Got the carbs back on..need help diagnosing if im rich or lean

[garyg199]

Hey guys

Had to start a new thread because my posts wouldn't save on my other one...

Now, I know there's many threads about this issue but as I had a few people invested in my carb cleaning issue, I figured I could get a little specific help.

I've got my carbs back on. They're on tight at the airbox and the engine side so no air leaks. I set my idle screws out 2.5 turns from seated, as advised. I also did a bench sync while I had them out.

Now, the bike started and idled fine. It was idling high at 4k so I had to adjust that. But it was also bogging down with throttle. Is this a symptom of being to rich or lean? I get it confused. I didn't have the tank on when I started it, but I had a funnel connected to fill the bowls with fuel. I couldn't really run it for long and mess with it due to time restraints, but I know it must be an air/fuel issue.

Could I have adjusted the valves wrong being my idle was set too high? Or are my idle screws out to much? I read a few posts that set sometimes 2.5 turns out from seated is either too much or too little. This is the first time they have been adjusted being they were still plugged.

Also, I'm missing my airbox cover so the air filter is exposed at the side. And my snorkel was off when I started it as well, so is that letting too much air in right there?

Tell me what you think.

[RacinNinja]

Put the air filter cover on. That should solve some bogging issues. Get the airbox together properly and the fuel system connected properly before you diagnose issues.

[garyg199]

I don't have the cover otherwise I would. It's missing. As in it was missing when I got the bike. Gotta order a new one. I was riding it without it before I started working on it and it was okay. Didn't discover it until I started pulling things off

[Motofool]

Originally Posted by garyg199

.......
Tell me what you think.

Could it be that the engine was still cold and in need of some choke?

If not, it seems a problem with the diaphragms/slides/needles.

If you watched the vid that I posted a few days back, you saw how the diaphragms open air+fuel supplies when the butterfly valves open and there is enough vacuum (created by the aspiration of the engine) in the manifold.

If for some reason that process does not work flawless, the mix gets out of wack and the combustion stops.

[Ghostt]

Until you get the airbox back to specs, don't waste you time doing diagnostics.

[jkv45]

I would agree about the airbox cover, get one.

Bogging down? When? Was the engine full warm and the choke off? What position (1/4, 1/2, full) is the throttle when it bogs? This is when you are actually riding, not just revving, right?

Setting the idle mixture screws to 2.5 should give you better running than the original settings. Adding shims to the needles isn't uncommon, but if everything is stock it should run OK without.

If it ran decent before, without the airbox cover, it tells you something still isn't right with the carbs.

[garyg199]

Well the bike was running well without the airbox cover so I'm at least trying to get it back to that state. It wasn't doing this before so Idk. Maybe I just didn't let it warm up enough. Like I said I wasn't able to mess with it too long but I just feel like maybe the mixture is out of sorts. I thought that if it bogs down with throttle it's getting too much air or fuel so I'm just trying to figure that out

[Motofool]

Originally Posted by garyg199

.......... I thought that if it bogs down with throttle it's getting too much air or fuel so I'm just trying to figure that out

Too much air.
Otherwise, you would see black exhaust and slower idle that before working on the carbs.

IMHO, either the top of the diaphragms is not hermetic, there is vacuum leak in the tubes or there is a mechanical restriction for the free sliding of needles and slides.

[jkv45]

Originally Posted by garyg199

Well the bike was running well without the airbox cover so I'm at least trying to get it back to that state. It wasn't doing this before so Idk. Maybe I just didn't let it warm up enough. Like I said I wasn't able to mess with it too long but I just feel like maybe the mixture is out of sorts. I thought that if it bogs down with throttle it's getting too much air or fuel so I'm just trying to figure that out

Bogging usually means it's not getting enough fuel - lean.

Stumbling or stuttering, with black smoke from the exhaust, usually means it's getting too much fuel - rich.

I'm guessing something is not assembled correctly, as your adjustments (2.5 turns out) and jet sizes (stock) should be close enough that it shouldn't bog - and it ran fine before.

[Ghostt]

Here are a couple helpful links.

http://faq.ninja250.org/wiki/I_want_...uretor_jetting

http://faq.ninja250.org/wiki/Why_wou..._my_jetting%3F

Here's a quote from one of them and one I highly agree with.

The best solution is taking the bike to a professional with a Dyno and an EGA (electronic gas analyzer, sometimes called a "Sniffer" or "4 gas analyzer") to see what kind of exhaust the bike is putting out at different rpm while under appropriate load.

Without the use of an exhaust gas analyzer, you'll be taking a best guess, I would recommend looking at the jetting database link on this forum, someone has already done the hard work for you.

[garyg199]

Yes everything on the bike is stock. And I might have bent needles or at least one bent needle. Not sure if any of you read my other post but my needles were damaged during the cleaning process and there seems to be a little bit of friction coming from the needle where it sits in the collar. It still comes down without hesitation but when I pushed it up slowly I felt the tiniest bit of friction. If I get home early enough today I'll try to let it warm up a bit and see if it still happens. However this never happened before so they're definitely has to be some sort of issue I'm thinking too much air. I did a bench sync too and my idle adjustment was up too high so I might have adjusted the other butterfly either to open or not enough. Either way I'll start it up again and see what happens. I might have to make more adjustments

[Ghostt]

Butterfly positions need to be left alone, assuming you did the bench sync correctly, they are not your problem.

You need to start eliminating the variables, if you believe the needles are bad, get new ones, check the diaphragms, any holes? Tears? Installed correctly?

Until you rule out a possibility, it's a variable.

[jkv45]

Originally Posted by garyg199

Yes everything on the bike is stock. And I might have bent needles or at least one bent needle. Not sure if any of you read my other post but my needles were damaged during the cleaning process and there seems to be a little bit of friction coming from the needle where it sits in the collar. It still comes down without hesitation but when I pushed it up slowly I felt the tiniest bit of friction. If I get home early enough today I'll try to let it warm up a bit and see if it still happens. However this never happened before so they're definitely has to be some sort of issue I'm thinking too much air. I did a bench sync too and my idle adjustment was up too high so I might have adjusted the other butterfly either to open or not enough. Either way I'll start it up again and see what happens. I might have to make more adjustments

I would check the needles closely. If one is bent, replace it.

As far as the damage to the needles from cleaning - it shouldn't be an issue. Clean it well, maybe use some polish on it, and it will be fine.

[InvisiBill]

Originally Posted by InvisiBill

There seems to be confusion about what's actually causing the slide to hang up. Just take the needle out temporarily and see if it acts the same. Maybe put some tape over the hole or something to avoid air flowing unnaturally though the new opening.

If the acts the same, the problem isn't due to the needle. If it acts different without the needle, then you know the needle is an issue.

Personally, I'd test if it was the needle causing problems before buying a new one.

[garyg199]

Anyone know where I could get a cheap set of needles? Think the cheapest I found em for was 18 bucks each. I'd like to just get a jet kit and do it all then but I was going to wait a few weeks to do that. But if I absolutely have to replace the needles I guess I shall. I really just think it needs to run a bit and it's to lean.

Guess we'll see. I will post an update here later

Anyone else is welcome to share their thoughts!

[vmax]

I think your bike too much air cause missing airbox cover. Try to install bigger mainjet until you can find the cover, start with min 102. You no need mess with needles. I have setup my bike with no snorkle (a little more air and stock needles) and my bike a liitle bog down, the i replace MJ 100, then everything was good. This why i suggest you to change you MJ to bigger one. Maybe 105.

[ducatiman]

Originally Posted by garyg199

Anyone know where I could get a cheap set of needles? Think the cheapest I found em for was 18 bucks each. I'd like to just get a jet kit and do it all then but I was going to wait a few weeks to do that. But if I absolutely have to replace the needles I guess I shall. I really just think it needs to run a bit and it's to lean.

Guess we'll see. I will post an update here later

Anyone else is welcome to share their thoughts!

PM sent on another option to consider

[garyg199]

So I was able to mess with it a little bit couple minutes ago and I let it warm up adjusting the idle up and down try to get it to idle right which I did at a few points. It's still bogging down with throttle though. Also when I put my thumb over the vacuum line that goes to the petcock I believe, it idles better. Basically the title will come up if I plug it up because the idle was too low. I got the snorkel back on. Still no airbox cover but I know that's not the issue. Is it bogging with throttle because I don't have the tank on with the vac line connected? I don't get it!

Oh,and if I roll on the throttle easy it will throttle. Or if the rpms are above 3k. But if I just blip it...it dies or bogs down

[Ghostt]

Sounds like a bad petcock to me, test it, if bad order you a new one, it's not worth rebuilding.

[garyg199]

Sorry my mistake. I still have the tank off. That's why I was asking about the vacuum line. Should I connect the tank and see if it gets better?

[Ghostt]

Originally Posted by garyg199

Sorry my mistake. I still have the tank off. That's why I was asking about the vacuum line. Should I connect the tank and see if it gets better?

It's okay to plug it while the tank is off.

[garyg199]

So shshould I def have it plugged while running it? Will it not run right with it not plugged?

[Ghostt]

Originally Posted by garyg199

So shshould I def have it plugged while running it? Will it not run right with it not plugged?

If left open, you have a vacuum leak, so it won't run right. Either put the tank back on, or plug it while your testing.

Also might as well check the petcock while you have the tank off. It's easy to test, just hook up a hose to the vacuum side and apply vacuum/suction. It should only allow fuel to flow when vacuum is present in the on or res positions. And in off nothing no matter what.

If fuel flows without vacuum, and/or you suck gas thru the vacuum side, then it's time for a new petcock.

Write-up time,

If your petcock is shot, save your time, and money and get a new one, the cost of rebuilding it isn't much cheaper, due to you need two separate kits, as they for some reason don't make just one.

New one cost about $65.00

1988~00 models
http://www.partzilla.com/parts/detai...1023-1139.html

2001~07 models
http://www.partzilla.com/parts/detai...1023-1393.html



Also be sure to order the orings(92022-183 WASHER,6.2X11X1.5)and new bolts(92001-1091BOLT,6X20),trust me you'll be better off in the long run.

Rebuilding kits are about $60 total.

K&L Supply Diaphragm Only for Fuel Petcock Repair Kit 18-6638 https://www.amazon.com/dp/B0055DWO60..._s1CGub1W9N3PH

K&L Supply Fuel Petcock Repair Kit 18-2723 https://www.amazon.com/dp/B001KO2JRW..._U1CGub05DT5NT

http://faq.ninja250.org/wiki/Rebuild...tcock/fuel_tap

IMHO not worth it rebuilding, also be sure to check vacuum and fuel lines for wear, holes, and cracks, if in doubt replace them. Also replace the two small O-rings on the bolts for the petcock part# 92022.

This is the time to add an inline filter filter, if you don't have one already.

K&N 81-0221 Fuel Filter https://www.amazon.com/dp/B000E2AR70..._ncMwwbE333H0E

[garyg199]

Thanks for the input about the petcock @ghost. However I have an 09 and only have an "on " and a "pri" position on mine. Prime let's the fuel flow freely via gravity feed and the on position I believe is vaccum fed

[garyg199]

I think I may have gotten everything settled. Seemed like when I plugged the vacuum like that goes to the petcock everything was back to normal. It idles good and I was able to rev it without it bogging or dying. In conclusion I think the bogging was a vac leak symptom coming from said line. The only issue I have which is minor and easily fixed is that it's still a bit lean because the idle does hang a little bit when the throttle is blipped. Gotta adjust the mixture screws. Sucks though I don't want to take the carbs back off so I can actually be able to test it while adjusting and the screw on the right carb is near impossible to get at. Any suggestions for that? I don't have a stubby driver and I was unable to access it, or at least access it and turn the screw. Was using a drill bit and a small ratchet driver. Just could get in there with my hand.

[Ghostt]

If you have a stubby screwdriver you can do it while their on the bike.

Here's my write-up on the subject

Your initial setting should be 3 full turns out from the bottom, remember just slightly tighten them, don't go all Conan on them.



Then warm it up, slowly turn 1 side pilot screw in until the rpms drop, then back out till RPM's peak (and no further)* Twist throttle...see how it reacts...tweak to taste.
Repeat on other side... test ride. You're looking for best throttle response and transition from just cracked to 1/4 throttle opening or so.*

Thats a quickie, 10 cent tutorial on setting pilot screws.**