52mm or 54mm carbs?

[brock]

Hi. I'm looking to replace my air box with a set of those chrome capped individual air cleaners. But I can't seem to determine whether I should get the 52mm or the 54mm. Anyone know what the size is on the intake boot? It apparently differs from the 79 and the 80-81. I'm riding a 79XS1100 special, tho.

thanks smart guys.

[Dennyz]

The the O.D. of the intake bell on the '79 XS11 is 52mm. It is the same across all years of XS11 carbs and possible the XJ11.

[chevy45412001]

i agree

that sounds about right,mine were a tad tight but stretched the few mm's to go on.

[fountainbiker]

Advantages???

Hi All,
I was wondering what the advantages are to the individual air filters verses the air box? Is the engine able to breath better with the individual air filters? Will it improve my sucky gas mileage? What does it take labor wise to swap them out, hours? Any instructions would help. Thanks!

[brock]

I'm wondering a similar thing. Before I go ahead and swap em out, is there anything I should know? it isnt gonna mess up my carb mixture is it?

I'm planning on doing it because I think they look cool. That's my major motivation, really. And besides that, i'm looking forward to getting that giant air box out of there, so i can get a little more room to work in there. Particularly, I'm always having trouble getting just enough fuel line in there to keep it from pinching. I'm thinking of putting some inline filters, too.

[rneal55555]

Yer probably gonna have to rejet and whiler not hard it can take a few times before ya get it right. In XS 650's the cheap EMGO (I think) cause problems. There are work arounds but I found it easier to go back to the stock airbox.

[rneal55555]

Also serch for POD using the search tab at the top you'll reading awhile.

[brock]

ya, so i was a bit worried about all that. most specifically, will i have to rejet my carbs? am i really taking in that much more air? How will i know that i have to rejet?

really the only reason i'm thinking of changing them is cause i think they look cool.. and i'd like a bit more room in there to work with.

[TopCatGr58]

Hey Brock and Fountainbiker,

The indy filters DO breath much better than the stock air box, think about that little snorkel under the seat, how much air can get thru it to feed all 4 carbs, along with all the channels, turns, that it has to make, then think about the simple OPEN Indy filters, direct line into the carbs, NO restriction aside from the filter material!

You monitor your engine by putting in NEW plugs, and then driving it a while with new filters, and then pulling the plugs and looking at them! IF they are fairly white with very little color, no tan/gray on them, then you are most likely too lean, and a resize will be indicated. Usually, it's about a 2 size jump, but if you also have modified Exhaust, then when combining affects, you don't always combine the total increase....per the jetting chart.... would be only 3 sizes for both Indy's and Exhaust instead of 4 sizes.

Also recommended is a support strap of some kind connected to the carbs to keep the stress more even, vs. allowing them to hang full weight from the intake boots!

As for mileage, it probably won't help! You can hear the engine a bit more with the Indys mounted, and some have noted a slight increase in throttle response. How you drive affects your mileage considerably, in town is much worse than highway; faster highway speeds is much worse than slower, etc.. Worn clutch plates slipping can reduce mileage, dragging brake pads, low air tire pressure, large fairing, poorly tuned-synched carbs, dirty plugs, weak ignition/coils, etc.!
T.C.

[brock]

Sorry to ask a dumb question, but i've never really done this sort of thing before.

Um, how do i know what size the jets currently are? is it listed on them somewhere? what sort of damage can i do by running too lean? I've taken the carbs apart before, so i assume that just changing the jets should be no problem, as long as there's nothing special i need to know. I just don't want to have to take it apart and keep switching them out 5 times. but you figure if its running a bit lean, just 2 sized bigger should do me?

You have the individual filters, right, tc? what do you use to hang them? a bracket from 2 and 3 to the frame?

[fountainbiker]

I'm new at this too!

I just won the right to buy (you never win anything on eBay) a 4-into-1-exhaust header on eBay, for only $114.50! Now I'd like to get the 4 filters. All this is new to me too and I'd like to do it right the 1st time with the carbs and jets. I too have always had a lean runner, and the gas smell is very noticeable.

I'd also like to post a pic of my baby so you all can see the progress so far with the eBay fairing and bags, mom & pop seat, after the $1,500 paint job. They still need to stripe them and add the trunk... but I don't know how to add a pic here. I know it's possible cuz others have included pics in their reply. How is this done? Thanks for the help.

[TopCatGr58]

Hey there Brock,

Yours should be 137.5 if they are still stock, and yes, they are usually stamped on the top of the jet, very fine writing!! They go up in 2.5 increments, so 2 sizes would be 142.5! Running too lean, in theory can burn a hole in the top of your pistons! The engine runs too hot!

Along with changing the jets, you'll need to be sure of your float height, and you may have to tweak your pilot screws as well!? You'll also want to verify your vacuum diaphragm needle setting, so depending on how it behaves; idle, off idle, transition into throttle, full throttle, etc., you can then make other adjustments as needed. Yeah, a bracket between 2-3 to frame works!!

Hey FountainBiker,

What you said about running lean, and a GAS SMELL doesn't make much sense!? If you're running lean, then there shouldn't be much if any excess gas fumes eminating from your machine!? However, if it's running rich, then folks usually report a noticeable unburnt gas smell!!

As for posting pics, there's info in the Main Forum "How To" section, Aside from the tech photos we have here, they are NOT stored on this server, so you have to provide an active and open link to a server to host the photos. Right click on any photos and select properties, and you'll see where folks are putting them. Some use their ISP's personal web space, others have found places like PHOTODUMP, that allow linking, but several others that USED to allow this stopped, ie. ImageStation, Yahoo and MSN pages!!
T.C.

[brock]

if you've got your pic on another server it's easy to post. just reply, then click on the IMG button,and you'll get a popup. then put in the url:



then hit enter. if i did it right, my turtle pic should appear above.

[chevy45412001]

jets

i have an xj 11,when i went to 4 filters my original jets were 112.5". I am currently running a 137.5. My plugs are a little black so i'm going down a size or two to fix that prob, and my gas mileage did increase with the air box gone and new jets. Hope to pick up even more with yet a smaller jet.

[wildbill]

I thought about using the stacks out of the air box and then using foam filters on the ends of them. I also thought about modifing the airbox itself so there will be a mounting bracket to hold the back of the carbs. It`s winter time and rainy so I have lots of time to think- so what do you think ?