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?
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:
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.
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.
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!
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
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
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
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.
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.
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.