05' 450r pops and wont idle

[Blkmaroman]

like the title says, i just picked up a 2005 450r. The problem im having is the damn thing wont idle for more than 10sec or so before it hiccups/pops out the carb and dies? It was dripping some fuel from the overflow so i assumed the carb was dirty, so i took it apart and cleaned it up(it was already clean) and its still doing the same thing,only now its not dripping from the overflow anymore. I noticed the pilot jet was k48 and the main was k118. It seems like the pilot is too big and the main too small but the quad runs good when your riding it,it just pops out the exhaust a whole lot and idles very erradically then pops out the carb and dies when you try to let it idle. Any help is appreciated,i want to ride it bad but im afraid with the carb the way it is ill hurt the motor. The motor has about 35hrs on it total, and the current topend(athena 480cc big bore)only has about 5hrs on it. The quad has pretty much sat its whole life. Thanks in advance guys, ive got the quad taken apart in the garage and its not going back together till i get this carb situation right.

[Blkmaroman]

well after further research ive found that 48,118 is stock jetting. Would going up on my pilot jet fix my idling problem? I think it would definately fix my popping exhaust. I just dont see my pilot jet being stock causing the bike to not idle and pop out of the carb. I have also checked my plug and it is white,so i definately need to richen this bad boy up. About what size main and pilot would get me in the ballpark? Ive got the athena 480cc piston kit, i believe its around 10.5 to 1 compression, uni air filter, and soon to be hmf slipon exhaust. Thanks again guys.

[d3ktrix]

Air box lid on or off?
You said it will soon have an HMF slip-on. Whats on it now? Stock silencer? Baffle in or out?

[Blkmaroman]

airbox lid is currently on, it has the stock silencer that has the baffle and then some removed. I watched a few videos of 450s on youtube and they idle really high, if i turn my idle screw up it will idle but it just seems like its too high.

[d3ktrix]

I see in ur sig that u also have a warrior. The 450r is going to want to idle MUCH faster then what your used to hearing from your warrior.
A warrior can idle lower and lug like no other engine I've ever seen :P
The 450r's are much higher strung and need more RPM.

For an 05 450r optimal idle is 1600-1700rpm.
Do you have a small tach you could hook up to the spark plug wire maybe?

If the idle doesn't clean up check for air leaks on the intake and exhaust header.

[Blkmaroman]

i checked the carb boot and both clamps are tight and the boot is visibly in good shape. The header bolts are tight and i dont hear any exhaust leaks. How would the idle on this compare to a 400ex? And any ideas on the jets? Im thinkig 50 pilot and 155 main? thanks

[d3ktrix]

If your airbox lid is on and stock silencer you should be fine with stock jets.
The 118MJ and 45pilot.
Dunno what would change with the baffle out.

If you take the air box lid off, with the baffle out or aftermarket slip-on though.
185MJ and 50pilot will do you good to start with.


A 155MJ would be something you'd use in an 06+ 450r.
Way too lean for an 04/05.

[Blkmaroman]

cool, ill be picking up the jets tommorow.

[Blkmaroman]

well, i picked up a 50 pilot jet and 180 main jet. The pilot jet was alittle bit longer but fit in the hole perfect, the main jet was keyster brand instead of kehin and i dont think it was on the same sizing scale because my bike wouldnt even take fuel without cutting out, it said keihin replacement on the box but they were all much larger inside than my stock 118, so i went back and got the only keihin jet in the box which was a 122 and my bike is running great, it fires up first kick and idles perfect now. Im gonna go down to honda and order the 185 jet for when i put on the exhaust and take off the airbox lid but for now its getting more fuel than stock and seems to be doing great.

[d3ktrix]

Did u have ur airbox lid off when you put that 185MJ in?
If you left it on it will do what you described.

Its fine to run no airbox lid with the stock exhaust and no baffle.

[Blkmaroman]

yes, i had the aitbox lid off and it was cutting out bad up top, i then put the lid on to determine if i was rich or lean and thats when it wouldnt even rev up. Ive got the airbox lid on now to help richen it up.

[JCoop]

HMF recommended to me to run 180 main and stock pilot. Thats with the airbox lid off and an HMF slip on.

Mine runs strong, it does pop on decel. Not a big deal though.

[Blkmaroman]

ya, im gonna get the keihin main jet in the next few days. I rode it all day today and it seemed to run good. It just wont run up to the rev limiter, it takes off good but kinda bogs in the topend i figured with 18" tires and down one on the front sprocket it would shoot up to the limiter in at least 1st, but it just kinda loses its pull and pretty much at that point the motor is just not climbing anymore. It does great down low and pulls the front tires with ease, but like i said it just dosent have anything up top. To put it in perspective my buddy has a bone stock kfx 700 and he pulled me hard, and i thought the 450 would pull him

[Blkmaroman]

well, after another day of riding i definately know im down on power somehow. I rode with several buddies, one was on his kfx700, one on a brute force 750, and one on a 2001 400ex and every one of them beat me on a two lane road, on topend and acceleating. I stayed pretty even with the 400ex until topend, the kfx and brute force pulled me beginning to end pretty hard. The only thing the 400ex has is a pipe and filter. The kfx and brute force were stock. But im dumbfounded. I know how to ride and i tried shifting at different points to get more out of it but its just not there. Ive got a stage two hotcam on the way and im gonna jet it and take off the airbox lid at the same time. I dont know if the cam timing is off a hair from where the people before me had it rebuilt or what but it starts up usually first kick and runs great, it does pop out the exhaust alittle when its idling. Ive got a uni air filter, athen big bore 480 kit, down one on the front sprocket and 18" tires out back. I figure i dont do great on topend because the tires and sprocket but then i should be doing great on acceleration and it still dosent have it. I know the 450r has enough power to beat a damn 400ex. I do have about 100LBS on the guy on the 400ex and about 60 on the other two but damn, i should still be pretty damn close shouldnt i? Im gonna dig into this bad boy because if this is all the 450 has, im going to get something else. My last stock 400ex would stay even with my buddies 400ex which is more than this 450 is doing at this point. And the compression is great on the engine but it should be because the topend is almost new. Im not giving up on the 450 yet, but im tired of hearing the trash talk, if anybody has any ideas on what to check im all ears or is it normal for a 450 to get walked by a 400ex and some utilities.

[espergre]

wow, you need some good help. why do you have a 480 kit with stock exhaust? most people will modify their exhaust and intake first. then get a cam and possibly a high comp piston. you got a big bore kit first without any other mods? your quads problem is not hardware, its tuning. your jetting is way off. every little thing you change will effect your air/fuel ratio. right not you have increased your air flow greatly by increasing your displacement (big bore). you are sucking more air into your cylinder per stroke. you have also reduced your back pressure from your exhaust system by removing your baffle. youve changed your stock filter for a high flowing uni filter, and youve removed your air box lid. So basically you have increased your air flow dramatically but have not increased your fuel by readjusting your jetting. You are running extremely lean (too much air, too little fuel). You must be backfiring like crazy and as stated, your spark plug must be pure white. You really need to stop riding till you fix your jetting, you may have allready hurt your piston by overheating. You need to adjust your main jet way higher than stock, but not as high as a 185. I would buy a kit with jets ranging from 150-180. put a 50 pilot in with a 165 main and see how it runs. If you are still cutting out go down one size at a time until you get a popping noise on decel. Go back up one main size and you should be very close to proper air/fuel ratio. you should NOT adjust your idle to fix bad jetting. put your idle back to stock. your quad should idle and start perfectly everytime with correct jetting and a correctly adjusted air screw. you may need to go up to a 52 pilot if the 50 is not correct. I know it is not expensive but a tuneup/dynotune is much cheaper than buying a new quad. A tuned 480 with intake, cam, and exhaust should smoke every moded 400ex and many 700's. good luck!

[Blkmaroman]

the guys who had the the quad before me put on the 480 kit because they said they overheated the engine and blew a headgasket or something to that affect. So they had the whole engine redone with stock honda parts except for the big bore kit because i guess they just wanted to say they had it. But right now ive got a 50 pilot jet in it and a 122 main jet. I left the airbox lid on to help it from running lean. But like i said ive got a cam on the way and today i should be getting the exhaust ordered

[espergre]

the stock main jet of 118 is much too small. Honda really restricts this engine from the factory for emmision reasons. Just taking off the lid or adding an aftermarket air filter really uncorks the engine. You will find that you need a main jet of 150 or larger. With a good flowing exhaust, cam, uni filter and big bore I am going to guess that you will need a 160 or larger main jet for an 05'

[d3ktrix]

Originally posted by espergre
the stock main jet of 118 is much too small. Honda really restricts this engine from the factory for emmision reasons. Just taking off the lid or adding an aftermarket air filter really uncorks the engine. You will find that you need a main jet of 150 or larger. With a good flowing exhaust, cam, uni filter and big bore I am going to guess that you will need a 160 or larger main jet for an 05'

If he takes the air box lid of an 05 450r he's going to need a much larger MJ then a 150 or 160. He'll be running leaner then the stock jetting with the air box lid on.

I don't know what his elevation or climate is like there, but I highly doubt it will require his bike to run jetting that lean.

The jetting on an 05 is much different then an 06+ 450R or a 400EX.

BTW I'm talking keihin jet sizes, not dynojet or anything else.

[Blkmaroman]

Well ive got a little update on the quad. I put a 185 main jet in it this morning and it didnt run any different but it cut out on topend, i had the airbox lid off and i now have on a full curtis sparks exhaust. So i decided to put my stage 2 cam in and check my valves and cam timing all together. As soon as i put the motor to tdc i saw that my cam was like 2 or 3 teeth off from being lined up with the mark on the front, so i think that was my main problem but i also checked my valve clearances and my exhaust valves are good but my intake valves are way too tight, i could barely get a .002 feeler guage in them. So im off tommorow to get a dial indicator to see what size shims i currently have so i can run down to honda and get the correct ones. My measurements for the valves were Exhaust .013, .011 and intake .0015,.002. So i deffinately need smaller shims for the intake and alittle larger for the one exhaust. But i think the bike is going to run great as soon as i get it back together with proper cam timing. This is the main reason i hate to get something somebody has worked on before me because you never know if it was done correctly and i always end up redoing everything that has been done because of situation just like this. But ill let you guys know how she runs when i get her all done. Thanks for the input.

[d3ktrix]

Sounds like u might of found your problem =)

And 2-3 teeth off from top dead center? Who ever put that engine back together sucked at life lol.

[Blkmaroman]

it shocked me when i saw it, they said they had a big time shop do the work but after seeing the cam timing, i dont think so. And btw the curtis sparks system sounds freaking awsome.

[Blkmaroman]

Just another update, i finished the cam install and adjusted the valves correctly. I just finished breaking the cam in and havent really rode the bike too hard yet but it dosent feel much different:confused: Ive got a 185 main jet 50 pilot and no airbox lid.