About to Carb Sync

[JCruze]

I bought a 4 gauge carb sync tool and I'm going to try and sync the carbs tomorrow. I know that I need to install the little plastic valves to minimize needle flutter but is there anything else I'm missing?

Compression is good, carbs have been thoroughly cleaned and I know to warm the bike up before hand. The instructions that came with the sync tool mention the choke being open during the sync but I feel thats kind of wrong. Any tips and pointers would be much appreciated as this is my first carb sync.

[Cobia]

JCruze,
When they say the choke should be "open" it means it should be OFF. That's the normal operating position. "Closed" means it's restricting air intake to maximize fuel delivery.
Oh yeah, make sure your idle speed is at 1.1k when you're synching, and check the needle progress as you rev it up as well as where they settle afterward. Adjust accordingly.
MAKE SURE ALL DIALS OF THE SYNCH TOOL ARE OPERATING PROPERLY AND SYNCHED, USE A MIGHTY VAC TO VERIFY THAT, AND ADJUST ACCORDINGLY.

[DGXSER]

Choke operation would normally refer to a restrictor to limit air flow. So it being open would equate to it not effecting the performance of the system. These carbs do not have an actual "choke", they use an enrichment cicuit, meaning they add fuel to the mixture instead of restricting air flow. So you are correct, once the engine is warmed up good, you do not want your enrichment curcuit open.

As Robert stated, you do want to calibrate the gages first. Each gage may well (and probably will) read slightly different from the same vacuum source. So either use a known vacuum source, like a Mity-Vac, or hook each gage up to the same cylinder one at a time. This will let you see how different they read at about the vacuum they will be measuring. You can then mark where the needle is at for the same vacuum reading on all four of them, defining the new "zero" for each gage in a way. So now you can determine their reading not from the actual factory numbers, but how far off they are from that "zero" indicator. Note, that your final vacuum for all four may well not be that "zero" point, but they all should be the same offset from their individual "zero" points.

[JCruze]

Thanks guys, working on it now.

[Tat2demon]

When I calibrated my gauges I picked up 3 little plastic T's from the pet store. Hooked 1+2 and 3+4 together, then hooked in the 3rd T between the pairs so I could suck on the line and make sure all 4 were showing the same. I check that way before I use them every time now.

[jwhughes3]

How can you tell that the amount of vacuum you are applying equals the readout ?

Seems very unscientific to me.

j/k - Sounds like a good procedure - good luck synching!


John

[DGXSER]

John he is an EOS.....Equal Opportunity Sucker! He sucks equally from all sources......umm...wait...not sure that sounded right.

[Tat2demon]

Was told they all just need to match. Doesnt matter what the vacuum level is. Easy to do when all hooked together.

[DookieTx1911]

Was told they all just need to match. Doesnt matter what the vacuum level is. Easy to do when all hooked together.

This would be correct.

[DGXSER]

They all need to be at the same vacuum level. Only reason I differentiate is that if you do not calibrate a four gage setup, getting the same reading across all four is not the same as all four at the same vacuum level.

[Rasputin]

As you will be doing this with an already warmed up engine, DO NOT forget to have a fan blowing on the engine. The first time you do it will take longer than you think, after that it is a breeze. The other thing to keep in mind is the engine RPM which should be as low as practicable or normal idle for these which is 1050 to 1100 or there abouts.
Also be sure of the correct procedure for adjusting the Carbs. #3 is your one that you have to adjust too. Balance #3 to #4 Then adjust #1 to #2, then do your adjustments to #1 and #2 to #3 and #4.
Clear as mud? Try this site http://www.youtube.com/watch?v=Hr6_Q...eature=related

[motoman]

As you will be doing this with an already warmed up engine, DO NOT forget to have a fan blowing on the engine. The first time you do it will take longer than you think, after that it is a breeze. The other thing to keep in mind is the engine RPM which should be as low as practicable or normal idle for these which is 1050 to 1100 or there abouts.
Also be sure of the correct procedure for adjusting the Carbs. #3 is your one that you have to adjust too. Balance #3 to #4 Then adjust #1 to #2, then do your adjustments to #1 and #2 to #3 and #4.
Clear as mud? Try this site http://www.youtube.com/watch?v=Hr6_Q...eature=related

close to mud..........three's the 'fixed' carb.......adjust #4 to #3(last screw).......#1to#2(first screw from left).......then bring the pairs together with center screw. R-adjust idle mixture.........and again re-sync. That re-sync SHOULD be done at lowest RPM motor will idle smoothly. Normally, that'll be around 800rpm's. After happy with results, re-adjust idle back up to its normal 1100rpm.

[Rasputin]

close to mud..........three's the 'fixed' carb.......adjust #4 to #3(last screw).......#1to#2(first screw from left).......then bring the pairs together with center screw. R-adjust idle mixture.........and again re-sync. That re-sync SHOULD be done at lowest RPM motor will idle smoothly. Normally, that'll be around 800rpm's. After happy with results, re-adjust idle back up to its normal 1100rpm.

Just wondering if you checked the video I posted as well. Kinda makes mud see through. When you say "last screw" I wonder how much clearer it makes the mud...Just saying. Also once a synch is achieved one must run the bike and do chops etc to make sure everything is the best it can be. If you want good mileage and good performance then you do all the steps.

[DGXSER]

I find it very interesting to see how nitpicky some people get about things that mean very little. for instance getting focused on the order of the first pair to synch. What difference is there if you synch 1 and 2 first or 3 and 4 first. None really. Either way, you are synching those pairs together.

Then you can synch the two pairs to each other with the center synch screw. No matter which two you started with, your going to be bringing the 1-2 pair to match the 3-4 pair. That middle screw does not change the throttle plate of 3 or 4. It does change no 2 throttle plate and by virtue of the synch screw between them, changes 1 to follow.

And why synch at a lower idle than where you will be running. I always synch at the normal idle speed.