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Thinking of changing to individual pod filters

  • Thread starter Thread starter kb_air
  • Start date Start date
K

kb_air

Guest
what would be the biggest change i'd experience with individual carbs on my 78 gs750 instead of the airbox? im thinking of doing that and moving my battery in the tail, any done this? ive recently put larger jets in the carbs and im running with a Vance and Hines megaphone.
 
Unless you're prepared to, and understand how to re-jet your carbs this would be a bad idea.
 
TheCafeKid said:
Unless you're prepared to, and understand how to re-jet your carbs this would be a bad idea.
Click to expand...

ive already put 2 sized up on them from stock, and i only changed the main jet. think it will need to go bigger?
 
Changing to pods requires re jettting... Depending on the jets you have, you may have to go through the carbs again, or go the easy way and go dynojet stage III. Whatever You do, get good pods. Ape, or K&N. I tried Emgo pods with my stage III, and could not get the bike to tune. Replaced them with Ape's, she tuned right in and runs great through the whole band.
 
my best advice would be stick with the stock airbox and insert a K&N into that!

I have owned several bikes with pods, and have changed them all back to original airboxes!

Riding in rain will mean that the outside cylinders richen up like you have the choke on.... because when the water mist blocks the pod surface it cant get enough air.

and interestingly enough, today I found this in an article by Greg Cope, drag racing guy:
Airbox
When running a full body and fairing combination on your drag bike it is essential that you install an air box. The air is streamlined around your fairing causing a dead air space in the area of your carburetors. This starves your carbs of air and performance is dramatically decreased as much as three tenths or more. Lining your airbox with a heat reflecting material will keep engine heat out so that you have clean cool air.

The factory setup was designed and tested, tried and works.

Almost all new bikes still come with airboxes, my recent research into WHY has shown that intake air is better from a less turbulent location, which is why most motorcycle airboxes have the snorkel on them.

Oh and as others have said, you WILL need to re-jet, there are "baseline" settings which will work, but they usually require considerable fine tuning to get them to the optimum settings.
 
right well I would be doing it for looks more than performance. just to hollow out that whole area, maybe put a small lithium battery in the tail and just remove the starter solenoid altogether and mounting the r/r under the seat or something and keep the airbox, i dont know, just looks awesome without it.
 
Hell yes, go for it! Tiny dirt cheap scooter battery if you want kick only, otherwise shell out for the lithium to crank her over.

I've done two 750's like that(well, battery tucked behind engine, not in a cafe hump, but same hallow idea). I'd say bump up to 17.5 pilots, needles in 5th notch leave skiny shim underneath and fat shim on top, 1 turn out on fuel screw, 1.5 out on air screw, and 125 mains, then tune from there.

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keman said:
Changing to pods requires re jettting... Depending on the jets you have, you may have to go through the carbs again, or go the easy way and go dynojet stage III. Whatever You do, get good pods. Ape, or K&N. I tried Emgo pods with my stage III, and could not get the bike to tune. Replaced them with Ape's, she tuned right in and runs great through the whole band.
Click to expand...

He's got VM's on the '78. Don't need to shell out on DJ kits, just a few jet sizes. In a pinch Emgos run OK on them too, but as you can see I'd go cloth or filter foam instead of that.
 
"Tune from there" being tune down in size. Better to be on the rich than on the lean side of things starting out. I still haven't gotten my a/f guage on either bike, so I can't say exactly where is best with either or my set-ups. Filter foam/headers only ended up with bigger mains than filter foam/stupid longs pipes just from reading the plugs though(kinda obvious it would end up like that). What would be your base line recommendation for him?
 
TheCafeKid said:
125 is too rich. 17.5 pilots aren't necessary.
Click to expand...

What he said, and there is no Dynajet kit for the 8v 750.

Maybe 117.5 - 120 ish main jets and 15 pilots, maybe one notch richer on the needle.
But each bike is different, careful tuning or buying a lot of extra gas forever will be required.
 
Depends on whether or not he's running stock exhaust or a header with a baffle (please god no straight pipes...) header and good pods, 120-122.5, stock system with pods 117.5-120. Dependent on state of tune as well. Get rid of the junk P&C ignition, clean carbs, adjust valve clearances before attempting a re-jet. You must start from a known good base line.
The needle clip will also need to be moved. I'd suggest one notch toward the point. Don't swap the nylon spacers. If you find that moving two notches toward the point is too rich, and one notch is too lean, a second metal washer or two can be used to shim a "half step".
The VM carbs are much easier to get to work with pods, but they're a bit more complicated because you have to re-sync every time you pull the slides to move the needle. Which can be a bit of a pita.
 
tkent02 said:
What he said, and there is no Dynajet kit for the 8v 750.

Maybe 117.5 ish main jets and 15 pilots, maybe one notch richer on the needle.
But each bike is different, careful tuning or buying a lot of extra gas forever will be required.
Click to expand...

You know, I wonder if you could use a stage three kit from a 78/79 1000E and just use the smaller of the two main jets?? I may have to try that some time. If anything, the DJ needles are better than stock.
 
TheCafeKid said:
You know, I wonder if you could use a stage three kit from a 78/79 1000E and just use the smaller of the two main jets?? I may have to try that some time. If anything, the DJ needles are better than stock.
Click to expand...

Dunno, the 1000 comes with 95 main jets, the 750 has 102.5 or 105, so the bigger would be the correct one. I don't think the DJ needles are better on VM carbs. I never had any trouble tuning the mid range or any other range with stock needles in VM bikes.
 
well i didnt get pods (yet) but i did take out the battery box, lose the starter solenoid hollowed out that whole area, got rid of back fender and chain guard and its looking 10000000x meaner. it looks so bare even without the pods, is sick. so ill decide in the future to get pods or not
 
I'm generally with the "stick with the stock airbox" crowd. It's just easier to get it right. Besides the stock airbox being highly optimized for good performance, it also does a great job muffling the intake noise. Yes, that's right, one of the main reasons for the stock airbox is to reduce noise. Change to pods and you will hear the difference. I think the added noise contributes to the impression your bike is faster, whether it is or not!

But people change to pods for performance and aesthetics, and I think this applies to KB who is working towards a custom look. So, if you're going to pods, (1) buy good ones like K&N, not those cheap Chinese paper ones that just look like K&N filters and cost 1/4 the price. (2) Adjust your carbs to match airflow (your original question).

The simplest approach is a prebuilt jet kit from DynaJet or Factory Pro. Call and tell them your setup and they can recommend the correct kit for your needs.

Here's some "required reading" from Factory Pro detailing how to jet your carbs:
http://www.factorypro.com/tech_tuning_procedures/tuning_carbtune,CV,high_rpm_engines.html
 
Ajay said:
I'm generally with the "stick with the stock airbox" crowd. It's just easier to get it right. Besides the stock airbox being highly optimized for good performance, it also does a great job muffling the intake noise. Yes, that's right, one of the main reasons for the stock airbox is to reduce noise. Change to pods and you will hear the difference. I think the added noise contributes to the impression your bike is faster, whether it is or not!
Click to expand...

I'm with you Ajay, mine is bone stock. I think a perfectly running GS looks really cool, but I'm all about function stock or otherwise. when they run like they are supposed to they look allot cooler to me.
 
TheCafeKid said:
Depends on whether or not he's running stock exhaust or a header with a baffle (please god no straight pipes...) header and good pods, 120-122.5, stock system with pods 117.5-120. Dependent on state of tune as well. Get rid of the junk P&C ignition, clean carbs, adjust valve clearances before attempting a re-jet. You must start from a known good base line.
The needle clip will also need to be moved. I'd suggest one notch toward the point. Don't swap the nylon spacers. If you find that moving two notches toward the point is too rich, and one notch is too lean, a second metal washer or two can be used to shim a "half step".
The VM carbs are much easier to get to work with pods, but they're a bit more complicated because you have to re-sync every time you pull the slides to move the needle. Which can be a bit of a pita.
Click to expand...

im running a 4-1 vance and hines ,megaphone (pictured in my sig). im leaning twards the pods just for looks sake. i have a pretty good cheap mechanic/friend that says he'll help me get it right. we will see. if nothing else i can always put the box back on. its just so big and unsightly :(
 
kb_air said:
im running a 4-1 vance and hines ,megaphone (pictured in my sig). im leaning twards the pods just for looks sake. i have a pretty good cheap mechanic/friend that says he'll help me get it right. we will see. if nothing else i can always put the box back on. its just so big and unsightly :(
Click to expand...

Well, just be aware that unless your mechanic buddy is familiar with your bike, and is good at it, or doesn't mind spending a great deal of time with trial and error, you could be opening the door way to motorcycle hell for yourself.
Even when you have a good idea where you need to be, there's still a bit of tuning involved, and doing that requires you to know what the bike is telling you....
 
I'm not trying to discourage you from doing it but I'm curious as to what is so big and unsightly about the airbox when it's covered up by the side covers?
 
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