[K.makry]

Hi Guys

I have a 2004 zx with DNA filter and an Acrapovic slip-on.(NO power commander)
Just yesterday i noticed that when on sixth gear and about 120mph(cruising)
,i crack the throttle fully open and the bike is not accelerating as it should be.It feels like there is not enough fuel.I did just that 4-5 times and it was the same.Surely something is wrong!
Unfortunately i did not test it with 5th or 4th gear,but i could say that until the 120-130mph the bike is ok.
I was keeping the throttle full open (from 120)until the 150mph and then i was aborting as the acceleration was not there.
The bike starts perfect every morning,no abnormal noises etc.but when fully serviced (june)we could not locate a fuel filter!Now the bike has 19000miles without a fuel filter change.


Any ideas?

PS I am positive that there is nothing to do with the filter and slip-on combo-(on the bike since June),because a friend of mine believes that the filter is causing this.

 

[Rspec99]

I agree that it doesn't sound like the air filter or the slip-on exhaust. These mods are not significant enough to throw the a/f so far out that it would affect the bike in the ways your described.

My suggestion would be to first check the fuel pressure coming out of the fuel pump. When I examined my fuel pump, I noticed that it doesn't have a filter sock like my R1. I believe there is a filter, but it is housed within the pump itself and may have to be partially disassembled in order to be cleaned. If the fuel pressure is fine, you may have to check the fuel flow at the injectors after that.

 

[sextaafondo]

It´s the fuel filter, for sure.
As Rspec99 said, you´ll have to take the fuel pump out of the tank and clean the fuel filter.

 

[Quick10]

Fuel pump is a common failure causing those symptoms do a search

 

[ducatiryder89]

It´s the fuel filter, for sure.
As Rspec99 said, you´ll have to take the fuel pump out of the tank and clean the fuel filter.

I wouldn't say its the fuel filter for sure. You say its not accelerating like it should? Is it falling flat on its face or is it slowly accelerating and then bang it hits you? As far as the filter goes if it flows more air "which the DNA does" it causes the air/fuel mixture to lean out. Don't worry its not a gotta worry lean. What's your cruising RPM? What's your gearing? I think if its stock gearing you're still to low in the RPM's. I believe you would be around 6-7K. It's not going to accelerate like in lower gears.

 

[K.makry]

I wouldn't say its the fuel filter for sure. You say its not accelerating like it should? Is it falling flat on its face or is it slowly accelerating and then bang it hits you? As far as the filter goes if it flows more air "which the DNA does" it causes the air/fuel mixture to lean out. Don't worry its not a gotta worry lean. What's your cruising RPM? What's your gearing? I think if its stock gearing you're still to low in the RPM's. I believe you would be around 6-7K. It's not going to accelerate like in lower gears.

Well,accelerates slowly it is not stalling,and i did not kept it nailed to check what happens a few seconds after the first symptom.
In your opinion with a stock air filter the bike should be fine?
I am asking this because it is far cheeper than the fuel tank removal and pump ckeck etc.
(This day i refuell the bike from a gas station and i doubt regarding the fuel quality,maybe is the fuel?)

 

[ducatiryder89]

Well,accelerates slowly it is not stalling,and i did not kept it nailed to check what happens a few seconds after the first symptom.
In your opinion with a stock air filter the bike should be fine?
I am asking this because it is far cheeper than the fuel tank removal and pump ckeck etc.
(This day i refuell the bike from a gas station and i doubt regarding the fuel quality,maybe is the fuel?)

It could be bad fuel or like I said it could just be the nature of the bike. In 6th gear unless you are pinned you'd have to be at least past 7K (with stock gearing) for the bike to pull anywhere close to accelerating in lower gears.
I think you'll be fine. Leave the filter in and don't worry to much about it. Unless its stubbling or fall flat on its face I don't think you have anything to worry about.

 

[Rspec99]

It is basically free to inspect your fuel pump. It really is not a hard job on the ZX10R especially with the "stop flow" fuel line connectors.

If the bike has been sitting outside in the rain, or extreme temps (cold) there may be water in the gas. If so, adding Methyl Hydrate usually does the trick. I doubt this is the case for you, but it does sound like a fueling problem of sorts by your description.

On the dyno, the stock air filter appears to flow as well as the aftermarket high flow filters. Some people have suggested that it might have a more pronounced affect when extra air is rammed through it at speed.

 

[K.makry]

It is basically free to inspect your fuel pump. It really is not a hard job on the ZX10R especially with the "stop flow" fuel line connectors.

If the bike has been sitting outside in the rain, or extreme temps (cold) there may be water in the gas. If so, adding Methyl Hydrate usually does the trick. I doubt this is the case for you, but it does sound like a fueling problem of sorts by your description.

On the dyno, the stock air filter appears to flow as well as the aftermarket high flow filters. Some people have suggested that it might have a more pronounced affect when extra air is rammed through it at speed.

That day it was cold,not extreme but cold.
For sure there is a problem,and firsty i will burn the remaining fuel and then i will try again with 100 octane fuel grade.

THANK YOU ALL FOR YOUR HELP I WILL REPORT AGAIN AFTER THE TEST

 

[cjordan310]

did you find out your problem ? because my 10 is doing the same thing

 

[SubDude]

did you find out your problem ? because my 10 is doing the same thing

Fuel pump, dude. It's a common failure on the gen 1. Mine went bad just like that at about 25k miles. Picked up a replacement on ebay and it was back to normal.

 

[K.makry]

did you find out your problem ? because my 10 is doing the same thing

It was a faulty throttle position sensor!
The bike has 2 of them,secondary and primary,-if i remember right-,check them!

ps Yes the fuel pump is the common problem but not always.