Pod filters/jets/plugs

[brock]

Hi, all. I've come to throw myself at the mercy of your excellent advice once again.

I just replaced my old cracked air filter housing with four pod style filters. Looks good, and fiinally gives me enough room to get all that fuel line routed around without getting pinched.

Took it out for a ride with new plugs, and to my surprise, they are black and sooty, which is indicative of a rich system, right? they were fine before, and now that I'm giving it much more air, it should be running lean. But the plugs don't lie. I popped in new ones again, and several miles later they're nice and black and dry.

am i missing something? also i'll be rejetting next week, I assume i'll just go up two steps from whatever they're at now. where should I look for new jets?

thanks.

[randy]

Brock,

Some pod filters restrict the flow of air at the carb throat, which may account for your rich condition. Check the inside diameter of your filter neck VS. the diameter of the carb inlet.

[brock]

Yes, I see how that might be. so even tho they stretch over the outside of the carb boots, since the neck is thin on the filter, it's still restricting the air flow. I guess the plugs don't lie.

So what should i do about this? am i going to rejet in the other direction? it's ironic that more surface area finally ends up restricting air flow to the carbs

[randy]

There's quite a few threads here about this, why don't you do a search?

[81xsproject]

After reading all the pod threads, I have decided to use pods in conjuncion w/ the stock stacks from the old air box.

[brock]

well my search didnt turn up anything about pod filters resulting in rich mixtures, or anything about narrow necks. maybe i'll pop the filters off and take a dremel to them. maybe i can get it just right without rejetting.

the best thing about these filters, i think, is that it gives me enough room to finally get all the fuel lines straitened out. i'm not sure if leaving part of the air box would allow that.

[ratbyk]

Brock, the filters you have are not going to work. As the revs go up so does the richness of the mixture. I have gone through what you are going through and was unsuccessfully after trying several rejettings down. Tried to cut away the inside rim of the collar were the go on the carb air horns but hit a metal flange just under the surface of the rubber collar.
Try and return the pods that you have and get a different make/manufacturer. As the revs go up the choking effect increases until the engine starts to loose all power and black smoke (unburned hydrocarbons) rolls out the tail pipe.
I bet if you pop the pods off and go for a run that the engine will run fine and the plugs will clean up. Put the pods back on and the plugs will foul up again.
Sorry to bear bad news but they won't work on an XS11 with 34mm Mikuni's.
Ken/Sooke

[TopCatGr58]

Hey Brock,

Where did you get the pod filters from? A local shop, or online store? Would be some good info for the group if you could also tell what brand they were, if they have a brand.

I can tell you that the Round Sponge cylinder style from JCW, they are Unifilter brand work just fine, and you can wash the foam and re-oil it. They aren't as pretty as the tapered ones, though!

The previous posts on this topic have stated that ACTUAL EMGO brand are okay, but some other generics have this pronounced lip that interferes with the air flow severely richening things up!!
T.C.

[brock]

well what brand should i look for then? thanks for saving me the trouble, but i still hate to go back to that air box.

[brock]

I have the box. They are EMGO tapered air filters model 12-55752 and are 52mm. the box says they're good for xs750/850/1100 thru 79. stupid box. shouldnt that mean somebody made sure it works first?

[tab1324]

similar situation

Brock,

I have similar experience on my 82 XJ.. I put on the pods about a week ago and I was getting pretty black plugs. I dialed in the idle mixture and the black plug problem went away. Now, I have the 54 mm carbs and I used the EMGO brand pods. So far haven't rejetted anything and my cruise RPMs show things are pretty close to correct. I think I may be a bit lean at high rpms but I'm not willing to change just yet.

I would try adjusting your idle mixture first. I originally had mine about 3 1/2 turns out and with the pods I'm now at about 2 1/4 turns, and it still seems a tad rich. I don't understand it either - with all the new air it's breathing it should be lean, but as you say, plugs don't lie.

Are your plugs staying black only at idle or at a shutdown from idle? Many on this site have suggested that in order to properly test the carb circuits after a change like this has been made it is important to run the bike under load for a couple miles at high RPM (6000-7000) and then kill it with the kill switch and roll to a stop. Pull your plugs right on the side of the road and take a look. I did this after a short run at 7000 and my plugs looked a tad on the white side.

My $0.02

Tom B.

[brock]

I'm always scared to mess with the screws. everything i always read says they're preset and i shouldnt ever adjust them. tho, i find it hard to believe that no one's ever turned those screws in the last 25 years. Aren't they for adjust idle mixture anyway?

If it helps, i never really get into high RPM's on this bike. Rarely over 5K, and usually closer to 4K. I won't be too upset if adjusting the screws solves my problem for lower rpm's, since i almost never push it too hard.

I'd like to see this bike run another 25 years, too, and as I get older I find I drive a bit more conservatively than I did when i was 17.

[TopCatGr58]

Hey Brock,

Well, that's interesting, the size that is, because I just measured the inlets on a loose set of carbs I have in a box labelled 79SF and they are 54mm. And the basket case 79SF I picked up a few weeks ago also measure 54mm!! I've heard and read in some posts that the earlier 78-79 carbs were supposed to be 52mm, but that's not what I'm finding!?!

So...try measuring your inlet bell and see if it's 52 or 54mm. IF they are 54mm, then you were just able to stretch the 52mm pods to fit, but that may explain why the inner lip is too narrow. Also, may explain why some folks reported NO problems with the EMGO's, but they were 54mm fitment!! Can you exchange them for 54mm??

With the properly sized pods, you may NOT need to adjust the pilot screws at all!? But you will want to get the right size, otherwise even though you don't use the powerband of the XS11, you will still be running "Choked" on your air flow, and will be a detriment to your fuel economy/mileage, not to mention the power won't be there when/if you ever needed to roll it on!

And once you get the proper size, then you may find that your plugs may actually then look very clean, cause you'll probably be running a bit leaner than OEM, and may need to change your main jets to keep it rich enough so you don't burn up your pistons!? So...you might as well learn to adust the pilot screws to tune it properly!
T.C.

[brock]

well, a quick innanet search, as well as this post:

http://www.xs11.com/forum/showthread...&threadid=6258

seem to confirm the fact that the 79xs11 special has a 52mm bell. Lemme go outsite and see what the carbs say.

well. a trip down stairs tells me that the filters are 54mm, and the carbs are 54mm, too. So my 54mm filters came in a 52mm box. now what's going on?

[TopCatGr58]

Hey Brock, and others,
A review of the Yamaha Parts catalog....BTW, they have changed their page and web site layout, and moved the page, here's the new link to it!
New Link Yamaha Parts catalog
Shows the following model numbers for the carb assemblies, and you will note that the 78E and the 79F aside from the prefix have the same #'s with the 10-00/11-00 ending, whereas the 79SF and all models later, have the same main # but with the 00-00 ending, and they all have the 54 mm inlet bells. SO....I figure the 78E and 79F are the ones that have the 52mm inlets.


81SH
3J6-14901-00-00 CARBURETOR ASS'Y 1
3J6-14902-00-00 CARBURETOR ASS'Y 2
3J6-14903-00-00 CARBURETOR ASS'Y 3
3J6-14904-00-00 CARBURETOR ASS'Y 4


81H Standard
3J6-14901-00-00 CARBURETOR ASS'Y 1
3J6-14902-00-00 CARBURETOR ASS'Y 2
3J6-14903-00-00 CARBURETOR ASS'Y 3
3J6-14904-00-00 CARBURETOR ASS'Y 4

80G Standard
3H5-14901-00-00 CARBURETOR ASS'Y 1
3H5-14902-00-00 CARBURETOR ASS'Y 2
3H5-14903-00-00 CARBURETOR ASS'Y 3
3H5-14904-00-00 CARBURETOR ASS'Y 4

80 SG
3J6-14901-00-00 CARBURETOR ASS'Y 1
3J6-14902-00-00 CARBURETOR ASS'Y 2
3J6-14903-00-00 CARBURETOR ASS'Y 3
3J6-14904-00-00 CARBURETOR ASS'Y 4

79SF
3H3-14900-00-00 CARBURETOR ASS'Y
3H3-14901-00-00 CARBURETOR ASSY 1
3H3-14902-00-00 CARBURETOR ASS'Y 2
3H3-14903-00-00 CARBURETOR ASS'Y 3
3H3-14904-00-00 CARBURETOR ASS'Y 4

79F Standard
2H7-14901-10-00 CARBURETOR ASS'Y 1
2H7-14902-11-00 CARBURETOR ASS'Y 2 (2H7-14902-10)
2H7-14903-11-00 CARBURETOR ASS'Y 3 (2H7-14903-10)
2H7-14904-10-00 CARBURETOR ASS'Y 4

78E
2H7-14901-10-00 CARBURETOR ASS'Y (2H7-14901-00)
2H7-14902-11-00 CARBURETOR ASS'Y 2 (2H7-14902-10)
2H7-14903-11-00 CARBURETOR ASS'Y 3 (2H7-14903-10)
2H7-14903-11-00 CARBURETOR ASS'Y (2H7-14903-10)
2H7-14904-10-00 CARBURETOR ASS'Y 4 (2H7-14904-00)

Brock, are you sure the filters are 54mm, and not 52mm that got stretched ?? T.C.