Synch vs Balanced

[koolaid_kid]

You are quite correct. If you chose to dial in each individual cylinder, you would need a bung in each pipe. If I were racing and cost (time, effort and parts) were no object, that is what I would do.
However, I am not racing, and cost is an object, so I choose to make all settings in all carbs identical. Therefore, I only need one reading, which can be at the end of the muffler (using a clamp for the O2 sensor) or in the collector pipe using a bung.
I would be interested to see a comparison between the two. I strongly suspect the gain in horsepower and torque would not be worth the effort, since you are basically tuning the engine 4 times, once for each cylinder.
BTW, when I tune a car, I also use the second method, since I cannot adjust each cylinder separately.

 

[Calvin Blackmore]

still indulgent meanderings and horse****.

what do any of you do for engines that have two port carbs with exhaust dumped into reducxtion non tuned exhausts.


the amount of repeat nonsense for the sake of saying something here for the simple sake of being heard is absurd.

NO NUMBERS NO measures NO nothing
KNOW nothing


to measure is to presume to know

 

[979roadrunner]

I am speaking of the mass of each piston rod assembly including the mass on each crank lobe

the statistical process control manifest in japanese indusrty would not have allowed a statistically signifigant difference to occur

ballance and blue print is from the days of the model t

Wrong, serious high performance and race engines are balanced and blueprinted.
all that fiddling and hand fitting to get them dimensionality and dynamically 'perfect' is a big part of the $10k+ price of a serious motor.
Model T era engines were not, for the most part, balanced and blueprinted, they were labor intensive to build because at that time they were dimensionally all over the map from being hand built on an individual basis.
The model T, the first mass produced car built on an assembly line, changed all that.
as for production tolerances making that big a difference in anything with tolerances as tight as a motorcycle engine that can live at 9k RPM, I'd agree there probably isn't any significant difference from one cylinder to the next.

 

[fastpakr]

Carb synching is to balance the individual carbs to each other. It has NOTHING to do with pumping volume of the cylinders. If you balance a carb rack on one motorcycle, it will be perfectly synchronized when pulled and installed on another.

Cafe Kid, you're making this far too complicated. Forget the engine side of the equation entirely.

 

[Guest]

. If you balance a carb rack on one motorcycle, it will be perfectly synchronized when pulled and installed on another.

.

So once sync'd always sync'd?

Please elaborate on your comment.

 

[fastpakr]

A carb can certainly go out of sync over time, so the answer to the question as stated is no. Not 'once sync'd, always sync'd. But it's a function of being bounced around on the bike and screws self adjusting from vibration, throttle plates wearing, etc. Not related to the engine.

You can rebuild a carb rack, synch it, toss it in a box (carefully packed, of course) and ship it anywhere in the world for someone else to mount on their bike. A member on one of the other forums I'm involved in has been doing that for other members for years.

 

[Steve]

If you balance a carb rack on one motorcycle, it will be perfectly synchronized when pulled and installed on another.

In a perfect world, yes. However, I am stuck in this world.

Differences in valve adjustments will subtly change how much a particular cylinder will draw. If one bike has different clearances on the valves, it will draw just a bit more or less air, which will affect the vacuum level.

Doing a vacuum sync on a bike then shipping the carbs will at least assure you that they are very close, but I would not guarantee them to be exact. :-\\\

.

 

[Dave8338]

In a perfect world, yes. However, I am stuck in this world.

Differences in valve adjustments will subtly change how much a particular cylinder will draw. If one bike has different clearances on the valves, it will draw just a bit more or less air, which will affect the vacuum level.

Doing a vacuum sync on a bike then shipping the carbs will at least assure you that they are very close, but I would not guarantee them to be exact. :-\\\

.

AAAGREEEEED.

If close is what you're after, close it is. To tune an engine "perfectly", it ALL has to be done as a package deal, with that individual engine.

Even variance in spark plug gap, plays a factor... :-\\\

 

[Calvin Blackmore]

OK i was mistook
I was wrong and obistantate in my obstinancy


I was harping on a theoretical notion not disputing a very well known fact


carbs is delicate
need to be balanced

and any signifigant differantion among the rack will cause major performance problems

 

[Calvin Blackmore]

AAAGREEEEED.

If close is what you're after, close it is. To tune an engine "perfectly", it ALL has to be done as a package deal, with that individual engine.

Even variance in spark plug gap, plays a factor... :-\\\

my ogd man nothing in the physical world is within the magical perfect spec

 

[Dave8338]

my ogd man nothing in the physical world is within the magical perfect spec

I am, but but but...as noted at birth, I am an anomaly!

 

[Calvin Blackmore]

I am, but but but...as noted at birth, I am anomaly!

happily anomaly loves company


cos in our english culture it rhymes so very very nice

 

[Dave8338]

happily anomaly loves company


cos in our english culture it rhymes so very very nice

NICE!

 

[BIKERTUCKER]

WOW ..... Have been away from the site for a while. Proof that drugs and motorcycles are a poor mix.