Issue with torque and power of my 2012 V-strom 650

[baMbyk]

Hello,

I think I have some issue with my 2012 V-Strom 650.

When I am at the rpm 3000 and twist the throttle the bike has torque to 5000 and a little above.
If I am at 6000 rpm and twist the throttle its like I am hitting the brake I.e. its like closing the throttle.
Took the bike to a mechanic to examine the sensors but there isn't any errors in the computer. He tested the sparks and the cables and said that they are OK.
Then I suspected that the fuel is not flowing normally and changed the fuel filter inside the tank. The old filter was full of dirt and the tank contains some rust inside. The issue is still there with the new filter.

Is there a problem with my bike or all other v-stroms are doing that?

I own Suzuki DRZ400 and the torque line does not have such issues. Also had a sport bike and no such issues either.

[wurzel]

I remember this being an issue on a member bike here some while back, I'm sure someone will be along here to point you in the right direction.
It will be to do with the filter and pump fouling, these motors are quite lively when running right, up to the high revs.

[baMbyk]

I will be glad If someone remember that other member.

Forgot to mention - I own the bike from 2 months and the issue is from the time of purchase. The bike has 40k km on dashboard.

[wurzel]

You will get put onto the solution here, and I am sure once it is running rigjt you are in for a pleasant surprise.

[Gert]

Too many variables to exactly pin-point the problem. Start with a fuel flow test, https://www.vstrom.info/Smf/index.php/topic,3981.0.html. From what you have described of rust in the tank, it is very likely that the high pressure filter is also blocked. Your mechanic simply cleaned the low pressure filter, but the high pressure filter is built into the pump and can't be cleaned. Due to the high cost of a fuel pump as a unit, many opt for the mod https://www.vstrom.info/Smf/index.php/topic,6105.0.html. But let's not get ahead of ourselves, do the fuel flow test 1st. Thereafter you can progress to step 2. PS some have had success to clear the high pressure filter by reversing the polarity of the fuel pump for a few seconds, google youtube for more info on this. 

[baMbyk]

Hello,

Here is my mesh filter which I replaced. Looks very dirty:
https://imgur.com/a/B1Pqs5V

And as I see in the diagram there isn't any high pressure filter. So it is located in the pump as you say:
https://imgur.com/a/iy5yrVt

Run through the forum thread for the pump test but they say to measure 1200ml for 30 seconds and my service manual says:
Fuel pump discharge amount - 167ml or more for 10 seconds, at 300 kPa (43 psi).

Is my pump's rate few times lower than the previous generation of v-stroms?

[Gassoon]

And another link to thread on here which describes your symptoms. Culprit in that case was the high pressure filter in the pump

https://www.v-strom.co.uk/smf/index.php?topic=28671.0

1200ml in 30 seconds seems to be right, apparently the handbooks have some errors

[wurzel]

that's the one I was trying to remember Gassoon,  hopefully  all the links provided will get the issue sorted out.

[sjrainsford]

And just to add, yes it doesn’t sound right. It should wake up at 6000rpm and go really well up until around 8k. There’s not much point taking them over that. You can make very good progress keeping them above 6k and changing at 8ish.

If it is otherwise running well then it does look like fuel starvation.

[baMbyk]

Thank you!
I've read all available threads and it is the case with my bike.
Could not find any filter mods for V-strom 2012 and up. But maybe I will examine the pump again and try to drill the proper hole. Fuel tank contains some rust and there is no point of buying new pump and then replacing it after some time when clogged again.

[Dave L]

Hi baMbyk,

The other members may be referring to a post I made a while back. My DL650 (2015 - bought new) seems reluctant to want to rev over 6000 rpm. It will rev quite freely up to 6000 rpm but after that it almost seems as if the bike is struggling, like it is not getting sufficient air. My Suzuki dealer has told me that they can find nothing wrong with the bike and I have just lived with this. I previously had an SV 650 (2006) and that bike revved up to past 7000 rpm quite easily. It's almost as if my DL has a heavier fly wheel or something. My bike now has 21000 miles on the clock.   

[baMbyk]

Hello,

Yesterday I disassembled the fuel pump again to try to fix the flow issue.
Observed the top part of the pump for about an hour but could not find a solution for drilling bypass.
For a time I thought about drilling wider hole where the fuel is entering and then removing the filter. But my brother advised me to clean the shit.

I soaked it in vinegar for some time and after that put а hose from the water sink in the hole where the regulator is mounted, then covered the outgoing hole where the fuel is filtered and let the filter clean from the water pressure. The flow is increased more than double. I hope that it will last for at least 10k km before clogging again.

Diagram of the holes:
https://imgur.com/a/eOWIACP

Fuel flow before cleaning (below 500ml):
https://imgur.com/a/PuuRTjG

Fuel flow after cleaning (about 1200ml):
https://imgur.com/a/CMXpGT9

The bike now feels almost like a sport bike. It pulls hard to 9000 rpm.
Never thought this bike can go that fast, I am very happy!

[Gassoon]

that's great news!   hope you got rid of some more rubbish in the tank, too?!

[baMbyk]

I'll wait until next time the filter is clogged and will clean the rust as well.
For now I'll try to keep the tank full most of the time.

Will update this thread when that happens again

[wurzel]

  Fantastic news!
And Sounds like you have discovered a quick fix, win win!