Build your own Manometer for Throttle Body Sync!

[trepetti]

Need to check my bike since I don't know if it's ever been synched. For anyone considering throwing out a hundred bucks for a carb tune you should consider a electronic manometer. As you're in that price range. I've got a Dwyer 477 and it's really easy to use and versatile. Pressure and vacuum readings in any unit there is, and will read a vacuum down to a thousandth of an inch WC. I use one regularly at work and getting the idea to use it to tune carbs at home was a game changer for me (just a tune it by ear guy before). The ability to use it for a lot of other tasks is what makes it worth the money for me.

That looks like a 2 channel manometer? More complicated to do a 4cyl engine. Nice to have the accuracy though. I have had my eye on this: https://www.instructables.com/id/DIY-Digital-Vacuum-Gauge/ I have done some PIC projects so I can do this. I contacted the author and he will have some boards to sell soon, so just need to purchase the components. Less that $100

 

[DeepBarney]

That looks like a 2 channel manometer? More complicated to do a 4cyl engine. Nice to have the accuracy though. I have had my eye on this: https://www.instructables.com/id/DIY-Digital-Vacuum-Gauge/ I have done some PIC projects so I can do this. I contacted the author and he will have some boards to sell soon, so just need to purchase the components. Less that $100

I've not used it on individual throttle bodies before, so I imagine I'd need to come up with a little 4-1manifold with valves on each leg for selecting them separately without a bunch of connecting and disconnecting of tubes. Probably $10 worth of stuff from the hardware store. The accuracy is certainly overkill for this kind of thing but handy for other tasks. And though it's two channel, only one port needs to be utilized. The other is usually used for comparing two sides of a system (like you want to know the pressure drop occurring after a valve or some such).

 

[Ohendo]

All done. I was way out of sync.



After adjustment, close enough!



Much smoother idle, no more hesitation on launch.
Weird after-effect though: after sync, I can only adjust idle to 1280. I can go lower, all the way down to 800 or so. But 1280 is now Max idle.

 

[Gary in NJ]

Correct idle is 1250 to 1350 rpm - so you are within the range...but something isn't quite right. Are you sure that all of the vacuum lines are reconnected and/or blocked?

 

[Ohendo]

Correct idle is 1250 to 1350 rpm - so you are within the range...but something isn't quite right. Are you sure that all of the vacuum lines are reconnected and/or blocked?

I was trying to adjust idle while the manometer was still connected to all four lines per procedure.
I've got it all buttoned up with the blockers in. I'll head back out and try to adjust idle again.

Update: Finally got out riding today. After warm I was able to adjust idle up to 1420 or so. Lowered it to about 1100 and left it. All good!
The smoothness of the engine is definitely noticeable post-sync. It’s like a new bike!

 

[TownsendsFJR1300]

I'd personally LOWER the idle a bit.

I keep mine at 1,100. Dead rock solid, NO vibs in the bars, no vibs in the mirrors at all.
A bit smoother going into first gear too. Gears aren't spinning quite so fast, much less clunking..

I've had it set for about 11 years, no issues..

 

[DeepBarney]

I built my mine per the OP's description, ie. 1/4 OD line, 3/16 couplers with restrictors, and two little F shaped fittings for the bottom/manifold portion, 5ft of hose for each one, and filled with ATF to about the 7inch mark (measured from F-fitting up). Warm bike up to operating temp (first time shut if off around 165*F, second time I waited until the fan came on and it went back to 212*F). Both times as soon as I've connected the synchronizer hoses to the bike and turn it on the fluid starts rushing up tubes (mostly the one connected to #4 cylinder).

Any idea what I'm doing/did wrong?

 

[Ohendo]

Any idea what I'm doing/did wrong?

First guess is an air leak in a fitting or connection. Does the fluid rise stop? Or does it get sucked all the way up the tube?

 

[DeepBarney]

I shut the bike off before it gets up to the restrictor, but it'll easily pull it up to over 36" within a few seconds.

 

[Ohendo]

My #4 shot up 24” or more right away but settled out. I purposely had about 8 feet of tubing for each cylinder just in case.

Maybe you’re just waaaay out of sync?

 

[DeepBarney]

I'm guessing so. It runs rich and I struggled to get it to idle over 1000rpm when I got the bike. I just started the bike again with the lines all pinched #4 rose up all the way (but steadily instead of in a bubbly rush). I couldn't get it down by adjusting #4 screw in any direction. Which way do you turn the screw to decrease the vacuum?

 

[Ohendo]

I believe it’s clockwise to lower the vacuum. Really sounds like you have an air leak in your setup though if you got no results turning the screw. I barely had to move them.

 

[DeepBarney]

I inspected the fittings and I can't find any thing that'd make me suspect a leak. Went ahead and put zip ties around each connection though. Still does the same thing. If I pinch off #4 hose, #1 tries to suck the fluid up instead. Maybe I'll unhook and cap the hoses for #1 and #4 and see how the remaining two react when checked on their own.

 

[DeepBarney]

Tried swapping the hoses between #1 & 2 TB's respectively and likewise with #3 & 4. The hoses for TB #1 & 4 still wound up shooting up real fast on their way to getting sucked in. So I don't think it's a leak in a specific hose. Might try motor oil instead of ATF.

 

[DeepBarney]

Well with 15w-40 in the tubes it started out well. Fluid in #4 quit rising around 40". But the oil isn't easy to see, especially once the bubbles start moving through it never really settles out either (ie always aerated). And no amount of adjustment of any of the screws (save #1 which I haven't touched) will bring #4 down or #1 down and bring the others up.

Thoughts on what's going on here?

 

[Ohendo]

Again, sound like a leak. You should not have bubbles! I had none. If it were air tight, where would the bubbles come from?

I’ll let someone else come in.

 

[TownsendsFJR1300]

Well with 15w-40 in the tubes it started out well. Fluid in #4 quit rising around 40". But the oil isn't easy to see, especially once the bubbles start moving through it never really settles out either (ie always aerated). And no amount of adjustment of any of the screws (save #1 which I haven't touched) will bring #4 down or #1 down and bring the others up.

Thoughts on what's going on here?

Couple things to check:

#1 and #4 black "access hoses," should both have a pink line around the end to identify them.

The below pic (which expires in 7 days), circled in blue, (although labeled by Yamaha as #2),
is your BASE CYLINDER to adjust off of ..

Turning the other small adjusters, (as I re-call), will pull up more fluid. (more vacuum).

****If you cannot get enough RPM's, or generally too low, you can adjust the base #1 screw a little. That will give you more room to adjust the others.


REALLY IMPORTANT (second pic below), between the two throttle bodies is a sync screw adjuster (that tie the two butterfly linkages together). It's NOT supposed to be adjusted, HOWEVER, that doesn't mean someone hasn't in the past... You may have to do a visual on the adjacent butterflys, (or possibly check with vacuum) to make sure they are "in sync".


As a side note, (and possible related) before I got my Carbtune Pro, I paid Yamaha to sync my '04 FJR (running issues).
After later buying the Carbtune (for the FZ), I checked the FJR and found the YAMAHA SHOP, HAD adjusted one of those mechanical sync screws.... You could see the white paint mark, painted from the factory, busted and that screw turned 1/4 turn... I set it back and re-sync'ed. Original problem turned out to be corrosion in an electrical connector that Yamaha couldn't find.

 

[DeepBarney]

Again, sound like a leak. You should not have bubbles! I had none. If it were air tight, where would the bubbles come from?

I’ll let someone else come in.

Yeah I'm going to take the hose assembly off and submerge it in water with ends capped except one hooked to a syringe. I'll then induce a vacuum and see if I get water in infiltrating.

#2 and 3 pull down so low air could be passing through them.

 

[DeepBarney]

Couple things to check:

#1 and #4 black "access hoses," should both have a pink line around the end to identify them.

The below pic (which expires in 7 days), circled in blue, (although labeled by Yamaha as #2),
is your BASE CYLINDER to adjust off of ..

Turning the other small adjusters, (as I re-call), will pull up more fluid. (more vacuum).

****If you cannot get enough RPM's, or generally too low, you can adjust the base #1 screw a little. That will give you more room to adjust the others.


REALLY IMPORTANT (second pic below), between the two throttle bodies is a sync screw adjuster (that tie the two butterfly linkages together). It's NOT supposed to be adjusted, HOWEVER, that doesn't mean someone hasn't in the past... You may have to do a visual on the adjacent butterflys, (or possibly check with vacuum) to make sure they are "in sync".


As a side note, (and possible related) before I got my Carbtune Pro, I paid Yamaha to sync my '04 FJR (running issues).
After later buying the Carbtune (for the FZ), I checked the FJR and found the YAMAHA SHOP, HAD adjusted one of those mechanical sync screws.... You could see the white paint mark, painted from the factory, busted and that screw turned 1/4 turn... I set it back and re-sync'ed. Original problem turned out to be corrosion in an electrical connector that Yamaha couldn't find.



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Yep they've got the marks so I know which ones I'm hooked to, and I already checked the screw between the TB's and the paint mark hasn't been broken. And at an earlier point when I had the air box off I checked that the butterflies were all aligned.

It idles around 1100-1200 so I think I'm good there, but I may need to play with the #1 screw as it smells a touch rich to me (yeah I know that's a piss poor diagnostic standard).

 

[TownsendsFJR1300]

If it's smelling rich, I suspect that (richness and unable to get a good sync) are indeed related..

Do any of your spark plugs look blacker/richer than the others?

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