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Gen 3 Throttle Body Sync Questions

7K views 22 replies 5 participants last post by  mentolio 
#1 · (Edited)
Hey Guys,

Gen 3 V, done 38,000 kms.

As part of the TB sync, i guess cleaning the throttle bodies is a good idea. Especially where I live, is very dusty, and the gas sometimes might not be the best (have just started using a liquimoly equivalent of lucas upper cylinder cleaner). My steps will be:

1. Check existing manometer readings and make a note.
2. Clean intake valves alone
3. Check readings again.
4. Adjust the left bypass screw to see if the readings come to spec.
5. If readings are too low/not to spec, remove entire TB assy and inspect bypass screws if they are choked - clean the rest of the TB while at it.
6. Reinstall, clean bypass screws/install new bypass screws
7. Take readings again.

Does this process sound right?

1. If I find the bypass screws on the TB assy black and choked with carbon, do I replace that whole thing along with the washer, O ring etc? Or Just cleaning both the screws with a high flash solvent and putting it back in will suffice?

Table Hand Wood stain Wood Furniture


I also understand to leave the right bypass screw alone, and adjust ONLY the left (that's the cylinder that fires first), and then hopefully, the right cylinder will readjust itself and calm down to match up with the left.

2. My other question is what if the left does not allow for any more adjustment - already turned out fully? And the cylinders then read about 32-33 kpa on the manometer. What then? The actual reading should be 37.8 kpa.

Many thanks,
 
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#2 ·
Vacuum Sync

First you list steps 1 through 7, I would have stopped at #1

http://www.kawasakiversys.com/forum...e-shim-vacuum-sync-2015-650abs-onewizard.html

http://www.kawasakiversys.com/forum...difications.html?highlight=throttle+body+sync
After doing a valve shim check, no adjustments needed to the vacuum sync screws, note vacuum line brought out from test ports permanently.

This is my 2015 after valve shim correction, at idle RPM, note I am using 2 of the 3/16 splice connectors to join to the Carbtune lines for testing

vacuum lines capped off at Denali compressor using 1/4 stainless 1.5 inch long bolts, with thread cut off at taper.
 
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#3 ·
First you list steps 1 through 7, I would have stopped at #1
So, if I understand correct - if the cylinders do not reach 38 KPA OR do not balance because the screws do not have any more adjustment options - then the valve shim check/adjustment is the obvious checkpoint.

Now Valve shim check needs to get done at my local dealership, I do not possess the space or the tools to get down to checking the shims myself. I am not too convinced of their own ability to do a good job at this. I am no longer in warranty, but finding a good shop who will do this work with sincereity is hard to find around where I live.

Considering I am close to 40k, the valve shim check is also obviously due.

Could you or someone else also help answer my other questions? The replacement of the bypass screws etc?
 
#7 ·
ByPass screw

I see it in the manual, I am just saying in almost 10 years on this forum, No One has ever mentioned replacing them. And to be clear, you are working backwards, a vacuum sync should have been done first, that is check and see if they are balanced. If extremely out a valve shim check should have been done first, you try and balance now and you may find when and if you do a valve shim that you will be way off again. That video link I posted had a second test, doing a compression check, both cyclinders should be identical, if they aren't, good chance you have tight valves and your motor could be getting tired.
 
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#6 ·
My KISS method to adjust throttle body sync. KISS...Keep IT Simple Stupid.

My home made (Port-a-gee) monomoter worked great. After valve adjust I hooked it up to discover the levels were off. After around 2/3's of a turn out on the left side balanced it out and she purred like a kitten. Bike has never run so good.
 

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#8 ·
Homemade / Carbtune


Yes I had a homemade set like that, had restrictions inserted , PITA , slightly off and transmission fluid heading into the test port, then I was at a buddies and saw his set up, far superior and no regrets, for a extra $$ I bought the 4 channel.




I assume that you are posting this after you did a Valve Shim check, as I see you have a MK-3 .My finding was my bike purred like a kitten after I did a valve shim check in which I had tight valves, those readings in the photo were taken after and no adjustment was needed, in other words it was originally set correctly at the factory, and the reason it wasn't purring like a kitten was because of the tight valves @ under 12000 KM , yes not miles KM
 
#11 ·
From my time on the KLR650 Forum I learned the 'mantra' - a TAPPY valve is a HAPPY valve, so from my first valve shim check I ALWAYS open them up to the MAXIMUM specified clearance.

On subsequent shim-checks I've found that they MOSTLY stay pretty close to that MAX setting, tightening up only SLIGHTLY.
 
#14 ·
Eddie, I read on another thread that Invader suggests the same (MAX setting).

I am trying to avoid buying a "whole" set of shims (80USD). Does it make sense to open the bike up and check what shims I might need and then place the relevant order? I would like to just replace the shims as opposed to machining them down.

If I need to open all 16 valves to maximum clearance, I expect to change the shims on all the 16 valves (the specs for each might change however). Is this understanding correct?

Each shim size comes in a set of 3 from someone like Hotcams which costs approximately 10 USD. 10 X 10 sets (lets say some valves have a similar reading) is 100 USD right there.

I am confused which way to go. Open, check and then order. Or just order the whole set (most of which will probably be unused?)

I have never owned a bike that needed this kind of work, all my previous motorcycles were Carb set ups.
 
#12 ·
Okay, this is good information. Thank you very much for this explanation. So the vacuum synch test is just like popping a thermometer to check what is up with the engine. If it fails that test, onto the valves check. And when doing the valves, try and keep it at the maximum possible tolerances as mentioned by eddie - to keep things going.

Right, I will get down to studying valve shim check a little bit in detail and post questions in the relevant thread. Thanks - its good learning here!
 
#13 ·
Valve Shim/ Vacuum Sync/ In That Order

:thanx::goodidea::thumb::thumb::thumb::eek:penarms:
 
#17 · (Edited)
NOTE: not intended as a thread hijack, just a question pertinent to this thread.

I just bought the same Carbtune synchro-tool that onewizard uses, mainly because of the difficulties with mercury (my old stick is running low after 25 years...imagine that). So I decided to give my bike (2015 V650) it's yearly check up. Last time I synced the throttle bodies, I did it with my old stick, which is low on mercury. Not ideal, but doable, and the bodies weren't really out of synch anyway. Check it this year: in synch, but vacuum is reading around 25cm instead of the recommended 28, so I start playing with the screws in an attempt to get some more vacuum. Something I noticed is that I can't really get these things OUT of synch, at least not significantly. Seems like nothing I do to these screws (one closed-off, one at two turns out, as an example) ever knocks the bodies out of whack any more than 1cmHg? After checking this thread a time or two, I decided to check the valve clearances, in spite of the fact I'm only at 6000 miles. While my valves may be reading at the tight-end of the spectrum, they are not "tight," so I left them alone. I cleaned the bypass screws and ports, little carbon on the bypass screw tips but nothing to write home about. I put it all back together, left each bypass screw 1/4 turn out, and tried the synch again. When all is said and done, I've got both screws approx 1 1/4 turn out, at 26cmHg, and synched, although I still can't really knock them significantly out of synch. Is this normal for EFI? I'm disconnecting the pulse hose, plugging it and it's port under the airbox, everything else left plugged in (for the test/tune, pulse plugged back in for regular running). Am I missing a step in the procedure that would cause so little difference in tune when messing with the screws?
 
#20 ·
Hmm...any idea which side screw is normally closed (making that one the primary I guess)? Truth be told, I can't remember. And the manual is no help there, basically stating: "when replacing the bypass screws, count how many turns they are out, and duplicate this with the new ones." They are basically "air screws," are they not? Essentially passing additional air into the mixture at idle/low throttle (like an air screw on a carburetor)? Can't be increasing fuel, as that all comes through the injector (and the tips are too fat, and the concern would be varnish more than carbon, etc...)? I did try it with both screws closed, and was able to get it started/running (required a LOT more idle adjustment than normal), and the synch was still on. Exhaust did smell different. If it's any help, my plugs come out very clean (no brown or red coloring on the electrode/porcelain, just white) indicating slightly lean running. I get 26cmHg at idle with the airbox installed. Admittedly I am using the bike's tach and my ear, but even if I'm off by 100 or so my synch does not change significantly at different idle speeds. I have a tach, but the pick up is too big to fit under the airbox and though it'll work without the pickup, it's less accurate that way and I can't get close enough to the leads -airbox again- for the tach to work anyway. Can I synch sans airbox (and the sensor attached at the rear right)? Boy, that would make it super easy to get at the screws! I am at sea level, and it was in the low 90's when doing it. Bike runs well, idles smooth, responds to throttle, and doesn't even really punish me with vibration at low rpms...I'm just trying to understand this system and optimize my tune. Maybe I'll tear it apart again and try again adjusting with screws closed, leaving one closed, then the other...whatta PITA! Almost makes me miss carburetors!

Fasteddie: I was wondering the same. Though if true it begs the question: if the closed loop system can adjust itself THAT much, why have these bypass screws or even a synch procedure/check at all? If the bike can synch itself, why does it need my to check it? When I worked on bikes for a living (back in the 90s), the Suzuki TL1000 was the new EFI hotness. After about two years on the market, I remember Suzuki publishing a separate little booklet (about 4 or 5 pages, if memory serves) that explained in detail a procedure for synching it's throttle bodies that was different than any other I had done up to that point. Those bikes were notorious for "popping" back through the intake (like a really tight intake valve may do), and this "new" procedure really seemed to help. At least it did on the one bike I did it on. I don't remember the details, other than it was significantly different than the manual suggested. I wondered if maybe I missed some minor procedural detail with this bike (leave a sensor disconnected, turn the idle up to 2500, stand on one foot while doing it, etc...)?

At any rate, thanks for the help. Maybe I should just stop worrying about it. "Hey, this guy's bike synchronizes itself! And the dope is complaining!" 😬
 
#22 ·
Just happen to still be on the site, since my sync was spot on after opening my shims to maximum, I decided to bring the lines out, as to which screw is tight, someone with a recent TBS on a MK-3 would need to pipe up here, what I question, is why when you were in that far and checked, you didn't go the extra to open all to maximum clearance, you did 90% of the work??
Like I said, I brought my vacuum lines out and capped them, 5 minute job to check. Maybe tomorrow I will take some photos with the carbtune gauges, OK maybe 10 minutes by the time I get everything out and then put it away.>:)
 
#23 ·
I can see your point, it's just not my practice to adjust valves that are not out of spec. I just wanted to eliminate a tight valve(s) as the problem. If they were actually outside of the factory specs, or if they were screw type valve tappets, sure I would tweak 'em. But I don't see the necessity of pulling cams, buckets, and shims when they're neither tight nor tapping, at least not when it's ridin' season. 😬 Maybe when it gets cold again...❄❄❄
 
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