A thought experiment on carb syncing thru-out the rev range

headshrink · July 14th, 2011, 07:58 PM

I just had a different idea that I wanted to get down on "paper" before I forgot it, and see if others thought it was even a plausible modification.

As most here probably know, when you sync your carbs, you are setting it to be synced only at idle, but when you rev it they will pull at different rates.... I don't know why it is, just that it is.

I have also done most of the regular mods around here to my bike, including jetting & drilling the slides.

So I got to thinking..... what if you only drill one slide (the one that pulls less under power), and leave the other alone? Theoretically they would then move at different speeds, and my thought was if manipulating the speeds [between] the slides would effectively keep the carbs closer to synchronization into at least part of the rev range. If this theory proved true, I would thing it could even be fine-tuned by different sized holes, although I imagine the margin for error would be extremely small.

As I was processing this idea, I remembered that Kawi put slightly different tapered needles in each carb, and adjusted the mixture at different points, right and left respectively..... I've always wondered WHY they did this, but just wondered if they were in fact trying to accomplish the same thing I was pondering above.

What do you guys think?

wayanlam · July 14th, 2011, 11:32 PM

too much work for possibly only a slight improvement? hehehe

headshrink · July 15th, 2011, 03:11 AM

Quote:

Originally Posted by wayanlam

too much work for possibly only a slight improvement? hehehe

Oh I wasn't volunteering.... that is why it is only a "thought experiment." Just trying to stretch my knowledge and understanding of how these engines work. Can I at least get an honorary doctorate in Ninjette buffoonery & uselessness for coming up with that one?

g21-30 · July 15th, 2011, 04:26 AM

Quote:

Originally Posted by headshrink

What do you guys think?

You have way too much spare time on your hands!

headshrink · July 15th, 2011, 08:51 AM

But would it potentially work?

Racer x · July 15th, 2011, 10:39 AM

Syncronizing the carbs is to adjust the throttlle plate so each plate is giving the proper Air /fuel ratio at idle. Each cylinder will need a specific amount of air and fuel .adjusting the stationary throttle blades for each cylinder gives a smooth idleAs soon as you open the throttle blades the vacuum slides automaticly give the proper amount of air for eaxh cylinder. From off idle to full throttle the aif fuel ratio is going from pilot jet to needle /main jet relationship to just the main jet. You can make the slides move faster by drilling the them But there is a lot of other factors involved. At the end of the day the engine does not need to be that spot on . If it is allittle rich or a little lean here and there you can't tell without a exhaust gas analizer.And the power or economy will not vary much. But after syncronizing the carbs for idle you tune the engine to get the best running using diffeent jets and needles.I hope this makes sense.

setasai · July 15th, 2011, 10:44 AM

Quote:

Originally Posted by Racer x

Syncronizing the carbs is to adjust the throttlle plate so each plate is giving the proper Air /fuel ratio at idle. Each cylinder will need a specific amount of air and fuel .adjusting the stationary throttle blades for each cylinder gives a smooth idleAs soon as you open the throttle blades the vacuum slides automaticly give the proper mixture for eaxh cylinder. From off idle to full throttle the aif fuel ratio is going from pilot jet to needle /main jet relationship to just the main jet. You can make the slides move faster by drilling the them But there is a lot of other factors involved. At the end of the day the engine does not need to be that spot on . If it is allittle rich or a little lean here and there you can't tell without a exhaust gas analizer.And the power or economy will not vary much. But after syncronizing the carbs for idle you tune the engine to get the best running using different jets and needles.

So to summarize Racer X, It makes little to no difference so just give up and focus your time and energy on something else. haha... Interesting theory, I probably would think something similar if I wanted to tinker with something like that. I'd imagine that getting something as unpredictable as an explosion in a steel cage to be perfectly the same EVERY single time would near never happen.

headshrink · July 15th, 2011, 02:01 PM

Quote:

Originally Posted by setasai

focus your time and energy on something else.

I think all the non-ADD folks are a bit jealous.
We ADDers are, after-all, the entrepreneurs of society.... thinking about the possibilities outside the box.

July 14th, 2011, 07:58 PM	#1
headshrink ninjette.org certified postwhore Name: Bob Location: CA Join Date: Dec 2008 Motorcycle(s): '08 Ninja 250r, '14 CBR500r Posts: A lot.	A thought experiment on carb syncing thru-out the rev range I just had a different idea that I wanted to get down on "paper" before I forgot it, and see if others thought it was even a plausible modification. As most here probably know, when you sync your carbs, you are setting it to be synced only at idle, but when you rev it they will pull at different rates.... I don't know why it is, just that it is. I have also done most of the regular mods around here to my bike, including jetting & drilling the slides. So I got to thinking..... what if you only drill one slide (the one that pulls less under power), and leave the other alone? Theoretically they would then move at different speeds, and my thought was if manipulating the speeds [between] the slides would effectively keep the carbs closer to synchronization into at least part of the rev range. If this theory proved true, I would thing it could even be fine-tuned by different sized holes, although I imagine the margin for error would be extremely small. As I was processing this idea, I remembered that Kawi put slightly different tapered needles in each carb, and adjusted the mixture at different points, right and left respectively..... I've always wondered WHY they did this, but just wondered if they were in fact trying to accomplish the same thing I was pondering above. What do you guys think? __________________________________________________ Honda Interceptor VFR800 DLX (2014, 8th gen) Honda CBR500r (2014) - FOR SALE Kawi Ninja 250r (2008) - Restored and passed-down within family, only to be abandoned

July 14th, 2011, 11:32 PM	#2
wayanlam ninjette.org certified postwhore Name: Wayan Location: Bali - Indonesia Join Date: Apr 2009 Motorcycle(s): 2014 Z250 Posts: A lot.	too much work for possibly only a slight improvement? hehehe __________________________________________________ Kawasaki Z250, Bored up to 300cc with 12.8 CR, 41hp at wheel 27nm torque, Two bros full exhaust with DB killer Dynojet Power Commander V, KnN Open filter, intake and exhaust ported, Puig Windshield

July 15th, 2011, 08:51 AM	#5
headshrink ninjette.org certified postwhore Name: Bob Location: CA Join Date: Dec 2008 Motorcycle(s): '08 Ninja 250r, '14 CBR500r Posts: A lot.	But would it potentially work? __________________________________________________ Honda Interceptor VFR800 DLX (2014, 8th gen) Honda CBR500r (2014) - FOR SALE Kawi Ninja 250r (2008) - Restored and passed-down within family, only to be abandoned

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July 15th, 2011, 10:39 AM	#6
Racer x ninjette.org certified postwhore Name: Eric Location: Iowa City Join Date: May 2009 Motorcycle(s): 2008 Kawmeracchi 350 2010 Project X Posts: A lot. Blog Entries: 54 MOTM - Sep '18, Feb '16	Syncronizing the carbs is to adjust the throttlle plate so each plate is giving the proper Air /fuel ratio at idle. Each cylinder will need a specific amount of air and fuel .adjusting the stationary throttle blades for each cylinder gives a smooth idleAs soon as you open the throttle blades the vacuum slides automaticly give the proper amount of air for eaxh cylinder. From off idle to full throttle the aif fuel ratio is going from pilot jet to needle /main jet relationship to just the main jet. You can make the slides move faster by drilling the them But there is a lot of other factors involved. At the end of the day the engine does not need to be that spot on . If it is allittle rich or a little lean here and there you can't tell without a exhaust gas analizer.And the power or economy will not vary much. But after syncronizing the carbs for idle you tune the engine to get the best running using diffeent jets and needles.I hope this makes sense.