450r Carb Help

[bkelley]

Whenever my bike is cold, the carb makes a strange gasping like noise every few seconds. Once it's warmed up it stops and doesn't do it again. I'm still working on the jetting, but I don't think the jetting is causing the sound.

Here's a video of it: http://www.youtube.com/watch?v=IOQ7pYQ54-E

Also, does anyone know what size the castle nuts are on the hubs? I know it's metric but I don't have a big enough socket. I tried a 1 1/8" and it's just a hair too big. So I'm assuming it's 28mm?

[JOHNDOE83]

I think, "from what I see in the video"...

Your a touch on the lean side, thats the poping back through the carb...

Only off by a hair, just enough to run lean on start up, and get better once its warm.

Id say pilot jet up a few sizes, also try taking your intake off and see if its worse? If it does get worse, its the pilot.

[honda400ex2003]

or you could try to turn the f/a out alittle bit i would say 1/4 turn at a time and see if it gets any better. If you are more than 3 turns out you may need a bigger pilot and start the process again. Did you find any other dj's to use for the inbetween jet sizes or did you switch back to keihins? Also the castle nut is a 28 i believe so you should be right. I use a 1 1/8" on mine with a quick shot of an impact now but to get them off initially i used a 28 i borrowed from a guy at work. I had to use a big breaker bar with the socket to get mine loose the first time.

[bkelley]

Think I'm just gonna order a Keihin kit from Jets-R-Us and not even bother with Dynojet anymore. The pilot jet would make sense sine we just left the stock 450r one in. I'm just gonna order the 400EX kit and a couple pilots from Jets-R-Us. Which size pilot should I shoot for?

[honda400ex2003]

i think the stocker is a 48, so go with a 50 and a 52. i cant recall if it is a 50 stock though if so then order a 52 and a 54. I am about 85% sure it is a 48 though lol. i have been wondering about it all week again lol. steve

[Wheelie]

48 is stock.

[honda400ex2003]

thanks for verifying for me. you should be good with a 50 and 52. steve

[bkelley]

Does Dynojet sell pilot jets?

[honda400ex2003]

not sure, let me know if you find out. i will be getting some keihins next time i am home to finish mine up. steve

[bkelley]

I want to just order the Keihin kit, but at the same time I'm hoping Dynojet has what I need since I don't have to wait for shipping. I want to take it out to the dunes this weekend to check everything out.

[bkelley]

My local shop has 50 and 52 Keihin pilots so I'm gonna run down a pick up some. As for the f/a screw, I'm not sure what it's at exactly, the guy told me it was at 2.5 but I want to make sure. Do I tighten it all the way and then count the turns out? I'm gonna try 155 DJ main, 50 or 52 pilot and 3.5 turns on the f/a to start. Still need to do a plug chop but I don't have anything to get my plug out with. My 18mm socket is too thick.

[honda400ex2003]

yup you will want to go all the way in then count out. Sounds like you are getting there with it. let me know how you come out. steve

[bkelley]

Can messing with the f/a help fix the bogging out in the top end? Or do I still need to go down on the main?

[honda400ex2003]

If it is that far off it will not change it enough, so i would say you will need a smaller main. you could give it a try and see if it makes any difference at all though. it is highly unlikely to effect it enough to lean it out where it needs to be. just my opinion though. steve

[bkelley]

Alright, yeah. So I'll pick up like 168-170 Keihin mains while I'm there, too. Can I use Keihin jets with a Dynojet needle?

[honda400ex2003]

this is a debatable topic now with that question lol. It is not recommended by dynojet but people do it. I dont think it is going to hurt anything but there is always a chance. i think when i get my new ones i am going to use the dj needle that is in mine since i do not have the stock needle for the 450 carb. I hope to get it dialed in with somewhere around a 180 main in mine. The 165 dj that i have in there is a bit on the rich side still which was right around a 184 dj. I plan to use the stock pilot, and leave the needle until i get the main close. this dj keihin crap is getting old with these machines. lol. let me know if the needle works ok for you with the keihin jets. steve

[bkelley]

Yeah, it really is haha. My carb didn't even have a needle in it when I got it and I don't feel like changing it. It was kind of a pain to get those screws out. I'll let you know how it goes.

[honda400ex2003]

that is exactly why mine will be staying in unless i have to raise it or something. my screws inside are stripped from the previous owner of the carb stripping them. i dont even know if the needle is in the stock position lol. It had a 180 dj in it when i got it. lol. steve

[bkelley]

168 Keihin main, 52 pilot, 3.5 f/a. This was from a cold start.

http://www.youtube.com/watch?v=sPKl7POQYSE

I think I'm still a tad rich (it backfires sometimes on de-acceleration) but it's a lot better than it was. Once I track down a plug wrench that actually fits down on the plug I'll be able to tell for sure. Gonna take it out soon to do some real testing. But man, it feels like a completely new machine. Very responsive and pretty impressive increase in power. The whole bike jerks when I rev it quick, never did that before. I'm really happy with the carb.

[JOHNDOE83]

backfiring on de-acceleration means its still a tad lean....

but that vid sounds good, glad its working out...

[bkelley]

That's what I meant haha. But yeah, I'm just about there. 168 was the only jet my shop had. It's doesn't backfire a lot, so I might be alright. Once I get to the plug chop I'll know. Runs like a champ, though.

[honda400ex2003]

sounds like you are getting closer. keep up the good work. I cant wait to go home and mess with mine a bit and see where it takes me. lol. I am not sure if i want to start running an airbox cover again or not. it is much more fun to hit the water than swerve around it all the time. lol. steve

[honda400ex2003]

although my carrier bearings have thanked me for not hitting every one lol. steve