1996 idle help!

[a.graham52]

hey guys, just picked up a mint 1996 250 couple days ago with 15k miles. been sitting since 2008 with gas in it etc.

was parked due to an idle problem. iv cleaned the carbs and removed califonia emissions and low and behold the idle problem is still present. apprently the dealer could even figure out the problem.

you can set the idle to run at about 1k rpms and it will idle. throttle responce isnt great though. turn idle up with the knob just a hair and the idle will jump way up to 3k rpms for about 3 seconds before dropping back down to 1kish.

i didnt see any tears in the rubber boots on the metering rods, vac lines, or carb boots.

any idea?

[Monkeytofu]

Nice purchase!


Aren't you supposed to turn the idle knob while its off? Gave me problems when I did it when my bike was on.

Also are you sure it's not just the bike needing to be warmed up? You try it out in different times of the day when it's warm/cold?

[Avenged7Fold]

When I was buying my Ninja, I looked at this mint quality bike that looked exactly like that. I was all ready to buy it when I noticed that the throttle response was very low. Already confused why it was so cheap for such a mint conditioned bike, I came to the conclusion that they blew the engine or something. Got all smokey and the throttle response was awfully slow. Just thought I'd share Seems to have the same problem as yours.

[csmith12]

Welcome Aaron!

If you are 100% sure you cleaned the carb well and I assume you are running fresh gas, then air box/filter, fuel filter then for vac leaks. They can be sneeky so get a can of carb cleaner/starting fluid and lightly spray around the vac lines and carb boots. If the engine revs... you found you leak.

Good luck sir and keep us posted on what you find.

[a.graham52]

Originally Posted by Monkeytofu

Nice purchase!


Aren't you supposed to turn the idle knob while its off? Gave me problems when I did it when my bike was on.

Also are you sure it's not just the bike needing to be warmed up? You try it out in different times of the day when it's warm/cold?

im positive the bike does not need to be warmed up. im not new to bikes but also to confirm, it was up to temp and even had the fan kicking in when this was happening. this is the first time its been running since 2008.

Originally Posted by Avenged7Fold

When I was buying my Ninja, I looked at this mint quality bike that looked exactly like that. I was all ready to buy it when I noticed that the throttle response was very low. Already confused why it was so cheap for such a mint conditioned bike, I came to the conclusion that they blew the engine or something. Got all smokey and the throttle response was awfully slow. Just thought I'd share Seems to have the same problem as yours.

thanks for sharing. i went and looked at this $400 dollar biking being prepaired for a wreck. i didnt realy care because my intent is to resell it for a bit more, least it was at the time. plans are in the work for this to be my gfs first bike. but, found out the person i bought it off of was a very good customer at the chevy dealer i work at. older guy who owns his own plumbing and heating company. he bought the bike for his daughter, got it off of a nother decent guy, put new tires and a chain on it but was never able to get it to run well enough for his daughter to use it (e.i the problem it has right now). dealer apparently couldnt even fix it. this guy is NOT hurting for money which is why i probably stole it from him.

the very first start there was a puff of smoke (burning oil), very minor and hasnt done it since. engine sounds real nice, minor tich from valve train. other then that this thing sounds great.

Originally Posted by csmith12

Welcome Aaron!

If you are 100% sure you cleaned the carb well and I assume you are running fresh gas, then air box/filter, fuel filter then for vac leaks. They can be sneeky so get a can of carb cleaner/starting fluid and lightly spray around the vac lines and carb boots. If the engine revs... you found you leak.

Good luck sir and keep us posted on what you find.

im a tech at a chevy dealer so i have a good idea what im doing around an engine (however not the perfect idea lol) so i think i got them pretty clean. i think what im going to focus on next is making sure the floats are at the right level. can somone throw me the specs? and also rebuild the petcock seeings how it has minor leak by every once in a while (a constant dribble out of the fuel hose.... but not all the time) i know how the vac petcocks work so i know thats not right. i did try the spray test but that didnt tell me much. im going to redo all the vac lines anyways. not that hard so one less thing to worry about.

[Avenged7Fold]

Originally Posted by a.graham52

thanks for sharing. i went and looked at this $400 dollar biking being prepaired for a wreck.

Are you telling me that Ninja was $400, or did I miss something?

[a.graham52]

Originally Posted by Avenged7Fold

Are you telling me that Ninja was $400, or did I miss something?

Yes 40,000 pennies or 400 dollars, which ever is cheaper lol

[Avenged7Fold]

Originally Posted by a.graham52

Yes 40,000 pennies or 400 dollars, which ever is cheaper lol

Wow, you could sell just the fairings and such for that much money!

[davenay67]

Originally Posted by a.graham52

you can set the idle to run at about 1k rpms and it will idle. throttle responce isnt great though. turn idle up with the knob just a hair and the idle will jump way up to 3k rpms for about 3 seconds before dropping back down to 1kish.

Sounds like it could possibly be a lean condition.

The usual suspects apply here:-

air mixture screws set correctly
vac leaks
float height
carbs completely dismantled and cleaned
make sure ALL the parts are in the carbs

The petcock comes apart very easily and it's pretty obvious how everything works.

This site will be your best (250 Ninja) friend....http://faq.ninja250.org/wiki/Main_Page

[alex.s]

it sounds like your bowls are getting too high from the messed up petcock and a leaky float valve.

[a.graham52]

welll i tell you what, iv run it on just the fuel in the bowls and the problem is still present. so i would assume that would rule out both the bowls and petcock for now. i cleaned the carbs again last night and tried it out, same problem. think unadjusted valves could cause it? im going to check them out tonight after work.

[csmith12]

Yep, valve clearances could be an issue. I also thought of carb sync/flap issues could maybe be a possibility as well.

[choneofakind]

Is there anyone near you that you could temporarily swap carbs with to narrow down the carbs vs the bike as the problem? It might seem dumb, but if this is still an issue after a valve adjustment and carb sync, that's what I would do.
Posted via Mobile Device

[a.graham52]

Originally Posted by choneofakind

Is there anyone near you that you could temporarily swap carbs with to narrow down the carbs vs the bike as the problem? It might seem dumb, but if this is still an issue after a valve adjustment and carb sync, that's what I would do.
Posted via Mobile Device

those thoughts have crossed my mind already. i dont know of anyone in my area with a nother 250. never had one before, nore did i care at the time. my sync tool should be here thursday but im hoping the valves will be the ticket.

[a.graham52]

just got done adjusting the valves. got as far as putting the valve cover back on but thats it. all the valves were wicked tight. figners crossed!

[a.graham52]

so... problem is still present, however much much better. i have control over the idle now! ibut if you rev it up the idle will hang coming back down. sounds like an effing vac leak but i cannot find one for the life of me! i do not have the boots between the carbs and the air box on right now for ease of removing the carbs, could that be my problem? carb sync tool should be here thursday so ill nail that out real quick when it shows up.

[a.graham52]

so i stuck the boots back on the carbs, put the air filters in and straped a small ice-ogger fuel tank to the fram and took it for a spin. all the vac lines are plugged, air filter completely intact and yet the idle will still hang. hung as high as 4k at one point. one person at work said i should shim the needles but i think that would only cover up the problem. also wunder if leaking float needles would cause this?

[choneofakind]

Maybe you posted this already, but I missed it; where are your mix screws set at?

[a.graham52]

Originally Posted by choneofakind

Maybe you posted this already, but I missed it; where are your mix screws set at?

currently at 3.5 turns. when i first got the bike one was at .75 turns and the other was 0.

[a.graham52]

Update:

problem still present. tomorow im syncing the carbs but i dont think it will have any effect. iv taken ALL the vac lines off and plugged them with new nipple plugs. even the two lines between the carbs.

lets say im on the bike and i go to ride it around... once i take off the throttle seems to hang, if i blip the throttle a few times the idle drops back down and some times goes as low as 1k rpms. im at a loss. once she cools down again im going to pull the carbs out again and lower the floats a bit and see if that helps. wtf....

oh and with a cold engine, if i slowling give it choke... nothing... nothing... nothing then it wants to kill the engine. tells me its running rich right?

[alex.s]

currently at 3.5 turns... how did you come to this number? try adjusting the mix screws with the bike running. yes having the carb disconnected from the airbox will completely change the jetting

it honestly sounds like something is wrong with your float valves. you are describing it changing from a lean condition to a rich pilot condition that means its changing. what can change in the pilot system? gas level. what can change the gas level? vacuum leak or bad float valve or float level adjustment. you said theres no vac leak so we will set that aside for now. unless your carbs are filthy thats about the only thing that can do what you are describing.

[a.graham52]

Originally Posted by alex.s

currently at 3.5 turns... how did you come to this number? try adjusting the mix screws with the bike running. yes having the carb disconnected from the airbox will completely change the jetting

it honestly sounds like something is wrong with your float valves. you are describing it changing from a lean condition to a rich pilot condition that means its changing. what can change in the pilot system? gas level. what can change the gas level? vacuum leak or bad float valve or float level adjustment. you said theres no vac leak so we will set that aside for now. unless your carbs are filthy thats about the only thing that can do what you are describing.

i removed the caps on the idle mixture screws, bottomed the screws. turned them out 3.5 turns out. thats how i got 3.5 turns.

i checked the float hights just now, iv got 17mm, 16.93mm. also tested the float needle operation with the bowls off. everythign good there.

BUT.. i may have stumbled onto something. i removed both idle mixture screws and this time i removed the springs and washers and o rigns too. only on washer! i checked everywhere for the other washer and cannot find it. must have been missing this whole time.

[alex.s]

well having one pilot system rich and the other lean could definitely do what you described. i would replace the missing part and then reset the screws to 3.5, then start turning in .25 turns each until it responds correctly. once its close, sync the carbs

[greg737]

Originally Posted by a.graham52

BUT.. i may have stumbled onto something. i removed both idle mixture screws and this time i removed the springs and washers and o rigns too. only on washer! i checked everywhere for the other washer and cannot find it. must have been missing this whole time.

We sometimes see this sort of thing here on the forum. A guy comes on, new to the 250 or even new to motorcycles but with some automotive experience. He aquires an EX-250 that needs some tuning so he pulls the carbs for a look-see that eventually turns into a full carb disassembly. This is were things get weird...

There are a few mechanic's errors that can occur during carb disassembly/cleaning/reassembly that will cause you to end up with an untunable EX-250:

1. Missing pieces, who's fault it is doesn't matter (prior owner or you). One of the most common missing pieces is the carb's needle seat which is known to simply fall out of the carb when you've removed the needle. It's a very small part and it can fall out completely unnoticed because guys are usually very focused on the needle and the diaphram at this point in disassembly.

2. Failure to reconnect the needle to the diaphram correctly. Nuff said.

3. Installing the carb-to-engine boots (one or both) backwards. This causes vacuum leaks. There's a reason these boots are labled with a "carb" end and an "engine" end.

We've had a couple of recent threads where guys were suggesting everything under the sun trying in vain to help out a new EX-250 owner. Nothing was working until the new owners finally discovered, in one case that both needle seats were missing and in the other case that he hadn't reconnected the needles to the diaphrams correctly.

But, damn, that is a great looking '96! And for only $400, that has to be the best buy I've seen in a long time. Congradulations on the purchase.

[a.graham52]

Originally Posted by greg737

We sometimes see this sort of thing here on the forum. A guy comes on, new to the 250 or even new to motorcycles but with some automotive experience. He aquires an EX-250 that needs some tuning so he pulls the carbs for a look-see that eventually turns into a full carb disassembly. This is were things get weird...

There are a few mechanic's errors that can occur during carb disassembly/cleaning/reassembly that will cause you to end up with an untunable EX-250:

1. Missing pieces, who's fault it is doesn't matter (prior owner or you). One of the most common missing pieces is the carb's needle seat which is known to simply fall out of the carb when you've removed the needle. It's a very small part and it can fall out completely unnoticed because guys are usually very focused on the needle and the diaphram at this point in disassembly.

2. Failure to reconnect the needle to the diaphram correctly. Nuff said.

3. Installing the carb-to-engine boots (one or both) backwards. This causes vacuum leaks. There's a reason these boots are labled with a "carb" end and an "engine" end.

We've had a couple of recent threads where guys were suggesting everything under the sun trying in vain to help out a new EX-250 owner. Nothing was working until the new owners finally discovered, in one case that both needle seats were missing and in the other case that he hadn't reconnected the needles to the diaphrams correctly.

But, damn, that is a great looking '96! And for only $400, that has to be the best buy I've seen in a long time. Congradulations on the purchase.

this isnt my first bike iv tuned. I have a stage ii jet kit with adjustable needles and pod filters on my bandit 1200. The needle seats are in there for sure, ill look into how the needles were put back in... Seemed simple to me. but i did set all the bparts and peices into a devided parts tray so to make sure i didnt loose or forget anything.

[a.graham52]

sorry ran out of room on my phone. Whats its doing now is what what the PO said it was doing for him, and the guy before him. Even our dealer was stumped. I was the one to drill out the idle mixture screw caps (doesnt mean someone couldnt have put new ones in) so the fact that the washer was missing has me wundering. This is the first time i removed the idle needles and o rings completly. Before i only remeved the needles. ill have to wait a week before the new washer comes in.

[alex.s]

with that washer missing, the bottom-out will be lower, no? so setting both carbs to 3.5 out from "bottom" actually means one carb is at 3.5 and the one without the washer is at 2.5 or something? i honestly dont know how the washer could be missing if you are the one who pulled the mix screw cap. maybe it came from the factory like that? maybe someone replaced the mix screw caps. maybe that carb has been replaced and that version simply doesnt have the washer? it seems like even if it had the mix needle at the same position, the lack of the washer could be letting more air in. if the carb actually works like that you might be able to just make sure the carbs are close to synced at the throttle adjust using a bench sync with feeler gauges, then adjust that carbs mix screw with the vacuum gauge on until they sync up.

[greg737]

No offense intended, just trying to help. Wouldn't have said a thing if strange stuff didn't just keep happening, even to experienced guys.

[a.graham52]

Originally Posted by greg737

No offense intended, just trying to help. Wouldn't have said a thing if strange stuff didn't just keep happening, even to experienced guys.

yeah, no worries, i know where ur coming from.

[a.graham52]

Originally Posted by alex.s

with that washer missing, the bottom-out will be lower, no? so setting both carbs to 3.5 out from "bottom" actually means one carb is at 3.5 and the one without the washer is at 2.5 or something? i honestly dont know how the washer could be missing if you are the one who pulled the mix screw cap. maybe it came from the factory like that? maybe someone replaced the mix screw caps. maybe that carb has been replaced and that version simply doesnt have the washer? it seems like even if it had the mix needle at the same position, the lack of the washer could be letting more air in. if the carb actually works like that you might be able to just make sure the carbs are close to synced at the throttle adjust using a bench sync with feeler gauges, then adjust that carbs mix screw with the vacuum gauge on until they sync up

what im kind of hoping for is without that washer the orings leaking a bit here and there. that would give me the random idle.

[davenay67]

Originally Posted by a.graham52

what im kind of hoping for is without that washer the orings leaking a bit here and there. that would give me the random idle.

Are you sure the washer is actually missing, and not still in the carb body..?? I only ask because I did exactly the same thing, and my washer was still in the carb body.

I wouldn't drive yourself nuts any further until the carbs are synced, as this could be the missing piece of the puzzle. I had tight valves and badly-synced carbs. Bike ran awful....adjusted those 2 things and it now runs like a Swiss clock.

[a.graham52]

yeah im sure the washer is missing, i pulled out the i ring and looked in with a flash light and it was no where in site. ill sync them at noon and see hwat happens.

[a.graham52]

synced carbs. they were only a couple inches off. nothing serious. however i have to pull the bowls off again. some reason its over fueling BIG time. wunder is something came apart yesturday when i had the bowls out.

[Kevin2109]

Duct tape over the air filter, some say thats a good fix

[Kevin2109]

Oh, and @alex.s told you so!

[a.graham52]

Originally Posted by Kevin2109

Oh, and @alex.s told you so!

well its the first time its ever done that since i had it. i pulled the bowls and i can stop stop fuel flow very easily by gently pushing up on the floats. put it all back together and fuel comes pissing out again.

any who... our intern just cleaned the carbs on the table onto the floor and im looking for a few more peices now. anyone have a set of carbs they want to sell for cheap? even if they need re cleaning? otherwise i know at this moment im looking for the black cap on the top of the carbs. need one.

[a.graham52]

ok, picked up the diaphram cover today and put the carbs back together. Verified on the bench that the carbs do not overflow with fuel. Installed and tried it out. Concern still present. Grab a handfull of throttle and let go... Throttle will hang at 3-4k, blip the throttle a couple times and the idle will drop, most of the time it will almost stall... Turn the idle speed up a hair and the idle will take right off. Adjusted the floats a bit lower and retested. Still there. when the engine revs up u can shake the hell out of the bike and nothing changes (thinking if fuel level was to high it woluld show here). did notice that if i lift the diaphrams by using my finger, one would make a healthy whissle when the diaphram drops. The other not as healthy however i cannot find any tears on the diaphram. Oh before i forget, hooked up my sync guages and when the engines revved up vacuum is the same for each carb. If i had a vac leak i would think the carbs would have different readings no?

[a.graham52]

installed new float needles due to still hydrolocking the engine if you let it sit, still hydrolocks even with the new float needles. must be because im not using a tank with a shut off. ended up taking the carbs all apart again and soaking them in pinsol over night. blew air through all the passages seem spotless to me. jets look good too. talked to dale walker from holeshotperformance and he said it sounds like one cylinder's idle/pilot circuits not working. i wish i could find this damn head ache.

[davenay67]

Originally Posted by a.graham52

installed new float needles due to still hydrolocking the engine if you let it sit, still hydrolocks even with the new float needles. must be because im not using a tank with a shut off. ended up taking the carbs all apart again and soaking them in pinsol over night. blew air through all the passages seem spotless to me. jets look good too. talked to dale walker from holeshotperformance and he said it sounds like one cylinder's idle/pilot circuits not working. i wish i could find this damn head ache.

At this point a set of carbs from a slavage yard might not be a bad option. You would have a side-by-side comparison and would have a source of possible spare parts.

A petcock rebuild kit is cheap for your bike, and would be the first thing I did at any sign of gas leakage.

[a.graham52]

Originally Posted by davenay67

At this point a set of carbs from a slavage yard might not be a bad option. You would have a side-by-side comparison and would have a source of possible spare parts.

A petcock rebuild kit is cheap for your bike, and would be the first thing I did at any sign of gas leakage.

at this point im using a fuel tank off of an ice ogger. probably only holds a quart of fuel at a time.