advice please - 84 DOHC going to pod filter

[zombie_andrew]

Please guide me XS world.

I've been reading and re-reading every carb thread related to pod filters here. I know LESS than before Pod filters must go on my 84 DOHC maxim to achieve the look I want.

I need to confirm a few things before submitting my online orders:
1) is the correct K&N pod filter # RC-2340?
2) when converting to the pod filter, should the main jets be the same size (whereas stock air box was two different sizes? Any recommended jet sizes in either case?
3) should I upsize the pilot jet too? size?

High 5 & thanks

 

[Scorpio1963]

You might be able to get away with doing nothing to the pilot jets,depends on how it runs after you resize the mains.You are correct on the dohc about both jets being the same size.Heres a general consenses with jetting if you go up two sizes on the mains also go up one on the pilot.sometimes you can turn out your fuel mix screws to compensate.
Sorry Im no help with the pods.
Are you modifying you exhaust also?

 

[zombie_andrew]

I'm hoping to change to a 2 in1MAC exhaust soon. I've read I'll have to go up one more size once they're installed.

 

[willem]

there's no one solution for this, that's why you can't find it.

Most people that switch to pods and a 2-1 mac exhaust go up 2 sizes on the mains and one size up on the pilot jets. But you might need more or less jetting depending on your bike, the air in your area (altitude), and your fuel quality.

I recommend doing both the pods and the exhaust at the same time, otherwise you'll have to rejet twice.

if you're only doing pod filters, yes you might be able to just adjust the idle mixture screws. Maybe go up a size on mains, maybe even one on the pilots.

 

[16VGTIDave]

If changing to pod filters on a DOHC that was otherwise stock, you will have to rejet the mains and pilots. The mains should be matched. Like Willen suggested, do the pods and exhaust at the same time so you don't have to rejet twice.

Also, seriously consider building stacks for the filters to mount to and incorporating the crankcase vent. Here is a write-up I recently wrote on how to build the stacks.

 

[zombie_andrew]

Three gurus all suggest exhaust mod at same time? That must surely be the way to go. Looks like I'm ordering the exhaust now too.

@Dave - do you know which size jets you're using? Your stack write up sounds just right.

 

[16VGTIDave]

My jetting won't help you much. You can use it as a starting point, but expect to have to make changes. Main jets: 140. Pilot jets: 47.5

 

[XSLeo]

On vacuum operated carbs as the BS34's on the xs400, most pleated element air filters such as the K&N's don't work well. They cause air turbulence through the carb that interrupts the vacuum signal for the slides. The shorter and more tapered the more the effect. Longer straighter ones are better.
This turbulence causes a flat spot off idle that is hard to tune out.
A straight round foam filter works better.
On a non vacuum carb like the Mikuni Round slides there is no vacuum signal to disrupt so they work good on them.
Leo

 

[iamunique127]

Also, seriously consider building stacks for the filters to mount to and incorporating the crankcase vent. Here is a write-up I recently wrote on how to build the stacks.

Do you have any photos of your stacks yet, Dave?

 

[16VGTIDave]

No. My working time in the shop has been limited by 5cm of water on the floor.

 

[robbiecampbellsoup]

Did you ever get this going with the pod filters and the 2-1?

-Robbie

 

[Watts up]

I am also running pods and a 2 into 1 exhaust and I am aware that jet sizing is a trial and error type of thing so I was going to order a few different sizes of mains and pilots. I have looked on mikes and been able to find the mains that I need but I can't seem to find any pilots for the bs 34s. If anyone can point me in any direction I would appreciate it. I am running a 79 xs400???? Not sure what kind

My apologies Andrew don't mean to hijack your thread. Go ice dogs.

 

[xschris]

The sohc xs400's bs34's use the same pilot jets as the 80-84 xs650.

 

[Unkle Crusty]

On vacuum operated carbs as the BS34's on the xs400, most pleated element air filters such as the K&N's don't work well. They cause air turbulence through the carb that interrupts the vacuum signal for the slides. The shorter and more tapered the more the effect. Longer straighter ones are better.
This turbulence causes a flat spot off idle that is hard to tune out.
A straight round foam filter works better.
On a non vacuum carb like the Mikuni Round slides there is no vacuum signal to disrupt so they work good on them.
Leo

Leo, do you have a part number for decent foam filters. I have found many adds that do not give the size. ID at carb is 55mm. Some are 54 but should fit. Overall length for me is 90 mm or 3 1/2 inches. I have retained most of my air box to support the battery. I just cut off the front section.
I am currently using the tapered EMGO filters and do have a slight flat spot. Had to come down in main size to 122.5 to get rid of hesitation at WOT in the higher revs.

Thank you. Unkle Crusty

 

[XSLeo]

UNI filters PK-92 have an opening that fits 53-55 mm. These work great on my XS650's BS34 as well as the EX500 Ninja carbs I have on it now.
So they should fit fine on yours.
From the mounting lip to the end off the body are about 3.25 inches long.
Leo

 

[Unkle Crusty]

Sweet.
Thank you Leo.

Unkle Crusty*