TBS Sync Plan - What do you think? Should I make any changes?

[Rider_FJR]

I’m planning on servicing my TBS this weekend. I’m just waiting for the Morgan Cartune to arrive from U.K.

Here is my plan, let me know if I’m missing anything:

1. Warm the engine to two bars.

2. Ensure ideal speed is 1,100RPM.

3. Remove the 4 rubber caps.

4. Install the carb sync tool on all 4 valves.

5. Ensure idle speed is 1,100 RPM and adjust if necessary.

6. Adjust throttle body synchronization to match #3 valve reading. After adjusting each throttle body, rev the engine 2 or 3 times and check the synchronization again.

7. When done, stop the engine and remove the measuring equipment.

8. Reattach the rubber caps and retaining clips.

 

[FJRMGM]

I’m planning on servicing my TBS this weekend. I’m just waiting for the Morgan Cartune to arrive from U.K.

Here is my plan, let me know if I’m missing anything:

1. Warm the engine to two bars.

2. Ensure ideal speed is 1,100RPM.

3. Remove the 4 rubber caps.

4. Install the carb sync tool on all 4 valves.

5. Ensure idle speed is 1,100 RPM and adjust if necessary.

6. Adjust throttle body synchronization to match #3 valve reading. After adjusting each throttle body, rev the engine 2 or 3 times and check the synchronization again.

7. When done, stop the engine and remove the measuring equipment.

8. Reattach the rubber caps and retaining clips.

put a floor fan in front of the bike to blow air over it so it doesn't get too hot.

 

[Rider_FJR]

Good point.

Thanks.

I’m planning on servicing my TBS this weekend. I’m just waiting for the Morgan Cartune to arrive from U.K.

Here is my plan, let me know if I’m missing anything:

1. Warm the engine to two bars.

2. Ensure ideal speed is 1,100RPM.

3. Remove the 4 rubber caps.

4. Install the carb sync tool on all 4 valves.

5. Ensure idle speed is 1,100 RPM and adjust if necessary.

6. Adjust throttle body synchronization to match #3 valve reading. After adjusting each throttle body, rev the engine 2 or 3 times and check the synchronization again.

7. When done, stop the engine and remove the measuring equipment.

8. Reattach the rubber caps and retaining clips.

put a floor fan in front of the bike to blow air over it so it doesn't get too hot.

 

[Fred W]

Yup. That's pretty much how it's done "by the book".

The alternative way is what I call the Really, Definitely, Completely Unauthorized TBS.

Most people who have tried this technique have netted more of an improvement (in reduced engine vibration and improving driveability) than in just doing it "by the book". YMMV

PS - You don't really need a floor fan, like we did for our old air cooled bikes. This is a liquid cooled engine and the radiator has its own fan, if it needs it. But it won't hurt anything so if you really want to, knock yourself out.

 

[Rider_FJR]

Hi Fred,

I have looked into the Unauthorized TBS sync, but after reading it, I dont fully understand it. I wish there was a quick, 1,2,3,4,5... plan, not a long 2-3 page explanation.

Yup. That's pretty much how it's done "by the book".

The alternative way is what I call the Really, Definitely, Completely Unauthorized TBS.

Most people who have tried this technique have netted more of an improvement (in reduced engine vibration and improving driveability) than in just doing it "by the book". YMMV

PS - You don't really need a floor fan, like we did for our old air cooled bikes. This is a liquid cooled engine and the radiator has its own fan, if it needs it. But it won't hurt anything so if you really want to, knock yourself out.

 

[Fred W]

Hi Fred,

I have looked into the Unauthorized TBS sync, but after reading it, I dont fully understand it. I wish there was a quick, 1,2,3,4,5... plan, not a long 2-3 page explanation.

The way I see it, to get the best possible results, you really need to know exactly what you are trying to accomplish, not just the step by steps.

But I could distill it into simple steps like this:

1. Warm the engine to two bars.

2. Remove the 4 rubber caps.

3. Install the carb sync tool on all 4 valves.

4. Ensure idle speed is 1,100 RPM and adjust if necessary.

5. Close down all 4 air screws on the throttle bodies (this will require opening the throttle slightly or the bike will stall out) Try to keep it ~ 1100 rpm but actual rpm is not important at this step.

6. Adjust the 3 linkage screws between the throttle bodies for a balanced vacuum. Use #3 as the reference.

7. Open each air screw 1 turn. (this will require releasing the throttle)

8. Adjust idle speed to exactly 1100 rpm.

If unable to get the idle high enough open all 4 screws an extra 1/4 turn and repeat this step.

If unable to get the idle speed low enough, close all 4 air screws 1/4 turn and repeat this step.

10. Touch up the air screws for perfect balance at 1100 rpm.

11. When done, stop the engine and remove the measuring equipment.

12. Reattach the rubber caps and retaining clips.

 

[SkooterG]

While interesting, in 300k miles I have never done the 'Un-authorized' TBS. I'm not really sure how 'necessary' it is. If you are a tinkerer, and you're confident you won't make it worse, by all means go ahead and do it.

As for your steps, I would eliminate steps 1 and 2. Those little caps can bit a bit of a PITA to remove, ESPECIALLY when the engine is hot. So remove them when cold, hook up your new fancy-schmancy Morgan carbtune, and then start the bike, let it warm up and set the idle to 1100-1200 rpm. Now perform your TBS.

 

[Fred W]

While interesting, in 300k miles I have never done the 'Un-authorized' TBS. I'm not really sure how 'necessary' it is.

And that is different from the "authorized" TBS how?

No, it certainly isn't 'necessary'. Neither is the authorized one. But the that does even less.

Balancing intake vacuum only makes the engine run a little bit smoother. That's the ONLY reason to do any kind of TBS.

The authorized version only significantly effects that vacuum balance at idle.

If you have engine vibrations at higher rpm that you want to balance out you won't fix it by just adjusting the air screws.

 

[SkooterG]

The authorized version only significantly effects that vacuum balance at idle.

If you have engine vibrations at higher rpm that you want to balance out you won't fix it by just adjusting the air screws.

Completely agree!

More of a hassle to do the unauthorized version if you don't really need it, and also the opportunity to make things worse.

Fred, not all of us have your smarts, tools, wrenching skills, or most importantly your level of anal-retentiveness. Thankfully, most of us DO have better looks than you.

 

[wheatonFJR]

...Fred, not all of us have your smarts, tools, wrenching skills, or most importantly your level of anal-retentiveness. Thankfully, most of us DO have better looks than you.

Don't worry Fred, you don't have any competition in that department from Skooter. This is the best picture I could find of him (He has his helmet on).

 

[Fred W]

Absolutely, I agree with you too, on all points, Skootie.

Though having seen many pictures of you, I'm not sure that you qualify in that final regard.

[edit] - while posting it seems that Wheaton has supplied some supporting evidence.

My thought was, if one is undertaking a TBS of any kind, where countless people have managed to bugger things up anyway, why not just go the extra distance and do it the way that it has the best chance of actually accomplishing something?

Or I guess the OP could just sell off the new Carb-tune and forget about the whole thing.

 

[wheatonFJR]

...Or I guess the OP could just sell off the new Carb-tune and forget about the whole thing.

No need to do that. He could epoxy it to the front of his fairing as a modified deer whistle...

 

[Rider_FJR]

Why didnt Yamaha make this be a "standard" If it makes sense and it provides better output, I would think that Yamaha Corp, would use this as a standard TBS Sync.

Hi Fred,

I have looked into the Unauthorized TBS sync, but after reading it, I dont fully understand it. I wish there was a quick, 1,2,3,4,5... plan, not a long 2-3 page explanation.

The way I see it, to get the best possible results, you really need to know exactly what you are trying to accomplish, not just the step by steps.

But I could distill it into simple steps like this:

1. Warm the engine to two bars.

2. Remove the 4 rubber caps.

3. Install the carb sync tool on all 4 valves.

4. Ensure idle speed is 1,100 RPM and adjust if necessary.

5. Close down all 4 air screws on the throttle bodies (this will require opening the throttle slightly or the bike will stall out) Try to keep it ~ 1100 rpm but actual rpm is not important at this step.

6. Adjust the 3 linkage screws between the throttle bodies for a balanced vacuum. Use #3 as the reference.

7. Open each air screw 1 turn. (this will require releasing the throttle)

8. Adjust idle speed to exactly 1100 rpm.

If unable to get the idle high enough open all 4 screws an extra 1/4 turn and repeat this step.

If unable to get the idle speed low enough, close all 4 air screws 1/4 turn and repeat this step.

10. Touch up the air screws for perfect balance at 1100 rpm.

11. When done, stop the engine and remove the measuring equipment.

12. Reattach the rubber caps and retaining clips.

 

[Zorlac]

Unless your TBS happens to be WAY off for some reason, this is just a "feel good" exercise IMO.

I've done it once, I'm good. :good: :grin:

 

[rbentnail]

My recommendation is to have spare caps on hand prior to starting. I get mine at O'Reilly's auto parts- a 5-pack of 5/32" rubber caps. I damaged one once trying to get it off and found one dry rotted and cracked last year.

 

[Rider_FJR]

I'm going to stop at Autozone today on the way home. I hope they have them.

And I'm assuming you didnt use any clips?

My recommendation is to have spare caps on hand prior to starting. I get mine at O'Reilly's auto parts- a 5-pack of 5/32" rubber caps. I damaged one once trying to get it off and found one dry rotted and cracked last year.

 

[Rider_FJR]

Well, I think I have my TBS Synced, but I wish those measurement things, didn’t go Up and Down so fast. I wish they would just sit statically, not jumping around. Is that normal for the 4 values on the actual TBS unit jump around so much?

 

[Fred W]

Well, I think I have my TBS Synced, but I wish those measurement things, didn't go Up and Down so fast. I wish they would just sit statically, not jumping around. Is that normal for the 4 values on the actual TBS unit jump around so much?

Yeah, pretty much. There is always a little jiggling up and down especially at low rpms.

Did you put the 4 little restrictors in line in the four vacuum hoses? That helps dampen the bouncing somewhat.

Here's a video showing the normal amount of variations

 

[Rider_FJR]

I have not used the 4 little restrictors, let me try them now.

Well, I think I have my TBS Synced, but I wish those measurement things, didn't go Up and Down so fast. I wish they would just sit statically, not jumping around. Is that normal for the 4 values on the actual TBS unit jump around so much?

Yeah, pretty much. There is always a little jiggling up and down especially at low rpms.

Did you put the 4 little restrictors in line in the four vacuum hoses? That helps dampen the bouncing somewhat.

Here's a video showing the normal amount of variations