crazy high idle

[tltcracing]

I run a 2005 R with a HRC cam, uni air filter with no lid, white bros. aluminum race pipe, stock carb and piston, and have the HRC 185 jet in. two days ago i got a FMF jet kit and got to work on re jeting. I live in florida so my evlivation is about 40 ft. Before i rejetted my bike idled a litle high (the idle stop was turned all the way down and i had yet to learn about the pilot screw). but after i met up by chance with atv racing rodney gentry (he and his dad tuned it) my bike ran better than i ever dreamed. but of course i have to go screw it all up. i used the FMF jet kit that has tiny little plug that goes in the main air jet witch i thought was strange becuse it plugs up the hole. but anyway i have the needle on the second clip and the 180 jet in. the pilot screw is turned in all the way and idle stop is all the way down and it still idles a litle high. i have tryed it on the third groove but the idle is higher. i dont know whats wrong and why the idole is so high. is it running to lean? I tryed every main jet and only found out that the larger the jet the better it gets but not perfect. should i go back to the stock jetting or do i have some leak someware. i really need help because i wouldent ride the bke if it was running like this.


EDIT: it backfires when i try to start it( about every third kick and i dont touch the gas) and back fires some where i le off the gas. the pilot screw is all the way in and i didnt think it was suposed to run with that all the way in. i have read about a pilot jet but the shop manuel doesnt use that term so i dont know what it is, is it the slow or starter jet ( 2 diffeent jets).

2nd EDIT: (im finding these things out as i go) using the hot start makes the motor slow down to where i want it. i think this means that the motor isnt getting enough air but does this mean that its not getting enough air or if its getting to much fuel? remember that i have i have tryed all jets and 2nd, 3rd, and 4th needle clip positions.

3rd EDIT: Ok, after about 6 hours of reading and working on the carb i think it may be caused by that little plug that goes in the main air jet. I think this because the motor runs better when i use the hot start. i think the hot start gives it more air and the little plug took away air. but i dont know how to ge it back out, it doesnt screw in you have to hammer it in. mable drill it? can you adjust the slow jet by screwing it in or out, or do you have to buy other ones? i am trying to be as thougho as posible so that there are no questions just answers.

Make sure the carb is pushed all the way in the front and rear boots. If it is sucking air it will make it idle high.

[tltcracing]

how high because it idleing around 5-6,ooo! i have never heard of something this bad before. pilot screw is all the way scrwed in! its crazy i have no idea what it is.

[tltcracing]

just checked to make sure the boots where all the way on and tight and they where. remember how i said the hot stard made it run better, whell now for some reason it has only a very sight effect on the idle. the throttle has play in it and nothing is sticking or loose. i really need someone with some carb know-how fast.

[GPracer2500]

Some Dynojet jet kits (the FMF kit is really a Dynojet kit) instruct to plug the main air jet. I'm not sure I understand why they do that. :confused:

For what it's worth, this is what the main air jet does: When low air pressure in the carb pulls fuel up through the main jet air also gets pulled through the main air jet. Air from the main air jet mixes with fuel from the main jet in the emulsion tube. This aerated fuel is much easier to atomize in the carb's venturi than raw fuel. Also, aerated fuel is less likely to drop back down into the float bowl between intake strokes.

It sounds like your on the right track. I'd get than plug out of there. You may have to drill a hole in the plug and use an extractor to remove it. I'd go back to your old settings and forget the "jet kit"--I don't care for them personally. You did write down your old settings, right?? If you need to change your jetting, just use factory Keihin jets.

But before you do that you may want to focus your attention on the pilot circuit first; just to see what happens. Jet kits always seem to be conspicuously missing proper attention to the pilot circuit. It could be that the plugged main air jet is only indirectly involved in your idle troubles. Getting your pilot curcuit adjusted to match the carbs configuration with the jet kit installed could solve the issue.

The trouble is, when you've got a jet kit installed that uses adapters, plugs, etc. traditional tuning methods may no longer apply. Nonetheless, try this: Pilot Circuit Guide (http://www.exriders.com/vbb/showthread.php?s=&threadid=229923).

A fuel screw (pilot screw) that is turned all the way in usually indicates a pilot jet that is too big (rich). That seems to jive with your experimentation with the hot-start. What size is the pilot jet? What size is stock? Have you tried turning the screw out to see what happens? Maybe the main air jet (although primarily a part of the main circuit) bleeds enough air over to the pilot circuit to affect it. With it plugged up your pilot ciruit might go way too rich and need leaning out. Also, check for air leaks everywhere between the carb and the engine.

BTW, pilot jet/circuit = slow jet/circuit.


Hope that gives you some ideas to go on.

ETA: Maybe the varience in the hot start's response is because of engine tempurature?

[GPracer2500]

Wait! You say 5-6000!?!? Something is way off for that to happen. Are you sure you got everything on/in the carb installed correctly?

If you can, get back to square one.

[tltcracing]

i know thats what i said it makes no sence why its that high!! i have no idea, proformance is just fine its just the idle. the pilot is stock at 48 i think, but i dont have any other pilot jets. throught out the course of today the hot start has made less and less of a diference as well as the pilot screw ( screw has no effect on idle anymore). i am deffinatly driling that stupid air plug back out but im really worried about having those metal shavings go back down into the carb.

[tltcracing]

right now i am back at square one! that makes the main air plug the only thing. i have alwase had a little trouble with haveing a high idle but nothing like this its just plain strange.

[tltcracing]

i know everything is back on right. i thought that it might be the needle, that it might be to short and letting to much feul go through without any gas. i dont know guys, i have run into hard probs with my bike before but nothing that didnt take me an hour to find and fix. i think i might just hand my bike over to a shop and let them fool with it because i obviously am not going anywhere.

[ryann mx68]

i would take the carb completly off, disassemble, clean all ports, jets, etc.

reassemble and install

you should be around:

180-185 main [keihn]

48-50 pilot [keihn]

middle clip position on needle [use your stock needle]

2 to 2-1/2 turns out on your fuel screw

get rid of that jet kit!!! sell it on ebay or something

this is pretty much what most 05's are jetted to, with your mods.
try this, and fine tune from there. also check your slide and make sure its seating properly.

[tltcracing]

how do i make sure the slide is seated properly? i did take the covers off it but didnt dissassemble it. im back to thinking that the plug is the culprit because all my settings are withen what you said. the bike was running fine before the kitbut i thought that i could get more power out of it becuse it wasnt tunned for the pipe of air filter.

[GPracer2500]

You can tune for the pipe and air filter using regular Keihin jets. Use ryann mx68's specs for a starting point.

Coat your drill bit with grease to help trap any metal shavings.

As far as the slide, just make sure it is moving freely and dropping all the way down.

[ryann mx68]

with the carb in your hand, and still connected to the throttle cable. use the thumb throttle to open and close slide, visualy checking that it is closing all the way. maybe it getting stuck on something?

this may sound stupid... but ive done it before, i had the choke on while i was trying to rejet. after an hour of swapping jets, air/fuel adjustments....i realized the choke was on, now that sucked!

dynojet mains and keihn run diff.

a keihn main #180, might be a dynojet #160, someone on here had a cross reference chart.

get that plug or whatever out of your carb, go back to your settings b4 you changed it out....

[tltcracing]

ok guys the plug is out and there is little to no change in idle. i dont know if some of the shovings are still blocking the hole or what but it is sill about 5,000 rpm. the pilot screw is turned all the way in so that means the pilot jet is too big. i just dont know how much smaller i should go. its stock right now at 48 and everything is back to the way it was befor i rejeted. ii dont know whats wrong. this sucks big time.

[450 Racer R]

how about your idle screw? mine did the same thing once when I was riding and when I pulled the seat off the air filter was just sitting in the box. It would only run wot, so I put the filter back on and ran her wide open for a minute or two and it fan fine. I guess whatever was stuck up in the carb blew out.

[GPracer2500]

Originally posted by tltcracing
ok guys the plug is out and there is little to no change in idle. i dont know if some of the shovings are still blocking the hole or what but it is sill about 5,000 rpm. the pilot screw is turned all the way in so that means the pilot jet is too big. i just dont know how much smaller i should go. its stock right now at 48 and everything is back to the way it was befor i rejeted. ii dont know whats wrong. this sucks big time.

Your pilot jet is not causing a 5000rpm idle. Something else is wrong.

[Zeke]

i would check into a new ignition

[tltcracing]

can you make me a check list of everything that needs to be on the R's carb to make it run right. maybe something got dis connected like a breather tube or something and i just dont have enough experence working with carbs to notice what it was. oh and every experiment i have run seems to piont twards there being a lack of air getting to the carb. with every test i do i run the quad for at lest five ninutes to make sure it works but do you think that i might just have to run it longer to have everything equal out again?

[tltcracing]

yeah, zeke hap a point. is there anything else outside the carb that would make it run like that? when i changed out the needle i didnt change the gasket and the book said you should. nether did i change the flaot cover when i looked in there. could the float be causing it?

[GPracer2500]

Doesn't sound like an ignition problem to me. The issue materialized right after you messed with the carb so 100 to 1 it's a carb issue. In addition, I've never heard of failing ingintion compenents causing a crazy high idle.

Have you removed the air filter, looked into the carb, and visually confirmed that the slide is dropping ALL the way down?? It's hard to imagine how you could be idling at 5000rpm with the slide fully closed.

You say the throttle stop screw is at it's maximum adjustment for lowering the idle. Are you SURE?

Have you checked your throttle cables for any hang-ups?

It shouldn't be necessary to replace the top cover or float bowl gaskets unless they are damaged.

[tltcracing]

i have looked at the slide operating but dont remember if it was hitting the bottom. i know there is a little play in the throtle linkage (feels stock)so i dont think its the line. but i will go back out and chech that the slide is closing fully.

[GPracer2500]

Originally posted by tltcracing
i have looked at the slide operating but dont remember if it was hitting the bottom. i know there is a little play in the throtle linkage (feels stock)so i dont think its the line. but i will go back out and chech that the slide is closing fully.

I believe it will audibly "clunk" when it hits the bottom.

[Chango]

ok one time i had the same thing happen i checked everything ,so i thought . The throttle cable sliped out of the adjustable housing but i couldn't see it because of the rubber boot .It was stuck at about 1/4 throttle .

[tltcracing]

i feel like a cmplete retard!!! on my throttle stop screw there is a bind when you try to reduce idle after a certin point. i had forgoten all about that. i remeber fooling with that before i did anything (i had preiously gotten past this point). i opened up the plastic side cover for all the throttle lines and saw that the throttle spot was sill engaging the lincage. i fiddled with the spot some more and it poped and then continued to loosen up. i was like you F~C&ing BI%T!!! now its just down on power so ill just re jet for that. what does it mean when it back fires when you lett off?

[GPracer2500]

Originally posted by tltcracing
i feel like a cmplete retard!!! on my throttle stop screw there is a bind when you try to reduce idle after a certin point. i had forgoten all about that. i remeber fooling with that before i did anything (i had preiously gotten past this point). i opened up the plastic side cover for all the throttle lines and saw that the throttle spot was sill engaging the lincage. i fiddled with the spot some more and it poped and then continued to loosen up. i was like you F~C&ing BI%T!!! now its just down on power so ill just re jet for that. what does it mean when it back fires when you lett off?

Lean pilot circuit. There's a guide in the How To section for setting your fuel screw and pilot jet.

Glad you got the idle sorted out!

[tltcracing]

i think i know why it is horrible now(but with ok idle) the pliot screw was still all the way in!!

[tltcracing]

oh i forgot! i have a slight bog when i get one the gas and by what all you nice people have told me i think i can fix it with a needle spacing change(everything is stock). whitch way should i go. and thanks again for all you guys who who provided info and theory of jets. you really helped me understand the carb thing better and wont be so out in the cold when i go to change jets again!!!


BIG THANKS!!!

one retarded machanic,
TLTC