Build your own Manometer for Throttle Body Sync!

If we knew that (^^^), this thread wouldn't be so long...

TB's attach to the head without gaskets, rubber intake manifolds only..

As posted way earlier, I would try the sync with an actual tool MADE for this.
It IS possible the homemade manometer is NOT working correctly..

.
Ok, just thought someone might have an idea of the mode of failure that would warrant replacement of such a major component. No way in hell though am I going to buy a new set of TB's on a notion that they "might just be bad", without a concrete certainty that they are at fault and it's irreparable (or not fiscally sensible to, $1300 100,000mile bike after all).

I'll see if I can get my hands on one, but based on my results not being dependent on which hose is hooked to TB #4 and my successful vacuum and pressure testing of the tool when submerged (no leaks).

Think I'm going to pull the airbox and everything around the TB's so I can better inspect where they mate to the engine and check again for vacuum leaks. Then remove the factory sync hoses and hook my manometer directly to them for one less variable.
 

TownsendsFJR1300

2007 FZ6
Site Supporter
Ok, just thought someone might have an idea of the mode of failure that would warrant replacement of such a major component. No way in hell though am I going to buy a new set of TB's on a notion that they "might just be bad", without a concrete certainty that they are at fault and it's irreparable (or not fiscally sensible to, $1300 100,000mile bike after all).

I'll see if I can get my hands on one, but based on my results not being dependent on which hose is hooked to TB #4 and my successful vacuum and pressure testing of the tool when submerged (no leaks).

Think I'm going to pull the airbox and everything around the TB's so I can better inspect where they mate to the engine and check again for vacuum leaks. Then remove the factory sync hoses and hook my manometer directly to them for one less variable.
I wouldn't buy new ones either..

I'd bet Flea Bay has em for 1/10 the price of new ones if not cheaper..
 
I wouldn't buy new ones either..

I'd bet Flea Bay has em for 1/10 the price of new ones if not cheaper..
Well I just meant a different set in general, not necessarily unused OEM from the dealer. Just checked the Bay and I'm seeing them for as low as $45. I was thinking they'd still be a few hundred for a decent condition set.

Think I'm going to take it all apart from the air box down to the engine and make sure I've not got any simple to resolve air leaks before I go throwing parts at it.
 

TownsendsFJR1300

2007 FZ6
Site Supporter
Well I just meant a different set in general, not necessarily unused OEM from the dealer. Just checked the Bay and I'm seeing them for as low as $45. I was thinking they'd still be a few hundred for a decent condition set.

Think I'm going to take it all apart from the air box down to the engine and make sure I've not got any simple to resolve air leaks before I go throwing parts at it.
Any updates??
 

TownsendsFJR1300

2007 FZ6
Site Supporter
I don't know if I've asked this before, but would cam timing it valve clearance effect this?
I wouldn't think so but another member just did a valve adjustment.

One cam was off one tooth and bike ran rich, and the mileage dropped but it ran..

Certainly can't hurt to check (and not as involved as an actual valve adjustment-pulling cams).
 
So I've had some more time to fiddle with the bike and after making sure all the rubber boots on both sides of the throttle body were tight, I've still got a vacuum leak I'm sure. I've tried spraying starting fluid at connections and such when it's running to try to find the leak, and while it does bog, it's not immediate and I can't pin down a location for where it's leaking in. There's added difficulty when the air box is on to see where all the spray is going and even with a straw attached it's tough to apply it in certain areas to see if it reacts. With the air box off it doesn't matter where I spray it because the vapors get pulled in through the tops of the throttle bodies regardless.

Since whichever line on my balancing tool is hooked to cylinder #4 pulls all the the fluid from the line hooked to number #3 (#1 does the same to #2 but not as fast/badly as #4), I'm starting to suspect it's leaking at #3 and #2 to a lesser extent. Specifically I'm wondering if it's leaking where the shaft goes into the two inside throttle bodies (where the return spring and little alignment screw is). I know on old high mileage carburetors it's not uncommon for the aluminum housings to get worn out around shaft where it passed through the body of the carburetor and leak there, on cars at least). The brass shaft eventually embiggens the softer aluminum hole enough air starts leaking in between the two. This bike has over 100k miles on it. I'm not sure if that's enough time and use to cause that amount of wear, but it's certainly higher than the average bike.

My worry is if I take the throttle bodies out to go chasing this I'm just going to invite more potential problems.
 

Ohendo

Site Supporter
Since whichever line on my balancing tool is hooked to cylinder #4 pulls all the the fluid from the line hooked to number #3 (#1 does the same to #2 but not as fast/badly as #4), I'm starting to suspect it's leaking at #3 and #2 to a lesser extent.
Are all four hoses connected together at the manometer end properly? I would think that an extreme vacuum in cylinder 4 should be pulling the fluid from each of the other 3, not just the adjacent tubing. Wondering if your tool is at fault?484B809D-881D-4496-A9C3-2EDF74E7A12F.jpeg
 
Are all four hoses connected together at the manometer end properly? I would think that an extreme vacuum in cylinder 4 should be pulling the fluid from each of the other 3, not just the adjacent tubing. Wondering if your tool is at fault?View attachment 74068
Yep, mine is set up just like that and no leaks (tested under vacuum and pressure with it submerged in water).
#4 is only going to drain all the others in the scenario it has more vacuum than all 3 others by a considerable amount. But #1 rises as well (again likely because there's a leak at #2). #4 isn't under extreme vacuum, it's just higher higher than the other cylinder it's paired with on the throttle body (#3).

I've tried connecting #4 and #1 cylinders so that they were adjacent tubes on the tool and a number of other non linear orders, but in all cases the fluid in the tube connected to #4 sky rockets, #1 keeps rising though not near as rapidly as #4, and #2 and#3 are drained.
 
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