Rejet with pods?

81 KZ 550. Is it necessary to rejet if I use pods, but keep the stock exhaust? My experience on other models is that it is rarely necessary to do so when you change pipes only, but essential when the airbox mods are done. What about if just the airbox is done? How much more air can be scavenged with the same stock exhaust?

Any input appreciated.

R

Yes , you will need to rejet. There are literally 8,795 postings on this forum regarding pods. I suggest you use the search feature to do some research before making the switch. Why do you want to use pods? I hope you are not expecting a better running engine or more power; if so you may be disappointed. Ed

If you have the airbox, and stock exhaust use stock jetting to get it running right first. Then you have eliminated the jetting as a variable. After the bike runs like new, then you can start messing with the jets. You'll have your hands full with compression, valves, advancer, timing, coils, wires, plugs, petcock, carb fuel level, fuel overflow leaks, vacuum leaks, syncing, etc. Don't throw jetting into the mix too, if you don't have to, at least not right away. If it seems like work to get the airbox on, it's nothing compared to the days and days of trying to jet perfectly by the seat of the pants.

I'm all for modding and rejetting, but it's the last step, not the first.

I would agree with avoiding POD's unless you know you have the abilities to tune accordingly, even then it's likely a long process and you may never be happy with the end result.There are a lot of variables like cross winds etc. that will upset whatever tune you end up with. If you have the stock airbox, you may be able to modify the intake, if you are looking for better flow, often the airbox is designed as a silencer for intake roar too so has a somewhat restrictive snorkel or suchlike that can be removed or on some even extra holes bored, I'm not familiar with 550 airbox. Also you can look at something like a Unifllter for the airbox that may have a much bigger surface area for air to flow through compared to a stock filter. I have one on my XR650, which is much better than stock because it has foam where the stock had metal end caps so the filtration area is probably 3 times the stock one.

There's a reason KZ1000 airboxes are selling for between $130 and $200 on eBay, everyone took them off in the day and threw them away, now people realize why they need them.

Thanks gentleman. I did search some but couldn't find the answer to using the stock exhaust, so thanks again. Have the air ducts on backorder and was gonna try some cheap pods, but I will delay based on the sound advice herein. R

If you ever decide you need pods in your life, do not buy cheap ones. The can create a whole different level of frustration.

I'm a bit confused here and the last thing I want to do is come off as a smartass. In fact I'm pretty much a dumbass.

Most everything I read here says that pods are nothing but grief. So how come K&N and Emgo and others sell (millions?) of these things? Presumably at least some are sold to riders who are not expert tuners.

Say you were me with a 76 KZ750 Twin. I'm as likely to find a stock exhaust system as I am to find a unicorn. So one side of the intake/exhaust equation is already broken. Maybe whatever aftermarket or custom bent exhaust I can find will work with the stock airbiox but why would I expect it would not work as well with pods?

Simple - the exhaust system does not change the air/fuel ratio of the charge coming from the carbs into the cylinders, but changing the air flow restriction associated with the air filtration does.

Plenty of pods are sold to folks who do not understand the affect they will have on the bike's performance. The same is true of plenty of aftermarket stuff.

If you don't believe it go ahead and buy a set of pods and install them on those CV carbs on your '76 KZ750. :laugh: :laugh:
Ed

Back in the lat 70's I recall reading an article about Pods in one of the Motorcycle publications. I don't recall all their findings but one I recall was that one problem with Pods was that at speed, they were trying to suck in air rushing past them at high speed, so they actually worked in the opposite way to how people envisaged they did, rather than improving airflow they decreased it. So even if a dyno shows a power increase that may not be the case in the real world. I think a lot of people buy Pods based on the assumption there will be a substantial increase in power, although I think the motivation initially is how much easier they make removing the carburetors than with the stock airboxes and it's something that's fashionable. In reality I doubt many see increased performance, while the majority lose performance and "rideability" as a result. I personally don't care for the additional intake noise they make either.

While noise regulations cause most stock airboxes of the late 70's and up to be somewhat restrictive to airflow, as stated earlier, there is usually some way to improve on this and it should also be remembered that for the restriction to be significant you will need to be at the top end of the demand for air i.e. full throttle and high revs, so unless you are racing your bike or similar how often would this even be an issue?

You also have to consider that the filtration provided by Pods may be inadequate too, I certainly would never use the cheap ones and even K&N does not provide the best filtration compared to a stock paper filter, that's why you don't use them on off road vehicles. The foam filters like the Unifilters do filter well, that's why motocross bikes etc. use them, they can even catch a lot of dirt without becoming restrictive.

Another problem with Pods is you have no "velocity stack" effect, there isn't a passageway that gets the air flow lined up before entering the carbs and this can be diruptive.

I think for most people Pods are a bad solution to a problem they don't have. If you don't have an airbox etc. then they provide an affordable solution to getting your air filtered, but without some really good reason I would never advocate removing a perfectly good air box and filer setup.

While a free flowing exhaust can create the need for bigger jets and improve performance the big difference is that it's effect is a constant. The problem with Pod filters is they introduce variables like cross winds, rain etc. into the mix so it will be hard to get a "one size fits all" situations tune. The exhaust might be better likened to someone making a performance airbox, as opposed to Pods which are a somewhat different concept.

first of all I am not an expert. Don't claim to be even close. But I had an occasion to help my son who bought a late 70's GS650 and before I could step in had cut the airbox apart to remove the carbs. We had no budget for an eBay air box and so he bought some cheap Pods at the local Kawi dealer. Now these were CV carbs. At the time I knew nothing about CV carbs other than we could not get it to rev past 4500 RPM under any condition even in neutral on the center stand. I thought it sounded way lean and decided to introduce some extra filtering. I used one single layer of those blue paper "shop towels" under the pod. I first cut the shop towel to a rough circular shape and held it over the carb inlet while we installed each pod. Using the pod rubber mounting to hold the new filter so it wouldn't just suck itself into the carb. Surprisingly it worked. I tried different materials, cloth, white paper towels etc but found that a single layer of that blue shop towel seemed to be good enough. Was it optimum? I doubt it. But the bike was totally ride-able with no flat spots and good throttle response. We ended up selling it to a guy a couple of years later. He reported back to me, after several weeks, that the bike ran fine and he was very pleased.

Later I told a friend about what I had done and he tried it on his CB750 "bobber" and it worked for him too. Now I don't endorse using this method but it did work for me. If you're stuck with having to use PODS maybe it can help you too.

FYI we did nothing with the stock jets. Just cleaned the carbs and set the float levels like normal. Reading the plugs after a couple of hundred miles indicated that it was running slightly rich but not carbon fouling the plugs.

I have seen the method you described used with good success multiple times (when other options were not immediately available or affordable to the rider/owner)...AND a suitable airbox was not an immediate option. In theory (at least to me) that method would be equal to restricting intake air flow to a more compatible rate for that particular engine configs...and miltiple layers or fabric consistencies (inside the pods) wld theoretically change the airflow rate resulting in varying engine performance results which cld be easily altered to the best performance for any particular engine with a simple hose clamp fastener? I'm no expert either. I'm perfectly at ease whether I'm lazily cruising scenic backroads on my cruiser or attempting 100mph wheelies on my hotrod. Solutions such as this can be handy inexpensive and effective ways to relieve stress, headaches and sleepless nights when none others are immediately available..............Mike

jdvorchak wrote: first of all I am not an expert. Don't claim to be even close. But I had an occasion to help my son who bought a late 70's GS650 and before I could step in had cut the airbox apart to remove the carbs. We had no budget for an eBay air box and so he bought some cheap Pods at the local Kawi dealer. Now these were CV carbs. At the time I knew nothing about CV carbs other than we could not get it to rev past 4500 RPM under any condition even in neutral on the center stand. I thought it sounded way lean and decided to introduce some extra filtering. I used one single layer of those blue paper "shop towels" under the pod. I first cut the shop towel to a rough circular shape and held it over the carb inlet while we installed each pod. Using the pod rubber mounting to hold the new filter so it wouldn't just suck itself into the carb. Surprisingly it worked. I tried different materials, cloth, white paper towels etc but found that a single layer of that blue shop towel seemed to be good enough. Was it optimum? I doubt it. But the bike was totally ride-able with no flat spots and good throttle response. We ended up selling it to a guy a couple of years later. He reported back to me, after several weeks, that the bike ran fine and he was very pleased.

Later I told a friend about what I had done and he tried it on his CB750 "bobber" and it worked for him too. Now I don't endorse using this method but it did work for me. If you're stuck with having to use PODS maybe it can help you too.