400EX. So either of those would be a good place to start.

I never removed that black cap from mine, not sure what it is for.

uchi

04-28-2009, 07:04 PM

gotcha thanks. im hoping to be able to leave the pilot alone and bump the main 1 jet higher than stock and im gonna hope its gonna be enough for me to get it to run right. although im thinking im gonna hve to invest in a jet kit. you guys know of any places that sell jet kits cheap?

GPracer2500

04-28-2009, 07:34 PM

I think you've already got a "jet kit". Which is to say someone installed a Dynojet kit. More on that in a second...

The black plug is just a plug. Leave it in place--it's suppose to be there. On most carbs with a starter jet, in there is were that jet is found. On this model carb, the starter jet installs into the side of that plugged tube.

Another place I think you've got a plug you should be aware of is in the main air jet orifice. Look at your pic looking into the carb from the filter side. See that brass part on the perimeter (about 7:30 o'clock position)? That's the main air jet. If memory serves, there should be a brass ring in the carb body. But yours looks like there's a plug in the center of that brass ring. It can be removed with a tiny easyout.

http://www.motorcyclecarbs.com/images/Flo-Commander/restrictor_removed_blue_sm.jpg

Dynojet kits for the 04/05 450r carb include a brass plug for blocking off that hole. If you decide you'd prefer not using Dynojet parts, be aware that would need to be removed to get yourself onto the same page as anyone who hasn't installed a Dynojet kit.

You don't really need a "jet kit". You just need a range of jet sizes to experiment with. Since you've got Dynojet parts intsalled, you can 1) stick with Dynojet jets (but know their mains are on a different scale) 2) junk all the Dynojet stuff and go back to Keihin parts or 3) mix-match parts (i.e. just get rid of the Dynojet main jet adapter and main and use Keihin mains but keep the Dynojet needle and MAJ plug). I'm assuming your needle is a Dynojet.

I'd prolly prefer option 2 but that would require buying a new needle and the hassle of removing that plug without buggering anything up. Option 3 is probably easiest but be aware that with a Dynojet needle and MAJ plug, your main sizes will differ a little from what you might otherwise need.

$0.02

uchi

04-28-2009, 07:39 PM

one more thing, i cant remember what year my carb is from. can you guys identify it just by looking at it or do i need to contact the manufacturer and send them the number on it? im looking at a jet kit on the http://jetsrus.com/ website. as said here the stock jet is a 118 for the 04-05 year carb and the 06-07 is a 162.

that being said i could have sworn i read somewhere that the stock jets are 180 or 185 for the main. im not doubting anyone in this thread but for some reason that number is stuck in my head. so if my carb has a 175 main jet in it im starting to assuming from an 06-07 carb, or perhaps the kid just rejetted it to a 175 from a 118.

uchi

04-28-2009, 07:48 PM

Originally posted by GPracer2500
I think you've already got a "jet kit". Which is to say someone installed a Dynojet kit. More on that in a second...

The black plug is just a plug. Leave it in place--it's suppose to be there. On most carbs with a starter jet, in there is were that jet is found. On this model carb, the starter jet installs into the side of that plugged tube.

Another place I think you've got a plug you should be aware of is in the main air jet orifice. Look at your pic looking into the carb from the filter side. See that brass part on the perimeter (about 7:30 o'clock position)? That's the main air jet. If memory serves, there should be a brass ring in the carb body. But yours looks like there's a plug in the center of that brass ring. It can be removed with a tiny easyout.

http://www.motorcyclecarbs.com/images/Flo-Commander/restrictor_removed_blue_sm.jpg

Dynojet kits for the 04/05 450r carb include a brass plug for blocking off that hole. If you decide you'd prefer not using Dynojet parts, be aware that would need to be removed to get yourself onto the same page as anyone who hasn't installed a Dynojet kit.

You don't really need a "jet kit". You just need a range of jet sizes to experiment with. Since you've got Dynojet parts intsalled, you can 1) stick with Dynojet jets (but know their mains are on a different scale) 2) junk all the Dynojet stuff and go back to Keihin parts or 3) mix-match parts (i.e. just get rid of the Dynojet main jet adapter and main and use Keihin mains but keep the Dynojet needle and MAJ plug). I'm assuming your needle is a Dynojet.

I'd prolly prefer option 2 but that would require buying a new needle and the hassle of removing that plug without buggering anything up. Option 3 is probably easiest but be aware that with a Dynojet needle and MAJ plug, your main sizes will differ a little from what you might otherwise need.

$0.02

some great info there. is there any way to tell who makes the needle?

i think i like your idea in option 2. junk the dynojet jet and switch over to one that everyones familiar with. that being said does the pilot look like its a dynojet part to you? also if i understand you correctly, do i simply just remove the main jet and adapter that goes into the carb and install the Keihin jet directly in there?

i think thats the best idea for me. actually looking back i think the pilot is infact a Keihin from the logo on it

http://img.photobucket.com/albums/v96/turbocav/carb/DSCN3127.jpg

so i think what ill do is order a 50 and one size up from that pilot jet. leave the needle at the 3rd notch and then order some mains. but im not sure what sizes. 180, 185, 190 perhaps? im running a basically stock o3 400 ex with an fmf pip k&n filter and the airbox lid has about a dozen 3/4 inch holes in it and by the time the carb gets changed ill have a sparks key installed.

also i remember seeing a chart that showed what each jet was in comparison to other brands but i cant find it, so any idea what that 175 is equivilant to in Keihin terms?

GPracer2500

04-28-2009, 07:50 PM

Your mixing showroom stock jetting with HRC kit jetting. Showroom stock 04/05 main is a 118. The HRC kit comes with a 185 main.

Showroom stock 06+ main is (I think) a 120 main. 06+ HRC main is a 162 (I think). The 04/05 carb is a completely different carb from the 06+ carb. You definitely don't have an 06+ carb.

None of that really makes too much difference though. You're not jetting the carb for a 450r. Your 400EX is probably going to want something different.

uchi

04-28-2009, 07:52 PM

found it

http://jetsrus.com/FAQ_mikuni_vs_dynojet_vs_keihin_sizes.htm

by the looks of it the dynojet 175 is probably a 176 and its equivilant to a 198 from keihin.

uchi

04-28-2009, 07:54 PM

Originally posted by GPracer2500
Your mixing showroom stock jetting with HRC kit jetting. Showroom stock 04/05 main is a 118. The HRC kit comes with a 185 main.

Showroom stock 06+ main is (I think) a 120 main. 06+ HRC main is a 162 (I think). The 04/05 carb is a completely different carb from the 06+ carb. You definitely don't have an 06+ carb.

None of that really makes too much difference though. You're not jetting the carb for a 450r. Your 400EX is probably going to want something different.

oh i definatly understand that. infact im looking at the specs for the stock carb and theyre showing me a 148 main. so im thinking that the jet thats in the 450r carb is probably gonna be too big for what im running and ill actually end up having to downgrade a bit. or maybe itll be just right if its a 185 and im at 198. i think im gonna grab main jets that are in between there and just play around with them. guess its gonna turn into a game of trial and error :)

GPracer2500

04-28-2009, 08:05 PM

Originally posted by uchi
...is there any way to tell who makes the needle?...
It should have some markings on it.

Originally posted by uchi
...i think the pilot is infact a Keihin from the logo on it...
Yep, that is a Keihin pilot.

Originally posted by uchi
....so i think what ill do is order a 50 and one size up from that pilot jet. leave the needle at the 3rd notch and then order some mains. but im not sure what sizes. 180, 185, 190 perhaps? im running a basically stock o3 400 ex with an fmf pip k&n filter and the airbox lid has about a dozen 3/4 inch holes in it and by the time the carb gets changed ill have a sparks key installed....
Others who have done the swap can give better starting point guidance.

Originally posted by uchi
....also i remember seeing a chart that showed what each jet was in comparison to other brands but i cant find it, so any idea what that 175 is equivilant to in Keihin terms?
That chart is only a rough guideline. Dynojet jets have tapered orifices so they are suppose to flow differently at different RPM's. OEM jets have no taper. I wouldn't worry about what the "conversion" may be. However, a 175DJ should be a larger jet than a 175K.

And yes, remove the adapter to install Keihin mains. The long piece with the small holes in it gets bottomed out onto the needle jet (not to be confused with the jet needle, which is the "needle") and the locknut is tightened to secure it. The needle jet may still be up in there if you haven't seen it.

uchi

04-28-2009, 09:06 PM

alright thanks for the writeup GPracer2500. gonna do some more reading and order some jets hopefully this week. :D

richards

04-29-2009, 07:19 AM

Originally posted by uchi
is there any way to tell who makes the needle?

Yes look at the top of the needle there should be some letters and numbers stamped on it. Let us know what it says. The 04-05 450R stock needle I believe is a C55D, that's what came in my 450R carb and everything in it appeared stock. And as mentioned above stock main for 04-05 is a 118 but ignore that, your 400ex is going to need something much larger.

What I ended up with on mine, stock engine with sparks 6 degree timing key, is a 50 pilot, 172 main, C55D needle with the clip in 4th from top groove. All jets are Keihin. I'm still experimenting but this works pretty well for me at 1-2000 ft altitude.

If you have some mods that promote better breathing and/or a larger piston you will likely need a larger main, and maybe a 52 pilot. Lower altitude will require a larger main as well. Look at the jetting thread, people are running mains roughly in the 170-190 range. So I say save your "jet kit" money and build your own - get a Keihin needle if you do not have one, get a 50 and 52 pilot, and get a 6 or so mains covering a range based on your mods. All that will cost less than a jet kit.