XJ650 carb tuning with the dreaded "pods"

Unfortunately the side covers only help on the 650 Seca. The front of the airbox is exposed on the other models, so the pods will also be exposed even with the sidecovers in place.

 

Ahh well unfortunately the side covers didn't come with this bike. I'd like to get a set, but I don't know where to look other than eBay.

 

and if you are going to cover the pods why bother going to them.

one member did cover the oem setup with a screen matirial to give the faux pod look

 

Well that just so happens to be the model I have!

 

I guess like the way covers give it a different look? Other than some better air flow, i wanted to free up some space under the seat.

 

fab something up or look in the sale/trade forum shipping to Canada is costly from US

 

Yeah I'll have a look, but I've bought tons of crap out of the US and so far shipping hasn't been that bad.

 

One of the things I miss about my scooter. Plenty of storage without needing luggage. Add a top-box and I could bring home a full week worth of groceries (including a 25 pound bag of dog food). This makes me think.....

 

Well if you think about it and look at the stock air box on how much room it eats up, it makes me scratch my head wondering why that damn thing should be in there. I think I'm gonna make a little lock box to store import stuff like wallet, keys, phone, etc and install a 12v charger on it so I'll never be with a dead phone! I actually did that to one of my old quads for navigation on my phone, it was awesome lol.

 

cost me 10$ to send a cd and throttle link to Canada.

 

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?

 

The bike was free and didnt run when i got it. Started by cleaning the carbs but took the stock airbox out before i put it back together. The current jets and setting were with stock exhaust but still work with the custom exhaust.

 

So your baseline for comparison is a non-running bike.

The most common (seriously, you can search for it) comment from new XJ owners after getting everything clean and set up to factory specs is, "I thought it was running good before. Now I know it what an XJ should run like," or words to that effect. I'm not boasting, not bragging, not trying to be contrary; just pointing out that what you see as "zero problems" probably isn't.
If you're happy with it as-is then keep on riding and have a good time with her, but she isn't giving you her best.

 

I was just refering to the pods only. I dont know what it ran like before but it runs great now. In my opinion i have had zero problems. Meaning that i tuned it. Its starts right away every time i ride it and it doesnt bog down or sputter or anything like that. The plugs dont foul. The thread was about tuning with pods and i was offering my experience with that. As far as the performance aspect im happy and im not building a drag bike so 1 or 2 hp is not an issue to me

 

Theres a dyno shop right by my house. I might look into getting it in there and get some actual numbers for comparison to the stock specs

 

I'd actually be very interested in this. The dyno don't lie, then we can compare with someone who has a stock air box. I guess for it to be fair, each bike would have to be stock except for the pods. Unless someone has a bike with a factory intake, re-jetted, and is using some kind of aftermarket exhaust(2-1 or 4-1). Everyone says a bike with pods will run lean without increasing your jet sizing, so that's why I'm suggesting that. Right there it might be a unfair advantage because you're giving the engine more air and fuel with a pod setup. Then compare it to a bike that has pods, re-jetted, and a 2-1 or 4-1 exhaust, but there might be some discrepancies based on what type of exhaust is used, and what size main jet is being used. That may change the HP by 1-3hp in my opinion, or it might not at all.

 

I called the shop. They charge 84 dollars an hour to dyno tune and he said 2 or 3 hours. As soon as i get a little extra money im going down there for sure. Ill post all of my bike info after that. The only "performance" upgrades ive done is add the pods, changed the main jet size, and built custom exhaust (cut off the mufflers and welded moto gp pipes on to the stock collector.

 

Maybe we should set up a Kickstarter for the Pods vs Airbox Dyno Battle Royale (with cheese). I'd offer up my bike but it's a 750 (and not currently back together yet) so it wouldn't be quite fair.

 

Im in lol. Im suprised with this such a one sided debate usually that nobody has any dyno numbers yet to back their claim

 

Well, I hadn't actually looked into it before, but I found 2 posts with relatively stock XJ's (they have the stock airbox at least) and they were running 52 and 56 hp at the rear wheel:

http://xjbikes.com/forums/threads/which-jets-to-change.24750/ - 56 HP

http://xjbikes.com/forums/threads/put-the-xj650rj-on-a-dyno-today.61581/ - 52 HP

Interesting

 

I believe that they measure the factory spec at the crank and not rear wheel.

 

Um hell yeah! It would be interesting if you wanted to invest a little cash and dyno your bike now, put some pods on it, re-jet, blah blah blah and see what kind of gains you get. I'd do it with mine, but it's not back together yet.

 

How does it sound? Like a crotch rocket lol?

 

So then there's a certain point where too much air becomes a bad thing...so with that being said, restricting your intake to increase velocity would be the way to go, but the question is how much? Would you agree that air flow and intake velocity are on a teader todder?

 

Lol that would be interesting to do, know of any FI systems that could work with this engine?

 

I think it sounds great. I have a short video of it running but i dont think i can post it on here. If you send me an email address ill send it to you

 

You can post videos, but you need to upload them to a hosting site like youtube first, then link using the icon with the two strips of film.

 

You guys thinkin what I'm thinkin....
http://www.ecotrons.com/products/400cc_to_800cc_engine_fuel_injection_kit/

 

i'm pretty sure i'm not thinking what your thinking