DubbleJay said:
Hey guys... So Ive got 4K on my bike and boy did she smooth out during break in, but I cant help but think there is more to be achieved. I keep reading about the TB sync and CO adjustments and maybe Im stupid but I just dont understand exactly how or what you need to do this.
There are a lot of threads here, but the jargon is sometimes inconsistent. Is it the same as the carb sync I used to do on my old VStar years ago? Do I need a special device? Is the TB sync and CO adjustment the same thing?
I'm wondering if someone wouldn't mind explaining what is needed and how to do it. Or at least point me in the right direction. OR if someone were interested Im in Pasadena, CA and will travel...
Probably the first question to ask you is how adept are you at motorcycle mechanics? Understand, the skills to working on and maintaining your own motorcycle are easy to learn, but if you're not familiar or don't understand certain basic concepts things can get mucked up pretty quick...
Now, to try to answer your questions... And keep it as simple as possible.
The "TB sync" refer to synchronized the throttle bodies. If you have a twin-cylinder with two carburetors then you have to *synchronize* those so they are opening and closing together equally, thereby supplying both cylinders with equal amounts of fuel and air - operating in *synchronization*, or in "sync"...
Now, on most fuel injection bikes they have individual throttle butterflies for each cylinder. These throttle bodies control the flow of air to each cylinder, so just like those carburetors they have to be "*synchronized* to each other so that each butterfly is opening and closing at the same time and rate. So a "TB sync", or throttle body synchronization is very analogous to synchronizing carburetors to each other on multi-cylinder motorcycles.
The "CO adjustment" is very, very different. With many fuel injection systems they try and *read*, or measure, certain gases exiting the exhaust. This is often done with an O2 sensor. This gets it's name from the fact that Oxygen in our atmosphere most often occurs as a binary molecule, and the periodic table symbol for Oxygen is "O"... and in a binary molecule that is represented as "O2". This sensor tries to determine the amount of unburned Oxygen downstream in the exhaust after combustion. Exhaust emissions are often measured by their content of Carbon Monoxide, and excesses of this compound are clues to inefficient combustion. For tailpipe emissions you want to tune for the lowest amount of CO (carbon monoxide) possible, and the O2 sensors (often also called "Lambda" sensors) help read the exhaust emissions and feedback info to the fuel injection's control unit to trim the fuel delivery amounts to optimize the exhaust gas. To meet emission regulations - and therefore to have minimal CO output - engines are often tuned very, very lean. This may make them burn very clean, emissions-wise, but often compromises throttle response, drivability, and power delivery. By richening up the mixture (i.e. delivering more fuel) can often improve these parameters, though often it will increase CO output.
Yamaha sets the fuel injection parameters for CO output at the factory, but they allow the ability for this to be *tuned* down the pike by accessing a menued control in the ECU's (engine control unit) diagnostic menu. On USA bikes this is normally only able to be accessed by the dealer (it is readily accessed and not "locked out" on Euro-Asian models), but with a very simple *jumper* lead at a plug on the Super Tenere you can access this menu just like the Euros, etc. do. In this diagnostic menu, which appears on your bike's dash panel when called up, is a CO adjustment screen, and there you can alter the factory set CO parameters to try and richen the fuel mixture at low speed and improve throttle response and power delivery right off idle.
Hopefully this will help you understand there is a rather *HUGE* difference between a "TB sync" and a "CO adjustment"... Best advice I can give you is to purchase a factory service manual first and read it - carefully - and then do some searches on forums like this to find specific information on the adjustments themselves, the tools you need to do them with, and how to best prepare yourself for tackling these tuning tasks. That said, until you have a firm grasp of the concepts, etc. involved you might want to stick with having your dealer or a professional shop handle these for you.
BaldKnob said:
CO and TB sync are different adjustments. The TB sync will be similar to the carb bike and the CO is adjusted with the instrument cluster buttons after grounding the tip-over sensor (I believe, haven't performed this yet). Both could help smooth and improve engine response. I think the crank design (despite the balancer) will always have an inherent amount of vibration (especially under throttle), just to remind you something's goin' on down there! Good luck.
Just for the record, a 270-split crank in a parallel-twin (like the Super Tenere) mimics a 90-degree V-twin in piston position, firing order, etc., and a 90-degree V-twin has perfect primary balance and is the smoothest of all twin-cylinder engine configurations. The reason a 270-degree parallel-twin *shakes* more than a 90-degree V-twin has to do with the fact the two rod journals are much further apart than with a common rod journal 90-degree V-twin, and this has a more amplified secondary "rocking couple" vibration. There are multiple ways to try and reduce this vibration, and a counterbalancer system like the Super Tenere has is one example of a way to do it.
*ALL* reciprocating engines have some degree of vibration... Some are better than others, with some - like 90-degree V-twins, certain inline 6-cylinders, certain V-12's, etc. - being exceptionally smooth. That said, *NONE* are vibration-free (and under throttle or not has nothing to do with balance factor, BTW).
Now understand, all I have tried to explain here was done as simply as I could. Each subject is much more complex and detailed than these simplistic outlines. Study, research, and experience are the only ways to learn about each in more detail.
Personally, the very best resource I have ever found for motorcycle dynamics material - like crank layouts, vibration modes, etc. along with chassis dynamics, steering, etc. - in over 40 years wrenching on bikes is at
http://www.dinamoto.it/
Check it out and see what you think.
Hope some of this helps.
Dallara
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