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-   -   Throttle body balancing (http://forums.sv650.org/showthread.php?t=122566)

RingDing 12-12-08 11:28 PM

Throttle body balancing
 
Just back in from the garage from carrying out the first service since the warranty ran out. Wanted to check the throttle body balancing but got a bit confused. I've had a search but can't find the answer I'm after...

Manual says to remove the airbox to gain access. Fair enough. In structions on removing the airbox say to disconnect the IAT and PAIR connectors and the IAP connector and vacuum hose (as well as the crankcase breathers). The instructions for balancing the throttle bodies then say to reconnect these :confused: but the only way I can see to do this means putting the airbox back in the way.


CALIBRATING EACH GAUGE (For vacuum balancer gauge)
•Lift and support the fuel tank . (=5-6)
•Start up the engine and run it in idling condition for warming
up.
•Stop the warmed-up engine.
•Remove the air cleaner box . (C -75-16)
•Connect the IAT and PAIR control valve sensor couplers .
•Connect the IAP sensor coupler and vacuum hose .



I should say that I'm pretty handy in the garage when it comes to rebuilding LC's and I've done the odd ZZR engine strip but these FI bikes are far too confusing with all their electrickery!

So, should I be reconnecting the bits above and balancing the airbox in the way or am I missing something really obvious. Plus the rubber caps on the stubs for connecting the balancer to are chuffing stuck!

TIA.

Baph 13-12-08 11:52 AM

Re: Throttle body balancing
 
OK, who or what has advised you remove the whole airbox on the SV? It's simply not required.

You CAN reconnect the sensors etc, but you pretty much have to leave everything dangling off the side of the bike (works best off the left side, leaving better access to the balancing screws).

But like I said, you don't need to remove the whole airbox. I've used a long screwdriver in the past without touching the airbox at all, but it is easier if you remove the top of the air box.

Basically, my steps:
  1. Tank up (obviously).
  2. CarbTune plugged in on vacuum nipples.
  3. Run bike to warm up (at this point, I've usually just changed the oil too, so use this to help check oil level).
  4. If I'm not feeling lazy, top of the airbox off, leaving the rest there.
  5. When warmed properly, with engine on, hold bike at 3k RPM, use rear TB adjust screw to match front cylinder. Then release throttle.
  6. Repeat the above step for 5k RPM and 7k RPM (my neighbours love me). Usually this is just a check, not an actual adjustment.
  7. Let the bike idle for a few mins, blip the throttle a few times & check balance whilst idling.
  8. Continue other work on the bike, or shut it town & put it all back together again if I'm done.

The above usually takes about 5 mins, as in practice I already have the tank up, carbtune in & the bike reasonably warm due to other work I'm doing on it.

pookie 13-12-08 11:53 AM

Re: Throttle body balancing
 
i ended up balancing without the hoses ok. Just make sure you dont drop anything into the engine.

RingDing 13-12-08 12:14 PM

Re: Throttle body balancing
 
Baph, it's the workshop manual that recommends that (the Suzuki one!).

I did think it looked possible without removing the airbox but I was having such a job getting the nipple covers (!) off that I thought it might be easier with the airbox off. Turns out I couldn't get them off anyway, even with a little better access.

Thanks for confirming it is possible without removing the box, I'll have another pop at it tomorrow and gear my self up for some serious nipple tugging.

Cheers.

Baph 13-12-08 12:17 PM

Re: Throttle body balancing
 
For the nipple covers, I find it pretty easy to remove them by hand when the engine is cold. I used to use long nosed pliers by grabbing the rubber boot, and pushing the pliers against the frame of the bike (put the pliers above the circlip & they pop off quite easy).

It also helps to twist them as you pull them off (if doing it by hand).

I've done my TB's so often over the last 36k miles that I needed to replace the rubber boots as they were starting to degrade.

thefallenangel 13-12-08 11:08 PM

Re: Throttle body balancing
 
do they always need adjusting or they normally pretty close or is it like valve clearances where it depends on wear and tear?

ThEGr33k 13-12-08 11:48 PM

Re: Throttle body balancing
 
I do it by ear. Adjust air screws till it sounds like its running smooth at tick over first, basically it doesnt seem to rise and fall in sound... Sounds constant.

Once you have the base level then start blipping the throttle. Basically what you are listening for is the engine picking up revs without coughting (bogging down) and returning to tick over without taking ages or coughing and spluttering and struggling to find tick over again.

Once the blipping of the throttle seems right then test ride it. Acceleration and decelleration should feel snappy and instant.

*NOTE* When adjusting the air bleed screws (on the throttle bodies) make sure you dont screw them too far out No more than 1.75 screw turns generally, get it as far in as possible while still running right. Start at about 1 turn out on each. If you do screw them out too far then youll lose bottom end and pulling off will be bad. You'll know. I did this through trial and error and the engine just died when you let the clutch out.

Hope this helps... :) I know it works because on my service a couple of weeks ago the fella said the Trottle ballance was perfect. Oh yes baby. Cant ask for better aye? :)

Baph 14-12-08 02:38 AM

Re: Throttle body balancing
 
Quote:

Originally Posted by thefallenangel (Post 1717887)
do they always need adjusting or they normally pretty close or is it like valve clearances where it depends on wear and tear?

If you go by the service schedule, you wont go wrong. Can't remember what the service schedule is for throttle bodies though, as every time I have the tank up I balance them - might as well since I have the carbtune & it only takes a couple of mins.

ThEGr33k 14-12-08 12:16 PM

Re: Throttle body balancing
 
Quote:

Originally Posted by Baph (Post 1717964)
If you go by the service schedule, you wont go wrong. Can't remember what the service schedule is for throttle bodies though, as every time I have the tank up I balance them - might as well since I have the carbtune & it only takes a couple of mins.


Id be worried if they needed adjusting too often :-?

jambo 14-12-08 12:17 PM

Re: Throttle body balancing
 
Quote:

Originally Posted by ThEGr33k (Post 1717926)
I do it by ear. Adjust air screws till it sounds like its running smooth at tick over first, basically it doesnt seem to rise and fall in sound... Sounds constant.

You are aware that adjusting air mixture is something completely different?

when ballancing the carbs or throttle bodies you are generally adjusting the throttle linkage between them, ensuring that the amount the throttle is open for each carb/TB is the same. this is a manual adjustment to the effective length of a mechanical linkage. Not that getting fueling right isn'timportant, but it's a different job.

I've not actually seen an air mix screw on a set of SV TB's but I've never felt the need to look for them. I would have thought that they'd only exist on carbs?

Jambo


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