Popping/backfiring when adding throttle is usually a sign that the bike is running rich. First thing I would check for that would be the air filter. Make sure it's not clogged or excessively dirty. What does the bike do when you back the choke off?

Quote from: qcbaker on September 21, 2018, 10:18:53 AM
Popping/backfiring when adding throttle is usually a sign that the bike is running rich. First thing I would check for that would be the air filter. Make sure it's not clogged or excessively dirty. What does the bike do when you back the choke off?

I couldn't take off tank because side bolts were so tight I just couldn't unscrew them.
So I unscrew two bolts that were beneath tank and then I took it off.
Since those two side bolts are ''unscrewable'' I can't reach air filter,but I did tried to blow it with my mouth to clean it that way at least.
I tried to spray WD-40,but it didn't help.
Since I always start with choke I started it this time too.I haven't start it without choke,but since it's night and it's raining,I can check that tomorrow if the weather clears.

Quote from: Petar on September 21, 2018, 10:45:16 AM
Since I always start with choke I started it this time too.I haven't start it without choke,but since it's night and it's raining,I can check that tomorrow if the weather clears.

I don't mean starting without choke, I mean starting it up with the choke on (don't add any throttle), waiting for it to warm up a bit (~2-3 minutes, still don't add any throttle), then backing the choke off. Once the weather clears up, post back and let us know what happens.

Quote from: qcbaker on September 21, 2018, 11:11:52 AM

Quote from: Petar on September 21, 2018, 10:45:16 AM
Since I always start with choke I started it this time too.I haven't start it without choke,but since it's night and it's raining,I can check that tomorrow if the weather clears.

I don't mean starting without choke, I mean starting it up with the choke on (don't add any throttle), waiting for it to warm up a bit (~2-3 minutes, still don't add any throttle), then backing the choke off. Once the weather clears up, post back and let us know what happens.

Oh,now i get it.OK,as soon as weather clears I will get back with info,but it could take some time because forecast is really bad,they even warn us to stay home if possible.

Quote from: Petar on September 21, 2018, 09:14:52 AM
Hello again everybody,

My fuel hose finally arrived today,so I went and connect it to petcock.Then when I started  the bike,at first it didn't want to start at all,it only made that sound of trying to start.Then I after 6-7 times,bike started normally (with choke ON),but when I twisted the throttle,it started to make loud popping sound from exhaust.
Now,every time when I add throttle,it pops.
Do you know what could be causing this problem and is it dangerous to bike?
PS
just for info,I drained out 90% of old fuel and tank up new 95 fuel,and i also charged battery.

Hope to hear from you guys.

Guessing it wouldn't start at first because the new fuel lines were dry.  If you didn't flip the petcock to prime, it would take some cranking to get the initial fuel flowing.  When you drained the gas, did you also drain the carb bowls?  If not, it isn't a disaster, but that fuel is less than fresh.  It may take a bit to run it out.  But it's not so old as to be likely to cause issues.

It's probably backfiring because of running on choke and maybe your plugs are a bit fowled.  You could pull them and either replace them or just clean them up with an old toothbrush if needed.

When the weather clears, fire it up and let it idle on choke for a few minutes, slowly backing off the choke.  Don't try to rev it up until it's idling smoothly with the choke at least halfway off.  If it's still running funny try cleaning or replacing the plugs if you haven't already.

It was running fine not that long ago, right?  It shouldn't take all that much to get it back on the road.  Just a bit of TLC is all. 

Quote from: Kilted1 on September 21, 2018, 05:19:42 PM

Quote from: Petar on September 21, 2018, 09:14:52 AM
Hello again everybody,

My fuel hose finally arrived today,so I went and connect it to petcock.Then when I started  the bike,at first it didn't want to start at all,it only made that sound of trying to start.Then I after 6-7 times,bike started normally (with choke ON),but when I twisted the throttle,it started to make loud popping sound from exhaust.
Now,every time when I add throttle,it pops.
Do you know what could be causing this problem and is it dangerous to bike?
PS
just for info,I drained out 90% of old fuel and tank up new 95 fuel,and i also charged battery.

Hope to hear from you guys.

Guessing it wouldn't start at first because the new fuel lines were dry.  If you didn't flip the petcock to prime, it would take some cranking to get the initial fuel flowing.  When you drained the gas, did you also drain the carb bowls?  If not, it isn't a disaster, but that fuel is less than fresh.  It may take a bit to run it out.  But it's not so old as to be likely to cause issues.

It's probably backfiring because of running on choke and maybe your plugs are a bit fowled.  You could pull them and either replace them or just clean them up with an old toothbrush if needed.

When the weather clears, fire it up and let it idle on choke for a few minutes, slowly backing off the choke.  Don't try to rev it up until it's idling smoothly with the choke at least halfway off.  If it's still running funny try cleaning or replacing the plugs if you haven't already.

It was running fine not that long ago, right?  It shouldn't take all that much to get it back on the road.  Just a bit of TLC is all. 

I did turn petcock to prime for 5-10 seconds.I didn't drain carb bowls.I don't have ratchet to remove sparkplug,but I will buy it if necessary.Yes,it was running fine until I drained fuel and put new.
Just for info,will backfire/popping damage bike or it's not big issue?

Quote from: Petar on September 22, 2018, 04:41:17 AM

I did turn petcock to prime for 5-10 seconds.I didn't drain carb bowls.I don't have ratchet to remove sparkplug,but I will buy it if necessary.Yes,it was running fine until I drained fuel and put new.
Just for info,will backfire/popping damage bike or it's not big issue?

If you still have the factory toolkit (under the seat, near the taillight) there should be a plug wrench in there.  A little popping shouldn't hurt any thing in the short term.  I've seen backfiring burst a muffler like a balloon, rather comical at the time but not an every day occurrence.

One more suggestion for when you're able to get out and tinker with it again.  Drain the stale fuel out of the carb bowls.  Let it run completely dry, close them up and flip to prime to let the bowls refill with the fresh fuel. 

The minor popping shouldn't damage anything, but actual backfiring is not good for the exhaust long term. A couple backfires here and there shouldn't really hurt, but over time stuff like that can burn away or otherwise damage the insulating material in the muffler, which isn't good. I've never heard of a backfire actually destroying a muffler the way Kilted describes, but I guess it isn't outside the realm of possibility...

As for your bike, Petar, if the bike ran with no issues before you replaced the fuel lines, I'm not really sure what would have changed that would cause it to suddenly run rich. It could very well be that your plugs are a bit fouled up from running it on full choke for a while, and that's causing it to not completely burn all the fuel each time the cylinder fires, which sends the unburnt fuel into the exhaust. The unburnt fuel combusts there, causing the popping/backfiring. If you can remove the spark plugs and inspect them, that could help eliminate that possibility.

Quote from: qcbaker on September 24, 2018, 06:22:57 AM
The minor popping shouldn't damage anything, but actual backfiring is not good for the exhaust long term. A couple backfires here and there shouldn't really hurt, but over time stuff like that can burn away or otherwise damage the insulating material in the muffler, which isn't good. I've never heard of a backfire actually destroying a muffler the way Kilted describes, but I guess it isn't outside the realm of possibility...

My bike backfires if I open the throttle too quickly whilst it's still cold (e.g. taking off from a light) - I think you can burn your exhaust valves if you're not careful, which definitely concerns me far more than whatever happens to the muffler!

Hello guys,
I apologize for not reporting status about my bike sooner.The weather was crazy and I caught a cold.
Anyway,I went to check my bike today,but I couldn't start it.
The lights and panel bulbs were on,but bike couldn't start when I pulled clutch and press power button.
It just made that sound of trying to start,but it couldn't..
Now I'm recharging battery,but what worries my most it that the battery is 4 months old,and I recharged it 2 weeks ago.
How can it lose power so fast?

@Kilted1 Oh yeah,I have plug wrench in toolkit.However I read that it may destroy sparkplugs if they are overtighted.Can I just tight them until they don't move anymore?
How can I know if the plugs are bad and they need cleaning?
Once I start to drain fuel from carb bowls,it should only leak fuel that was in carb and not in tank,right?
If you could please tell me,how exactly do I drain carb,should I unscrew that small screw and that's it,or is there something else I should do?


@qcbaker I will try to remove plugs,but I don't know if they are bad,or they need cleaning?Can you tell me what should I look once I remove them?

@Kookas,I will try to fix it


EDIT:I found info on how to drain carb bowls,but when I tried to do it,the screw head from drain screw was damaged and unscrewable.
It was so damaged that I can barely place screwdriver on top of it.
I sprayed it with WD-40,but I think it's unfixable.
Is there any other solution?

Yeah, the plug wrench in the kit isn't great, but it should be sufficient.  Any wrench can destroy things if over-torqued.  The plugs need to be tight enough that they don't work loose but they often get tightened far beyond what's needed.  I'm guessing you don't have a torque wrench but just snug them down and then go a little more, or as someone here put it, a "small grunt" should do it.  With the toolkit wrench, it'll probably get painful on your hands before you do any damage. 

Try an image search for "Spark plug condition" and compare what you find to your actual plugs.  If they look questionable, at least they're inexpensive.

To drain fuel from the carbs, first make sure the petcock is NOT in prime.  Otherwise it will just free-flow fuel from the tank.  There's a small nipple on the bottom of the carb, this is the drain.  I attach a bit of tubing going to a bottle but you can just put a catch can or something on the engine case to collect the drained fuel.  Then there's a horizontal screw pointing at the nipple, that's the drain plug, loosen it a turn or three and the fuel will dribble out.  Whichever side you do first will get a bit more than the second one as you're also draining part of the fuel supply line.  Snug up the valves and you're done.  Don't forget to switch the chicken to prime for a minute to refill the bowls.  If you really want to be thorough you can repeat the process to also replace the fuel in the lines.  That probably isn't necessary unless you have a bunch of water in the fuel.  If you have the drained fuel in a clear container, any water will sink to the bottom and you'll see it like a small bubble.

All batteries lose charge over time.  Charge it up and go from there.  You have bigger demons right now.  Best way to keep up a battery is to ride the bike often!   

Quote from: Kilted1 on October 02, 2018, 09:48:18 AM
Yeah, the plug wrench in the kit isn't great, but it should be sufficient.  Any wrench can destroy things if over-torqued.  The plugs need to be tight enough that they don't work loose but they often get tightened far beyond what's needed.  I'm guessing you don't have a torque wrench but just snug them down and then go a little more, or as someone here put it, a "small grunt" should do it.  With the toolkit wrench, it'll probably get painful on your hands before you do any damage. 

Try an image search for "Spark plug condition" and compare what you find to your actual plugs.  If they look questionable, at least they're inexpensive.

To drain fuel from the carbs, first make sure the petcock is NOT in prime.  Otherwise it will just free-flow fuel from the tank.  There's a small nipple on the bottom of the carb, this is the drain.  I attach a bit of tubing going to a bottle but you can just put a catch can or something on the engine case to collect the drained fuel.  Then there's a horizontal screw pointing at the nipple, that's the drain plug, loosen it a turn or three and the fuel will dribble out.  Whichever side you do first will get a bit more than the second one as you're also draining part of the fuel supply line.  Snug up the valves and you're done.  Don't forget to switch the chicken to prime for a minute to refill the bowls.  If you really want to be thorough you can repeat the process to also replace the fuel in the lines.  That probably isn't necessary unless you have a bunch of water in the fuel.  If you have the drained fuel in a clear container, any water will sink to the bottom and you'll see it like a small bubble.

All batteries lose charge over time.  Charge it up and go from there.  You have bigger demons right now.  Best way to keep up a battery is to ride the bike often!   

Thanks for reply.
I will check spark plugs tomorrow (it's night here in Croatia).
I didn't knew battery can lose power in period of 2 weeks,that's really surprised me.
Thanks for explaining how to drain fuel,I tried few hours ago with online instruction,but that draining screw is damaged,and I can't turn it.
I tried to spray WD-40,but It's so damaged that I think I will need miracle to unscrew it.
Do you perhaps know some solution for this?

You'd have more luck using a dedicated penetrating spray/oil than standard WD-40. Maybe try some locking-pliers (vise grips), or screw extracting pliers (e.g. Engineer PZ-56), to get the drain screw out. Work it back and forth rather than trying to get it all the way out in one go to try to avoid the head shearing off.

If you need the size of some hose to drain the carbs, I use 6mm ID clear PVC.

Quote from: Petar on October 02, 2018, 12:09:54 PM
Thanks for explaining how to drain fuel,I tried few hours ago with online instruction,but that draining screw is damaged,and I can't turn it.
I tried to spray WD-40,but It's so damaged that I think I will need miracle to unscrew it.
Do you perhaps know some solution for this?

There are many threads here and on the Internet about how to work with stuck screws. 
http://gstwins.com/gsboard/index.php?topic=69784.msg838865#msg838865

Heating the screw sometimes helps, but as there's gas in your carb this is definitely NOT a good option.

Otherwise you can try the vise-grip pliers, or cut a deeper notch in it to get your screwdriver to hold.  Getting JIS pattern screwdrivers is a good investment if you intend to have Japanese bikes.
Else my favorite trick is to get a sharp chisel and hit the screw lightly, perpindicular and in the direction you want to turn it.

Make sure you get a replacement screw before though!  Once you get that old one off, you don't want to reuse it.

@max I don't have locking pliers,but I'll ask guys at work if they have one.
Also thanks for hose dimensions,I was going to ask that once I sort this problem with screw.

@Endopotential I'm afraid that I will make even worse thing with cutting notch deeper,but I can try.
JIS screwdrivers is good idea,maybe this woudn't happened if i had those.
I will try to get locking pliers at work,because they are really expensive,maybe somebody at work have them.
As for  replacement screw,what dimensions do I need?
Can I buy it at local hardware store,or do I have to order it from OEM?

Petar, if you are not able to get locking pliers or they do not help, I would look into getting a small screw extractor kit like this one. They have worked well for me in the past. They WILL make the screw essentially unusable afterward, but you can just replace the damaged screw with a new one. I don't personally like the idea of trying to cut or grind notches into screw heads, since there's so much potential to damage something if you slip up. A good screw extractor set solves the problem without those risks.

As for the battery losing charge, if you've been trying to start the bike since you last charged the battery, it could simply be drained. I would say to charge the battery fully, then attempt to start the bike and see what happens. If it still does not start, I would say to check your plugs. Here is a chart showing various conditions:



The insluator material should be white or tan, and the electrodes should be clean and free of any residues. The main things for you to look for would be black residue on the plugs, or if the plugs are wet with fuel. If you post a picture of their condition, we can make some more recommendations as well.

Quote from: qcbaker on October 03, 2018, 08:21:01 AM
Petar, if you are not able to get locking pliers or they do not help, I would look into getting a small screw extractor kit like this one. They have worked well for me in the past. They WILL make the screw essentially unusable afterward, but you can just replace the damaged screw with a new one. I don't personally like the idea of trying to cut or grind notches into screw heads, since there's so much potential to damage something if you slip up. A good screw extractor set solves the problem without those risks.

As for the battery losing charge, if you've been trying to start the bike since you last charged the battery, it could simply be drained. I would say to charge the battery fully, then attempt to start the bike and see what happens. If it still does not start, I would say to check your plugs. Here is a chart showing various conditions:



The insluator material should be white or tan, and the electrodes should be clean and free of any residues. The main things for you to look for would be black residue on the plugs, or if the plugs are wet with fuel. If you post a picture of their condition, we can make some more recommendations as well.

Thanks for help,I manage to unscrew it with a pliers I got from buddy at work,it was pretty easy too.
Anyway,I manage to drain carb bowls,but on the right side was much less gas then on left one.
Then I turn fuel in tank to ON and put petcock to PRIME for minute.
I used that tool from toolkit to remove plugs,and they are black as night.
This picture you posted helped a lot,and was exactly what I was looking for.
From what I can tell it's either Carbon Fouling or Oil Fouling,but I think it's carbon.
Anyway I took few photos with my web cam since my smartphone is in repair shop.
As for battery,I read on many other forums that battery can last for month or more if the bike wasn't ridden
Mine barely lasted for 2 weeks.
Here are the photos of plugs.

Once again thanks for the help

Hard to tell from those pictures but they look like dry carbon plugs to me, not oil. The easy way to tell is to rub the black soot of the plugs between your fingers,if it feels dry the soot is from too rich (petrol). If it feels oily/greasy, the soot is from oil.

QuoteIt just made that sound of trying to start,but it couldn't..

Do you mean the engine turned over or you just heard the sound of the starter powering but engine not turning over? My money is on your battery being bad. My battery is over 4 years old and recently I had to park the bike in a container for a year and the bike started right up afterwards. I did do a deep recharge after that to condition the battery. Losing power in two weeks means either you have a wiring problem (easy to check with a decent multimeter - check current draw on the battery when bike is off and key removed. It should be unmeasurable,i had 0,000 volts current draw with ignition off) or a dud battery. IM sorry to say that there are often problems with "new" batteries, especially in dealers who do not sell many batteries. There should be a date code on the battery. What does it say?

I rubbed soot and it's dry.
What should I do with that problem,so it won't happen again with new plugs?

I heard  the sound of starter powering,and it was identical like in this video:
https://www.youtube.com/watch?v=t7NDJ3VWfTA
I don't have multimeter but I'll ask guys at work if they got one.If not,I'll buy it.
The thing is that same thing happened with last battery,but it held up for 1 month.
Shop where I bought battery is specialized in selling car/bike battery.
I checked date code,but there isn't any on it.
PS
I spoke with one guy I know who own motorcycle,and he told me it could be parasitic load.
If indeed is parasitic load,do you know how to fix it?
He told me he only know that it's one of possibility but he don't know how to fix it.

If the soot is dry, the plugs are definitely carbon fouled. This happens when the fuel in the cylinder is not fully combusted, usually a result of a rich fuel:air mixture. I would say that is most likely because of all the starting attempts with the choke on. When the choke is on, the mixture is richer than normal, to help the bike start when cold. Normally, this is temporary and the mixture returns to normal once the choke is backed off after the bike warms up. Any residue usually gets burned off while the bike is running normally. But, if the bike doesn't start and never gets to warm up, the residue left on the plugs is not burned away and the plugs end up dirty like that.

Like herennow, if it were my bike, I would also suspect the battery as the culprit. A weak battery causing weak or no spark could create this situation. However, if you previously had another battery go bad after a month of being used on this bike, I would say that its also possible that you may have a wiring problem. Perhaps there is a short something that is draining your battery even when the bike is off. This would be that "parasitic load" that guy told you about. Fixing it would require you to inspect the bike's electrical system. First thing I would do is inspect all the wiring and make sure it's all intact. If you don't notice any immediate issues, you'll need to get a multimeter to investigate further.