HondaCB650

I need to get an air filter, but I’ve noticed some people got filters that attached directly to the carbs and got rid of the air box. Just wondering what you guys think is the best route.


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Is the original airbox broken? If not dont use pods if you dont want to rejet the carburetors.
I believe the PD carbs are worst to use pod filters on but the CV types can be more forgiving.
I think someone on this forum said that the carbs on the CB 650 and most of carb using motorbikes usually work best with the original airbox. That is carbs work best if they got air without turbulence and that is what an airbox can provide, and with the original airbox you got the best possible MPG.
But if the MPG dont bother you so much the CV carbs is the best to use pods on i think.
I hope this info helps?

MEHall wrote:Is the original airbox broken? If not dont use pods if you dont want to rejet the carburetors.
I believe the PD carbs are worst to use pod filters on but the CV types can be more forgiving.
I think someone on this forum said that the carbs on the CB 650 and most of carb using motorbikes usually work best with the original airbox. That is carbs work best if they got air without turbulence and that is what an airbox can provide, and with the original airbox you got the best possible MPG.
But if the MPG dont bother you so much the CV carbs is the best to use pods on i think.
I hope this info helps?

Thank you! Very helpful!
Thank you!
I’ve been able to find a filter for the original air box


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MEHall wrote:I believe the PD carbs are worst to use pod filters on but the CV types can be more forgiving.

It's the other way around.

Folsoml wrote:

MEHall wrote:I believe the PD carbs are worst to use pod filters on but the CV types can be more forgiving.

It's the other way around.

Ok, i just thought it was as i wrote, i bend for the expertise.
Correction: The PD carbs will work better with pods and CV carbs wont work as easily with pod filters, period.

So There you got it, PD carbs, yes to pods, CV carbs, dont use pods if there is a better alternative such as the original airbox.

The PD carbs have slides that are mechanically operated. When you twist the throttle, the throttle cable raises the slides. The CV carbs have slides that are controlled by vacuum pressure. You twist the throttle and it opens the butterflies. Pressure differentials will then raise the slides. The PD carbs more readily accept pods because once to adjust the jetting, you will always get a consistent air to fuel mixture. The CV carbs will not so readily accept them. The CV carbs need a consistent supply of still air. The airbox provides this. When you remove the airbox and install pods, air turbulence will prevent the vacuum operated slide from taking in the correct amount of air. This turbulence can also effect the amount of air one carb is receiving compared to the carb next to it.

I was able to get a filter for the original air box, so going with that!


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Well if it is so as you say, and i concur, what to do with CV carbs if you face the situation where no used airboxes is to obtain and the one you had on the bike is broken beyond repair?

MEHall wrote:Well if it is so as you say, and i concur, what to do with CV carbs if you face the situation where no used airboxes is to obtain and the one you had on the bike is broken beyond repair?

Then I guess that you would have no other choice than to try an alternative air filter system, but OEM would always be the better option. CB650 says that he has had no problems running pods on CV carbs so maybe he would be the guy to ask.

MEHall wrote:Well if it is so as you say, and i concur, what to do with CV carbs if you face the situation where no used airboxes is to obtain and the one you had on the bike is broken beyond repair?

I guess you would do the same as you would with any other part that you can no longer obtain.

Folsoml wrote:I guess you would do the same as you would with any other part that you can no longer obtain.

And what should that be? Maybe it's I'm Swedish that i dont know exactly what you mean.
Either day my CB650 will be so old but still drivable, that most plastic details may have disintegrated. Or something else may happen to the airbox. Then it would always good to know what the best solution is to that problem.
Is the volume of the airbox important besides the most important of still air? And is the flow of air through it also important? It's always good to know that in case of airbox breakage.

MEHall wrote:

Folsoml wrote:I guess you would do the same as you would with any other part that you can no longer obtain.

And what should that be? Maybe it's I'm Swedish that i dont know exactly what you mean.
Either day my CB650 will be so old but still drivable, that most plastic details may have disintegrated. Or something else may happen to the airbox. Then it would always good to know what the best solution is to that problem.
Is the volume of the airbox important besides the most important of still air? And is the flow of air through it also important? It's always good to know that in case of airbox breakage.

It really depends on how old YOU are, not your bike I know damn well that I'm gonna break before any of my bikes do

So you say! Well i'm 17 years older than my Motorbike and it's a year 1980 model.
My bike have the pd slide type of carbs so i can use pods if i like.
But as i understand it will decrease the MPG and that is no good to me as my economy is pretty small.
And the price in $ for gas/petrol here in sweden is $ 1.88 for regular and around 66 % is tax so i want my bike to run on the highest MPG as possible. Premium is $ 1.94 same tax level as regular.
I have heard somewhere that US citizen complains about high fuel prices, that is like a joke to us here in sweden as USA have one of the lowest fuel prices in the world.

That was a bit off topic but my reason to know if there is possible to perhaps build a airbox? So what is the properties an airbox for a 650 engine needs?

If I absolutely had to make one, if there were no replacements available, I would either use marine grade plywood or 5mm plasticard sheets. Not sure how the latter would hold up to the heat but I'd give it a go and see what happened, I'd probably copy the layout of the original as much as possible at first just to iron out any problems then I'd experiment to see if I could improve on it. In the real world though, there doesn't seem to be a shortage of replacements on ebay

GeorgeSweety wrote: In the real world though, there doesn't seem to be a shortage of replacements on ebay

Especially since so many people pull them off and try to use pods.