Hit a wall and need some help PLEASE

[Waldo1]

My son picked up a 95 EX250 from a buddy. The price was right (FREE). It has been a fight to get it running right. It has stock pipes (reamed out) and K & N Filter pods. The bike will not idle. If you get the RPMs above 3000 it runs great. I have ultrasonic cleaned the carbs, replaced with new the pilot jets, main jets, emulsion tubes, slide needles, float needles, whatever that valve is on the side (deceleration valve) and all the gaskets/seals/o-rings. I have also checked and checked again the valve clearance. Leak tested with it holding 97%. Ohmed the coils.

I bought a little pencil looking tester which is supposed to sense the spark in a spark plug wire. The left cylinder has constant spark but the right is showing intermittent. This is constant with my inductive timing light. Makes me wonder if the cap is bad. Or maybe the CDI.

Any help would be greatly appreciated.

[tfkrocks]

I read the title and thought you meant it literally. I was expecting a crash story. Oops. Good luck figuring it out.

[ninjakuma]

I'm not an expert by any means or mechanic but this is what my intuition is telling me:

You say your right plug is only showing intermittent spark. The bike doesn't idle below 3000 rpm. Since increasing rpm increases voltage output from the battery I would hypothesize there is a poor electrical connection somewhere in the circuitry between the battery and that plug or the plug itself is bad. With enough voltage a spark can arc across a gap that may be too large. Try checking that out. A wiring schematic would help you tons, I don't know where to find one online off the top of my head.

Is the air filter clean?

[LittleRedNinjette]

Originally Posted by tfkrocks

I read the title and thought you meant it literally. I was expecting a crash story. Oops. Good luck figuring it out.

So did I!

Good luck getting it running!

[csmith12]

First off, gratz on a FREE bike score!

Swap the plug sides, if the problem moves to the other side... then you know the plug is bad and a new set of BOTH plugs would be a good start. Since you note the bike runs fine above 3k, I would suspect; battery connections, clean and tight? Pick up coil, ohm meter test. Maybe it just needs to be cleaned up a bit. Coils still could be an issue but if ya tested them they should be ok.

Hope it's something simple for ya.

[Ninjinsky]

Not sure why my post was removed
Anyway here it is again
I had a misfire that turned out to be an HT lead pulled a quarter inch or so out through the coil cable grip. It all looks normal so is hard to spot unless you unscrew the cable grip.

[Jinx08]

Thanks for the tips when we figure out we will let you know

[agentbad]

With pods and customish exhaust you'd probably need 40 pilots, maybe 110 or 112 mains, and a few shims under the each needle to make the carbs happy. The fuel screw would probably need to be out more then just 2.5 turns out as well maybe closer to 3. Are the float levels set correctly?

[Waldo1]

We swapped the caps and coils. They both seem to be working fine now.

I bought a range of pilot jets from 40 to 50, Main jets 100 and 105, and a stock needles.

When we started today the carbs had a 38 pilot, 105 main and OEM needles.

First we put the 50 in to see what would happen. The bike started and idled but the fuel screws did not make an effect. We then changed to a 45 pilot. It idled but would die. Next we took the OEM needles out and put the adjustable after market needles back in but this time we moved the clip to the top and put washers on top (leanest as possible). The bike started running better. This time the fuel screw made a difference. This tells me we were pulling fuel during the idle mode from the main circuit.

I still need to do some work on the pilot circuit. Maybe keep going down. That will have to wait until tomorrow.

Thanks everyone for all the ideas and help.

[rubber side down]

With having to lean it down to have it make a difference, have you checked your float height?

[Waldo1]

New float needles and they are set at 17mm

[Waldo1]

We had put the bike on the back burner for a while since my son bought a F4i. I still would like to get this bike street-able. I am thinking I need to head down the Remove and Replace ignition path. I think different coils, CDI and pickup coil. Than we will see what happens.

[agentbad]

Originally Posted by Waldo1

We had put the bike on the back burner for a while since my son bought a F4i. I still would like to get this bike street-able. I am thinking I need to head down the Remove and Replace ignition path. I think different coils, CDI and pickup coil. Than we will see what happens.

If you are running stock jetting it's going to run poorly with that setup.

[kxpower?]

Originally Posted by Waldo1

We swapped the caps and coils. They both seem to be working fine now.

I bought a range of pilot jets from 40 to 50, Main jets 100 and 105, and a stock needles.

When we started today the carbs had a 38 pilot, 105 main and OEM needles.

First we put the 50 in to see what would happen. The bike started and idled but the fuel screws did not make an effect. We then changed to a 45 pilot. It idled but would die. Next we took the OEM needles out and put the adjustable after market needles back in but this time we moved the clip to the top and put washers on top (leanest as possible). The bike started running better. This time the fuel screw made a difference. This tells me we were pulling fuel during the idle mode from the main circuit.

I still need to do some work on the pilot circuit. Maybe keep going down. That will have to wait until tomorrow.

Thanks everyone for all the ideas and help.

What do your plugs look like now when you try to get it to idle? The post I've quoted makes me think that you were chasing around a mixture problem, it may still just need dialing in.

Oh--and you're absolutely certain there aren't any vacuum leaks? Like I mentioned on the other thread, mine likes having idle set around 2500-3k. Not ideal I guess but it was pretty happy that way.

[Waldo1]

Well I picked up a set of carbs which I was told came from a running bike. That did not fix my problem. We tried the CDI but they are not the same. I guess the next step is to swap the entire harness over and see if that fixes it.

The one off my son's bike is the one on the left

[InvisiBill]

https://www.ninjette.org/forums/showthread.php?t=241339 could save you some trouble/money if you're replacing a bunch of ignition stuff anyway.

But it sounded from your previous post like the spark issue had been fixed. I assume you cleaned/refreshed the caps and wire ends already?

[Waldo1]

Originally Posted by InvisiBill

https://www.ninjette.org/forums/showthread.php?t=241339 could save you some trouble/money if you're replacing a bunch of ignition stuff anyway.

But it sounded from your previous post like the spark issue had been fixed. I assume you cleaned/refreshed the caps and wire ends already?

Thanks for the link, I have done this mod on my RC51 but did not think to do it on the Ninja. I do have some spare coils from a R6. I will have to see if the Ohms are the same.

I have not replaced the caps or wires but we have unscrewed them and reinstalled the Ign wires and caps.

[kxpower?]

Ok let's try and get the discussion of diagnostics off the classifieds thread.

If it's just idling fast, honestly if it were me I'd just ride it. I'm not seeing this as a big problem, or what am I missing? I have a 21119-1233 igniter box, but the cover is pulled off meaning at some point I suspected it didn't work. You're more than welcome to it, but I have my doubts that it will help. All the igniter does is throw a "switch" to fire the coils; it should just either work or not work.

Originally Posted by kxpower?

OK so you have the 21119-1233? I had a few of these around, I may have the 21119-1233. I'll dig around in storage and see if I can put my hands on it tomorrow. I had to use the wrong one on mine, just re-pinned the connector on the harness and made a couple of jumpers. There's half a dozen different ignition module part numbers for various pre-gen model years.

I though you said in the other thread that you had corrected the problem? You couldn't get it to idle down? Could you re-state what exactly is wrong at the moment? I had a 5,000+ RPM idle on my gs450 (also a twin with CV carbs), and it turned out at some point I had knocked the butterflies out of sync. 15 minute bench sync and it purred like a kitten, after chasing the problem around for 2 months.

Originally Posted by Waldo1

Is there a way to re-wire my current system to use the CDI you sent? I guess I could just replace the whole harness.

I am trying to get the bike to run below 3k and/or idle. Still have not fixed the problem.

Two different sets of carbs and still have the same problem.

[kxpower?]

Did you say you bench synced the carbs?

[Waldo1]

The carbs I rebuilt had been bench syn but these second set I have not messed with. The idle is uncontrollable. If it drops below 3k it falls off all together. This will not work of a beginner rider. I am trying to get this bike right for first time riders.

I did switch to the coils/wires/caps and had the same problem.

The valves have been check by me three times, my son and a mechanic buddy both check them twice.

[RacinNinja]

K&N pods eh? There's your problem. It's not ignition.

Pick up a used airbox on Ebay or Craigslist and install it. I'm willing to bet it runs pretty well after that, provided you go back to stock jetting, or just a tad richer.

[Waldo1]

I have a OG air box with stock and K&N filter and pods. I have tried all three with the same result

[RacinNinja]

Originally Posted by Waldo1

I have a OG air box with stock and K&N filter and pods. I have tried all three with the same result

Hmmm....well, there goes that.

Almost two years working on this, that's nuts!

Still, I would put the intake system back to 100% stock. This will negate any jetting or air or fuel issues and allow you to diagnose the issue further. Stock jets, stock air box, etc. Then, once you get the issue sorted and found, you can work forward with jetting, K&N filters, etc.

Dropping off below 3K RPM indicates to me the idle/pilot circuit is still dirty. I know you've said you've ultrasonic the carbs, etc but....provided your ignition is OK, which it sounds like it is, it's idle circuit.

If it starts to fall off at an idle, and you turn the choke on a bit, does it come back? If so, you've confirmed the idle is still dirty or not right.

[ducatiman]

Originally Posted by Waldo1

My son picked up a 95 EX250 from a buddy. The price was right (FREE). It has been a fight to get it running right. It has stock pipes (reamed out) and K & N Filter pods. The bike will not idle. If you get the RPMs above 3000 it runs great. I have also checked and checked again the valve clearance.
Any help would be greatly appreciated.

Sounds like the PO had his fingers deeply imbedded in this bike.....I see you've checked valve clearances...but have you confirmed valve timing to be unmolested?

[Waldo1]

Originally Posted by RacinNinja

Hmmm....well, there goes that.

Almost two years working on this, that's nuts!

Still, I would put the intake system back to 100% stock. This will negate any jetting or air or fuel issues and allow you to diagnose the issue further. Stock jets, stock air box, etc. Then, once you get the issue sorted and found, you can work forward with jetting, K&N filters, etc.

That was my thoughts so I rebuilt the carbs back to stock and used the stock air box.

Originally Posted by RacinNinja

Dropping off below 3K RPM indicates to me the idle/pilot circuit is still dirty. I know you've said you've ultrasonic the carbs, etc but....provided your ignition is OK, which it sounds like it is, it's idle circuit.

If it starts to fall off at an idle, and you turn the choke on a bit, does it come back? If so, you've confirmed the idle is still dirty or not right.

I agree I believed it was in the idle circuit that is why I bought a set of carbs from a bike without this problem. I still have the problem.

[Waldo1]

Originally Posted by ducatiman

Sounds like the PO had his fingers deeply imbedded in this bike.....I see you've checked valve clearances...but have you confirmed valve timing to be unmolested?

Not sure what you mean by "fingers deeply imbedded"

I can/t remember if I check the valve timing. I will try that next.

[RacinNinja]

Originally Posted by Waldo1

That was my thoughts so I rebuilt the carbs back to stock and used the stock air box.

I agree I believed it was in the idle circuit that is why I bought a set of carbs from a bike without this problem. I still have the problem.

You're awfully good at shooting me down.

That pretty much eliminates the carbs from the issue.

I'd have a look at Ducatimans suggestion.

Could be a vacuum leak. Have you checked the petcock diaphragm for a leak? I didn't see that in this thread. What about your gas cap plugged up creating a vacuum in the tank? Are you using the same overflow/vent hoses? Could one of those be plugged and not allowing enough fuel into the bowls?

[Waldo1]

Originally Posted by RacinNinja

You're awfully good at shooting me down.

THANK YOU for your time and thoughts.

Originally Posted by RacinNinja

That pretty much eliminates the carbs from the issue.

I'd have a look at Ducatimans suggestion.

Could be a vacuum leak. Have you checked the petcock diaphragm for a leak? I didn't see that in this thread. What about your gas cap plugged up creating a vacuum in the tank? Are you using the same overflow/vent hoses? Could one of those be plugged and not allowing enough fuel into the bowls?

We have used two different petcocks (one vacuum and one non-vacuum). For the longest time I thought my problem was vacuum hose. When we got this bike the hoses were all over the place. It has taken some time and searching to figure them out. I was glad when this second set of carbs showed up looking like mine. I do not think it can be a tank vacuum problem. The bike would run worse the longer it ran. The higher the RPM would use more fuel which would cause the problem quicker. plus I thought of this and removed the fuel cap. No change.

I had a clean running 250 in the shop the other day. I so wanted to see if the guy would let me take it home and play.

[ducatiman]

Originally Posted by Waldo1

Not sure what you mean by "fingers deeply imbedded"

meaning..it seems the PO was a "mod type"....had his hands in everything...no telling whats he's done in attempts to "improve". Valve timing? i'd check it, for sure.

[RacinNinja]

Originally Posted by Waldo1

THANK YOU for your time and thoughts.

We have used two different petcocks (one vacuum and one non-vacuum). For the longest time I thought my problem was vacuum hose. When we got this bike the hoses were all over the place. It has taken some time and searching to figure them out. I was glad when this second set of carbs showed up looking like mine. I do not think it can be a tank vacuum problem. The bike would run worse the longer it ran. The higher the RPM would use more fuel which would cause the problem quicker. plus I thought of this and removed the fuel cap. No change.

I had a clean running 250 in the shop the other day. I so wanted to see if the guy would let me take it home and play.

I hope you realize I was joking. No harm, no foul.

I'm down to charging system, low voltage to coils while idling and something internal to the engine.

[Waldo1]

We spent some time on it a couple weekends ago and came down to it being the carbs. We replaced the entire electrical system, went back through the valves and put the second set of carbs on. NO CHANGE.

I was spraying the carb boots with brake cleaner and the rpm changed. We double check the boots and they were good. We believe the vacuum leak is in the throttle shaft seals. The felt in both sets of carbs are gone. It makes sense to me if you are leaking from the shafts you would not be able to idle. I did some research on the web and found where people are saying the ultrasonic destroys the felt seals.

I have some felt seals coming and will let you know.

[ducatiman]

these are OEM Keihin 30mm CVK's you are running?

[Waldo1]

Yep

[ducatiman]

posted some info, but must redo for clarity and accuracy.

Keihin doesn't "service" any throttle shaft parts. The CVK master and slave carbs do differ in their methods of sealing.

Mikuni does offer seals for certain models...are you substituting Mikuni seals?

Don't need to advise you of the incredibly tight side to side tolerances between throttle plate and throttle shaft plate mount holes within the venturi. Any added, thicker tolerance parts added to the shaft will cause shaft centering changes resulting in assembly difficulties or dangerous binding. Shaft geometry must remain perfectly centered (dictated by centering of the plates) and must offer the ability to freely rotate. There is no lateral "room to play" or tolerance.

IMHO...we set our pilot screws to meet the demands of a given cylinder and hit the "sweet spot" of the mixture...thereby compensating for miniscule throttle shaft false air.

I wish you luck, but think you are misdiagnosing.

This bike not idling under 3000RPM...I think you're way off on a tangent.
Many bikes go over 100,000 miles (or more) with original carbs. You got 2 sets of lemon carbs? Nah.

Did you ever check/confirm cam timing is not advanced or retarded a tooth (or more) on either cam?

[Waldo1]

It has all been checked.

When the shafts are sprayed with a liquid (which seals them) they run fine.