Took carbs out, then the issues started

[jesse]

Hey all!
I need a bit of help with some issues I've been having. Here's everything you might want to know, minus everything I don't know enough about bikes to tell you. So def feel free to ask questions.

I took the carbs out of my 2010 250r yesterday because of some dirty carb symptoms I've noticed:

1) The bike just won't idle without the choke on or the idle screw in a bit (and even after warming up it doesn't seem like the rpms go up at all)

2) If I don't start the bike after a day, it gives a loud pop on start up

3) Gas mileage is not what I expected. I'm getting about 180 miles to the tank

Here's everything I know about the bike. I bought it with 5k miles on it. It already had a Danmoto GP installed (holy hell it's so annoyingly loud), so I also just installed a baffle from Danmoto. The forks were both leaking so I fixed that, too. Passed inspection. When I took the carbs out, they looked immaculate. I ended up screwing the pilot jets in to set, then unthreaded them about 2.5 turns. Put the bike back together. It started no problem. I drove it about a mile before it died and I realized I never set the petcock to flow gas after putting it back together. So I did that on the side of the road. The bike still wouldn't start and I noticed gas was dripping out of the exhaust where the Danmoto meets the pipe. Then while walking it home I gave it one last effort and tried opening the throttle up while starting it and after a minute of the noises sounding better and better, I got it to go again (thank god... a storm was literally rolling in at this point.) Today I go to start the bike and it won't start again, so I try opening the throttle and it finally gets going.

How do I get this bike to just behave, damn it!?

[Triple Jim]

From your description, something is causing fuel to be dumped into the engine. Leaking float valves are a good place to start looking. Keep an eye on the engine oil level, because fuel may be getting in there.

[ducatiman]

"So def feel free to ask questions."


could you reveal your carb cleaning procedures?

[superkain]

set all your carb config back to baseline.

[jesse]

Ok, I've gotten through 2,000 miles no problem on this bike. Today it just totally crapped out on me 30 miles from home and I had to leave it there.

Here's what happened.

I rode my 2010 ninja 250 about 30 miles. Parked it and hung out at a cafe. Couple hours later I decide to go home, so I start the bike and go into first gear to hit the road. 15 feet into the road the bike starts losing power at 3-4k rpm and then finds life again at idle (in the middle of the road). I back the bike out of the road and start reving it in neutral and the same thing happens. I couldn't get the bike to rev up past 3 or 4k rpm- it would just start bogging and then die. The symptoms got worse and worse and then the bike wouldn't even start up. I unplugged the fuel line from the carb and found the fuel filter mangled up and stuck inside the line instead of inside the plug that the line fits over so I fixed that and hoped that was the issue. It wasn't, but the bike did start up for a solid 6 seconds before dying again. A few people pulled over to help, but nobody could figure it out- the last person thought it might be the spark plug.

Any thoughts?

[jesse]

Originally Posted by ducatiman

could you reveal your carb cleaning procedures?

I open everything up and it looked clean as a whistle. I sprayed a little carb cleaner just to make sure I wasn't missing anything, but it really looked like brand new.

[ducatiman]

In addition to a (deeper) carb revisit, I'd suggest adding a petcock teardown/inspection.

On totally disassembled carbs (using compressed air) check ALL passages are clear, verifying air passing through related circuits. This AFTER your chosen cleaning methods....ultrasonic, soda blast/rinse etc etc.
EVERY passageway must be cleaned and verified clear.

[jesse]

Just tore the petcock off and don't think there's anything noteworthy going on there. Set to prime the gas just flows, and set to on the gas slowly drips. that sound right?

Have the carb off now and will be diving in today

[Triple Jim]

Originally Posted by jesse

Just tore the petcock off and don't think there's anything noteworthy going on there. Set to prime the gas just flows, and set to on the gas slowly drips. that sound right?

It definitely should not drip when set to "on" with the engine off. It should stop the flow of gasoline completely.

When vacuum is applied to the petcock diaphragm, fuel should flow like it does in the "prime" position. Sucking on the vacuum hose with your mouth gives plenty of vacuum to operate a properly working petcock.

[ducatiman]

the vacuum diaphragm oring/sealing surface/spring tension likely at fault. And when rebuilding petcock, I choose to use a softer oring.

[jesse]

Ok, so my petcock is messed up then. Shouldn’t that not be “the” issue though as long as gas is flowing with it set to prime?

I took the carbs completely apart and cleaned everything. I also cleaned the air filter and reoiled it. Bike is still not starting. It sounds like it wants to, but the engine just isn't catching. What the hell is going on with my bike??

[ducatiman]

please post the overall mileage and mileage since the last valve adjustment

suggest trying a start with an open fuel cap (thus eliminating a venting issue)

You've examined/changed spark plugs recently? Ditto air filter?

Carbs have all stock jetting present?

The above include just a couple of guesses before suggesting a more intense carb service is needed.

[jesse]

Originally Posted by ducatiman

please post the overall mileage and mileage since the last valve adjustment

suggest trying a start with an open fuel cap (thus eliminating a venting issue)

You've examined/changed spark plugs recently? Ditto air filter?

Carbs have all stock jetting present?

The above include just a couple of guesses before suggesting a more intense carb service is needed.

Mileage is about 7,200 and I bought the bike at 5,200. No idea about last valve adjustment.

Have already tried with fuel cap open.

I have not examined spark plugs. That is going to be my next area. Air filter is a k&n and I just gave it a thorough cleaning. There was only one jet (per carb) that seemed adjustable and I set that to 2.5 turns out.

Thank you for your help here, by the way!

[ducatiman]

tight valves can easily cause starting difficulties, FWIW. From mileages that you describe, I doubt they've ever been checked. Shim type adjusters, requiring camshaft removal IF they are out of spec.

The adjustment screw you reference is, in fact, the pilot screw. 2 1/2 turns should get you started.

You are quite welcome for some input.

[ducatiman]

During your carb cleaning efforts you removed each pilot screw (and associated spring, washer and oring) and cleaned the hole in each, no?

In reinstalling carbset, you re-inserted them into the rubbers fully? Airbox fully reinstalled?

[DannoXYZ]

compression test, kinda proxy indicator for valve-adjustment

[ducatiman]

OP posted previously:
"Mileage is about 7,200 and I bought the bike at 5,200. No idea about last valve adjustment."

Maintenance schedule shows valve check due at 7500 miles, no? In this case, I'd forego any testing prior.....suggest to directly go for it! Yes, even 300 miles early.
Proof'll be in the puddin' (your specific findings).

[jesse]

Yes to all your carb cleaning and re-installation questions. Took me a while to make sure the hoses were right!
Upon reading this:

"A sure sign that it's time for a valve lash adjustment is if your engine is making a loud clicking or tapping noise when starting up or if you experience a loss in engine power"

I'm now damn sure I need to adjust my valves. Oh boy, valve adjustment sounds like a lot. Any good resources on how to tackle that?
Should I even bother getting spark plugs today?

[jesse]

incase it helps with a diagnosis, here's my bike not working.

https://www.youtube.com/watch?v=ujd9pjxNXd4

[Triple Jim]

I don't hear any attempt to run. Mine sounds the same way if I don't pull the enricher lever all the way rearward and the engine is cold.

[ducatiman]

@jesse any news/updates to report?

[jesse]

Originally Posted by ducatiman

@jesse any news/updates to report?

Actually yes- happy to report success! Last night, on a whim, I took my petcock apart (again), and realized I hadn't taken it fully apart the first time. This time I found about eighteen pounds of gunk in there that was definitely getting mixed into my fuel. Cleaned every little nook and cranny in that sucker as well as dumping all my old fuel from the tank and carb bowls. I put a fresh gallon in and presto, the bike came to life! I had a very smooth 30 mile ride today that involved some highway time. Don't want to jinx myself but... I think I'm good?

[ducatiman]

superb!

[CaliGrrl]

Glad you found and fixed a problem! Glad to hear the bike runs.

[jesse]

I'm encountering a new problem of course. My throttle snaps back pretty quickly, and there is a little bit of play when it's not applied, but for some reason my engine doesn't want to rev down as quickly as it used to. Any thoughts?

[Triple Jim]

That could indicate something like an intake system air leak or valves out of adjustment. If you haven't checked your valves, do that next so you can eliminate it as a possible cause of various problems. If your valves are out of spec, you can end up chasing carb problems forever.