82 GPZ750 BS34 cv Carbs Stock air box or K&N pods

OK I know this has been debated for years, so lets have the 2015 version. I have the BS34 carbs on my GPZ750. Lets hear the pros and cons of PODS VS Stock Air Box. Bring on all the opinions. I want to get educated. Wired George swears he can jet the carbs for pods perfectly. But,, I have also heard that these carbs never run correctly with pods. Bring on all the comments for 2015 !

Same comments as 1915.

It can be done. It usually is not easy. There are very few benefits, especially on an otherwise stock engine. heavy rain and strong cross winds can be problematic.

- The are no meaningful performance advantages to using pods on a stock bike; any minor power gains at one rpm are offset by power losses at another rpm.
- Pods cost more than the stock air filter and are more of a chore to maintain. The stock air filter can be replaced by a new one in one minute; not so with pods.
- Pods require rejetting and you are unlikely to hit the magic combination on the first try. Rejetting is not free - it costs money for jets, etc. and time to pull the carbs apart to install the parts.
- Pods can be affected by wind and by rain.
- Pod remove the rear support of the carbs which can lead to premature carb holder leak as the weight of the carbs pulls on the holders.

Some folks like the fact that pods make removing the carbs easier. Big deal? I think not. I have removed and reinstalled my carbs exactly twice in 38 years and the airbox adds 10-15 minutes to the task. That's 20-30 minutes in 38 years. I challenge anyone to rejet for pods in 20-30 minutes, so there is no time saving with pods.

All the above is my personal view. Here is the view of the Mikuni engineer who worked with the motorcycle companies to develop the air boxes. Below that is a detailed study on pods that was done back in the day by professionals. Ed

Thanks for the detailed article. It was very informative. that is the best answer I have seen.

K&N's flow more air than your typical OEM air filter because they don't clean the air as well. In other words, more dirt gets through to your engine.

Regarding George Wired, the guys on GS Resources have posted photos of some of his work and all I can say is GOOD LUCK. You know what they say about a fool and his money...

The main argument I have with pods is this, I live off a road with a 9% grade after 2 miles head start. Gets windy here too coming from the west. The grade is E/W so heading into a head wind it tough enough. With the pods going up the grade in 5th, the bike seemed like it was starving for fuel. That's with the stock 28's. I put in larger float needles and seats. 2.0 Yeah, it improved acceleration on the flat but did nothing on the grade issue. Miller told me when I put on my 33's to install a air box. Heading into the wind, on a grade, taxed the engine more than normal. That was a good thing. It demonstrated just what he was talking about. With pods there was a vortex behind my legs and around the carbs, thus starving the carbs of air flow. When I put in the air box, (I had to make the holes larger for larger boots) the problem went away. That's with VM carbs. CV carbs would been worse. He explained, the frame is pressurized at speed. The air box gets positive pressure, pods get negative pressure at speed. I for one will never use pods again unless I have 1/4 mile flat track racer that will only run for a few seconds. :woohoo:
Steve

My R1 runs very nicely on pods, it has been upjetted quite a lot and seems to have an air corrector kit fitted.(brass insert on the right).



There are some disadvantages I know, but for me I prefer pods. Clean looks, throaty sound and ease of maintenance being important for me. Unless you have the original linked 4-2 pipes I think you might lose some of the advantages of an airbox anyway.

I had an 81 GPz550 bolt standard with 4-2 and airbox and the bottom end was noticeably better, with good fuel consumption and 120 mph. Having owned quite a few over the years it was nice to at last try a bolt standard bike.

Interesting what the article said about 'spit back' at high speeds increasing fuel consumption, also about 'aftermarket products generally operate with more resonance tuning...it would be good to see the same test results but with hot cams and gas flowed heads plus a lot more set up time.

A Dyno test would prove/disprove everything. All I know is what I feel. Knowing this bike as well as I do, I can tell if something is a miss.
Steve

Oh, and that brass insert is a air jet. Fine tuning for the main circuit the quick way.
Steve

I've been through the loop on Pods with my FCR35s, and hear's what I've learned.

Something a lot of folks probably don't notice, but at least in my case, the K&N pods are over-oiled out of the box. And with them bolted right to the carbs, the oil is sucked into the engine. After some run-time I pulled the carbs and the bores were coated with the sticky filter oil. And to make things worse, it produced a black carbon film on the pistons and combustion chambers -- which will never come off without a tear-down. After that, I use a light coat of transmission fluid and service the filters more often.

The other biggie is the crankcase vent. Without the airbox the blow-by fumes/smoke are just dumped into the atmosphere (a little filter on the vent does nothing). It's annoying coming to a stop and getting a whiff of hydrocarbons, at the same time the blow-by is contaminating engine oil more so without any negative pressure drawing the fumes out of the crankcase. I built a custom PCV system to remedy that problem.

The airbox does support the rear of the OEM carbs, and over time they will sag in the back and produce unwanted stress on the intake tubes. As a matter of fact I'm going to find some springs to support the back of the carbs at the frame, or maybe some kind of post to prop them up from the crankcase.

I don't want to talk about jetting. But my situation was a bit more complex with the bore, compression, cams, porting, and flat slide carbs. It shouldn't be so bad with just intake and/or exhaust mods on a stock engine.

autotech2@tx.rr.com wrote: I've been through the loop on Pods with my FCR35s, and hear's what I've learned.

Something a lot of folks probably don't notice, but at least in my case, the K&N pods are over-oiled out of the box. And with them bolted right to the carbs, the oil is sucked into the engine. After some run-time I pulled the carbs and the bores were coated with the sticky filter oil. And to make things worse, it produced a black carbon film on the pistons and combustion chambers -- which will never come off without a tear-down. After that, I use a light coat of transmission fluid and service the filters more often.

The other biggie is the crankcase vent. Without the airbox the blow-by fumes/smoke are just dumped into the atmosphere (a little filter on the vent does nothing). It's annoying coming to a stop and getting a whiff of hydrocarbons, at the same time the blow-by is contaminating engine oil more so without any negative pressure drawing the fumes out of the crankcase. I built a custom PCV system to remedy that problem.

The airbox does support the rear of the OEM carbs, and over time they will sag in the back and produce unwanted stress on the intake tubes. As a matter of fact I'm going to find some springs to support the back of the carbs at the frame, or maybe some kind of post to prop them up from the crankcase.

I don't want to talk about jetting. But my situation was a bit more complex with the bore, compression, cams, porting, and flat slide carbs. It shouldn't be so bad with just intake and/or exhaust mods on a stock engine.

Mind to share the details on your "custom PVC system"?

It's a network of tubing, Ts, elbows and grommets which connects the crankcase vent to the back of each pod. Duplicating the function of the original tube from the vent going into the OEM airbox.

I take it you know where I'm coming from with the annoyance of an open crankcase vent?