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Any tricks to installing air box?

Started by Fj1100 Rebuild project, August 20, 2023, 09:34:34 PM

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Fj1100 Rebuild project

Hey guys I'm trying to install my factory air box on my 84 fj1100 but I don't know what the best way to do it is. I pulled the carbs and muscled the air box into place (it's a tight fit) but when I went to reinstall the carbs there wasn't enough room. I'm thinking about just using a generic air filter that bolts directly to the carbs and ditching the box altogether but I'm not sure how that would affect the air fuel mixture and I'm trying to keep the bike stock and reliable, any suggestions?

Millietant

To remove and re-install your carbs, the easiest way is to loosen the 2 bottom sub-frame mounting bolts, then remove the top 2 subframe mounting bolts and let  the subframe slowly rotate backwards to sit the inner fender on the tyre.

This gives enough space to easily remove and replace the carbs. :good2:
Dean

'89 FJ 1200 3CV - owned from new.
'89 FJ 1200 3CV - no engine, tank, seat....parts bike for the future.
'88 FJ 1200 3CV - complete runner 2024 resto project
'88 FJ 1200 3CV - became a race bike, no longer with us.
'86 FJ 1200 1TX - sold to my boss to finance the '89 3CV I still own.

balky1

If you are not willing to remove the subframe bolts you can still do it. Don't screw the air box with its three screws, but first put the carbs on and tighten the boots. It is a tight and gruesome operation. Oil the carb intake rubbers, just a drop. It will be easier to push them in.
Since the rubber boots on the air box tend to crack at this age, the best solution are the intake filters from RPM. Jetting recommendations can be found here.


FJ 1100, 1985, sold
FJR 1300, 2009

Waiex191

Covered here:
https://fjowners.com/index.php?topic=20022.0

Also leave the elbow connected to the breather hose. Get it lined up with the rubber grommet and push it in with a large flat blade screwdriver.

I'm in the "happy with my stock airbox" group.

What Dean (Millietant) says is right on.
Bryan
1989 FJ1200
1981 Suzuki GN400
Poplar Grove, IL
 

Pat Conlon

Quote from: Millietant on August 21, 2023, 12:35:08 AM
To remove and re-install your carbs, the easiest way is to loosen the 2 bottom sub-frame mounting bolts, then remove the top 2 subframe mounting bolts and let  the subframe slowly rotate backwards to sit the inner fender on the tyre.

This gives enough space to easily remove and replace the carbs. :good2:

This tilt on the subframe works great on the '84 to '90 FJ's but not so well on the '91-95 bikes.
Those pesky muffler mounts (on the subframe) get in the way so you've got to unbolt your mufflers.
RPM UniPods for me!
1) Free Owners Manual download: https://tinyurl.com/fmsz7hk9
2) Don't store your FJ with E10 fuel https://tinyurl.com/3cjrfct5
3) Replace your old stock rubber brake lines.
4) Important items for the '84-87 FJ's:
Safety wire: https://tinyurl.com/99zp8ufh
Fuel line: https://tinyurl.com/bdff9bf3

Fj1100 Rebuild project

Quote from: Millietant on August 21, 2023, 12:35:08 AM
To remove and re-install your carbs, the easiest way is to loosen the 2 bottom sub-frame mounting bolts, then remove the top 2 subframe mounting bolts and let  the subframe slowly rotate backwards to sit the inner fender on the tyre.

This gives enough space to easily remove and replace the carbs. :good2:
Sounds easy enough but is there anything I need to watch out for when doing this? Don't want to accidentally ruin the wiring harness or misalign something

Fj1100 Rebuild project

Quote from: balky1 on August 21, 2023, 04:20:30 AM
If you are not willing to remove the subframe bolts you can still do it. Don't screw the air box with its three screws, but first put the carbs on and tighten the boots. It is a tight and gruesome operation. Oil the carb intake rubbers, just a drop. It will be easier to push them in.
Since the rubber boots on the air box tend to crack at this age, the best solution are the intake filters from RPM. Jetting recommendations can be found here.
Oh yeah I don't know why but lubricating the intake boots completely escaped my mind lol when I reinstalled the carbs I just used a heat gun and some brute strength

Fj1100 Rebuild project

Quote from: balky1 on August 21, 2023, 04:20:30 AM
If you are not willing to remove the subframe bolts you can still do it. Don't screw the air box with its three screws, but first put the carbs on and tighten the boots. It is a tight and gruesome operation. Oil the carb intake rubbers, just a drop. It will be easier to push them in.
Since the rubber boots on the air box tend to crack at this age, the best solution are the intake filters from RPM. Jetting recommendations can be found here.
So would I have to re tune the carb if I were to get aftermarket intake filters? Looking at the way the air box is set up it really doesn't look like air flow would be too different

RPM - Robert

Most people find that going up one main jet size and shimming the main jet needle is all that is needed. Some people found that doing nothing worked for them.

balky1

Quote from: Fj1100 Rebuild project on August 21, 2023, 05:42:52 PM
Quote from: balky1 on August 21, 2023, 04:20:30 AM
If you are not willing to remove the subframe bolts you can still do it. Don't screw the air box with its three screws, but first put the carbs on and tighten the boots. It is a tight and gruesome operation. Oil the carb intake rubbers, just a drop. It will be easier to push them in.
Since the rubber boots on the air box tend to crack at this age, the best solution are the intake filters from RPM. Jetting recommendations can be found here.
So would I have to re tune the carb if I were to get aftermarket intake filters? Looking at the way the air box is set up it really doesn't look like air flow would be too different

You should sync them every time you remove them. As for jets, Robert gave you the answer.


FJ 1100, 1985, sold
FJR 1300, 2009

Millietant

Quote from: Fj1100 Rebuild project on August 21, 2023, 04:15:48 PM
Quote from: Millietant on August 21, 2023, 12:35:08 AM
To remove and re-install your carbs, the easiest way is to loosen the 2 bottom sub-frame mounting bolts, then remove the top 2 subframe mounting bolts and let  the subframe slowly rotate backwards to sit the inner fender on the tyre.

This gives enough space to easily remove and replace the carbs. :good2:
Sounds easy enough but is there anything I need to watch out for when doing this? Don't want to accidentally ruin the wiring harness or misalign something

Nope, nothing to worry about. Just put a towel over the tyre to give the subframe some scratch protection when it's lowered down.
Dean

'89 FJ 1200 3CV - owned from new.
'89 FJ 1200 3CV - no engine, tank, seat....parts bike for the future.
'88 FJ 1200 3CV - complete runner 2024 resto project
'88 FJ 1200 3CV - became a race bike, no longer with us.
'86 FJ 1200 1TX - sold to my boss to finance the '89 3CV I still own.