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Discussion Starter #1
Recently bought my 11 Vulcan 900 classic low miles at 4000, the guy had it stored overtime with ethanol free gas. As I bought it, a popping noise came at low rpms when giving it gas to go off a stop. Been running premium since. I have been throwing in fuel cleaners, injector cleaners etc. the popping got so bad the airbox cover broke and when it pops it reliefs out of the box. Earlier this week I ordered new injectors. I tore out mine to see what they look like, other than small tint of heat score they looked fine. Threw them back in and my fuel economy went to shart. I was coming to the end of the tank today when I threw In sea foam to ride the freeway to see what would happen. After 10 minutes the Vulcan would only hit 80 mph and I felt a pull back in sync with a certain rpm. So my body was going back and forward back and forward very steady like. Coming off the freeway I felt that in all gears, loss of power in high rpms and a popping noise at low rpms.
Another side note was that it sounds like air whisping unless I gun the throttle

kawi dealer said new injectors.
That being said I’m waiting for those to come in and for now I’m stuck with a tweaked horse

any ideas or knowledge to be spread?
 

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Welcome to the forum from North Carolina. Congratulations on your new ride. I have a 900 also. The injectors very rarely fail on these bikes. I would not replace them. For the Kawasaki dealer just to say injectors tells me you should stay away from that dealer. Do not run premium fuel. The bike is designed for 87 octane and doesn’t run well on premium. I put some in mine when I first got the bike and it ran like just like yours. Went home changed out the fuel to regular, installed iridium spark plugs, and added a full can of Seafoam. The bike runs great again. There have been a lot of favorable posts about the iridium plugs. NGK CPR7EAIX-9 are the iridium plugs for your bike.
Have you shined a light into the fuel tank and checked for any corrosion or rust? Just in case you do not have a factory repair manual, here is a link to download one. Thanks for becoming a member of the forum. Be well and Ride Safely.

 

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Discussion Starter #3
Welcome to the forum from North Carolina. Congratulations on your new ride. I have a 900 also. The injectors very rarely fail on these bikes. I would not replace them. For the Kawasaki dealer just to say injectors tells me you should stay away from that dealer. Do not run premium fuel. The bike is designed for 87 octane and doesn’t run well on premium. I put some in mine when I first got the bike and it ran like just like yours. Went home changed out the fuel to regular, installed iridium spark plugs, and added a full can of Seafoam. The bike runs great again. There have been a lot of favorable posts about the iridium plugs. NGK CPR7EAIX-9 are the iridium plugs for your bike.
Have you shined a light into the fuel tank and checked for any corrosion or rust? Just in case you do not have a factory repair manual, here is a link to download one. Thanks for becoming a member of the forum. Be well and Ride Safely.

Thank you so much for the information
I have been searching and trying all different kinds of stuff to the sweet ride. Glad I came upon this before buying 200 dollar injectors
I will keep you posted on the progress
 

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Tourer’s advice is good: never run high octane fuel, these bikes are not made for it. I’ve been running 91 (we don’t have 86 in Australia) with the very occasional 95, but sticking with 91 from here out.


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'05 800B
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popping or backfiring out the airbox is a sign of a lean air/fuel combustion mixture, maybe too much air
 

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'05 800B
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and with motors, if a motor is under a 10:1 compression rating, only use regular 87 octane
 

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2009 Vulcan 500
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162 Posts
Injectors usually live much better than a carb than has been sitting with fuel with alcohol .
One dose of techron will clean em...don't run the machine hard while the techron is in the tank.
Gap your plugs favoring the wide side of the gap.

Sent from my SM-A115U1 using Tapatalk
 

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After you've tried everything and you are still getting popping from the air cleaner and loss of power at higher rpms, then I agree with btom that your motor is running too lean. Since the bike was stored for some time, the bad gas might have damaged the fuel pump. Since your bike is a US bike, it probably does not have O2 sensors, and therefore runs open loop for the fuel mixture. This means accurate fuel pressure is necessary to maintain a correct air/fuel ratio. The only good test of this, is to get a fuel pressure gauge that you can see while riding, so you can see what the fuel pressure is at any given throttle setting. It will most likely be good at idle, but fall off at higher power settings. The correct fuel pressure is 43-44 PSI. It has to remain at this pressure at all throttle settings, for the fuel injectors to inject the correct amount of gas at any power setting.
 

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Discussion Starter #10
Eez
After you've tried everything and you are still getting popping from the air cleaner and loss of power at higher rpms, then I agree with btom that your motor is running too lean. Since the bike was stored for some time, the bad gas might have damaged the fuel pump. Since your bike is a US bike, it probably does not have O2 sensors, and therefore runs open loop for the fuel mixture. This means accurate fuel pressure is necessary to maintain a correct air/fuel ratio. The only good test of this, is to get a fuel pressure gauge that you can see while riding, so you can see what the fuel pressure is at any given throttle setting. It will most likely be good at idle, but fall off at higher power settings. The correct fuel pressure is 43-44 PSI. It has to remain at this pressure at all throttle settings, for the fuel injectors to inject the correct amount of gas at any power setting.
This morning I just put in new plugs bike runs and has power 0-100% throttle
The tank is still 1:4 ratio premium to 87
So there is a small pop here and there but for now it doesn’t bother me much, I’m sure once I’m on 87 100% the bike will do fine. I’m looking to get a new air box soon here after this one has taken explosive pops and develop a knarly crack
 

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Discussion Starter #11
If anyone can help I still have a small pop issue I have a video of it but I can’t put it on this post maybe someone can see it and help me
 

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2009 Vulcan 500
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Check for vacuum leaks...if you have an air filter that requires oil..be sure its oiled up..tape up that air box the best you can..gap your plugs on the wide side of the specs.

Seems like alot of people are having trouble this year

Sent from my SM-A115U1 using Tapatalk
 

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Discussion Starter #13
Check for vacuum leaks...if you have an air filter that requires oil..be sure its oiled up..tape up that air box the best you can..gap your plugs on the wide side of the specs.

Seems like alot of people are having trouble this year

Sent from my SM-A115U1 using Tapatalk
Will do if you want to see a video I can send it to you
 

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2015 Vulcan 900 Classic, 2015 Vulcan S
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Welcome to the forum from North Carolina. Congratulations on your new ride. I have a 900 also. The injectors very rarely fail on these bikes. I would not replace them. For the Kawasaki dealer just to say injectors tells me you should stay away from that dealer. Do not run premium fuel. The bike is designed for 87 octane and doesn’t run well on premium. I put some in mine when I first got the bike and it ran like just like yours. Went home changed out the fuel to regular, installed iridium spark plugs, and added a full can of Seafoam. The bike runs great again. There have been a lot of favorable posts about the iridium plugs. NGK CPR7EAIX-9 are the iridium plugs for your bike.
Have you shined a light into the fuel tank and checked for any corrosion or rust? Just in case you do not have a factory repair manual, here is a link to download one. Thanks for becoming a member of the forum. Be well and Ride Safely.


A respectful skepticism about octane here. Thanks for the good advice on spark plugs and the link to our service manual!

Please tell me how I’m wrong on octane. My understanding is that a higher octane is simply more stable under higher compression and won’t pre-ignite, while lower octane has a danger of pre-ignition in super high-compression engines and therefore is only safe to use in lower-compression engines. Meaning, you can use premium octane in any gas engine, while 87 octane is a terrible idea for higher compression engines.

Thanks!
 

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No Sacred Cows
2011 V900 Custom
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68 Posts
A respectful skepticism about octane here. Thanks for the good advice on spark plugs and the link to our service manual!

Please tell me how I’m wrong on octane. My understanding is that a higher octane is simply more stable under higher compression and won’t pre-ignite, while lower octane has a danger of pre-ignition in super high-compression engines and therefore is only safe to use in lower-compression engines. Meaning, you can use premium octane in any gas engine, while 87 octane is a terrible idea for higher compression engines.

Thanks!
I'm with you. Been using the highest octane gas I can get since it's been available. When I owned Harleys we always used the best we could find and the same when I owned my Goldwing. Since I bought my V900 10 years ago I've been using the highest premium available (94) because it doesn't contain any ethanol and my bike runs better on premium.
On the technical side you're absolutely right, the higher the octane (or "aromatics" like benzene, toluene and xylene) the lower the combustion temperature. After 10 years, with the bike winter-stored for 6 months every year, I've never had rotted fuel pump, rusted fuel tanks or clogged fuel filter.
 

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No Sacred Cows
2011 V900 Custom
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68 Posts
Please tell me how I’m wrong on octane.
I knew I saw in the manual something about octane rating so here it is. Notice that Kawi says to use a minimum of 87. Below that it says that if engine knocks or pings use a higher octane. Nowhere does it say not to use premium or high octane. As well, the manual says that the compression ratio for the V900 is 9.5:1, which is pretty close to 10:1 and considered a mid to high range compression ratio.

248218
 

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Like caldan and others, I usually fill up with 91 or higher, but park it for the winter with a full tank of 94 because it's ethanol free. I find the bike runs better on the higher and mid octane rated fuels.
And as the Manual states, 87 is the MINIMUM recommended.
 
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