"advanced" Throttle Body Synchronization

[dobias]

Radman,

Thank you very much! The drinks are on me if we ever meet. You're a scholar and a gentleman.

It sure can't be seen by anyone standing alongside the bike. I had to look up under the frame and that ain't easy with bi-focals.

dobias

 

[Windjammer]

Sure glad I found this most excellent thread with the search function. Went to do my first TB sync today and found the service manual info to be lacking in detail and somewhat confusing (poor diagrams, IMO).

Now I should be all squared away, after I replace my shitty vacuum gauges! Thanks to those who took the time to give a detailed procedure showing all the adjustments, not just the air screws.

:clap:

 

[Woodstock]

Sure glad I found this most excellent thread with the search function.

Yea, the search function here rocks. It's so cool actually being able to _find_ something. :clap:

 

[Just Plain Dave]

OK dudes, I read all this great information and ordered a Motion Pro Economy carb Tuner. It arrived today. :yahoo:

I was a bit concerned when the UPS guy sat it on my front porch, rang the doorbell, and as I arrived he was running for his truck which was backed into my driveway apparently for a quick getaway. :huh:

Sure enough when I got to the box I was a bit concerned. The tuner is about 24" long and the box it came in is 42" long. The problem is in the fact that the box had about a 60 degree bend right in the middle.

I jumped in my pickemup and headed the direction he darted off, but he was gone. :bye:

My question is; how accurate will the reading on my manometer be if the mercury has to go around the corner when displaying the vacuum reading? :blink:

 

[markjenn]

I suppose you could still use it, but I'd bet a dollar to a donut, it's broken - thin plastic capillary tubes don't make 60-deg bends very well.

- Mark

 

[Windjammer]

OK, now that it's fixed I can admit I fucked it up. Let me explain:

I took my old vacuum gauges, calibrated in "bar" and went after my fjr with them. Diagrams in my service manual confused me about the adjusting screws. So I figured it had to be similar to the carbureted inline fours I've synched in the past, and I began twisting the "wrong" screws - the ones that adjust the butterfly valves - the ones I wasn't supposed to mess with according to Yamaha. I did keep track of how much I moved them though, so it was easy to get back to where I started. To make matters worse, my gauges were not fine enough in the adjustment scale to even see what was happening. Went to Ebay and bought Morgan Carbtune from a dude out east. Read up here on all the detail Yamaha left out of the service manual.

Went back at it with instructions in hand. It took patience and a few rounds of adjustments but I finally got it to balance at idle, and balance at 4200 RPM, and all four Carbtune rods move up and down together at the same speed when changing throttle settings. In short, it's set correctly now.

And boy can I tell a difference when riding. Wayyyy smoother at speed, sounds smoother, idles smoother, runs like a proper motorcycle engine and almost NO vibes at the bars now. Big difference there. Now THIS is the engine all the magazine testers raved about being so smooth. And here I thought they were just full of shit all along.

Changing the air screws alone, per the service manual, was not enough to fix the imbalance on this bike. Not even close! I made significant adjustments to all three throttle valve screws to balance the engine at speed, and after doing so I had to rebalance the air screws, and the idle speed.

One has to wonder how factory service mechanics can possibly balance the throttle bodies if they follow the Yamaha book. Now I know that all bikes are not necessarily as far off as mine was, but how would they ever know if they don't check?

Thanks to you guys, I no longer have to worry about that, and my bike runs great!

:clap: :dance: :drinks: :jerry: unk:

 

[sparky3008]

Ok here is the screw for doing the normal idle sync.

Where are the throttle valve screws.

Can they be located in this picture or even discribed.

Does anyone have a picture of what I am looking for?

Are they in the service manual / page #.

On my carbtune 1&4 were very low at idle. I set them as close as I could as the carbtune numbers are very close and fluctuates a bit.

On slowly increasing idle 1&4 seem to be the ones that remain low as the rpms rise.

Thanks for any help

 

[NorthRider]

Went back at it with instructions in hand. It took patience and a few rounds of adjustments but I finally got it to balance at idle, and balance at 4200 RPM, and all four Carbtune rods move up and down together at the same speed when changing throttle settings. In short, it's set correctly now.
And boy can I tell a difference when riding. Wayyyy smoother at speed, sounds smoother, idles smoother, runs like a proper motorcycle engine and almost NO vibes at the bars now. Big difference there. Now THIS is the engine all the magazine testers raved about being so smooth. And here I thought they were just full of shit all along.

Changing the air screws alone, per the service manual, was not enough to fix the imbalance on this bike. Not even close! I made significant adjustments to all three throttle valve screws to balance the engine at speed, and after doing so I had to rebalance the air screws, and the idle speed.

One has to wonder how factory service mechanics can possibly balance the throttle bodies if they follow the Yamaha book. Now I know that all bikes are not necessarily as far off as mine was, but how would they ever know if they don't check?

Thanks to you guys, I no longer have to worry about that, and my bike runs great!

:clap: :dance: :drinks: :jerry: unk:

I did the UTB 3 weeks ago. As far as I remember there are 2 screws available only for adjusting the throttle buttefly valves at 4200RPM. One screw adjustment for cyl 1&2 and another for cyl 3&4. There are 4 air screws in which you adjust 3 of them in order to match cyl #3.

I tried to adjust cyl 3&4 then 1&2 at 4200 RPM then I adjusted the 4 air screws at idle.

I got them all fairly close to each other @ 4000 RPM but I found that the vibration just shifted from 4200 to the 5200 RPM range. Am I doing something wrong?

Pictures showing the adjustment screws for the buttefly vaves would be useful.

I later installed the PCIII with the Wally Map. Found the throttle to be very smooth and more linear. Better yet, I find that my FJR doesn't get as warm as before. With regards to the vibration I dont find that the PC III makes much of a noticeable difference. The PC III has improved the heat issue and improved the throttle response.

To those that have done the UTB Am I doing something wrong?

Should I re do the UTB again since I did add a PC III?

 

[radman]

The actual TB synch screws are on the throttle shaft itself, same location, and same adjustment as on a carb motor. When doing the TB synch using the air bleed screws at each TB, first set all at 1/2 turn open. This will get #3 back to about where it should be, especially if someone has played with them before. You may find the main idle speed has to be reset when doing this. Then adjust all TB's evenly at idle. Make small adjustments, then wait till all stabilize. Blip the throttle a few times to see if all retain settings. Rinse and repeat. When all set, buzz motor to 4 thou or so and observe readings. Unless a large discrepancy is observed, leave the shaft synch screws alone. Once you start getting into these, amatuer night is over, and unless you completely understand what you are doing, what each step of the proccess entails, and why you are changing things, you can get into trouble fast.

 

[sparky3008]

Ok here is a picture I was looking for. Why do some mention a phillips screw?

 

[radman]

Because those aren't the synch screws-they are throttle stops. Once again, the synch screws are on the throttle SHAFT . 1 between 1-2, 1 between 3-4, and 1 at the center to mate the two pairs. There is no locknut on these phillips screws, they are spring tensioned. You must look down between the TB's to see them.

 

[sparky3008]

OK! I guess I should just look and do as I am told.

Thanks

I had found this picture on one of the other sites and didn't notice anyone correcting him on doing this procedure.

Hadn't found one of the phillips screw.

again,

Thanks

 

[NorthRider]

Because those aren't the synch screws-they are throttle stops. Once again, the synch screws are on the throttle SHAFT . 1 between 1-2, 1 between 3-4, and 1 at the center to mate the two pairs. There is no locknut on these phillips screws, they are spring tensioned. You must look down between the TB's to see them.

I had found two sync screws ( Slotted, slotted & painted). I guess I missed the middle one :huh:

 

[radman]

The middle one is right at the cable connection. It's to synch the left and right side, and is the final adjustment.

 

[RTSR1/FJR]

I need a new sync stick, mines shot! Where are you guys getting this Morgan Carbtune II?

 

[BrunDog]

I did my first sync today (@800 miles). And for the life of me, I could not reach the 250mm mark. The screws reached bottom at 230mm. So I adjusted them all at 230mm. I am in Chandler, AZ, which is at about 1100' above sea level, is there a compensation factor for the elevation?

The markings on the MP Econo tuner are inaccurate. Use a ruler and measure from the top of the Hg pool to the top of the Hg in the tubes.

-BD

 

[Captain Obvious]

I need a new sync stick, mines shot! Where are you guys getting this Morgan Carbtune II?

Casporttouring.com

 

[Rogue]

I need a new sync stick, mines shot! Where are you guys getting this Morgan Carbtune II?

Casporttouring.com

Casporttouring.com sucks!

I had so many problems with them on my last order I'll never shop there again!

 

[radman]

Got mine directly from Morgan. Google it.

 

[Captain Obvious]

I need a new sync stick, mines shot! Where are you guys getting this Morgan Carbtune II?

Casporttouring.com

Casporttouring.com sucks!

I had so many problems with them on my last order I'll never shop there again!

I've bought from Casporttouring many times, never had a single problem. I heard that they did have a problem with some orders right after they switched their software, but that was a while back. IIRC I even got an e-mail from them explaining what happened.

My carb tune shipped was around $20 less then buying from Morgan and shipping from England.