2012 FJR Throttle Body Synch

[Lockback]

Getting ready to tackle a spark plug change & TBS on my '12 and have a couple of quick questions for the experts here.

1) I believe the #3 cylinder is the base to which the other throttle bodies are synchronized. Is this correct?

2) In addition, when replacing the plugs, is it worth it to invest in, say, iridium units or just stick with stock?

Thanks in advance!

 

[Intech]

Yes to #3 being the reference cylinder. No real difference in performance or life between standard and iridium. If you do go with iridium handle them carefully. The electrodes are fragile.

 

[Lockback]

Thanks so much for the reply. I appreciate it!

 

[want2ride]

Since you will be replacing the plugs every 16-17k save the money and use the regular plugs. Same spark for that period of time IMHO.

 

[ionbeam]

The Gen I and Gen II FJRs used a 'waste spark' system so that 2 plugs would fire from the center electrode to the side electrode; 2 plugs would fire from the side electrode to the center electrode. If you rotate the plugs, swap plugs 1 & 3; swap plugs 2 & 4 you will extend plug life.

Focus on getting all the TBs equal and don't worry about the absolute vacuum readings. I highly recommend that you keep the idle speed adjusted to 1,100 during the TB sync process. This prevents the idle adjustment screw from bottoming out or toping out and becoming unable to adjust idle speed.

 

[Lockback]

Thanks for the advice.

Okay ... one more question:

Once the rubber boots are removed for hooking up the Carbtune hoses to the throttle bodies, I assume I'll be using the supplied adapters to screw into the brass fittings? And if so, what size?

 

[ionbeam]

The Carbtune hoses will slip over the throttlebody fittings with no adapters. You do want to follow Morgan's instructions and cut then install the dampers in each hose at the specified locations.

 

[Lockback]

The Carbtune hoses will slip over the throttlebody fittings with no adapters. You do want to follow Morgan's instructions and cut then install the dampers in each hose at the specified locations.

Beautiful! Thanks . I've already installed the dampers.

I won't be tackling this for a few more weeks but wanted to get my ducks in a row. The advice is greatly appreciated.

 

[eflyguy]

Lockback, have you found a nicely documented thread on this? I've got (and read) the service manual but there's usually things they don't include that would be nice to know..

 

[Lockback]

Lockback, have you found a nicely documented thread on this? I've got (and read) the service manual but there's usually things they don't include that would be nice to know..

There are a few floating about the internet but some of them are pretty old, a bit spotty and the photographs are lousy.

TwoWheelObsession has an excellent video on YouTube. It's worth watching.



Like a lot of things in life, I've got a pretty good idea of what to expect but until you actually dig in and do it, you can never be totally sure.

I'm sure once I start taking things apart, I'll get a surprise or two. My main goal is to eliminate as many questions as I can before I get those tools in my hand!

 

[RaYzerman19]

The sync procedure on a GenIII is slightly different than a GenII. On your GenII as Ionbeam says, as long as you get them all equal that is the key. You should use #3 as the reference. IF you find you can't get enough adjustment on one or more of the screws, turn all of them in lightly to seat and back them out at least 3/4 turn to one turn. Then sync again with #3. (Sometimes Yamaha did not have #3 far enough out).

 

[Lockback]

The sync procedure on a GenIII is slightly different than a GenII. On your GenII as Ionbeam says, as long as you get them all equal that is the key. You should use #3 as the reference. IF you find you can't get enough adjustment on one or more of the screws, turn all of them in lightly to seat and back them out at least 3/4 turn to one turn. Then sync again with #3. (Sometimes Yamaha did not have #3 far enough out).

Thanks, RaYzerman. I appreciate all the feedback. Very helpful.

When I get the thing done in a few weeks, I'll report back.