XJ650 carb tuning with the dreaded "pods"

I know why it's in there, and it really does have a purpose. See page 5 of the pod filters link in my signature.

 

I put usb charging port in my Maxim 550 chain box. putting one in the Seca 550 tail section

 

You guys pay far less than what we pay on shipping period. 10$ actually sounds pretty good to me, that's usually the norm for small stuff like that.

 

the link is the size of a nickle . less than 3 oz shipping weight
$1.25 I could send it to the west coast of US.

I am 60 miles south of Canada next time I will ride to a Canadain Post and mail it from there.
Sounds like a good ride.

 

Hah, I just read it. But you know tuning engines isn't everyone's cup of tea. It just seems to me that nobody wants to bother with the hassle of trying to figure it out. I'm patient, so eventually if it doesn't quite run right, I'll get it to. I mean, how many mechanics are actually on here and know what they're doing? No offence to the diy guys.

 

Hah see what I mean? Canada post rapes everyone.

 

I'm only an eight hour drive north of you!

 

its simple take the path of least resistance just buy slide carbs.
Do you think Yamaha would go to the bother of an air box if pods, jet changes and wind cover was the fix ?
like I said before many have "done" it. why can't they tell you how?

sorry a stage 3 dyna jet kit someone else put in is not a How to do it answer.
what jets came in the kit ? slide needles , did they need shims? did his friend drill holes in the carb body , or slides, have to wet set out of spec to compensate. did not get an answer on where his flat spot was.

I would rather spend my time riding than wrenching and I love my wrenches.
soon I will rescue a pod bike and spend time working on the nemesis known as POD.

I know there is a difference between good enough The best it can be.

in the end if you tune the flat spot out of your driving style I guess some can call that a win.

When you get to the end of your journey Please tell us how you got there.
I mean no disrespect.

 

You've made some very valid points! But, anything can be done with time and patience. To be honest I think I'd like the flat spot at the beginning. It's almost like the idea of a turbo spooling up. Starts off slow, and then takes off like a rocket!

 

I hope it works for you. It is an interesting challenge.
another thing to consider is it has been stated that the pods will affect the top end speed .

 

How is top speed affected?

 

wrong. you can shim a needle jet needle up but try shimming it down. or maybe even a different taper. what happens if you need a different slide cut? then when that's all taken care of, it only works
below 30 mph and goes south above 45 mph. and if you ever change brands of pods you can do it all over again.

incase you didn't know, turbo lag is the biggest complaint about turbos

 

Hater

 

That isn't the issue. Tuning won't change the nature of how constant velocity carbs work. Pods increase airflow, and drop intake velocity. Dropping intake velocity messes with the slie speed and travel which messes with fuel metering in an inconsistent way.

Being a mechanic does not guarantee that one knows what one is doing. It does increase the odds, but it's not a guarantee. The days of simple tuning and intake mods netting big horsepower gains died just around the time the Xj series (and the competitors) were being developed. Even the best period-correct mods (individual filters, rejet, and a tuned Supertrapp 4-1 was one of the best) only gained 3HP at the top end, while also gaining .....(wait for it)...a flat spot in the midrange. Right where the powerband begins.

Yes you can get the engine to run with pods. Yes it may be acceptable to you. No, it won't be better than the enginered system without re-engineering the system.

FWIW, if you read through over a decade's worth of posts (some of which were made by mechanics and former professional racers) you'll see why pods on CV carbs just aren't worth the hassle (unless all you are going for is the look).


Addendum:

The second best way to run pods on an XJ is to fit carbs with cable-operated slides. That will greatly ease the tuning game, and diminish (but not eliminate) the issue with reduced intake velocity. Fuel economy will suffer however.

The first best way is to fit an FI system.

 

The truth hurts sometimes, but it's still the truth.

 

And has been all but eliminated through careful engineering.....but not everyone wants to listen to engineers.....

Yay single-stage turbos. All of the powerband of a 2-stroke, but without all that pesky predictability and control.

 

Uneven fueling due the the slides not being able to lift fully/predictably. Turbulance will cause the slides to constantly rise and fall (flutter), instead of settling into the correct height to meet engine demand.

 

We sell pods, K&N and Uni and Emgo brands. And make a pretty good mark-up, since we are distributors of their products........much more profit on those items than on stock pleated-paper filters.

We also sell a variety of over-sized fuel jets too, make a bit on them too (nothing to write home about, though...).

We would absolutely LOVE to sell everyone pod filters and a plethora of the various over-sized jets that you'll need to "tune" the carbs to get rid of the problems that pods create.

After MANY years in the powersports and motorsports industries, I think that I can say with some certainty the following:

USE POD FILTERS IF YOU WANT TO LOOK COOL, AND LIVE WITH THE REDUCED PERFORMANCE, ADDITIONAL EXPENSE, AND ADDED FRUSTRATION THAT COMES WITH MUCKNG WITH A VERY FINELY ENGINEERED, WELL-DEVELOPED ENGINE SYSTEM.

But if you want MAXIMUM PERFORMANCE, reduced expenses and efforts, and superior drivability and durability, stick with the un-sexy, un-cool, nerdy, weak, wimpy, stupid, ugly stock system.

Pods and such are for racers, who don't give a flying pod about any of the above things and run (and tune) their engines to run very well in a very limited range of operation and conditions. Most street riders get tired of the INHERENT shortcomings of looking good but running poorly over the long run.

 

I have uni pods and custom exhaust on my xj650. I had to shim the needles with 1 washer on each and change the main jet only. Ill look tomorrow and post the size i ended up with. I have only ever tuned by ear and plug color. The mixture screws are out 3 3/4 - 4 turns. This bike starts right up every time usually without the choke idles great and runs. After the initial tuning and figuring out what jets i needed i have had zero problems. Just make sure you keep your pods clean and oiled and clean your carbs every year

 

Did you ever ride it (clean carbs, properly set-up) without pods?