carb sync issue

[ReCycled]

Having a little trouble and hoping for a little advise

 

I don't have a 4cyl sync tool so trying to balance carbs in pairs.

 

I see where the service manual got a little dyslexic and that didn't help but I searched here and see it wasn't just me, SO...

 

 

First I synced #1(LR) to #2 (LF) using the hardest to reach screw #3 (long Philips from right side of bike)

Then I synced #3 (RR) to #4(RF) using screw #2 on the right side of the bike

 

But then I am unable to balance #2 to #3 Using screw above choke knob on left side of bike

 

 

 

Basically I can sync each side front to rear but cannot get the two sides balanced, same results no matter checking 2-3,2-4,1-4,or1-3

 

Any thoughts?

 

Oh, and I'm plugging the two open vacuum ports during all testing.

 

 

TIA

[cowpuc]

I have done my 83's hundreds of times but only did an RSV sync one time.. To my recollect,, the OEM instructions on the process were wrong and I had to figure it by trial and error.. Before it got stolen out of my shop I used a handy little Twinmax digital that would only do 2 at a time too and used it successfully many times on other twins,, I am sure you can do the same.. Hold on and I will see if I can find some info to help you out!!

[cowpuc]

Here ya go brother!!! Straight from the guru's!!! If this dont answer your question/solve your problem hang around and one of these pro's will figure it out!!!

 

https://www.venturerider.org/forum/showthread.php?258-Syncronizing-the-Carbs

[ReCycled]

I'm familiar with the Twinmax, though I'm using an electronic one called a Harmonizer. I like it better than the Twinmax because there's no calibrating and especially because it has a built in tachometer.

 

I had found that helpful thread which was real nice because the manual really had me off. I think I'm following the instructions correctly, only difference being the 4-port vs 2-port tool.

[Patch]

So we covered this in another thread by DuRon... I don't remember when tho..

 

The first is to understand that what you are reading is low pressure or vacuum. Vacuum must be generated by the intake stroke! We can predict this by knowing what the compression strokes are doing, so what are those numbers? Do they fall in spec?

 

Next is you by now have no bench sync so you need dance a bit to find the best compromise?

Whoops there more, what rpm are you setting at?

Did you first read the measurements off your tool by comparing the reading to one single carb before you hooked up all 4?

[Marcarl]

I don't know what these other guys are talking about, but to keep it simple:

Sync the throttle side first, so 1 to2

Nest sync the other side so 3 to 4

Now you need to sync the one bank to the other and I'm quite sure it's the back 2 cylinders that are hooked together, but you can see that with the linkage.

Now if you are turning on the wrong screws you will get a different reading alright, but all you might be doing is messing things up more than they were already. So take some time to really identify what each screw is doing, like,, which carb is it adjusting.

If I remember correctly, and it's been a couple of years, 1 and 2 have a screw right on the carb, and the idle adjustment tumb knob is there as well. 3 and 4, have a screw to balance between the two, but when you need to sync the one bank to the other, the screw is is on the left side, only turnable from the right side so you'll need a long handle phillips.

And I bet it just got a whole lot more confusing.

[BlueSky]

Here is the old training video on the subject.

 

 

Now, heerrees PUC!

 

[cowpuc]

Here is the old training video on the subject.

 

 

Now, heerrees PUC!

 

 

He's talking RSV though Sky and those are MK1/MK2 syncs.. Totally different syncing..

[BlueSky]

He's talking RSV though Sky and those are MK1/MK2 syncs.. Totally different syncing..

 

Thanks. I thought I was getting even more senile but I went back and reread the his post and he didn't specify what model he is working on.

[Patch]

I don't know what these other guys are talking about, but to keep it simple:

Sync the throttle side first, so 1 to2

Nest sync the other side so 3 to 4

Now you need to sync the one bank to the other and I'm quite sure it's the back 2 cylinders that are hooked together, but you can see that with the linkage.

Now if you are turning on the wrong screws you will get a different reading alright, but all you might be doing is messing things up more than they were already. So take some time to really identify what each screw is doing, like,, which carb is it adjusting.

If I remember correctly, and it's been a couple of years, 1 and 2 have a screw right on the carb, and the idle adjustment tumb knob is there as well. 3 and 4, have a screw to balance between the two, but when you need to sync the one bank to the other, the screw is is on the left side, only turnable from the right side so you'll need a long handle phillips.

And I bet it just got a whole lot more confusing.

 

Are we not forgetting the basics?

Step one, check lash

Step two check compression

Step two might just point to step one so reverse the order to assume to know step one!

What good is syncing carbs if you do not know the condition of the engine you are trying to sync?

 

Just sayin

[Freebird]

I didn't read through this thread in detail but just wanted to issue a reminder. The manual for the RSV, at least the earlier manuals, have the sync procedure wrong. Please see this thread for the proper method.

 

https://www.venturerider.org/forum/showthread.php?258-Syncronizing-the-Carbs

[saddlebum]

Are we not forgetting the basics?

Step one, check lash

Step two check compression

Step two might just point to step one so reverse the order to assume to know step one!

What good is syncing carbs if you do not know the condition of the engine you are trying to sync?

 

Just sayin

Ok now your getting picky Patch... . Your not wrong but I prefer the take it for granted method ...... in other words the bike is basically running fine so just sync the carbs, go back to all that other work if syncing fails to produce the proper results and another problem may be indicated. Lazy mans tip #1.. ..if it aint broke don't mess with it...

[Patch]

Ok now your getting picky Patch... . Your not wrong but I prefer the take it for granted method ...... in other words the bike is basically running fine so just sync the carbs, go back to all that other work if syncing fails to produce the proper results and another problem may be indicated. Lazy mans tip #1.. ..if it aint broke don't mess with it...

 

And miss the learning curve? lol

I know!

[saddlebum]

And miss the learning curve? lol

I know!

I figure learning curves come around often enough, even the ones you don't want

[ReCycled]

Admittedly I have not checked valve clearance within the last 5000mi and have not checked compression, and yes I was working with the assumption that the motor was basically ok.

 

Syncing the carbs mostly for peace of mind because I don't know when it was last done.

 

The Harmonizer I have can measure vacuum with just one hose so I could measure each carb individually for reference. In the meantime, I think I will get to work on making my own four hose manometer.

 

 

 

So can someone just confirm if my understanding is correct:

 

a) The two Philips screws accessed from right side of the bike(one with long screwdriver) adjust balance single carbs front to rear.

b) The one flat head screw accessed from left side of bike balance left bank to right bank.

[Patch]

Admittedly I have not checked valve clearance within the last 5000mi and have not checked compression, and yes I was working with the assumption that the motor was basically ok.

 

Syncing the carbs mostly for peace of mind because I don't know when it was last done.

 

The Harmonizer I have can measure vacuum with just one hose so I could measure each carb individually for reference. In the meantime, I think I will get to work on making my own four hose manometer.

 

 

 

So can someone just confirm if my understanding is correct:

 

a) The two Philips screws accessed from right side of the bike(one with long screwdriver) adjust balance single carbs front to rear.

b) The one flat head screw accessed from left side of bike balance left bank to right bank.

 

Just for exchange of information:

If you know the bench marks are equal then you could sync with a drill bit as a feller gauge!

that you checked lash just 5K ago is good!

But don't sell compression short it is what we count on

The fact

[cowpuc]

Thanks. I thought I was getting even more senile but I went back and reread the his post and he didn't specify what model he is working on.

 

Yep,, I hear that Sky!! Had my weathered eye not noticed I was for the RSV tech section when I innocently got drawn into this discussion I would have easily of done the same.

[cowpuc]

Are we not forgetting the basics?

Step one, check lash

Step two check compression

Step two might just point to step one so reverse the order to assume to know step one!

What good is syncing carbs if you do not know the condition of the engine you are trying to sync

Just sayin

 

Just for exchange of information:

If you know the bench marks are equal then you could sync with a drill bit as a feller gauge!

that you checked lash just 5K ago is good!

But don't sell compression short it is what we count on

The fact

 

ahhhh,, not necessarily so IMHO.. Thinking back in history of my times spent furiously CTFW on these 1st Gens I can count on a hand with no fingers how many times I have pulled the covers and checked/set the lash on one of my V-4's,,, translated Frenchy - means in well over 1 million miles ridden aboard 6 1st Gen MK1's I have never,, not even once,, opened one up and even checked the valve lash.. On the other side of the coin though,, because the quad carb bank is mechanically linked (easy to lose sync) and knowing how easy it is to sync them up (20 minutes max) I always checked sync at oil changes when home,, usually ends up being at least a dozen times a year. Same with checking compression,, I only do/use that when I am seeing something happening that I dont like and I wonder if it involves a compression issue.. That said,, I can only think of one time that I did a compression check on one of my V-4's - yep,, these V-4's have been that reliable/durable in my situation..

[cowpuc]

Here ya go brother!!! Straight from the guru's!!! If this dont answer your question/solve your problem hang around and one of these pro's will figure it out!!!

 

https://www.venturerider.org/forum/showthread.php?258-Syncronizing-the-Carbs

 

Admittedly I have not checked valve clearance within the last 5000mi and have not checked compression, and yes I was working with the assumption that the motor was basically ok.

 

Syncing the carbs mostly for peace of mind because I don't know when it was last done.

 

The Harmonizer I have can measure vacuum with just one hose so I could measure each carb individually for reference. In the meantime, I think I will get to work on making my own four hose manometer.

 

 

 

So can someone just confirm if my understanding is correct:

 

a) The two Philips screws accessed from right side of the bike(one with long screwdriver) adjust balance single carbs front to rear.

b) The one flat head screw accessed from left side of bike balance left bank to right bank.

 

The link in the post above will take you to a complete explanation of the correct procedure IF you are working on an RSV and not a MK1 or MK2 Recycled.. Click and take a peek!!

[Patch]

ahhhh,, not necessarily so IMHO.. Thinking back in history of my times spent furiously CTFW on these 1st Gens I can count on a hand with no fingers how many times I have pulled the covers and checked/set the lash on one of my V-4's,,, translated Frenchy - means in well over 1 million miles ridden aboard 6 1st Gen MK1's I have never,, not even once,, opened one up and even checked the valve lash.. On the other side of the coin though,, because the quad carb bank is mechanically linked (easy to lose sync) and knowing how easy it is to sync them up (20 minutes max) I always checked sync at oil changes when home,, usually ends up being at least a dozen times a year. Same with checking compression,, I only do/use that when I am seeing something happening that I dont like and I wonder if it involves a compression issue.. That said,, I can only think of one time that I did a compression check on one of my V-4's - yep,, these V-4's have been that reliable/durable in my situation..

 

Non of that makes it the correct procedure!

Calling me Frenchy aint going to get me to duck neither!

Not checking compression is a well proven NONO!

Much OLDER Brother!

[cowpuc]

Non of that makes it the correct procedure!

Calling me Frenchy aint going to get me to duck neither!

Not checking compression is a well proven NONO!

Much OLDER Brother!

 

makes more sense then pulling the top of the motor all apart everytime you wanna do a simple syncing of the carbs little french brother of mine!!!!!!!!!!!!!!!!!!!!!! :rasberry:

[Freebird]

I'm kind of on the same page as Cowpuc on the compression issue. Having owned an '83, 88, 89, two 99's and an '05, I have NEVER had a compression issue on these bikes. Can it happen? Sure it can. If you are having some major issues then of course it would be worth checking. Everybody knows that compression is very important but it's such a rare problem on these bikes that it is certainly not the first thing I would recommend checking. Like Put, I have always checked my carb sync a couple times a year. Usually doesn't need much tweaking if any but it literally takes about 10 minutes to check them.

[Patch]

For the record: I don't disagree with just syncing the carbs providing you know and understand what the differences are and why you can't achieve a cure-all thru just a sync.

In fact I know that syncing is in and of itself a solid learning experience. But it is simply a step in the process of maintaining a sports machine.

As for compression testing a sports unit that sits for long periods, well on that I cannot be persuaded.

 

We often think we don't want to know the results when all they really are is a measure of existing condition. Stuck rings a perfect example, get them early and no problem. Above high limit is another example. These are common issues on these 4's and almost all engines.

They are discovered thru compression checks. Another can be valves not seating tight.

 

It has been part of the sport ever since I've been in it and beyond

[cowpuc]

For the record: I don't disagree with just syncing the carbs providing you know and understand what the differences are and why you can't achieve a cure-all thru just a sync.

In fact I know that syncing is in and of itself a solid learning experience. But it is simply a step in the process of maintaining a sports machine.

As for compression testing a sports unit that sits for long periods, well on that I cannot be persuaded.

 

We often think we don't want to know the results when all they really are is a measure of existing condition. Stuck rings a perfect example, get them early and no problem. Above high limit is another example. These are common issues on these 4's and almost all engines.

They are discovered thru compression checks. Another can be valves not seating tight.

 

It has been part of the sport ever since I've been in it and beyond

 

See little brother,, there ya go again,, making another claim I simply do not subscribe to... Have I ever dealt with a stuck ring,, of course, but never ever in one of my V-4's - no common issue there IMHO. Have I ever experienced rings gone to high limit or had valve lash gone tight, dozens of times but again,, never ever on one of my V-4's - no common issue there IMHO. Frankly,, this is one of the reasons I chose and have ridden the V-4 Venture as my CTFW cross country family go-to bike since 1987.. Besides never needing to spend more than a grand for one (less than 1/2 that for a couple just cause they were already missing 2nd gear) and getting well over 200,000 miles out of that thousand dollars coupled with the durability of these machines has just been amazing!!

IMHO,,, most of the sync jobs on these V-4's end up being just that,, a simple sync job (because they do go out of sync due to the mechanical nature of the carb linkages).. My advice,, pick up a set of vacuum gauges or a Carb Tune or make a set of Manometers (used to have and used a mercury sticks but those days are longgg gone) or what ever and learn to just do a simple sync job.. Your scoot will love you for it!!

 

,, you ever make a Poll little brother? Its kinda fun!! You should make a Club Poll asking how many of these lop eared Yamaha V-4 riding VR club varmints have experienced stuck rings or worn out to high limit rings or valve lash gone tight (If I had to bet money, I would bet that the valve lash going tight will have wayyyy more positive votes than the ring wear as, even though I have never needed to do one in any of my bikes, I have read of numerous occasions of varmints setting their valves) just to see exactly how accurate your claim above is!! Unless your skeered too:witch_brew: :rasberry:

[venturesome]

I just spent more time than it takes to perform a carb sync trying to find an adequate French word for condescending.

Can anyone help me?