carb sync

[Polisher]

I'm fairly mechanically minded and can turn my hand to most things. Never done carb sync's before and just paid someone £75 to do mine. (which I tough was a bit steep, but as I cant do them myself....)

How easy is it to do using these carb balancing kits, guys?
Neil

[Neosophist]

I'm fairly mechanically minded and can turn my hand to most things. Never done carb sync's before and just paid someone £75 to do mine. (which I tough was a bit steep, but as I cant do them myself....)

How easy is it to do using these carb balancing kits, guys?
Neil

EASY!

You need a set of vaccumn gauges (i.e morgan carbtune) etc.

An Angled screwdriver makes the job 1000x easier (morgan sell these also)

Step 1.

Remove side fairings and connect gauges to cylinders.. (each cylinder has a screw in it that you unscrew and fit the connecting adapter into)

Step 2.

Fire up the engine, warm it up, set your idle just above normal.

Step 3.

Using the angled screw-driver you'll find 3 screws under the linkages of the carbs. You adjust the 3 other carbs to match the one that isn't adjustable.

Turning each screw will adjust the vaccumn of all the carbs, turn them until there within 1 bar of each other (if using a morgan device)

Done!


..if you have eyes and can use a screwdriver you can balance carbs.

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[studricho]

I wonder if the sync balance I use would work on the VFR's. I know the one I use works great in the CBR's 250 and any other carby sticking up so I think it would.

I get a picture up later of what I'm talking about.

[Neosophist]

I wonder if the sync balance I use would work on the VFR's. I know the one I use works great in the CBR's 250 and any other carby sticking up so I think it would.

I get a picture up later of what I'm talking about.

Sync balancer?

Does it work on vaccumn? I've got a few different ones that do, a plastic pipe with two ball bearings in it, a set of davida gauges, a morgan carbtune and an 80's honda LCD digital tuner.

I prefer the morgan as its easiest to use and works on all 4 cylinders at once so you can see whats going on.

[studricho]

http://cgi.ebay.com.au/Weber-New-Carbur ... 286.c0.m14" onclick="window.open(this.href);return false;

This is the one that I use. I like it cause it's simple and I'm measuring the air speed at the velocity stacks, not at the inlet manifold.

I've actually lent mine to a few mechanics to compare this to the manometer and they all agree this is much easier method.

I checked if it would fit the VFR and it does.

I did a group buy for the cbr forum and ending up getting them much cheaper.

[Neosophist]

Oh yeah I know.

Using a set of proper vaccumn gauges isn't difficult plus you dont need to take all the tank / air box off to adjust the carbs either so i'd say that the vaccumn gauge method is probably easier?

I'd say that its more accurate to measure the vaccumn of the actual engine than the air in the velocity stacks, due the fact of how the air travels through each carb might not be identical due to wear / tear / different tolerances / different cylinder condition.

Also with the airbox / filter on the flow is going to be different too?

Also do you have to keep re-iterating the tuning process with that as when you adjust one carb it tends to effect the other carbs too and that only does one at a time?

No doubt it obviously gets the job done to a fairly accurate leve. I have a feeling if you used a morgan / similar device you wouldn't go back,

Only need to take off the side panels. I can balance a set of VFR carbs to near perfect level in 5 - 10 mins :)

[Smev]

This may seem a bit of a stupid question but I'm going to ask it anyway!!

I have a Carbon Fibre HRC style tray fitted between the carbs and engine so can't easily get access to the carbs and adjusters.

If I was to fit the carbs without the tray, sync'd them and balanced them, then took them off to re-fit the tray - I'm not going to upset anything am I?!

Cheers

Smev

[studricho]

Neosophist I have never balanced a set of VFR carbs so i don't know, but I have done too many to remember on CBR's.

That's an interesting take on where to measure the air speed/flow from. You point is valid and I would like to compare them side by side.

What's this morgan one look like?

[micpec]

...consider getting yourself a morgan carbtune and an angled screwdriver off their website and you can do future synch's yourself, plus friends etc etc :)
....

Funny that...I've ordered them this week, and there're in the post rightnow to me...

i'll be interested to hear how you get on with them jason, can you post the results up on here please fella ?

Rhory, to come back on these morgan carbtune and angled screwdriver kit....it is very straight forward to use (a bit strange explained in the haynes manual to get the plastic adapters on the vacuumports of each cylinder). I never ever done carb synch job before, but it was not hard to do. In fact, it was nice to do as I could get my hands nice and warm during synch with current temperatures in autumn. After all tubes attached on the adapters, and engine started, the readings on the carbtune was a bit out of line 2+4 and 1+3. To get to the screws underneath the carbs the angled screwdriver did help loads! I am happy with the result. Throttle response is just little more quicker/smoother...engine sounded smooth too when blipping on throotle. I would recommend this kit of Morgan including the angled driver.

[Cammo]

Using a set of proper vaccumn gauges isn't difficult plus you dont need to take all the tank / air box off to adjust the carbs either so i'd say that the vaccumn gauge method is probably easier?

I'd say that its more accurate to measure the vaccumn of the actual engine than the air in the velocity stacks, due the fact of how the air travels through each carb might not be identical due to wear / tear / different tolerances / different cylinder condition.

Also with the airbox / filter on the flow is going to be different too?

I can balance a set of VFR carbs to near perfect level in 5 - 10 mins :)

Personally I don't place much importance on having the carbs perfectly balanced. The only downside if they're badly out of synch (which hasn't happened to me as I regularly synch them) is less than perfect off idle performance and a wobbly idle which annoys some people....


There are many other factors also which will affect performance that you have little control over, e.g. different vacuum piston spring tension which will affect carb fuelling. How many peeps make sure that all 4 springs are the correct length and strength?? (FWIW I check spring length every 6 months or so - you'd be surprised at how some can be out).