Top Speed

Disclaimer: If you get a speeding ticket it's your fault.

Download the digihub app. Tape your phone to the tachometer and go for a ride.

Gary H.

 

I use the radar trailer the PD parks around town to check my speedometer.

 

He's asking about top speed. About five years ago before I cleaned my speedo drive I paid a decent fine for going 73 in a 50. I thought I was going 55 or so.

Gary H.

 

Stuff the speedo, a raz down the 1/4 mile a few times is worth it just for fun's sake.

would pods instead of the stock airbox really take so much performance away?
I´ve been reading more and more about the carbs and the air filters and air flow and starting to get a sense for the influence that the air flow and relative air pressures can do to the performance of the engine.
So a tuned in set of Pods in your opinion will still strip off quite some hp off the engine?
(I know this is now sort of off topic)

 

Yep

 

just to know how fast the bike will go ...

there is a post in a thread where Yamaha explains why you should not pod.

it is likely possible to get it right if you have the proper equipment and knowledge base.
we have a few people here who run pods but they seem to keep what they did to themselves.

 

Yes, yes and yes.
CV carbs don't like all that free air. If you change the style of carbs then that's different. Not many in the XJ community are going to drop a grand on a set of carbs so they can get the benefits of pod filters. That's more that they paid for their bike.
POD filters look good but make the bike suffer in performance and fuel mileage.

 

Our town has a radar speed display coming into town on one road. It is a 25 mph zone. I use it to test my speedo, and it is accurate to 30 mph. Since I don't want a ticket, I'm not testing it further!

Some years back I ordered an air filter from the nearby Kawasaki dealer - they got me a pod filter. I guess a lot of people convert.

Me, I'm keeping my bike as close to stock as I can.

 

we get pulled over at 12 mph over limit ticket at 15 over.
our trailer is moved around to different speed zones.

 

the air box design allows backwash gas to be sucked into the other carbs,with out the common connection , pods would keep the excess fuel in filter until next cycle.
the oval filters used for 2 carbs would be eaiser to use,
if you had a well designed pod you could work the carbs to the pod. Pods are for max air flow which is what I see as the problem using them on cv carbs.
then of course there is the boot which serves as a velocity stack.
the best place to install pods would be inside the air box, but then you lose the "look" of having pods and still have to deal with excessive air flow=lack of vacuum

part of podding may well be as simple as changing the spring in the diaphram setup to allow it to rise easier.
interconnection of pods might help.
many thoughts just no desire to spend money trying to work it out. Each change in the pod would require expermenting with jets.
I would rather be riding as I can not see the pods when rolling down the road

 

Pods really aren't for max airflow though. They look like they should flow more air, but in practice they don't always. The XJ airbox is realtively restrictive, but the advantages from the waveforms generated in the airbox overcome that restriction. In addition to providing the airflow necessary to allow the carb slides to move properly (and quiet intake noise), the airbox also uses the resonance developed from the "blowback" of the cylinders (a consequence of valve overlap) to force-feed a little more air through the one carb that is working on the intake stroke. With individual filters that free-supercharger (as Kevin Cameron calls it) does not exist.
Have a look at what a modern aribox looks like on a sportsbike. They are huge, and have many different shapes within to further tune the resonance for maximum effect in the midrange (exactly where we see pods cause a flat-spot in our XJs). This is done even on (most) fuel injected race bikes, where one would think that pods would have an advantage without causing any fueling issues.

 

well that was a good fishing trip of mine. A mine of information.
Super thanks to you all for shining a flood light on the issue.

A

 

Yeah it will do better then 100, but not much. And it's the Transmission Restricting it so you really can't do much about it. Especially because it's Shaft Driven..