blipping throttle from idle, engine "pops"

[roadrun_fr]

Now that I used to go to track sometimes with my Aprilia RSV 1000, I try to quickly accelarate (clutch lever engaged of course) before downshifting to reduce engine braking and control rear wheel.

On the road, I'm training to do it right with my VTR.
But, 20% of the time, when I accelerate the engine does a "pof" sound and does not take revs.
Am I doing something wrong ? (It never happens on my RSV 1000 like I do that ...)
What should I check ?

[Stormin Ben]

Sounds like you're fuelling is not right
Have you got different exhausts, air filter etc on it?

If so and they haven't been set up properly the engine response will be rubbish


Ben

[roadrun_fr]

I may have badly explained ... so i prefer to say it once more :

To reduce engine breaking and avoid blocking rear wheel during high braking and quick downshifting, you do have to :

- brake firmly and doing that :
- dis-engage the clutch
- Open throttle for the engine to take more revs (as it is like on neutral)
- down shift
- re-engage the clutch
and so on until you reach the right gear.

You cannot downshift quickly and avoid rear blocks if you don't do that specially on a big V-twin bike.

My problem is : Sometimes, when I open throttle, the engine does not take revs and instead do a "pop".

My 2001 bike is completly stock : air filter / exhaust / jets / etc ....
No mods on fuel setup ( pilot screws , etc ...) Idle at about 1250/1300.

[roadrun_fr]

I has tested it again and take care of it returning home this evening.
It does it from idle too at neutral "blipping" the throttle.

It doesn't "pop" at low/mid temperature but after riding into traffic/town and at high temp (100°c) it does several time.

Does it tell us something more precise ? Rolling Eyes

[Pete.L]

Hi Roadrun
Belated welcome on board

My problem is : Sometimes, when I open throttle, the engine does not take revs and instead do a "pop".

Ahhh the joys of a carbed bike I'm afraid. You could try pulling off the carb brether pipes (between the carbs) and just let them dangle, It helps on some. Exicited use of the throttle seems to upset the ballance of the fuel flow on these buggers and banging and popping is quite normal I'm afraid
Some nice free flowing pipes and a jet kit helps
Pete.l

[Fireman on a Storm]

Sound's like the carbs need to be balanced

[Stormin Ben]

I did understnad what you meant mate.
If you're setup standard then you WILL be running rich, mainly caused by the standard bung/filter
What you blip the throttle the air can't get through the filter fast enough to match the sudden increase in air reqd

If you fit a brand new filter it will definitely feel better, if you fit an aftermarket one (K&N or Pipercross) AND GET IT SETUP PROPERLY it will feel hugely better

Ben

[roadrun_fr]

I have a honda genuine air filter that have only 1000 kms.
Why does it seems to happen at high temperature ?

[Stormin Ben]

I have a honda genuine air filter that have only 1000 kms.
Why does it seems to happen at high temperature ?

Coz the air is less dense the hotter it gets
Its why your bike feels crisper on a nice fresh spring morning than a hot sunny summer afternoon

I take it that if you open the throttle gently it revs up fine, its just if you snap it open it bogs down?

Ben

[roadrun_fr]

Yep opening throttle slowly it revs fine.
If i snap it fast, it sometimes "pops" near the airbox without reving.

One another thing I've seen, is that, on neutral, snapping the throttle, revs returns to idle pretty slowly.

[sirch345]

Sounds like the normal spit back through the carbs (on the VTR) compliant to me, that some people get (like myself) There's been quite a lot written on this, so perhaps you might like to do a "search" just above. Remember though that the VTR has (like Pete said) huge carburettors where as the RSV is fuel injected, which is a lot more precise

Chris.

PS. That would not explain your last comment though, about the revs returning to tick over very slowly when in neutral at a stand still