Loss of power

[lonebiker]

Hi all I hope someone can help. I have an 03 rsv midnight. I installed 2 pod air filters and now I have a power problem. Seems that if I am riding into a head or side wind and at around 120k in 5th gear all if a sudden i lose speed and have not throttle no matter how I twist on it if I shift down I can pick up speed again untill I shift up again. Now if I am going with the wind or no wind lol I can hit 160 170 all day long with out a pickup. I also notice exhaust popping and if i crank the throttle in neutral it backfires on right side or no. 3 4 cylinders

[Marcarl]

Don't fool with the air filters, put the OEM back on.

[BlueSky]

PODs don't work well on CV carbs. Go back to the stock air filter.

[Freebird]

I agree. Though the pods can work ok, it requires much more work that just changing the air filters. You will have to experiment with the jetting in the carbs to ever get it to run ok.

[Patch]

Hi all I hope someone can help. I have an 03 rsv midnight. I installed 2 pod air filters and now I have a power problem. Seems that if I am riding into a head or side wind and at around 120k in 5th gear all if a sudden i lose speed and have not throttle no matter how I twist on it if I shift down I can pick up speed again untill I shift up again. Now if I am going with the wind or no wind lol I can hit 160 170 all day long with out a pickup. I also notice exhaust popping and if i crank the throttle in neutral it backfires on right side or no. 3 4 cylinders

 

Your friend that told you that pods = more air = more power = don't know what he's talking about!

More air at velocity = more power!

If the wind is moven faster than the air flow thru the carbs then choose to ride in winds heading in your direction; kind of like learning to sail your bike;)

 

On a more serious note tho your description of the effects is very telling. Pods on a direct slide carb work but degrade low end torque, with some gains at near WOT. On a CV Carb there is no benefit unless mods have only left that as the only option.

Patch

[bongobobny]

What everybody above says!!! Unless you want to spend endless hours re jetting and tweaking your carbs, non stock filters are a bad thing. Along with the tweaking, you will also need to re-synchronize your carbs every time you do any changes. The fact that you stated popping on deceleration suggests at very least your synchronization is off, but you may also have an issue with your air injection system on the exhaust...

[Patch]

Really the problem is that the air flow is slowed and unorganized. If we disturb the the flow above the slide's the design efficiency is lost. Perhaps if we think of it as a crowd of people moving through a gate all at the same time verses in an organized fashion resulting in a faster passage thru.

 

Lets look for a moment at the design of the slide, it is round, it changes length and its tip when close is a port. Bernoulli & Venturi's rules not only apply here but are critical; they are in fact what drives the function of these carbs, in other words there is no bypass or override that will reset the balance of flow/velocity (these two combined are working partners). 2 examples that may shed some light, a fire fanned is the same as adding velocity to air, a variable intake verses the old styles single short port runs is similar in comparison.

 

Zag some time back described in few words that he had to use washers between the pods and carbs, that is above the slides. As in the other post last week, the hard part to envision is why we need to carry the low pressure above the slides. The washer Zag mentioned does just that but, it will not settle or reorganize the air flow so in this case yes it will patch the rapid loss to atmosphere of vacuum, will actuate the slide or reduce stall but, the turbulence directly over the slide is a mess so efficiency is lost and atomisation at the main is severely effected!

 

Changing jets will not correct the problem of lost velocity.

 

There is more to consider as well; fatter jets cause compression issues over time and will lead to ring ware. Fatter jets only produce more energy if air flows and velocity are also increased (you have to keep heat expansion up), a pod alone will not do that.

Which slides are installed in the carbs, and why? If you are running a touring bike then smooth acceleration or deacceleration are design features; this means the return springs and the slide cal port (the spring loaded hole in the port) are not designed for hard acceleration rather for smooth power! On the other hand running these touring machines a touch leaner makes for less maintenance than a rod that is built around snap acceleration. Velocity stacks are a fixed quantum/scale (the purest may object to the use of quantum) so then there is more to be found from the effects of the air chamber above the stacks and that is where the remaining balance is to be found. Just as a side note, these air chambers also produce harmonics, a totally different side effect but an added feature.

 

Anyways...

Patch