Stumped isn't even the word. Any suggestions appreciated.

[A.J.]

***PROBLEM SOLVED*** holed right piston. New motor build! ETA mid-July (2wks)

Bought a 2001 Ninja 250r about 5 weeks ago. Been at my friends shop the whole time. Just been a cat and mouse game. They're working at it. It's had
Carb rebuild
New fuel tank (original was so dented it leaked fuel)
New fuel filter
New ignition
Went out today and pulled an air box off a junked 250

"Ninja 250r hesitant to start won't idle till warms up stalls as soon as you give it gas. Can find no air leaks both carbs rebuilt idle screw set at 2.5 turns out"- mechanic

It's getting a spark, gas, everything it needs. Give it throttle and she falls on. her face. Backfires etc. was running much better today then we swapped out the air boxes because the air box that it had had some missing parts like what holds the filter in place and the "lid". Put the correct one on and runs worse. Checked all the vac hoses made sure they were all properly routed. @Ram Jet has been helping me out a little but we are miles apart so only so much he can do over email. Just feel like it's something stupid we are missing. The damn thing runs but can't get the RPM's up. The air:fuel ratio isn't right. Air is winning. Completely stumped don't know where to go next.
Here are a couple videos wish I had better ones especially of it earlier when it was running better. But the thing still probably wouldn't go over 40 but we thought there was progress.

https://youtu.be/40GJlfbjCvE

If you listen close on this one you can hear little backfires.

https://youtu.be/asPrpYjkoGo

Wish I had better videos I'll try and get more. Any and all input will be appreciated. At this point ready to give up.

[Triple Jim]

Is it running on both cylinders? (both head pipes heat up quickly when starting?)

Giving it throttle and having it stall may indicate either incomplete carburetor cleaning, or incorrect jets from a rebuild kit.

[A.J.]

Originally Posted by Triple Jim

Is it running on both cylinders? (both head pipes heat up quickly when starting?)

Giving it throttle and having it stall may indicate either incomplete carburetor cleaning, or incorrect jets from a rebuild kit.

I will forward this to the mechanic.

[Ghostt]

This maybe something, or nothing but either way it's not a, waste of time, as its quick to do.

Have you cleaned the spark plug caps, and renewed the HT leads? Also check the power, and ground leads going to the coils, to make sure they are clean, and tight.

Write-up time.

Even bad plugs should do something, unless they are totally shot.

Did you renew the HT leads, and disassemble the caps?

Make sure you disassemble the caps, and clean them, and yes the caps get cruddy.

Here my write-up,

Short explanation: The inside of the hard plastic caps accumulate crud the can short out the spark. This can cause rough running or failure to start. Every time you do any work on the bike: remove them disassemble and clean them and renew the wires or at least the connections.

The long Explanation, Warning engineering information can cause Drowsiness.
The ancient cylinder design of the engine dictates that the spark emanate form the center of the combustion chamber. In order to get it there, the plugs had to be located down deep in a well between the cams. This well is a perfect place for dirt and moisture to accumulate. Then because there is no cooling water at this point the metal around the plug runs very hot. Surround this with the large amount of cool metal and you have a recipe for condensation. Now K did drill a drain hole between the fins to help (a little) but it often gets plugged up.

The moisture boils off the base of the plug and the vapor condenses on the cool plastic cap and the plug insulator. This moisture forms a easier path for the electrons to ground than jumping the gap at the plug to make a spark. Misfire.
This issue is right up there with Pilot jets as a cause of trouble.

Here's some pictures that might be helpful. I took these when I replaced the wires themselves, as it was a good time for a write-up, and the wires were OEM from 1998.

Wires are just 7mm copper core, with clear silicone jacket









IMPORTANT NOTICE: make sure to use a proper screwdriver, make sure it fits, as the parts are made of brass inside the spark plug caps





Important notice: the wire must be screwed on the spark plug cap, note the screw like object inside the spark plug cap?



Important notice: be careful to not loose the ferrules on the HT leads, these keep the wire from falling out of the coil. Below is an example of ferrules on a pressure fitting, looks familiar?

[A.J.]

Appreciate the response this thread is being followed by a couple people.

My mechanic wanted me to add this and I sent him a link to this thread so he can keep an eye out. These are his words as to what's going on
"Ninja 250r hesitant to start won't idle till warms up stalls as soon as you give it gas. Can find no air leaks both carbs rebuilt idle screw set at 2.5 turns out."

[Triple Jim]

So the idle mixture screws have not been properly adjusted, just set to 2.5 turns out. I maintain what I said in post #2 above.

I respectfully suggest you become your own mechanic, or seek help from someone who is more familiar with the procedures to set up carbs on pregen Ninja 250s.

[A.J.]

Originally Posted by Triple Jim

So the idle mixture screws have not been properly adjusted, just set to 2.5 turns out. I maintain what I said in post #2 above.

I respectfully suggest you become your own mechanic, or seek help from someone who is more familiar with the procedures to set up carbs on pregen Ninja 250s.

Thanks Jim. He's been forwarded your post. I've seen you help many so I don't doubt you one bit. I'll let you know the outcome of post #2

[Racer x]

My guess is the pilot jets are clogged.

[A.J.]

Carbs were rebuilt but I'm not sure if they were cleaned I wish I could answer that. I'm the newb here when it comes to motorcycles in general. And I know cleaning carbs; it has to be done carefully and thoroughly as there are so many almost hidden passageways. So sounds like there is no air leak. Carb issue after all. I suspected it. I'm sure he's thinking the same.

[Triple Jim]

Have you talked to Ducatiman about getting the carbs in good working order?

[ducatiman]

Yes, we've corresponded.

Has the mechanic confirmed valve clearances are within spec...not out of whack?

[Triple Jim]

Always a good question, Gordon.

[ducatiman]

Checking/adjusting valves on a purchased used bike "new to you" could reveal radical errors created by a PO....or OTOH reveal a total disregard for that mileage dependent, critical maintenance procedure.

Either way, the parts removal and inspection process "going in" to the valve cover is revealing....and once completed assures everything involved is up to *your* satisfaction and standards.

As AJ made no mention of valves....its incumbent on the shop involved to make the most valid suggestion to check. Did they?

250 Ninja or not....the first procedure on *any* used bike "new to me"....check valves....

The cleanest carbs in the world will not mask (nor compensate for) other tuning deficiencies left undiscovered. Start from the inside and work outwards, says I.

[ducatiman]

Forgot to add....no mention of petcock function.

I don't want to tell the shop how to do their job...but they should also be probed on assuring the float bowls are actually filling to proper height.

A true "carb rebuild" should have been accompanied by a bench wet test to accurately set the working fuel levels....followed by confirmation *on the bike* that they are indeed filling to spec...no flow issues.

[Lazarus]

Make the carbs great again and clean them. Lol

Rebuild could just mean they replaced the float bowl gaskets and a couple other things but never actually cleaned the carbs. Worth a shot at this point.

[ducatiman]

A true "carb rebuilding" implies they've been taken fully apart....and while apart, every component should automatically be cleaned, as appropriate, within the process. At least thats my interpretation and understanding of the use of the phrase "carb rebuild."

Unless someone has applied some "creative licence"?

Or simply performed a substandard job?

I still submit review all 3 in a non-runner "new to you" ..valves, fuel delivery, carbs.

[Lazarus]

I suspect substandard job.

[Mohawk]

Is it runintended stock coils or Coil on Plug conversion ? Reason I ask is I converted mine & it worked for a little while then did exactly what you describe. I went back to the stock setup & it works a treat.

[A.J.]

Appreciate the feedback guys I'll let you know how it goes and answer the questions after the holiday but yes carbs were cleaned. Machanic plans to check valves. That's why I'm enlisting you guys because you've all worked on these bikes many times. Thanks again.

[bob706]

if you do narrow it down to the carbs, I would suggest a complete disassembly and a two day soak in pine sol. I did this to both my bikes and it cleans the heck out of them. Followed with water rinse, air compressor and carb cleaner. Good luck

[NaturalFlavored]

I don't know a lot about carbs, I've worked on a single carb. I've learned backfire usually means too much gas, others have also stated not enough. But I've only backfired with too much gas which the spark plugs can tell you how the bike running. Black means it's getting too much. You want a more brownish color.
Someone can correct me if I'm wrong please, but this is what I was told and learned over about a year.

[A.J.]

Well my mechanics called me today. Not sure how most people would take this news but for me it's great since I only paid $100 for the bike. Hole in the right piston.
Gonna order the part and get her fixed. Feels good to know the problem finally. So the bike will of had a complete carb rebuild and a great running motor when she's done. Can't thank the guys enough for their hard work on these hot and humid summer Illinois days. I'll let you guys know how she runs once it's fixed.

[jkv45]

Originally Posted by A.J.

Well my mechanics called me today. Not sure how most people would take this news but for me it's great since I only paid $100 for the bike. Hole in the right piston.
Gonna order the part and get her fixed. Feels good to know the problem finally. So the bike will of had a complete carb rebuild and a great running motor when she's done. Can't thank the guys enough for their hard work on these hot and humid summer Illinois days. I'll let you guys know how she runs once it's fixed.

That's a whole (no pun...) 'nother can of worms.

Typically, the cost to repair a Ninja engine exceeds the value of the bike - especially with shop labor. Most people find a good used engine instead. Once it's opened-up there will most likely be more issue that present themselves.

I guess I'd be a bit pissed to have paid for carb work and then find out there's major engine damage. Seems like that should have been found first. The plug should have been trashed on that side.

Be careful giving them a blank check.

We just sold our last Ninja 250, and have a spare engine. PM me if you are interested. I'll check what my son wants for it. It's located near Madison, WI, so not too far from you.

[Triple Jim]

A simple compression test would have revealed a major problem like that before going off on tangents. I agree, get a good running engine and make the swap. It would be very unusual if there weren't significantly more damage in the engine, if there's a hole in the piston.

Swap the engines yourself. There's a recent thread here that indicates that even a person who is not particularly handy with tools can successfully swap a 250 engine.

[A.J.]

Actually it's gonna cost $240 for a whole new rebuild he's gonna go ahead and do. Sounds cheap but I'm just in a fortuntane situation. Well labor isn't an issue either. He said all the other stuff looks good but while he's in there if it were his bike he would replace most of the stuff just in case there's damage they aren't seeing. Said he just would feel better. I just got off the phone. He said I'll essentially have a new motor. He's trying to keep it into Lemans terms for me lol. Oh and the cause is the faulty fan. The cooling system stopped working (the fan) and that caused it to heat up and do the damage. Now I wish I could record him because it would all make perfect sense to you guys with the wrenches but he's 100% confident she's gonna be screaming.
He's inspected every key part. Unfortunately the kid I bought it from was a 20yr old country boy that could care less if the motor was overheating. He cared nothing for the bike. But I do.

[A.J.]

Just ordered the parts. Whole new front end but I knew it was a possibility which is why I only gave $100
He went ahead and had me get everything just to cover all the bases and in case there might have been damage that went unseen. He just said it's better to spend the extra money now and do it all new and right.
1- COMETIC head gasket
1- new pistons for both cylinders
1- Engine cylinder jug
1- cylinder head

I want to help with this to make for a good learning experience.

[NaturalFlavored]

Nice. Investing into something that you'll love and have fun with for years isn't a bad investment. Every vehicle car or bike will always be considered a sinkhole.
I know my engine won't last long, I want to rebuild another engine over time so when I do install it it's like a brand new engine.

[A.J.]

Originally Posted by NaturalFlavored

Nice. Investing into something that you'll love and have fun with for years isn't a bad investment. Every vehicle car or bike will always be considered a sinkhole.
I know my engine won't last long, I want to rebuild another engine over time so when I do install it it's like a brand new engine.

Absolutely man. I know swapping it out would be the quicker and easier thing to do but buying all the parts and helping to install them for my first rebuild is going to be something I can teach my kids. And I have an attachment to this bike. So what if it's "just a 250"? It's a bike I'll ride until I can't ride any longer. And now she's gonna have a new heart. It's exciting. The money isn't an issue I had an amount set aside for her when I bought her and I haven't come close to exceeding it even after the rebuild. That's why you buy CHEAP. Had this 2001 been a grand or more I probably would've said goodbye to her, reluctantly.
I appreciate your post man. I know everyone here is trying to be nice and the knowledge here is astounding. But this was my decision and I'm happy with it. A couple weeks from now I'll be ripping the heart of a brand new bike. I can't wait to hear her after this new motor gets put in. And I'm super excited to help bring Rosie back to life!

[NaturalFlavored]

I spent $1200 on mine plus about $500 for a tune-up and everything to get it going. I love it, almost a 1000 miles on it in about month

[A.J.]

Originally Posted by NaturalFlavored

I spent $1200 on mine plus about $500 for a tune-up and everything to get it going. I love it, almost a 1000 miles on it in about month

And as long as it's worth it to you that's all that matters. I'm sure she's with more than that in the blue book anyway. What year is she?

[NaturalFlavored]

03. 16.5k miles when I bought it

[A.J.]

Originally Posted by NaturalFlavored

03. 16.5k miles when I bought it

Mine is an '01 and only had 9500 mi on it but unfortunately before me she suffered under a bad owner. Sad when people just can't take care of things.

[NaturalFlavored]

Yep. Mine was not taken care of as much as it could of. My cam has some extra wear than it should.
But I want to rebuild it. Sort of.

[A.J.]

The kid ruined the motor over a faulty fan. Blows my mind how people can just not do the simplest of things.

[Ghostt]

Not for nothing, but a melted piston is signs it was running way lean.

[DannoXYZ]

Yeah, hole in piston can't be done by running hot due to faulty radiator-fan. Heck, I ran 6-hours last weekend at full-throttle in 105-F temps (135-F track-temp) without a fan at all!!!

Nah, hole in pistons is just symptoms (result) of real problem. If you just put another piston in there without fixing real problem, you'll just end up with another holed piston in short order. Real problem, as pointed out, is having too-lean air-fuel mixtures. Most likely due to clogged and dirty carburetor, so send them to ducatiman when you've got them removed for a full refurb service.

You've been warned, if you come back in 3-months complaining about another piston with hole in it, I'm going to point out this thread and laugh at you!!!

[A.J.]

Originally Posted by JacRyann

Yeah, hole in piston can't be done by running hot due to faulty radiator-fan. Heck, I ran 6-hours last weekend at full-throttle in 105-F temps (135-F track-temp) without a fan at all!!!

Nah, hole in pistons is just symptoms (result) of real problem. If you just put another piston in there without fixing real problem, you'll just end up with another holed piston in short order. Real problem, as pointed out, is having too-lean air-fuel mixtures. Most likely due to clogged and dirty carburetor, so send them to ducatiman when you've got them removed for a full refurb service.

You've been warned, if you come back in 3-months complaining about another piston with hole in it, I'm going to point out this thread and laugh at you!!!

No reason to be a pompous know it all but it's to be expected. Came here for help. This place is full of help and knowledge. Said thank you countless times. My mechanic rebuilt the carbs and cleaned them. I am a novice and trying to communicate to you guys who are all very skilled when it comes to these ENGINES. I am learning. I understand that ducatiman is probably the best when it comes to carb cleaning, I don't doubt that. And for the price he charged it would be stupid of me not to send the carbs to him if I didn't think they were cleaned properly. They were. My bike is being worked on by professionals not just a couple dudes in a garage just trying to fix a bike but professionals who have built hundreds of carbs on all different makes, models, "hidden passageways".
I'll be sure to report back to this thread either way in 3 months. I do agree, it was because the previous owner did not properly take care of the carbs. That has been addressed by a professional. Again, input appreciated even if some of it is laughing at me. I have thick skin I can handle it. I can admit I'm new to motorcycles and at times don't know a bit of what I'm talking about. But when I report back to this thread in 3 months that too will be different. I'll even tag ya buddy for good measure. If I hole another piston I'll let you have your laugh. Hell I'll do you one better I'll post a pic of both pistons after 3 months @JacRyann
Thanks again!

[Triple Jim]

You have lots of friends here, AJ.

[A.J.]

Originally Posted by Triple Jim

You have lots of friends here, AJ.

Jim,
Appreciate that man and I've noticed trust me. I value you all. Everyone here has knowledge that it's going to take me years to come close to obtaining but I'm getting started. Thanks again buddy! As always everyone is always so willing to help. Truly is amazing.

[DannoXYZ]

Originally Posted by A.J.

No reason to be a pompous know it all but it's to be expected. Came here for help. This place is full of help and knowledge. Said thank you countless times. My mechanic rebuilt the carbs and cleaned them. I am a novice and trying to communicate to you guys who are all very skilled when it comes to these ENGINES. I am learning. I understand that ducatiman is probably the best when it comes to carb cleaning, I don't doubt that. And for the price he charged it would be stupid of me not to send the carbs to him if I didn't think they were cleaned properly. They were. My bike is being worked on by professionals not just a couple dudes in a garage just trying to fix a bike but professionals who have built hundreds of carbs on all different makes, models, "hidden passageways".
I'll be sure to report back to this thread either way in 3 months. I do agree, it was because the previous owner did not properly take care of the carbs. That has been addressed by a professional. Again, input appreciated even if some of it is laughing at me. I have thick skin I can handle it. I can admit I'm new to motorcycles and at times don't know a bit of what I'm talking about. But when I report back to this thread in 3 months that too will be different. I'll even tag ya buddy for good measure. If I hole another piston I'll let you have your laugh. Hell I'll do you one better I'll post a pic of both pistons after 3 months @JacRyann
Thanks again!

Just wanted you to take a second look at who you're trusting to do your work. I hope the "professional mechanics" aren't the ones that couldn't even look at your bike for 5-weeks. Heck, anyone can be a professional, but that doesn't mean they're any good or even close to the best. I had Porsche-certified factory-trained SAE-acredited "professionals" working for me that needed to be watched and micro-managed like a hawk or else they'll mess up.

I won't bother to search and list endless numbers of posts from people who've posted about difficulty starting or poor running issues. All of our suggestions has been exactly the same: disassemble the carbs down to last nut and bolt and thoroughly refurbish them. Or send them out to a pro who can really do it.

So hearing your story of trusting "pro mechanics" at a shop, I really wonder if they really did it. Because all those others who swore to us up & down hundreds of times that they "cleaned" their carbs, turned out to have just sprayed some cleaner solvents down the throat.

Sorry if I came across harsh, it's not directed at you, but those mechanics you may be trusting a bit too much. Did they really do this?