After a great day of riding, bike won't run. Help troubleshooting?

[JabezStone]

Hi, everyone!

Last week I rode my bike (2005 Ninja 250R, 4500 miles) for about 5 hours... great time! I brought it home hot, parked in the garage, and 3 days later went to start it up, and all it will do is crank... doesn't even try to start. I'll share the quick back-story, then share what I've done so far.

BACKSTORY
Bike had sat in garage for about 3 years. I pulled, stripped, and cleaned the carbs, flushed and cleaned the fuel tank, put it all back together, and it had been running great for a few weeks... until this episode.

WHAT'S HAPPENING
When I tried starting the bike after sitting a few days after a successful ride, it would crank fine, but does not attempt to start... no combustion. Tried choking it, thinking maybe it was too cold. Still wouldn't start. Tried with a little throttle, still wouldn't start. Confirmed fuel is coming from bleeds under both bowls. My first thought was "carbs must be gummed up again". Then I went through the following...

WHAT I'VE DONE SO FAR

• Ensured fully charged battery throughout work and testing.
• Removed and cleaned the carbs again, reinstalled, no luck.
• Inspected the air filter. It was deteriorating, so I removed it, cleaned the air box out, replaced with new filter from dealer. Checked all the airways (all clear). Tried starting again. Still no luck.
• Checked all the fuel and vent lines. All clear. Carbs are fully getting fuel.
• Removed spark plugs, tested for spark against engine, and both had good spark. Cleaned, checked gaps (.7) and replaced. Still no luck.
• Pulled the carburetor again, and this time installed a factory rebuild kit with new needles, jets, pins, gaskets, washers, o-rings. Reassembled, tested again. Bowls filled with fuel, still no combustion.

So, I'm really at a loss guys. I've tested everything I can think of... air, fuel, spark. I'm really perplexed because it was running great before I set it up for a few days.

Any thoughts on what I might try next? Thank you!

[jkv45]

Hmmm...you have covered a lot of the possible issues.

After a starting attempt, have you looked at the plugs to see if they are wet or dry?

Are you charging between attempts?

How old is the fuel? Any chance you picked up a significant amount of water or condensation?

I might try some new fuel, bypassing the tank, after draining the old fuel from the floatbowls.

[DannoXYZ]

Pour about 2-3cc petrol down into airbox
wait 30s
Does it start now?

[JabezStone]

Originally Posted by jkv45

Hmmm...you have covered a lot of the possible issues.

After a starting attempt, have you looked at the plugs to see if they are wet or dry?

Still dry.

Are you charging between attempts?

Fully charged.

How old is the fuel? Any chance you picked up a significant amount of water or condensation?

A week old… no condensation at all.

I might try some new fuel, bypassing the tank, after draining the old fuel from the floatbowls.

I’m pretty confident the fuel isn’t the issue on this one since the tank was cleaned, lines are clear, and fuel is fresh.
Thank you so much for the feedback!

[JabezStone]

Originally Posted by DannoXYZ

Pour about 2-3cc down into airbox
wait 30s
Does it start now?

I just tried this, and no change.

[ducatiman]

"2005 Ninja 250R, 4500 miles"

have valve clearances ever been checked? No mention in your prior posts.

[JabezStone]

Originally Posted by ducatiman

"2005 Ninja 250R, 4500 miles"

have valve clearances ever been checked? No mention in your prior posts.

No, I haven’t done this… I don’t have experience with that, but I’ll do some research on how. I’m pretty much game for getting my hands dirty with anything.

[DannoXYZ]

Originally Posted by JabezStone

I just tried this, and no change.

Then forget looking at carbs, you don't have fuel-flow problem as even directly putting fuel into engine doesn't make it run.

So next ... ignition, compression (related is valve-timing). Do compression-test before and after valve-clearance check & adjustment.

[jkv45]

It's odd that it just ran fine not long ago.

Checking the valves is a good idea, though unusual, it's possible a rocker popped off or there's something unusual going on under the cover...

If all that checks out, a couple last-ditch effort things to try would be Starting Fluid (Gordon doesn't like it because it's bad for any plastic in the carb. Maybe lift the slides and open the throttle plates before giving it a shot). If it sputters at all, it tells you there is a fuel/carb related issue.

The other thing would be trying to bump-start it.

Oil level is good? No chance of fuel draining into the crankcase?

[JabezStone]

Originally Posted by DannoXYZ

Then forget looking at carbs, you don't have fuel-flow problem as even directly putting fuel into engine doesn't make it run.

So next ... ignition, compression (related is valve-timing). Do compression-test before and after valve-clearance check & adjustment.

Okay, so I gave it another try and this time opened the throttle… I got combustion! It didn’t fully start and it’s not running, but this is a good sign of life!

So, now I’m thinking I’d better break my carbs down again and do a more thorough job, cleaning out the hidden channels. I skipped those this last time.

[JabezStone]

It’s running!!!!
I can’t even tell you how thrilled I am right now… I don’t want to shut it off! 😂🤣
I really didn’t do anything different, but Danno and JKV’s thoughts about getting fuel through the air box made me just try it again and after a few cycles it just fired up.
I do think now that I’m dealing with a carb issue, so I think pulling it back off and thoroughly cleaning and adjusting it is the next move.

Thank you everyone! I’ll reply back when that’s done and hopefully I’ll just have good news to share.

[JabezStone]

Here it is!

[DannoXYZ]

It's not uncommon for used bikes to work briefly then die. This is caused by crap in tank taking their time to work their way towards exit and clog petcock and filter.

So in addition to carbs, pull petcock and rebuild it with K&L kit.

Also fish out internal filter from fuel-hose between petcock and carbs. Toss it and replace with external filter that you can inspect easily to determine amount of debris collected and replace as needed.

[JabezStone]

Thanks, Danno. I placed an order for filters and spring clamps through Amazon the other day and they should arrive today. Looking forward to getting the inline filters in place, and they’re very cheap in bulk these days.

I’m not having luck locating a petcock rebuild kit yet, but will keep searching. Thanks again!

[jkv45]

Originally Posted by DannoXYZ

It's not uncommon for used bikes to work briefly then die. This is caused by crap in tank taking their time to work their way towards exit and clog petcock and filter.

So in addition to carbs, pull petcock and rebuild it with K&L kit.

Also fish out internal filter from fuel-hose between petcock and carbs. Toss it and replace with external filter that you can inspect easily to determine amount of debris collected and replace as needed.

Make sure you check this.

[JabezStone]

So, I think I may have an issue… would love your thoughts.

While riding around the city today, I thought I noticed a noise coming up through the area in front of my gas tank (top of the engine).

After coming home and installing my new in-line filter, I took it for a spin and very clearly heard the noise again.

What’s happening is, between about 2500 and 3000 RPMs, I hear a vibration (probably more of a rattle) coming from that area. I was able to replicate it multiple times by going slow in first and second gears at those RPMs.

I’m not sure if it’s normal, or cause for concern. Any thoughts?

[JabezStone]

FALSE ALARM!

So, after some forum searching I suspected the issue was a CCT rattle, and just pulled, cleaned, and reinstalled it... and noise is gone! It sounds amazing now.

Good info on the ninja250 wiki, along with a nice (but oooooold) walkthrough video here: https://www.youtube.com/watch?v=E4eH0d2E73g

[thedrewski86]

Originally Posted by JabezStone

FALSE ALARM!

So, after some forum searching I suspected the issue was a CCT rattle, and just pulled, cleaned, and reinstalled it... and noise is gone! It sounds amazing now.

Good info on the ninja250 wiki, along with a nice (but oooooold) walkthrough video here: https://www.youtube.com/watch?v=E4eH0d2E73g

That video is great I had a similar cam chain noise the other week (after the bike sat for a while) and started to go down this path myself. Thought for a few minutes before busting the tools out and fired it up again: oil warmed up and the CCT clicked out a little more. Noise gone. Oh well, I think I'll clean the CCT later! I was outta Mtn Dew like Travis had in the video, so I wasn't prepared anyway.

[JabezStone]

Hahaha! Mountain Dew would have certainly added to my experience. 😂

[JabezStone]

Originally Posted by DannoXYZ

It's not uncommon for used bikes to work briefly then die. This is caused by crap in tank taking their time to work their way towards exit and clog petcock and filter.

So in addition to carbs, pull petcock and rebuild it with K&L kit.

Also fish out internal filter from fuel-hose between petcock and carbs. Toss it and replace with external filter that you can inspect easily to determine amount of debris collected and replace as needed.

Got it… Thanks so much!