Cant get full sync

[Vesmak]

Yesterday i sync my carbs so long and cant get all of my carbs sync.

This is where it is now. Idle. Other setup is where 1st, 3rd and 4 is about sync but 2nd is very low. Cannot see any leaking spot.


But when i take rpm's to 3k then there are all full sync. Is that very bad thing if i leave this idle settings on?

 

[chuck hahn]

Once you get 1/2 and 3/4 cylinders lined up like that, you use then CENTER adjuster to bring the 2 sides into sync. May then need to do some very minut tweeking at that point.

 

[Vesmak]

When i that point using center adjuster, only 3rd going up and 2nd going down.

 

[chuck hahn]

turn it the other way and see what it does...and the idle will chnge so youll be ready to use the idle knob to adjust. And sync with the RPMs arounr 2000 to 2500

 

[Nessism]

To sync the carbs you first set the idle up to about 2500 rpm.

Tweak the center adjuster and get 2-3 level.

Next adjust 1 and 4 to be level with the two center carbs. The order of which you adjust first doesn't matter.

Always use a large fan blowing on the engine when doing this sort of work.

Needless to say, you must have the valves properly adjusted, a clean air filter installed, and the entire intake system sealed properly. Also, set the pilot screws to 2.5 turns open or close, based on the highest idle test.

 

[chuck hahn]

I always have done them the way i posted because thats the way all the "pros" that have racing shops show CV carb syncing on thier websites and youtube pages.

 

[chuck hahn]

Here..even though its a CBR its still a 4 cylindered inline 4 bike and the principle is exactly the same on a GS with CV carbs. Funny how the Brit inn the video is counting 1 as the right side and 4 as the left side when we Americans go from left to right.


https://www.youtube.com/watch?v=KHGPqP6G9cA

 

[Nessism]

I always have done them the way i posted because thats the way all the "pros" that have racing shops show CV carb syncing on thier websites and youtube pages.

That's not the right way chuck. 2-3 need's to be done first. If you do 1-2 and 3-4 first, when you do 2-3 everything will then be off.

 

[Dave8338]

That's not the right way chuck. 2-3 need's to be done first. If you do 1-2 and 3-4 first, when you do 2-3 everything will then be off.

That has been my experience, as well.
Doesn't matter if is a four pack of webers on a Opel OR CV carbs, or flat sides, or...

 

[Guest]

In THEORY, it shouldn't matter which ones you do first, but I have observed that the factory-recommended sequence works best.

Sync 2/3, then 1/2, finally 3/4. Of course, when they adjust 1/2 and 3/4, they are setting the outer cylinders "half a ball" higher than the inner cylinders, but that "half a ball" is only repeatable if you have the official Suzuki sync gauge. I think I saw something a while back where somebody tested that and found that "half a ball" was about 2cm on a real gauge. Most of us will set them all the same height, and not worry about that "half a ball" difference.

 

[JTGS850GL]

The "half ball" difference only applies when using the stock exhaust. On a 4-1 exhaust you would align all the levels equal.

 

[Guest]

The "half ball" difference only applies when using the stock exhaust. On a 4-1 exhaust you would align all the levels equal.

1. I never have heard a good explanation why that is. Do you have any idea why they wanted that half-ball difference?

2. The OP never says what type of exhaust system is on his bike.

3. Suzuki never mentioned ANYTHING about removing the stock exhaust and what adjustments would have to be made if you did.

 

[Vesmak]

I have stock exhaust. 4-2. Yesterday i drove about 30km and not problems at all. Very cold out there still, 3 celsius to 8 celsius (37.4 F to 46.4 F).

 

[JTGS850GL]

1. I never have heard a good explanation why that is. Do you have any idea why they wanted that half-ball difference?

2. The OP never says what type of exhaust system is on his bike.

3. Suzuki never mentioned ANYTHING about removing the stock exhaust and what adjustments would have to be made if you did.

The "half ball" thing is related to the stock exhaust being a 2 into 2 with a crossover tube.

 

[Nessism]

That half ball business is iffy at best. I've never heard of that with other model bikes, just Suzuki, and lots of different models use a crossover. Just set the vacuum equal across the board and call it done.

 

[JTGS850GL]

That half ball business is iffy at best. I've never heard of that with other model bikes, just Suzuki, and lots of different models use a crossover. Just set the vacuum equal across the board and call it done.

Yep, pretty much what I do. All my bikes have 4-1 exhausts though. Not saying that stock exhausts must be adjusted the "Suzuki way", just explaining where the "half ball" thing came from.

 

[Guest]

The "half ball" thing is related to the stock exhaust being a 2 into 2 with a crossover tube.

That half ball business is iffy at best. I've never heard of that with other model bikes, just Suzuki, and lots of different models use a crossover. Just set the vacuum equal across the board and call it done.

Yep, pretty much what I do. All my bikes have 4-1 exhausts though. Not saying that stock exhausts must be adjusted the "Suzuki way", just explaining where the "half ball" thing came from.

I know that it's there and pretty much just a "Suzuki" thing, I am just curious about the physics behind it and why Suzuki feels it's necessary.

I had a couple of Kawasakis that had crossovers, but they were after the collectors on each side. Cylinders 1 and 2 came together on one side, 3 and 4 came together on the other side, then there was a crossover. I think I have seen that on some Hondas, not sure about Yamahas. Suzuki seems to be the only one that had the crossover before the collector. I think that is what gave them their unique sound, but I can't see where it helped to make any more power.

I synchronized carbs for years before I ever saw that half-ball difference in a Suzuki manual, and I continue to set them all the same.

 

[Nessism]

I have stock exhaust. 4-2. Yesterday i drove about 30km and not problems at all. Very cold out there still, 3 celsius to 8 celsius (37.4 F to 46.4 F).

Did you fix the sync to make the columns level (or at least level within the 1/2 ball business)?

 

[robertbarr]

I know that it's there and pretty much just a "Suzuki" thing, I am just curious about the physics behind it and why Suzuki feels it's necessary.

I recall talking to a dealership mechanic years and years ago who said that the slight difference is because the inner two cylinders don't get quite as much cooling as the outer two.

I suppose it's as good a reason as any, but if he's still around to ask what his source was, he'd have to be about 109 years old.

 

[Vesmak]

Did you fix the sync to make the columns level (or at least level within the 1/2 ball business)?

Im not fix that yet. And dont know at all what is that ball thing. Maybe some day in this week i take that sync again. What if i leave it in that sync? Stressing more other sylinders or what.