Crossover tube for pod filters

[Jschneid100]

Hello! First time poster here. So, many put pod filters on their bikes, and many more chastise them for such. What if I could build a crossover manifold between the carbs and the pod filters. It would equalize the vacuum pulses between the cylinders, and perhaps make the CV carbs a bit more manageable. I just purchased a gs850 basket case that I plan on making a brat bike out of, while currently finishing one that is a cb350. Has anyone tried this?

 

[Tom R]

I think it’d be an interesting engineering endeavor, but the engineers at Suzuki already did that. K&N or APE pods and a dyna jet kit are an easier way to go..... not necessarily better if you have the stock air box though. The 16v 1100s respond nicely to pods and a pipe, not so sure about the gains on an 850.

 

[Rob S.]

Like to see that CB350. I had a '71 with extended forks, custom lights and seat. Later bored it from 325 to 435cc and installed extreme cams.

 

[Big T]

Interesting idea, but wouldn't something designed by an engineer, like the air box, be more practical?

You are looking for greater velocity thru a CV carb, thus more vacuum, to lift the slide

And, chastise is too strong of a word
This forum is built on decades of accumulated knowledge and many have found intake changes on CV carbs to have little value and unnecessary expense

There are little to no gains in performance with pods. Especially on the 850

 

[Steve]

The issue is not "equalizing the pulses", it's more like simply adding enough fuel to maintain the proper ratio for the additional air.

As others have mentioned, the stock airbox is a wonderfully-engineered device to ensure proper carburetion, but for those who are going for a "look", like a brat or cafe, the visual impact of the airbox is not good. In that case, there is no chastisement, merely a caution to brace yourself for the jetting adventure ahead. :encouragement:

.

 

[Guest]

What if I could build a crossover manifold between the carbs and the pod filters.

If your 850 has one of the 2 piece airboxes then you can simply remove the rear portion that houses the OEM air filter and put a large K&N filter on the back of the plenum that feeds the 4 carbs.

There are little to no gains in performance with pods.

On the 850, I agree, but that is not at all a blanket statement. The 16 valve 1100's really come alive with a pipe and pods, there is no comparison at all to a stock 1100.


Mark

 

[Big T]

If your 850 has one of the 2 piece airboxes then you can simply remove the rear portion that houses the OEM air filter and put a large K&N filter on the back of the plenum that feeds the 4 carbs.




On the 850, I agree, but that is not at all a blanket statement. The 16 valve 1100's really come alive with a pipe and pods, there is no comparison at all to a stock 1100.


Mark

There is no mention of a pipe in the original post. So, I stand by my statement.
You have any dyno comparisons to confirm your assertion?
Because the one posted long ago about 4-1 pipes showed little,no and negative gain over stock

 

[Steve]

If your 850 has one of the 2 piece airboxes then you can simply remove the rear portion that houses the OEM air filter and put a large K&N filter on the back of the plenum that feeds the 4 carbs.

Thankfully, the 850 was never "blessed" with a 2-piece air filter/manifold setup. ray:

The larger shafties (850, 1000, 1100) have a WONDERFUL one-piece airbox assembly that is a pleasure to work with. :encouragement:

.

 

[Guest]

There is no mention of a pipe in the original post. So, I stand by my statement.
You have any dyno comparisons to confirm your assertion?
Because the one posted long ago about 4-1 pipes showed little,no and negative gain over stock

Fair point on the pipe. Pods on their own are pretty useless. I have a dyno chart of my 1100E from the PO who had the rear half of the airbox removed with a single large K&N filter on the plenum. It now has APE pods and is significantly stronger than this run.

I didn't think it was running all that well as I got it, the jetting was quite rich in the midrange and it wasn't particularly crisp or smooth. After installing the pods and rejetting it runs much better and is noticeably stronger everywhere. I live at 3400ft and a stock 1100E would maybe make 90rwhp back in the day. I would guess it is now somewhere around 105-106rwhp, but haven't bothered to spend the money for some dyno runs to know for sure.


Mark

 

[Guest]

I have a GS1000. I use the sync ports and vacuum line to cross over from 1-4 and 2-3. It definitely helps with a smoother idle and a little extra power at the low end. My bike is older so I have the VM carburetors. It should work with CV carburetors. I also use a 4-1 exhaust and Pods with a stage 3 jet kit.

 

[bwringer]

That's just an airbox with extra steps...

 

[Nessism]

Repeat story that I've mentioned a few times before...

Back in the day I had an XS400 Yamaha in need of new air filters. That bike employs two filters which fit behind the side covers, along with rubber/plastic ducting connecting the carbs to the filters along with a crossover between the two. I couldn't afford OEM filters so I purchased uni pods instead but couldn't get the bike to run right. Long story short, I wound up using the plastic rubber ducting and clamping the pods to the ends of those, pods hidden behind side covers now, and the bike ran great. Bottom line is that intake runners including crossovers can help smooth out the airflow and reduce jetting sensitivity when running pods.