throttle body balancing went bad

[Guest BIGGERJIM]

well i got feeling a little froggy after putting in the new front springs ,

decided to adj valves and do a T.P.S. and throttle body balance,

well the valve adj went well, and had the balance at idle almost perfect,

thanks to the excellant advice on this forum,,,but when i went to balance the bodies

at about 3000 rpm with the white knob on left side every thing went bad ,

i think the knob was turning but not the rod, by that time the bike was getting pretty hot

so i shut her down, now she sounds like single instead of a twin,

what is the thoughts on the balancer shaft adj at 3000 rpm

do i need to do that if the idle is balanced ....

don't it just counter act what you just done at idle

 

confused

 

[Guest ratchethack]

Jim, it's important not to overheat while you balance the TBs. I use 2 fans, one for each cylinder, both full blast, and I don't push it. Yes, you need to do the balance at 3K as well as at idle. Chances are pretty good that you won't be able to get them both perfectly dead-nuts, but you need to get the balance as close as you can, idle off in one direction, 3K off about the same amount in the other direction.

 

Don't sweat it, and don't overheat, either.

[dlaing]

i think the knob was turning but not the rod

That is normal.

Try balancing at 2000RPM instead of 3000.

This will give you more time before it gets too hot.

Like Ratchet said, use fans, or if that is not practical take your time and do it one minute on, five minutes off to cool down.

Once you get the hang of it, you can balance it fast enough to avoid over-heating.

Did you follow these incredibly amazing TPS instructions?

http://www.v11lemans.com/forums/index.php?showtopic=12204

[Guest ratchethack]

Try balancing at 2000RPM instead of 3000.

This will give you more time before it gets too hot.

Not wise. Now Dave, I'm not going to argue this with you but this is wrong. There's a reason to go up to 3K for balance RPM. Without it, you lose very significant ability to balance the TBs properly for operation on the road at higher RPMs. Just because it's more difficult to do it right is no reason to change the procedure!

 

NOTE: For cryin' out loud, this IS NOT a personal attack!

[Dan M]

Not wise. Now Dave, I'm not going to argue this with you but this is wrong. There's a reason to go up to 3K for balance RPM. Without it, you lose very significant ability to balance the TBs properly for operation on the road at higher RPMs. Just because it's more difficult to do it right is no reason to change the procedure! <_>

 

NOTE: For cryin' out loud, this IS NOT a personal attack!

 

I agree with this. The throttle plates are open such a small amount at 2000rpm especially on an unloaded motor, you will not get an accurate balance. I go to at least 3000. I bought a couple of small contractor's fans from the power tool section of a Home Depot or one of those big box stores. They are fairly cheap and flow considerable air. I aim one at each cylinder and tune to my heart's content.

 

*no political activists were harmed during the writing of this post*

[Greg Field]

IMO, attempts to balance at 3,000 rpm are a waste of time, unless you do it on a dyno, with the engine under load. Sitting in neutral, on the bench, the throttle is cracked what, 1/16th open to maintain 3,000 rpm? Far less, anyway, than it would be if the engine were under load. Also, once the throttles are opened much, breathing variation between the two heads is what causes the imbalance, not the throttle plates, unless the plates are way, way out, which they won't be if you first get the synch right.

[Guest ratchethack]

IMO, attempts to balance at 3,000 rpm are a waste of time, unless you do it on a dyno, with the engine under load. Sitting in neutral, on the bench, the throttle is cracked what, 1/16th open to maintain 3,000 rpm? Far less, anyway, than it would be if the engine were under load. Also, once the throttles are opened much, breathing variation between the two heads is what causes the imbalance, not the throttle plates, unless the plates are way, way out, which they won't be if you first get the synch right.

Greg, correct me if I'm all wet here, but aren't the inevitable differences between the way the heads breathe on a twin the very reason you need to balance this out with the throttle plates to begin with at 3K RPM as well as at idle, with the additional help of the air bypass screws (at idle)? I'm sure that using a dyno to balance the TBs would be much more effective. If I had a dyno, I reckon I'd balance it all the way up the powerband. But most of us just make do with wot we've got when balancing TBs, and for the most part it seems to work out extremely well at idle and 3K RPM -- or at least it has in my case with the Guzzi, just as it has with every twin I've owned and balanced myself (and that's all of 4 of 'em).

 

Then there's The Weej, who probably does it (arguably) better than can be done on a dyno -- he sets the balance by "seat o' the pants", whilst underway.

[Guest BIGGERJIM]

tb update &&&& I think i have the tb as good as i can get them, the idle is dead nuggetts even.

and the balance at 3000 rpm is pretty good but not as good as idle,

i test drove it after adj the tps and it seems like i lost power when you gag it at about 4500rpm

could that be my tps, it was about 495 at idle, the idle speed is 1000 rpm when fully warm,

what would give me my top end power back.

any suggestions would be welcome

i done this with a homemade water manometer..

 

 

 

thanks bigger jim

[Guest ratchethack]

Jim, the recommended idle RPM is 1100-1200. I'd correct this to ensure adequate oil pressure at idle. If you simply crank up the throttle stop, according to your current read of 495 mV, you should wind up somewhere just shy of 525 mV without touching the TPS, which is about right. As far as why you lost power at 4500 RPM, this is not related to TB balance or TPS setting.

 

More details about this power loss, por favor? Does the power come back above 4500 RPM, or just drop off altogether? Does the motor miss, or just not pull as hard??

 

BTW -- a home-made water manometer is the way I do it too. Works like a Champ.

[Guest BIGGERJIM]

Rachet

it dont pull as hard as it used too

is the tps set at 150mv with the engine off and the key on

i will turn that idle up some i just hate to mess with it, it's so smooth right now

but i sure would like to get that power back...

[Guest ratchethack]

Jim, the TPS is set at 150 mV, TBs disconnected, throttle screw backed off, throttle advance disconnected, engine off, key on. This should be the same as 500-525 mV, TBs connected at throttle setting that gives idle RPM (1100-1200 RPM), engine off, key on.

 

Y'all gotta get that power back, Jim!!

[dlaing]

tb update &&&& I think i have the tb as good as i can get them, the idle is dead nuggetts even.

and the balance at 3000 rpm is pretty good but not as good as idle,

i test drove it after adj the tps and it seems like i lost power when you gag it at about 4500rpm

could that be my tps, it was about 495 at idle, the idle speed is 1000 rpm when fully warm,

what would give me my top end power back.

any suggestions would be welcome

i done this with a homemade water manometer..

 

 

 

thanks bigger jim

Struggling with a homemade water manometer may require fans!!!

I tried building one but it did not work very well.

Be sure to reverse the left and right to make sure you are getting equal balance in each direction.

 

As for using 2000 rpms. It will give you "good enough" results.

In THE TPS thread, Mr. Bean was told by Moto International to balance at idle and at between 1800 and 2000rpm.

I initially thought it was too low, but trying it I found that the result was very close to running it up to 4000rpm watching the variation and making compromise. But compromise is subjective.

Lower rpm balance is more critical, and the balance varies in waves as you go through the rpms.

The closer you are to idle, the more critical the balance becomes, so balancing at 2000 rpms makes more sense than at 3000 rpm.

The transition from idle balance to balance at about 2000 RPM greatly effects smoothness of operation.

If you get idle and 2000rpm right, your bike should ride well.

This is one of the reasons to use the left idle set screw rather than the right, to keep the tension in the linkage so it does not slop transitioning from idle to throttle.

 

 

 

As for the lack of performance at higher RPM.

Did you do anything else?

New spark plugs, but did not gap them?

Forgot to cap off throttle body balancing taps?

Did throttle cable come off the pully?

Did you adjust the throttle position sensor, or just the idle to change the readout?

What did you set the air bypass screws to?

As Ratchet said, your idle is a little low. It should be about 1150 rpm, giving you a TPS reading of about 521mV.

The 150mV TPS reading is done with throttle linkage disconnected, "choke" not interfering, and right set screw not interfering with the butterfly valve completely closing. Yours might be off?????, but considering you got 1000 rpm at 495mV, you probably aren't far from 150mV??? Still it might be a good idea to get it perfect.

[Greg Field]

Greg, correct me if I'm all wet here, but aren't the inevitable differences between the way the heads breathe on a twin the very reason you need to balance this out with the throttle plates to begin with at 3K RPM as well as at idle, with the additional help of the air bypass screws (at idle)? I'm sure that using a dyno to balance the TBs would be much more effective. If I had a dyno, I reckon I'd balance it all the way up the powerband. But most of us just make do with wot we've got when balancing TBs, and for the most part it seems to work out extremely well at idle and 3K RPM -- or at least it has in my case with the Guzzi, just as it has with every twin I've owned and balanced myself (and that's all of 4 of 'em).

 

Then there's The Weej, who probably does it (arguably) better than can be done on a dyno -- he sets the balance by "seat o' the pants", whilst underway.

 

Not really. The imbalances in breathing often change with rpm, so it's a moving target that you'll never get balanced everywhere without port work aimed at doing so.

[Guest BIGGERJIM]

hello everyone

 

i did forget to tell, i adjusted the valves to 04 in and 06 ex i think they had them close to 6 and 8

and took out the bosch plugs and put in ngk

but beside that i have not changed anything.

i will get out there tonight and get that idle up to specs and rebalance at idle.

i bought some staintunes out of the classifieds on this forum from plexiform and

they are great sounding mufflers,

i am tweaking my guzzi for the warm weather,but i'm riding my goldwing to work.

 

 

 

 

thanks for the help ,, bigger jim

[Tom M]

Sort of OT but if anyone is looking for cheap carb sticks this looks like a deal: motion pro

 

At $10.95 this is probably less money that I could build a home made set for, but it does use mercury.