Carb syncing help

[cmills83]

Uhh does this seem normal? I just cleaned and put my stock carbs back on, everything seems fine on them even the diaphragms.

I haven't synced carbs with gauges before, just a manometer I had built. Im not really sure how to begin here, I was hoping they would be slightly different and I could just adjust the screw in the middle accordingly.

I've been having a stalling issue at idle, I turned the idle up to 1800 but I am trying to track this down.

 

[YamadudeXS650C]

You need to dial-down on the air volumes on your gauges to stabilize the needles. There's a screw on each for that purpose.

 

[YamadudeXS650C]

Slowly screw in (clockwise) the air volume screws with the engine running.....

 

[YamadudeXS650C]

BTW, its a good idea to set up a fan, directed at your top end, to keep it cool during the synch process.

 

[5twins]

Your homemade manometer is actually better and probably more precise than those cheapo gauges. Even with the air volume dialed way down, the needles will most likely still flutter around some. And there's also the possibility that the 2 gauges aren't synced to each other. You can test for that by trying each gauge on the same cylinder to see if the readings match.

 

[TwoManyXS1Bs]

Can also swap the hoses, left-for-right, note the difference, cut the difference in half.

Can also "T" the two gauges together, run to a single cylinder, note if they're the same...

 

[cmills83]

Cool thanks for the feedback. So there was no screw on those gauges, I remember now they had little fish tank air valves that are supposed to be inline on the hoses. I went ahead and ordered a better set of gauges to hopefully do this right.

 

[TimG]

Cool thanks for the feedback. So there was no screw on those gauges, I remember now they had little fish tank air valves that are supposed to be inline on the hoses. I went ahead and ordered a better set of gauges to hopefully do this right.

What gauges are you using and which ones are you planning to order. I have a set of barbed carb holders to add to my 75 so that I can sync them but need to order gauges. Please post your progress. Thanks!

 

[xjwmx]

So there was no screw on those gauges, I remember now they had little fish tank air valves that are supposed to be inline on the hoses.

Something you can do to steady the needles is clamp the hose with a vice grip and then back it off until there is just a bit of air flow. I don't have a problem using a cheap single type gauge for synch'ing, because you're interested in the cylinders relative to each other, not absolute values. IOW if it's off it'll be off the same on both cylinders.

 

[aldo5468]

a couple of pilot jets inserted into the hoses remove almost all the fluctuation

 

[cmills83]

Thanks for all the feedback. I went ahead and broke down and bought these, they worked great and I synced the carbs in < 5 min.

https://www.amazon.com/gp/product/B004MSE9JO/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1