IACV & throttle body balance questions ??

[Tiger-G]

Hi all  ,

As it was a sunny day today, I thought I'd start on Tigers' annual service 

I was having a go at balancing the throttle bodies with my home made balancer, that has worked ok in the past. It's the usual three hoses with a thick oil in them effort. I disconnected the IACV hoses and connected the balancer tubes and started the engine. The oil shot straight up number 3 (rear brake side) hose, and was nearly inside the throttle body before I had a chance to turn off the engine.

Any idea's why this would be ?? Could the throttle bodies be that far out of balance ?? I swapped the hoses to double check it wasn't a problem with them, and the same happened again 

Oh.....and numb nuts me.........when I took the two bolts out that hold the IACV in place to move it out the way, the plunger popped right out when the engine started, exposing the spring, etc !! Having never worked on these before, I wasn't sure what to do about it, and the plunger wouldn't go back in. When I turned the engine off I could hear the motor inside cycle, and the plunger went back in. Will I have broken it, or put it too far out of spec, or will it be ok once I've put it on TuneECU ??

Looking forward to your answers on this one 

[Timbox2]

Firstly the stepper motor, many of us have done the same, so the piston didnt actually come all the way out?.  If its pulled back in you may be ok, you'll only really know when you next start it.

As for the balancing sounds very odd, if you open the throttle do the butterflies all appear to move the same, and by eye do the gaps appear similar when shut

Just thought about this a bit more,  a leak somewhere may also cause this, not unheard of for a leaking Throttle Body base gasket

[Tiger-G]

Yeah, unfortunately, the piston came out. But I could feel the motor "grip" it and pull it back in. I cycled it a few times with the ignition on and off, and it seemed to move in and out as it should. Hopefully, all will be well.

I balanced the TB's ok last year, with no issues at all, and everything looks like it did then. Will have another go at it again tomorrow, and keep an eye out for leaks.

Cheers.

[Timbox2]

Does sound like you may have got away with it, mine was bolloxed when it happened to me, new one at £60 odd

[Tiger-G]

I've uploaded the video I made of my home made manometer to show you it working properly last year. As you can see, it's pretty much in sync. Hopefully, I can crack it tomorrow.

https://www.youtube.com/watch?v=-EQ73rf1zXA&feature=youtu.be

[Tiger-G]

All sorted  :icon_wink:

Turns out number three was just really out of balance, and I think my home made manometer is very sensitive.

I only tried balancing the TB's for the first time last year, so I'm still really new to it. After reading the Haynes Manual this morning, you can't put any pressure on the adjusting screws, and even minor adjustments cause significant changes.

The manual recommends using silicone on the screws to stop them turning, does anyone do this ?? I didn't bother.

Thanks for the advice Tim 


Edit: Took the bike out for a spin, and it looks like I've got away with the IACV, but the bike did have a couple of flat spots on hard acceleration through each gear 😕