DIY carb sync tool
09-11-2010 | 09:20 PM
#1
Thread Starter
Member
Squid
Joined: Aug 2010
Posts: 34
From: Southeast WI
DIY carb sync tool
Had my carbs goo up on me Friday night. Started popping, idling like crap, etc. So, about midnight, I decide to rip it all apart and clean them out and hopefully tune them in a bit better. Dug into them from instructions on here, found the rear pilot plugged and the pilot screws WAAAAYYY out of adjustment (front 3/4 turn out only, rear 1.5 turn out) Set them, put it all together, set the TPS to 502 and it ran much better, but still not perfect. Had a short stumble when you crack it. I figured they were out of sync. So.. I decide to look for a set of carb sticks today. Good luck. So.. I sat around and came up with this goofy idea:
I bought a 3' steel rule ($1.97) 20' of .170 clear tube ($1.49) a roll of clear vinyl tape ($2.49). I took the tape and attached the tubing to the rule, of course leaving long, even legs off the top and about a 4" loop on the bottom so it won't kink. I then dug out an old quart of ATF and put one end of the tube in the jug of oil and sucked about 3' of oil into the tube. I let it sit a few minutes with the long legs elevated so the oil would run to the bottom. I them spun it around my head use centrifugal force to push the bubbles out, then took the loose ends and slung them around to toss the rest of the excess oil out. I then put a T in the vacuum line per the instructions and tapped into the allen with a tapered hard rubber fitting from my brake bleeder. I hung the gauge from the garage door opener, fired up the bike, and then adjusted the balance. Worked like a charm! The carbs were a mile out of adjustment, dialed them back in. Test ride confirmed the tool worked. No more flat spot!
I bought a 3' steel rule ($1.97) 20' of .170 clear tube ($1.49) a roll of clear vinyl tape ($2.49). I took the tape and attached the tubing to the rule, of course leaving long, even legs off the top and about a 4" loop on the bottom so it won't kink. I then dug out an old quart of ATF and put one end of the tube in the jug of oil and sucked about 3' of oil into the tube. I let it sit a few minutes with the long legs elevated so the oil would run to the bottom. I them spun it around my head use centrifugal force to push the bubbles out, then took the loose ends and slung them around to toss the rest of the excess oil out. I then put a T in the vacuum line per the instructions and tapped into the allen with a tapered hard rubber fitting from my brake bleeder. I hung the gauge from the garage door opener, fired up the bike, and then adjusted the balance. Worked like a charm! The carbs were a mile out of adjustment, dialed them back in. Test ride confirmed the tool worked. No more flat spot!
09-12-2010 | 07:02 AM
#3
Senior Member
SuperBike
Joined: Aug 2009
Posts: 1,978
From: thorold ontario
nice, good work man, the guy who does my carb syncing for me usese 2 pickle jars and some vac lines and uses water in them and happens to get my carbs set dead on each time he plays with them. nice to see a little creativity 
09-12-2010 | 07:15 AM
#5
Thread Starter
Member
Squid
Joined: Aug 2010
Posts: 34
From: Southeast WI
In the pic you can see there is more oil in it that I posted in the instructions. I added some to see how it changed the response. It responded slower, but if you got way out of balance it was easy to pull the oil over the top.
09-12-2010 | 09:58 AM
#6
Senior Member
MotoGP
Joined: Aug 2006
Posts: 2,934
From: altoona, pa
What steve29 and myself learned from multiple attempts is that more oil gives slower respone as does WD40 plastic tube( i call them baffles) inserted in the ends of the aquarian tubing.
When the carbs a whacked out like yours were, screw the adjuster all the way full in (clockwise)and start engine. This allows you to remember that you're always going counterclockwise-easy to remember for dumbasses like me. haha. Of course the oil will pull immediately, so shut bike off and back screw off a quarter turn. Start again and shut off if when oil moves(eighth of a turn). Repeat until oil starts to move slowly and you know you're getting close. Then use a tiny wrench so that you can fine the adjuster nut because we're talking hairs of movement to get the oil to stabilize.
When you bike is runing well or you messed with your carbs and want to do a sync check, you can start it up to see if the oil moves. If it does, shut off quickly and screw the adjuster clockwise a quarter turn and follow above procedure backing off/one direction.
The key thing to remember is to start up and shut off quickly as soon as you see the oil moving so as to alleviate air gaps in the tubing and get to where you can fine tune in the shortest amt of time. It helps to have help to start and stop engine quicker. No bubbles, no swinging over your head, less wasted time waiting for oil to settle.
When the carbs a whacked out like yours were, screw the adjuster all the way full in (clockwise)and start engine. This allows you to remember that you're always going counterclockwise-easy to remember for dumbasses like me. haha. Of course the oil will pull immediately, so shut bike off and back screw off a quarter turn. Start again and shut off if when oil moves(eighth of a turn). Repeat until oil starts to move slowly and you know you're getting close. Then use a tiny wrench so that you can fine the adjuster nut because we're talking hairs of movement to get the oil to stabilize.
When you bike is runing well or you messed with your carbs and want to do a sync check, you can start it up to see if the oil moves. If it does, shut off quickly and screw the adjuster clockwise a quarter turn and follow above procedure backing off/one direction.
The key thing to remember is to start up and shut off quickly as soon as you see the oil moving so as to alleviate air gaps in the tubing and get to where you can fine tune in the shortest amt of time. It helps to have help to start and stop engine quicker. No bubbles, no swinging over your head, less wasted time waiting for oil to settle.
09-12-2010 | 10:38 AM
#7
Former Superchicken Owner
SuperBike
Joined: Sep 2008
Posts: 1,607
From: Ft. Worth, TX
I have used the manometers before and I will say that without a doubt one of the best investments I have ever made was the Carbtune tool. It is so easy to unplug the vacuum lines, plug in the Carbtune and check the sync. I am done in 5 minutes.
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