XJ11 - Replacing the airbox. Any pointers?

[KA1J]

I'm going to replace the airbox on the XJ11. I'd removed it to put pods on the bike but am going to give it a try with rebuilt carbs & a tuneup to see if it runs ok.

I had to first remove the boots to get the carbs out which required Houdini & then it was a Biach removing the airbox & snorkel so I just hogged everything out last fall. I'd appreciate suggestions on how to easiest put it back seeing as it came out hard. It's probably different than the XS11 airbox, at least the filters from the XS11 won't fit it.

Thanks!

[DGXSER]

All I can tell you is that the XJ airbox is a different animal than an XS11. And it is a documented fact on this site that it is a much bigger PITA than the XS11 air box when it comes to carb removal and replacement. I would think your only hope of getting one in is to rmeove the carbs first.

Hopefully one of our XJ owners can give more sage advice.

[KA1J]

All I can tell you is that the XJ airbox is a different animal than an XS11. And it is a documented fact on this site that it is a much bigger PITA than the XS11 air box when it comes to carb removal and replacement. I would think your only hope of getting one in is to rmeove the carbs first.

Hopefully one of our XJ owners can give more sage advice.

I'm here to tell ya it's a Biach to get anything carb related out... I do have the carbs out and I thought about cutting the box into sections to facilitate replacement but that would cause its own problems. The location of the idle adjustment knob on the XJ650 is behind the carb & below, just above the starter where you can reach it. On the XJ11 it's in a tight compartment and next to the head fins where you feel pain from the heat... Not a brilliant design as regards maintenance...

Ugh...

[natemoen]

A long flat blade screwdriver gets in to the idle screw without pain.

[KA1J]

A long flat blade screwdriver gets in to the idle screw without pain.

The idle adjustment knob is in the middle of the bank, has a Phillips screw holding the knob on with the screw facing downward & though there is a flat head screw on the other side of it, that's for syncing cylinders 1&2 to 3&4. The only way I see to turn the knob is to go at it from the front and twist it.

What am I missing?

[cywelchjr]

The idle adjustment knob is in the middle of the bank, has a Phillips screw holding the knob on with the screw facing downward & though there is a flat head screw on the other side of it, that's for syncing cylinders 1&2 to 3&4. The only way I see to turn the knob is to go at it from the front and twist it.

What am I missing?

That knob has notches on it. You can catch the notches with a long blade screw driver and press on the notch and turn the knob that way. I carry a screwdriver in my saddlebag just in case I need to adjust the idle on the road (not often but one never knows.)

[natemoen]

Unless the XJ carbs are different Cy is right. I have a set of 81 carbs and they have the notches as well and the idle is in the same spot on those as the XJ.

[KA1J]

Aha! That makes sense, never thought about moving the knob like a ratchet.

I'm so used to being able to hold onto the XJ650J's nearly identical knob and turn it easily & with room from the backside of the carb. The XJ650's carbs are Hitachi & these by Mikuni are different.

Thanks to all for the suggestions.

Any idears on how to get the XJ11 airbox back in gracefully or do I need C5 & a blasting cap?

[bikerphil]

Any idears on how to get the XJ11 airbox back in gracefully

Air box goes in first, then the carbs.

[brcree]

Air box

I have found that run-en pods opens up a big can of worms........unless you know alot about jetting and want to take the time in finding the correct combo, I'de stay with what was designed for your bike (Stock). Unless you are going racing, the orig works pretty good!

[KA1J]

In an earlier thread I'd questioned about pods for this bike in that it came with a MAC 4-1 & the carbs were POed badly. I bought a set of dynajet for the XJ11 & was going to install those but found my gas mileage would drop and all I want is to have a proper fuel/air mixture, the XJ11 has more than plenty of power for me as stock.

Since I don't have an original exhaust and have to make an air filter for it, I'm going to re-assemble it stock except for the MAC andf see if it runs OK. I'm doubtful it'll be a proper mix but I really don't want to bite into the gas mileage. What to do, what to do...

I'll be running the XJ650 Maxim to save gas & use the XJ11 for longer trips.

But now to reassemble the carbs (hoping I remember where everything goes... and re-installing the airbox (which started this thread).

Wish I could have found an un-needed set pf pipes & exhaust for the XJ...

[DGXSER]

Unfortunately, the stock exhaust for these bikes is about as easy to locate as the abominable snowman and worht just as much when found in pristine condition.

[KA1J]

I've wondered... If it's the restriction of the original exhaust that's the issue, there ought to be a way to attach a restrictor in an aftermarket exhaust/s that would make it the same as the originals. I'd think the restriction would be the greatest variable between new & aftermarket as regards performance.

[crazy steve]

I've wondered... If it's the restriction of the original exhaust that's the issue, there ought to be a way to attach a restrictor in an aftermarket exhaust/s that would make it the same as the originals. I'd think the restriction would be the greatest variable between new & aftermarket as regards performance.

Unfortunately, it's more than just restriction. The internal construction of the baffles, crossover, etc on the stock system all contribute to it's performance. The aftermarket systems simply don't have the same parts in the same places, so performance will be at least different, and sometimes less in certain parts of the power curve.

Good stock exhaust systems is the hardest single part to find for these bikes...

[natemoen]

I think a big part of it is that the headpipes are really functionally only like 3/4 inch in diameter causing a significant amount of restriction. as well as the engineering of the rest though.