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Discussion Starter · #1 ·
Usually, when I go for a ride she runs perfectly and full with power. But sometimes she just randomly begins to stall. The bike begins to misfire and I hear loud pops come from the exhaust, it starts to idle lower, and it stalls every time I pull in the clutch which has been scary when it happened while I was splitting lanes. The bike won't idle without being revved and when it dies it won't start unless you give it a rev. Then sometimes it just goes away and runs perfectly again. Literally perfect, all the problems go away. Pretty stumped on what actions to take, suggestions are greatly appreciated thanks.

Bike is a 2006 SV650N
 

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Sound like one cylinder is cutting out.

Has the bike been in rain lately? A shorted front spark plug is common if the bike has seen rain and if the front cyl plug cavity drain hole is clogged.

If not that, sometimes the connection between the sparkplug cap and high tension wire fails, or the plug cap itself can fail.

A third place to check, but less likely, is the spade connections at the ignition coils.
 
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Discussion Starter · #3 ·
Sound like one cylinder is cutting out.

Has the bike been in rain lately? A shorted front spark plug is common if the bike has seen rain and if the front cyl plug cavity drain hole is clogged.

If not that, sometimes the connection between the sparkplug cap and high tension wire fails, or the plug cap itself can fail.

A third place to check, but less likely, is the spade connections at the ignition coils.
Yes it actually had been in the rain about two weeks ago. Im not sure if I noticed less power as I was too focused on the stalling, when it happens again ill have to see if turns into an sv325.
 

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Discussion Starter · #5 ·
Sound like one cylinder is cutting out.

Has the bike been in rain lately? A shorted front spark plug is common if the bike has seen rain and if the front cyl plug cavity drain hole is clogged.

If not that, sometimes the connection between the sparkplug cap and high tension wire fails, or the plug cap itself can fail.

A third place to check, but less likely, is the spade connections at the ignition coils.
So I’ve been riding it for a couple days now and hadn’t had the problem come up yet but instead the bike just feels weak. It’s almost as If in the beginning of the ride it has power and then starts to become weak. I’m pretty sure both cylinders are running but not sure what’s happening.
 

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Seeing how the problem would suddenly come and go, I was thinking the issue was electrical.

But if now the engine is just down on power, and both cylinders are firing, check for fuel issues as mentioned.

Did the bike sit for a while? Is there any sign of rust in the tank?
 

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I would take a look inside the tank to see if there is any debris or water sitting at the bottom.

It's possible that the rainwater got into the tank and, depending on where the water sits, it gets picked-up and drawn into the fuel lines occasionally.

Have you done any maintenance or replaced any parts recently? Fuel pump is original?
 

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Discussion Starter · #9 ·
Seeing how the problem would suddenly come and go, I was thinking the issue was electrical.

But if now the engine is just down on power, and both cylinders are firing, check for fuel issues as mentioned.

Did the bike sit for a while? Is there any sign of rust in the tank?
The previous owner kept the bike garaged for about 5 years I would say. Im not sure if he kept the tank filled with gas in storage but when I bought it and took it home it had a little gas and ran fine. The tank looks pretty clean on the inside. Im also pretty sure the fuel pump is original.
 

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Discussion Starter · #10 ·
UPDATE:
Took her out for a ride today and something weird happened. At this point, I'm not sure if both cylinders are firing and one of them is weaker than the other or if I'm experiencing the sv325. My mind is going back to the original possibility of water being trapped after leaving it in the rain( As I can't recall any problems before it rained) The bike is definitely running weak. Today I tried to pop a little power wheelie and right when I hit around 5-6k RPMs the bike bogged heavily and my bike turned into a horse. Anytime I would go past around 5-6k RPMs it would start to bog and feel really weak. It felt like it was bucking, the higher I revved it past 5-6k the more intense the bog/buck would feel. Under 5-6k it ran somewhat smooth but weak. I turned off the bike and turned it back on and the problem went away for a while but the bucking came back after 20m or so, this time not as strong. So I turned it back off and turned it on, and had full power, doing a power wheelie was once again super easy until it becomes weak once again and will barely power wheelie. It also doesn't idle consistently. Jumping around from 1k to around 1250k.
 

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The two likely candidates are spark (possibly SV325) or fuel (maybe clogged fuel filter).

A search on "SV325" will yield hundreds of posts with good info on how to fix and also prevent the problem in the future.

For fuel, search "fuel volume test". Basically, you want to see 6oz in 10 seconds. Also, when doing the fuel volume test, look closely for possible water at the bottom of the catch container.

Post again if either of those does not solve it.
 

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Discussion Starter · #13 · (Edited)
UPDATE 2:
You know that noise you hear when you turn the key and hear the fuel pump? Now when you start the bike you still hear the fuel pump and it sounds like it's barely alive whining trying to keep the bike from stalling. Before you couldn't hear the fuel pump. I propped up the gas tank and found these two hoses disconnected. I plugged them back in (as you can see in the pic) then I started the bike to find that nothing changed. I followed the hoses and they both just ended going nowhere. Is that right? I know the previous owner worked on the bike quite a bit but is one of these hoses a vacuum hose? Maybe they were plugged at one point but I have little knowledge on this. Thanks for the help.
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... I followed the hoses and they both just ended going nowhere. Is that right?
Yes. Those hoses are routed/connected properly. One is the gas tank vent hose, the other is the filler neck overflow hose. Good idea to replace the cracked hose but the crack is not causing the running problem.

The fuel volume test is good which means the fuel filter is not clogged. It is possible to have good fuel volume but low fuel pressure but that is uncommon.

I would focus back on electrical, the SV325 sparkplug problem. Cleaning and drying the spark plug area and clearing the drain hole is step one. SV325 can also be caused by a damaged spark plug cap(s) or a bad connection between the plug cap and high tension wire.

Is the bike still cutting in/out the same?
 

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Discussion Starter · #16 ·
Yes. Those hoses are routed/connected properly. One is the gas tank vent hose, the other is the filler neck overflow hose. Good idea to replace the cracked hose but the crack is not causing the running problem.

The fuel volume test is good which means the fuel filter is not clogged. It is possible to have good fuel volume but low fuel pressure but that is uncommon.

I would focus back on electrical, the SV325 sparkplug problem. Cleaning and drying the spark plug area and clearing the drain hole is step one. SV325 can also be caused by a damaged spark plug cap(s) or a bad connection between the plug cap and high tension wire.

Is the bike still cutting in/out the same?
The bike doesn’t cut out anymore, now it runs poorly all the time. The owner did tell me before that the bike sat and built rust but he cleaned the tank out. Perhaps the fuel pump could’ve gone bad? The bike will only start without a rev from a cold start. And once it does start you begin to hear an abnormal whine from the pump which sounds like it’s dying. It idles low and poorly and you can smell gas. Eventually it’ll stall if you don’t give it gas and the throttle now feels delayed. I give it gas and it doesn’t kick in until over a second has passed. Scared the hell out of me. It also appears to run worse when it’s low on gas.
 

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If both cylinders are running poorly (you can check front/rear header temperature with a cheap IR thermometer to compare) then likely the problem is fuel. If the previous owner had to clean the tank then there may still be a rust problem. Probably time to remove the fuel pump assy and take a look.

The fuel volume test is good but if water had been in the tank it is possible for the fuel pressure regulator (not the filter) to fail. Not common but does happen.
 

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Discussion Starter · #18 ·
If both cylinders are running poorly (you can check front/rear header temperature with a cheap IR thermometer to compare) then likely the problem is fuel. If the previous owner had to clean the tank then there may still be a rust problem. Probably time to remove the fuel pump assy and take a look.

The fuel volume test is good but if water had been in the tank it is possible for the fuel pressure regulator (not the filter) to fail. Not common but does happen.
Ok cool, how do I test the fuel pressure regulator? Would I need to replace it or clean it?
 

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The test is done with a fuel pressure gauge. Spec is 43psi.
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Keep in mind a bad fuel pressure regulator is a rare failure. My gut feel is it is not the problem. In the past 12 years on SVRider, I do not recall a single failed regulator post. However, odd noise coming from the pump is a clue (and we know the volume test passed), so it might be worth checking, but maybe do not get your hopes up.

I wish I had more to give you. Intermittent funky running problems are the hardest type to debug over the internet.
 
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Discussion Starter · #20 ·
The test is done with a fuel pressure gauge. Spec is 43psi.
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Keep in mind a bad fuel pressure regulator is a rare failure. My gut feel is it is not the problem. In the past 12 years on SVRider, I do not recall a single failed regulator post. However, odd noise coming from the pump is a clue (and we know the volume test passed), so it might be worth checking, but maybe do not get your hopes up.

I wish I had more to give you. Intermittent funky running problems are the hardest type to debug over the internet.
Could it be possible that the fuel pump is failing? Maybe from when the previous owner cleaned the tank he could’ve let some gunk in that causes damage? Also any knowledge is greatly appreciated.
 
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