FJowners.com

Hey guys, Im new to motorcycles and 4 stroke engines.  I had a lot of experience working on my banshee and feel pretty confident about working on my fj 1200.  I would like to clean my carbs today but i havn't built a syncronizer yet.  Can i take my filters off, and clean carbs with them still attatched to intake and be able to get the bowls off?  And if i leave them on the bike and open the throttle will i get an idea of how off they are now by eyeballing the level of each carb valves as they come up?  Any suggestions to get started will help thanks.

 :negative:

you need to remove them to take them apart, It may be a pain,  but you will thank yourself when your working over the bench.

Yep.... the only way to clean them right is off the bike.  That way you can turn them upside down or sideways to get at everything...

Will,

Unlike the typical slide carb you'd find on a 2-smoke, these are CV carbs that lift the slide by vacuum.  So, trying to set the slide cutout to some distance over the floor of the carb throat won't work.  And, trying to eyeball the diff between the slides as they come up will be very difficult for two reasons. 1. you can't get a good view straight into them - way too much stuff in the way of your head 2. Even if you could look straight into the throats, can you tell a difference of 1 or 2 mm ?
You're gonna need some kind of manometer to sync them.

Cheers,
Arnie

Gets worse, even.  It's a 4t engine, so even if they started with an exactly equal measurement for where the synch should be, it'll be wrong unless each cylinder pulls exactly the same amount of vacuum.

Newp, do it right or don't bother at all.

You don't synch the slides.  You synch the throttle plate position.  The slides are constantly dancing up and down in response to the cylinder intake pulse.  No way to gauge synch by looking at the slides.

The slide just controls the airflow velocity and thus the vacuum signal to the circuit ports in the carb throat.  The throttle plate controls the amount of airflow and that's what synching is all about, matching the amount of airflow to each cylinder by making the vacuum signals all equal.

DavidR.

Hey guys, thanks for the info.  Before you guys had a chance to answer i took the filters off and tried to see the slides on the carbs move when i moved the throttle  but they didn't and now i know why.   Thanks.  I plan on making my on carb synch devise based off of what you guys have posted up here.  Another question is that my filters seem to be really big because they have to be bent to fit inside the frame.  Are these possibly not the right k&n filters?

Newp, they're undoubtedly the right K&N filters.  Problem is, the kit that K&N sold for these bikes was utter shit and they don't fit for a damn, as you can now see.  You may be able to flip the outside pair upside down to help them fit a bit, but it's a pretty minor improvement.  Either you fight with them, or you replace them with a set of UNI's, which are 1/4 the price, fit better, and make the same power.