Fixing a motorcycle that wont start after sitting a long time | Page 3 | GTAMotorcycle.com

Fixing a motorcycle that wont start after sitting a long time

sometimes it is easier to replace the pilot jets rather than trying to clean them.

they cost about five or ten bucks each - you will need two for your twin.

winners circle or a dealr should get them for you - having them b4 taking the carbs off is a good practice.

take your time and only do one carb at a time. remember brass is soft and often found in carbs. careful with, don't over tighten or strip stuff.

two heads are better than one; an exp helper would be best and recommended ! A novice mechanic can quite easily wreck a carb in short order.

best luck!
 
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Contrary to some of the above opinions, clean the carbs yourself.

Watch a few YouTube videos and give it a try.

Buy a siphon and drain the gas. Throw it in your car. It'll be diluted and will burn fine.

Remove the empty tank.

Remove the airbox.

Remove throttle cables.

Undo the throttle body clamps.

Drain screw in the bottom of the carb float bowl.

Flip the carbs over.

Remove the float bowl screws.

Flat head screwdriver to remove the jet from the emulsion tube.

8mm socket to remove the emulsion tube.

Soak jets and tubes in carb cleaner.

Blow parts clean with compressed air, or use an old toothbrush and carb cleaner to clean out the bowls.

Make sure there is no tears in float bowl gaskets.

Reassemble.

Fresh gas in the tank.

Put it on prime to fill the carbs.




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And have a good set of screwdrivers with sharp strong tips to remove those small brass emulsion tubes ie: Suzuki in-line fours).
 
It’s not the same thing but I can say I’ve never had cold start issues until I got my yz250. This thing is a ***** in anything below 10c

I suspect it may be related to the limited choke adjustment, where my street bikes have fully adjustable choke the yz has 2 positions. Pretty much on and off

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Carb'd 2 strokes can be even more finicky. You should be rejeting for temp and/or elevation changes.

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Hey folks,

So I got the carbs out, I purchased a carb re-build set and took them to a guy who cleaned the carbs and re-installed the new set and we put it back in the bike.

We got the bike to run, it was running great. I rode it in the underground, did a few laps. I shut it off and left it for 2-3 nights.

I tried to get it going again, now, same problem, it would start and idle at low rpm's, anywhere between 5 seconds to even 20 seconds. but then it turns off. And if I apply any throttle, it immediately dies.

I am trying to diagnose this new problem. Can I rule out the battery? under the assumption that if it were the battery, it couldn't start and stay on for 15-30 seconds, or is the battery possibly a problem.

Otherwise, I am thinking of possibly needing to change the petcock and fuel lines.
 
Hey folks,

So I got the carbs out, I purchased a carb re-build set and took them to a guy who cleaned the carbs and re-installed the new set and we put it back in the bike.

We got the bike to run, it was running great. I rode it in the underground, did a few laps. I shut it off and left it for 2-3 nights.

I tried to get it going again, now, same problem, it would start and idle at low rpm's, anywhere between 5 seconds to even 20 seconds. but then it turns off. And if I apply any throttle, it immediately dies.

I am trying to diagnose this new problem. Can I rule out the battery? under the assumption that if it were the battery, it couldn't start and stay on for 15-30 seconds, or is the battery possibly a problem.

Otherwise, I am thinking of possibly needing to change the petcock and fuel lines.

What is the resting battery voltage?


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Is the choke on all the way?
So I am on the motorcycle right now. Its actually running with the chocke all the way on.

It wont die, it keeps running, been 5 minutes now. If I try to put it in gear and ride off, the rpms will keep coming down until it dies.

I can rev it to about 4 k rpm, then it comes down to 1.5.

But if I rev it to 7k, it will start to come down and show hesitance like its about to die.

If I try to turn the choke off, it starts to sound like it will die. I am going to see if it just needs to run like this for a while to get fuel back in the carbs.
 
What is the resting battery voltage?


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I am not sure. Its running now. The battery was on a trickle charger when i was doing all the work with the carbs, but not sure about voltage.
 
I am not sure. Its running now. The battery was on a trickle charger when i was doing all the work with the carbs, but not sure about voltage.

One of the most important tools you should own is a multimeter. It doesn’t need to be expensive…you can probably find one on sale at Cdn tire for $20-$30. All troubleshooting starts with a fully charged battery.

Resting voltage is one measure of the battery’s health and should be one of the first things checked when having an issue starting the motorcycle.

Also, good to check the battery voltage at idle and at specific rpms to verify the charging system is working properly.

Please don’t just go by the battery tender green light. I have a battery needing replacement right now that will show fully charged (green light) on the tender and the next morning it has a resting voltage of 12.29 .


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I just rode it around the garage for 10 minutes in circles. I was able to shut the choke all the way off. Running well now.

I am confused, it took so long to get it going.

My first road bike was a Kawi 250. It was a bit temperamental on colder damp days or if it sat for a while. I would have to start it on choke, warm it up and then ride the first minute on half choke just to wake it up.


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I just rode it around the garage for 10 minutes in circles. I was able to shut the choke all the way off. Running well now.

I am confused, it took so long to get it going.

That sounds pretty similar to my old Ninja 500. On cold days it could take 5+ minutes to warm up on full choke. And by "cold", I mean anything below 15 degrees.
 
Something doesn't sound right if it was only parked for a few days after running great. How hard was it to start after reinstalling the carbs? Did you start it, or was it someone else, and did you watch their technique with the choke? If it has a lever, it's not just on or off - use it like a throttle, and slowly close it to maintain the lowest RPM it will cleanly run at until it's closed all the way.
 
On my Ex500 I had to adjust my idle speed (look at YouTube) to get the bike to run reliably from a cold start (is it possible you need to reset this after your carb rebuild?). My bike also loved seafoam…lots of seafoam….to clean out everything.
 
Also…I consider having a temperamental carbureted bike a kind of rite of passage of being a motorcyclist. Everyone should have one at least once with the added bonus that you become even more fluent in using swear words in everyday sentences.
 
Also…I consider having a temperamental carbureted bike a kind of rite of passage of being a motorcyclist. Everyone should have one at least once with the added bonus that you become even more fluent in using swear words in everyday sentences.
You will never truly appreciate fuel Injection without going through this 🙌
 
I just rode it around the garage for 10 minutes in circles. I was able to shut the choke all the way off. Running well now.

I am confused, it took so long to get it going.
My wife had a ninja 500 when we met that would never start for crap or run well cold. The choke bracket was bent and not fully opening the enricher took me about 5 minutes to straighten it and it started easy from then on.

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So I am on the motorcycle right now. Its actually running with the chocke all the way on.

It wont die, it keeps running, been 5 minutes now. If I try to put it in gear and ride off, the rpms will keep coming down until it dies.

I can rev it to about 4 k rpm, then it comes down to 1.5.

But if I rev it to 7k, it will start to come down and show hesitance like its about to die.

If I try to turn the choke off, it starts to sound like it will die. I am going to see if it just needs to run like this for a while to get fuel back in the carbs.

Any idea how old the fuel was? IE, when did the previous owner regularly ride it last?

Honestly, this sounds a lot like old crappy gas, or old ethanol gas that has phase separated and now has some water in it.

Drain out all the old gas and get some fresh stuff in there.
 
Also…I consider having a temperamental carbureted bike a kind of rite of passage of being a motorcyclist. Everyone should have one at least once with the added bonus that you become even more fluent in using swear words in everyday sentences.
The most temperamental bike to start that I owned was an injected bmw. When it was below zero, I carried a torch under the seat and I would pull and heat the plugs before cranking. Had the injectors cleaned and flow tested with no improvement.
 

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