Carb sync question

[jjmertes]

I have a 1980 GS850. I have never syncronized the carbs. Does anyone know if it's necessary to purchase a manometer, or can you just connect an engine vacuum guage to one carb at a time and adjust until they are all the same? Any help would be appreciated.

[bexabarr]

Hey, I'm sure everyone will tell you that buying a manometer is the way to go. I have seen the cheap ones sell for around $25 compared to the more expensive ones that sell for $50 +. People have tried the vacuum gauge route, but I think that the manometer will give greater balance between the three. If you already own a vacuum gauge think about trying out something like this... (make sure you have ther right type of vacuume gauge (30 in??)

http://www.xs11.com/forum/showthread.php?threadid=986

… and tell us how it went. I was wondering the same thing, and found the link someplace on this forum. I like the valve checks, where you can get a reading from any carb by just turning the knob.

Either way, they are all going to tell you to buy the manometer... I know because I've asked... and in fact if you have the money it is probably the best way to go.



here is a link to a forum I started that kind of relevant. Good luck!

http://www.thegsresources.com/_forum/showthread.php?t=89139&page=1

[5RON5]

I just this very minute got back from Harbor Freight w/this gauge in the picture! Funny, I am getting all the parts together to make it. I hope this is the right gauge & it works all right. I never heard from anybody weather or not this even works. Man I hope so! My valve from the fish store will be in on Tuesday. I waited to get the right size PVC pipe, till after I made sure this was the right gauge, & how far across it was. Now, since it's identical to the one in the picture, I can go ahead & get the pipe, so the gauge & everything will be able to fit into it, as a tool carrier inside itself. Does anybody know where I can get the 4mm/-3/16ths hose connectors for the carbs? Any knowledge of this thing working for anybody else would be appreciated. Thanks. Ron...

[earlfor]

You will need a manometer that will connect to all four cylinders at the same time. It is nearly impossible to synchronize 4 carbs with moving a single guage back and forth because everytime you make an adjustment on one cylinder it will change the vacuum levels on the other three cylinders also. Some cylinders will increase, some decrease and none will change by the same amount. You must be able to see what the vacuum levels on all carbs at the same time.

Earl

I have a 1980 GS850. I have never syncronized the carbs. Does anyone know if it's necessary to purchase a manometer, or can you just connect an engine vacuum guage to one carb at a time and adjust until they are all the same? Any help would be appreciated.

[Sunburn]

I don’t remember what it cost so I guess it could have not been that much but I had a simple one that used “mercury” to sink all four at once. I think I still have it but the mercury is gone. The vacuum would move the mercury for each cylinder tube, you adjusted them until they all was reading they same. It had to be less then $45.

[Rake78GS]

LOL
I got SOOoooooooo lost reading this thread!
About all I understood was "mercury"

My carbs will most definatly need to be balanced as I dont think they EVER have been since it was new!

[bexabarr]

5ron5... please let us know how it went!!! I'm verry curious, because I've been thinking about doing it for some time. I'm just curious did you happen to get metal fish valves from ebay?? I was looking at those lol..

It is nearly impossible to synchronize 4 carbs with moving a single guage back and forth because everytime you make an adjustment on one cylinder it will change the vacuum levels on the other three cylinders also.

if this is infact the case, then the one gauge tool will prob not work, since it is based on the asumption that when you adjust one carb, the other will stay the same... right? good point earlfor...
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http://www.indysuperbike.com/customer/product.php?productid=112067&cat=25790&page=1

this is the "economy cab tune".. for $26- make sure you select 'cab sync tool' in the drop down, or else you will end up buying replacement parts.

I have not used this, and therefore I can't vouch for it.. I'm sure someone else can...

[jjmertes]

5iron5 - I saw the brass adapters at denniskirk.com. $13 for a set of 4. I'm interested to see if that method works.