So you DID use the SyncPro.Glad ya got it goin.

* Last updated by: Grn14 on 10/10/2015 @ 4:34 PM *

Hub, got a question about bypass valves: Does a bypass valve let more air into the Tbody thereby increasing flow and boosting vacuum or does the valve close off the hole sealing more vacuum into the Tbody to increase the vacuum? It seems the latter based on what I discovered about tightening v loosening.

* Last updated by: Rook on 10/10/2015 @ 5:48 PM *

---

So you DID use the SyncPro.Glad ya got it goin.

Yeah, grn. It's a good tool but requires a lot of fuss to use. One you have it figured out, I guess it might be worthwhile. I do like the fluid columns for visual reference but the ABN gauges are so big, I don't think it will be a problem to read them + they provide a reading of the actual vacuum which of course the SyncPro cannot do.

---

All done. Wish I could post a pic but my REAL computer is in the shop. No pics til she comes back home.

The final stages were going back to the center screw to reduce the vacuum in the RH pair which had crept up from the bypass adjustments. It seemed as though it would not turn back counterclockwise any moe so I did not try to force it. Then back to bypass #4 to increase it and finally I hit #3 to reduce it a hair. Any time you adjust one screw, it seems to have some impact on the vacuum of the other Tbodies. It was a process of bouncing back and forth between all 5 screws zeroing in until I got it right. End result was that all four columns were nearly perfectly level and I maintained the highest vacuum I originally had only in #2 across all four Tbodies. Sounds nice and smooth. It never was rough. I still have a little bit of my lopey sound which I like.

Next time I remove the Tbodies, I'm going to try to remove that center screw and replace it with a socket cap allen screw. I'd also like to replace the bypass screws with something easier to turn but I imagine the screw is a part of the valve itself so it may not be possible.

Hope to test out the ABN vacuum gauges tomorrow and maybe go for a test ride early next week.

Glad this is done. I learned a lot.

* Last updated by: Rook on 10/10/2015 @ 8:12 PM *

---

Checked the vacuums with my new gauges. #1 was at 222 mmmHg and the other three were at 224. That's close enough for me and I know I can't get any more out of #1 anyway because I have the bypass closed all the way off.

The service limit is 258 +/-10 mmHg. I'm out of spec. The SM recommends removing the bypass screws and cleaing them but I don't have time to keep at this. Good enough until next time. It's an old bike.

* Last updated by: Rook on 1/13/2016 @ 6:56 PM *

---

Rook, opening the bypass increases how much air is going into the cylinder which lowers the vacuum you are reading.

This is because the engine is always trying to draw in the same volume of space, if the throttle plates are wide open, then the engine can suck in as much air as it likes which would result in a very low vacuum/no vacuum.

With the throttle plates closed only a small amount of air (pretend its 10cc of air) can be sucked into the engine, but the piston is still trying to draw in the same volume (450cc/cylinder, this difference (440cc) would result in a vacuum (technically, its just a low pressure and not a real vacuum).

While I have tried and gave up on syncing the TBs on this bike (those screws are in a horrible spot and mine were close enough to not bother), on my previous bike the overall vacuum reading (222mmHg in your case) is actually irrelevant. Its the difference between the cylinders that's the biggest issue.

That being said, on my previous bike you would increase the idle of the engine to conduct the sync (since it would stabilize the readings), adjust the plates so they're drawing the same vacuum per cylinder then adjust the idle back to normal.

Since your bike has a vacuum reading on 222mmHg and the book states it should be around 293mmHg that means its:
-You're letting too much air in past the throttle plates, which would result in higher engine idle (adjust the idle speed or air bleeder/bypass valves)
-The engine compression is low, which would mean either worn piston rings, out of spec valves, or other top end issues.
-Most likely, the gauges are simply giving you the incorrect vacuum reading.

Don't sweat it, the TBs are all pulling nearly identical vacuum and the idle is set correctly so you're good to go.
As a side note to gauges, typically dial/gauge manometers needs to be calibrated to a single cylinder. You hook up the first gauge, take a reading (100mm), then hook up the 2nd gauge (90mm), adjust it to match the 1st gauge (100mm), rinse and repeat for the other 2 gauges. The actual vacuum reading is irrelevant.

Since your bike has a vacuum reading on 222mmHg and the book states it should be around 293mmHg

I made an error on the thspecced range i listed above and I went back and edited that info. the specced vacuum range is

258 mmHg +/-10 mmHg

I'm still low but not that low.

Thanks again for sheading light on this topic, Nightmare.

Rook, opening the bypass increases how much air is going into the cylinder which lowers the vacuum you are reading.

This is because the engine is always trying to draw in the same volume of space, if the throttle plates are wide open, then the engine can suck in as much air as it likes which would result in a very low vacuum/no vacuum.

With the throttle plates closed only a small amount of air (pretend its 10cc of air) can be sucked into the engine, but the piston is still trying to draw in the same volume (450cc/cylinder, this difference (440cc) would result in a vacuum (technically, its just a low pressure and not a real vacuum).

Great explanaition, Nightmare. Thanks. So-- even though you are closing a valve when you tighten the bypass screw, you are increasing vacuum. makes sense. vacuum is the opposite of flow. Restrict flow, you increase vacuum.

While I have tried and gave up on syncing the TBs on this bike (those screws are in a horrible spot and mine were close enough to not bother), on my previous bike the overall vacuum reading (222mmHg in your case) is actually irrelevant. Its the difference between the cylinders that's the biggest issue.

That being said, on my previous bike you would increase the idle of the engine to conduct the sync (since it would stabilize the readings), adjust the plates so they're drawing the same vacuum per cylinder then adjust the idle back to normal.

Yes, it's not necessary to have in spec vacuum to balance the Tbodies but you would want to know if it's out of spec because that suggests one of the problems you mention next.

-You're letting too much air in past the throttle plates, which would result in higher engine idle (adjust the idle speed or air bleeder/bypass valves)
-The engine compression is low, which would mean either worn piston rings, out of spec valves, or other top end issues.
-Most likely, the gauges are simply giving you the incorrect vacuum reading.

SAd to say but I do have compression that is a little low. Valves were checked just recently and all ok. I'm trusting that the gauges are pretty accurate because they all read the same right after using the manometer to balance the vacuums. If they were not accurately calibrated, I'd expect they would show some variation after syncing with a manometer. True though, if you just want to sync, the exact values the gaugse shows doesn't matter as long as they are all calibrated the same.

As a side note to gauges, typically dial/gauge manometers needs to be calibrated to a single cylinder. You hook up the first gauge, take a reading (100mm), then hook up the 2nd gauge (90mm), adjust it to match the 1st gauge (100mm), rinse and repeat for the other 2 gauges. The actual vacuum reading is irrelevant.

Good point. I zeroed all of mine but I did not calibrate them off of a single cylinder. Next time, perhaps. I suppose if you want the gauges to show you accurate values, you would need to calibrate them off of some source that you know for sure is a particular mmHg. There must be some sort of device to that but I suppose simply buying a new set of gauges when you feel the old ones are getting out of whack is what most people do.

Thank for making those points Nightmare.

* Last updated by: Rook on 1/13/2016 @ 7:06 PM *

---

I did test each vacuum gauges with my mityvac. The mityvac gauge read the same as each vacuum gauge. The mighty vac pump is only strong enough to produce 15 CmHg but if that gauge is accurate, so are the test gauges...at least up to 15 CmHg.

---

Yes, it's not necessary to have in spec vacuum to balance the Tbodies but you would want to know if it's out of spec because that suggests one of the problems you mention next.

Likewise, it's not necessary to have the idle at precisely 1100 rpm while syncing. The SM says to use a highly accurate tachometer to adjust the idle to exactly 1100 rpm but it's not at all necessary to be dead on 1100 if you are only concerned about balancing. If you wanted to check if the vacuum was in spec, then I guess you would need to be pretty darn close to exactly 1100 rpm. As Nightmare mentioned, the vacuum reduces as the rpm increases so if the engine was idling a 1200 rpm the vacuum would be lower than it would be at 1100 rpm. I suppose if the engine was idling at 1000 rpm, that would make the vacuum higher than it would be at 1100 rpm.

I did notice the fluid columns reduce in height rapidly when I applied throttle during the vacuum sync. I don't know if there is any danger of sucking fluid out of the manometer by running the engine at too high of an rpm as long as the fluid columns are at a reasonable height at idle speed. The SyncPro instructions claim it is possible for the engine to suck fluid out of the tool if the engine is run over 6000 rpm with the tool attached....go figure.

* Last updated by: Rook on 10/14/2015 @ 7:32 AM *

---

Does a bypass valve let more air into the Tbody thereby increasing flow and boosting vacuum

Look at it this way... 14.7 is the constant. It's how fast the void is taken up or filled. Less holes, more vacuum applied. If I WOT I go to zero or 14.7 pressure, or watch how the liquid drops when the throttle is opened. If I go thru a smaller opening I create more pressure, the liquid climbs. Watch how the liquid drops you wick up the throttle. Look how the liquid drops you turn off the key is 14.7 is filled in the static. You just do not see it; the liquid being too slow to show it [key off at the intake fill think].

or does the valve close off the hole sealing more vacuum into the Tbody to increase the vacuum?

Keep that thought. Whereas the fuel has filled that loss. Look at the proportion of 14.7 is the low vacuum pull of say 9 pounds: give or take. Look at how the ring gap goes wide, more vac is lost past down the ring gap; how much pull does that do to the liquid level? Lowers it as if the key is off and 14.7 has no vacuum pull on the way down to raise the liquid. This is when the piston sealing is being compensated for the other 3. Look how the other cylinder is sealed tighter and that vacuum pull; is the piston on the way down. Look at how the plug turns black-wet, no kinetic or sealing factor. Look at how the compression numbers show the oiled plug beginning to occur out of the blueprint specs.

Look at how we are discussing air pressures, not fuel to air ratios. Now we think two void fillers. One being the air, the other is fuel. We have to look at a constant and that is 14.7. We then mess with air passages and we could think like this. I'm going to fill the pool with a fire hydrant is the big t-body hole. We look at the bypass as a garden hose. We turn the garden hose off, that proportion is now filled with fuel; and remember the speed of who enters to create a proportion. I drop the garden hose out of the filling, the fuel is more condensed in that mix as the void fills in a millisecond of time anshit.

See how you are now running in a richer environment; is a tune of the AFR. 14.7 remained the constant. Richer/smoother/torque window is this slight tune/sync. Look at the sync now. You took 1 and 4 as the blades are being tweaked by the center screw alone. You turned off the garden hose so you are stuck with the worst and most pressured cylinders to compensate for wear? I would find the higher compression cylinders on either side and run the blade cut>> off of those. Let the other 2 lag, the idle lops who cares. At least the blades are close on the WOT.

Look how you'd have the one blade bank more closed or lowered on the WOT. That drag is a closing blade, right? The higher compression cylinders would open the blade more, yes? And since you are done with the blade cut, you add the other 2 hoses to the sync, open the bypass screws and blend the sync level with all 4 air screws. You just crack [any one of] them: open until it reads at the liquid and adjust the other 3 to that. Look how one might have to be opened less or more, [depending on the compression test] and those numbers not being too consistent. Look how you changed the AFR and threw the fuel out at the close of the valve. Look how you did not change the fueling via a pig, just by air entry and who filled the void sooner. Didn't you have both the hydrant and garden hose both running upon startup? You did change the air to fuel ratio; as if the bypass screw is a pig fueling tool like a pc.

Look how you take in all this sync work for both AFR and smoothness all thru the blade/screw opening. Look at how they anal about an accurate tach but the lower the idle, the smother the sync. The constant does not give a shit about rpm accuracy. That's formula in a book lining up numbers in a tube. If you understand the constant, the void, the [AFR] filling there of, balance is balance no matter the rpm.

---

"Does a bypass valve let more air into the Tbody thereby increasing flow and boosting vacuum"

Look at it this way... 14.7 is the constant. It's how fast the void is taken up or filled. Less holes, more vacuum applied. If I WOT I go to zero or 14.7 pressure, or watch how the liquid drops when the throttle is opened. If I go thru a smaller opening I create more pressure, the liquid climbs. Watch how the liquid drops you wick up the throttle. Look how the liquid drops you turn off the key is 14.7 is filled in the static.

Copy that. Open throttle, vacuum goes down because you just opened the door and let the vacuum ou (or air in as it were). Same as unscrewing the lid on a brand new jar of pickles. Slooowly you unscrew, sllllloooowl the vacuum in the jar releases until POP goes the center of the lid, the vacuum is broken and air rushes in. No more vacuum. Same thing with WOT in your Tbodies. And the bypass valves act the same way your throttle plates(butterfly valves) do. Screw the bypass IN, you are closing the valve and this lets air in slower so the vacuum increases. Screw the bypass valve out, now it's like you are screwing the lid off the pickle jar, air comes in and vacuum is reduced.

"or does the valve close off the hole sealing more vacuum into the Tbody to increase the vacuum?"

Keep that thought. Whereas the fuel has filled that loss.................... Now we think two void fillers. One being the air, the other is fuel. We have to look at a constant and that is 14.7. We then mess with air passages and we could think like this. I'm going to fill the pool with a fire hydrant is the big t-body hole. We look at the bypass as a garden hose. We turn the garden hose off, that proportion is now filled with fuel; and remember the speed of who enters to create a proportion. I drop the garden hose out of the filling, the fuel is more condensed in that mix as the void fills in a millisecond of time anshit.

See how you are now running in a richer environment; is a tune of the AFR.

Yes. If you increase vacuum in a Tbody, you are letting the air into our proverbial pickle jar more slowly. If there's more vacuum, then that increases the proportion of pickle juice (fuel) to the proportion of air.

I would find the higher compression cylinders on either side and run the blade cut>> off of those. Let the other 2 lag, the idle lops who cares. At least the blades are close on the WOT.

that's what the SM suggests. I was actually pretty satisfied with balancing the strongest of the pairs but it was so much work to get that far, I couldn't see not playing with the bypass screws to get those vacuums up to balance with the strong Tbodies.

And since you are done with the blade cut, you add the other 2 hoses to the sync, open the bypass screws and blend the sync level with all 4 air screws.

That's how I did 'er. Actually, what ended up happening was that one of the strong vacuums went even higher than the other strong it was balanced to by turning the center screw clockwise. this imbalance of the strongs seemed to happen when I adjusted a bypass screw of a weak (I think). ...So, I ended up jumping back and forth between bypass screws of the weaks and turning the center screw back countercloclockwise. In the end, all were balanced and the center screw was tuned right about back where it started before the sync or perhaps just a few degrees counterclockwise of where it started (actually seemed like it wouldn't turn anymore). Anyway, all are synced and the blades probably weren't changed much from factory setting so I'm happy.

Thanks for all the help, Hub. I'm looking forward to getting the Tbodies out again some day so I can have a close look at those screws and how they work. Meantime, stay tuned for pics and Tbody sync tutorial. It's a lot of fussy work but like all of this stuff,do it once and it will be so much easier to do and understand the next time. hhaha--took me over 2 years before I finally got to it!

* Last updated by: Rook on 10/15/2015 @ 11:27 AM *

---

Got your plugs, D. The high mag photography hath begun.

FYI... your plugs are worn.

---

Yup saw that. fire and brimstone, salt my peter (Hubism). Thanks for the scientific testing!

---

It's too bloody cold for a proper test ride but I had a little run up the road just now. Difference after the sync? I'm not really feelin it. It idles a little smoother I think but no big change riding. It ran great before an it still runs great. Final note: If you want to get a little more intimate with your ninjee, go ahead and sync but if the bike was already running fine, don't count on any big eye-openers.

fin

---

If you want to get a little more intimate with your ninjee

Oh... I won't tell you about the unspeakable depravity to which I've subjected mine: much to her delight, I might add.

Mmmmmmmm... I make it hurt soooo good.

---

---

FYI, sucking the manometer fluid into the engine is a real concern, the mercury filled manometer that I used to have came with restrictors to reduce how much vacuum the tubes would see.

I don't THINK the fluid that they are using in today's meters would cause much of a real problem to the engine; just means you have to buy more of the fluid and fill up the reservoir.

FYI, sucking the manometer fluid into the engine is a real concern, the mercury filled manometer that I used to have came with restrictors to reduce how much vacuum the tubes would see.

The SyncPro also has a brass restrictor for each hose that comes from the Tbodies. It works very well. It keeps the fluid level from fluttering. I don't know if it reduces the vacuum but it does slow it down. I used the SyncPro hoses with restrictors for my vacuum gauges to and that worked perfevtly for keeping the needles from shaking.

I don't THINK the fluid that they are using in today's meters would cause much of a real problem to the engine; just means you have to buy more of the fluid and fill up the reservoir.

Sucking fluid in is not uncommon. If you don't follow the SynPro instructions and experiment with the tool before you know how it was intended to work, it might suck up some fluid. I've only heard the SyncPro fluid is totally harmless to the engine. It's no worse than getting a few drops of engine coolant down your intake. The SyncPro instructions say the fluid is a water based fluid containing ethyl glycol. They say it is not for human consumption but is non toxic in small amounts. They recommend flushing old fluid down the kitchen sink drain. If they sold the fluid in larger quantities, they would probably have to call it a hazardous substance whichwould lead to a lot of problems with selling it. I believe it is plain old antifreeze and water but no more than a quarter fl oz is in the tool.

* Last updated by: Rook on 10/18/2015 @ 7:12 PM *

---

Keeping to my word, here's a pic of my sync. Not EXACTLY perfect but mighty close.

The tape marks indicate the vacuums before the sync. All were brought up to the highest vacuum which was on cyl #2.

The tutorial is well under way. It's going to be another epic almost the like of the valve lash adjustment tutorial. I got so much great info off of this thread and I want to say thanks to you all. Gotta give a special thanks to Hub for following along with me in the early stages of this project right up to the end. Reading over this entire thread, I see there are LOTS of great bits from all of you guys. I'm combing through it all and including every single bit of info in the tut. Stay tuned. Thanks, all! i really learned a huge amount from this.

* Last updated by: Rook on 1/13/2016 @ 7:36 PM *

---

Well shit, Rook, you could take on a part time job at a bike shop come spring time. I think you're ready. Well, you were ready, but this is the place you can show your portfolio off to.

---

Already tried that and the guy didn't take me up on it. I might try again when Spring comes around because I will be out of work when school's out.

---

Been thinking, the center adjuster screw only seemed to affect the RH pair no matter how far I turned it clockwise or counterclockwise (it only seemed to turn about 90° before i couldn't turn it anymore). Is it possible that center adjuster screw only effects the RH side of the actuator arm?

If so, how would you adjust the vacuums via blades in the LH pair? To accommodate the need for blade adjustment in the LH pair, you could adjust ALL of the blades open or closed with the idle adjuster nob, no? Then go back and use the center adjuster to do what you need to do to the RH... No?

* Last updated by: Rook on 1/16/2016 @ 12:18 PM *

---

Blades bank1 and blades bank2 are just that. 4 equally machined slots cut into a single rod [cut flat] to accommodate 4 blades of equal diameters. Cut the rod in half so 1-2 and 3-4 cylinder banks pulse independent of each other, but still act as one blade for both cylinders. So as to confuse you by saying; use the sync nipples 1-3 if 3 is not being used for the recovery tank say. No matter the combo of 1-3, 1-4, 2-3, or 2-4, it still lines up bank1 so as to match the vac pulls for bank2.

1. The manometer is not sensitive enough on that one bank pull is a readjust at the meter.
2. Can't be the compression or you'd have zero pull of the fluid in the mano tube.
3. The bank's nipple being used is clogged so as no reading no matter the set screw.
WOT am I missing?

---

I had vacuum in all t-bodies but adjusting the center screw only effected the RH bank. Couldn't be clogged nipple or zero compression or I'd have no vacuum. Im sure the manometer was sensitive enough because the manometer reacted to adjustments made to the LH bank bypass screws.

WOT am I missing?

Only things i can think of is that I didn't turn the center adjuster screw far enough. Maybe at some point it stops adjusting the RH bank and starts adjusting the RH bank but I couldn't get it to turn that far.

So I definitely should be able to adjust the blades on both the LH bank and the RH bank by turning the center screw?

* Last updated by: Rook on 1/16/2016 @ 8:49 PM *

---

We are back to how I start out first thing = Close all low screws.
Then I can nipple up either combo-side to adjust the shafts/blades = 2nd move.
Then I open up 1/4 (1/8th means richer) turn and readjust = Step 3.

I never adjust the center screw once I open the lows. I set the lows as if no shaft at all, but 4 individual t-bodies leveled against each other. The only way to find out is to close the screws, hook up 2 hoses, run the center screw and note change. I'm thinking that if you have 4 hoses hooked up, the lows are throwing you off? Because if you can change the low and it reacts on that side? I don't follow book just for that reason you showing no response and me seeing the lows interfering. I could be wrong.

---