Well I've been attempting to sync my carbs for a month now (don't want to rush into anything) I even bought a new digisync (works great). They are "in" right now (172-174) digisync numbers but adjustment was a bit difficult. After setting the throttle cables I started with carb #2 then moved to carb#1 but when I start to get 1 close to 2 2 starts to come off of idle eventually I get them close at 1000 k then I move to #3 and set it to #4 but when I go to bring 3/4 in sync with 1/2 1/2 start t to come off of idle again. Eventually I can get them close (172-174) is this a normal scenario with these racks or have I done something wrong again. I've got 5 sets of carbs and everyone of them has been pre messed up before I got them so I'm not really sure if they're right as far as the sync screws and springs go. I've tried to find a good picture of the rack assembled correctly. Maybe there is nothing wrong but they just don't seem right.
Overly sensitive adjustment?
- Thread starter tinman22
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Traumahawk
Well-Known Member
I talked to Danny one time about syncing carbs. He said that sometimes the tabs that are under the syncing screws can become bent. You dont even have to get rough with them, just sometimes they will get bent. I wonder if thats the underlying issue?
When I sent my carbs to he for rebuild, he put everything back in working order.
When I sent my carbs to he for rebuild, he put everything back in working order.
Could very well be, I'm going to take them off again and look everything over again. The problem is after I put some miles on it and hook up the digisync again the numbers are out of whack they've gone from 170-174 to anywhere from 165-208 and number 3 is running lean. If I can't figure it out I'm going to have to send them to Danny before I screw something up.
blaxmax
Well-Known Member
Try a bench sync with a small drill bit when you have them off. You will get a lot closer to a good sync and will not be as much work. Also when syncing try raising your idle a little more.
I did the bench sync each time and it certainly shortens the sync process. I usually use a dial caliper down each throat and set them to zero. Then I bring the idle up too 1000 to sync at this point I'm usually within a 15 point range say 165/180 then I get them within a couple of points like 171/174 which runs pretty good. But it doesn't stay
. I'm wondering if the #1 carb bringing #2 off of idle during adjustment as well as when trying too sync 3/4 to 1/2 that also brings #2 off idle isn't a sign that I've done something wrong
. I'm wondering if the #1 carb bringing #2 off of idle during adjustment as well as when trying too sync 3/4 to 1/2 that also brings #2 off idle isn't a sign that I've done something wrong
blaxmax
Well-Known Member
tinman, how are you going from carb #2 to carb#1? There is only one screw on the left side that balances #1 carb to carb #2?
I also sync at a higher rpm than 1000 after starting at 1000rpm.
I also sync at a higher rpm than 1000 after starting at 1000rpm.
blaxmax
Well-Known Member
Are you starting the engine with the digisync turned off?
No. But it doesn't sound like something I would do 1 or 8 times! It cals up right and works great way better than the old blue tubes. The problem isn't with the digisync it with the sync screws. for example when I get 1/2 good then 3/4 good when I try to bring them together with the front screw on the right side as they start to get close 1/2 start to come up off of idle. I mean you can physically see the linkage come up off of the idle thumb screw?!!? It seems like the 3/4 to 1/2 sync screw spring is weaker than the #2 idle spring (if there is such a thing) . I've done many sync jobs but never on a v4 and lately most everything doesn't need it. As of right now I've got them set again maybe this time it will last longer than a tank of gas.
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blaxmax
Well-Known Member
The digisync is supposed to be off then start the bike and turn it on. It can be a sync spring in the wrong place (sometimes put back together with a round of the spring wrapped over the tab). It can also be a bent tab or you pushing too hard on the last screw that syncs both sides together.
For what it's worth I had a harder time syncing the carbs on my 85 as it racked up the miles. By the time I sold it at 127K miles, it was getting tricky to sync. I always figured it was worn throttle shafts.
Sure, we have room. Send them over and I'll take a look, sounds like it might be a mechanical problem of some sort.
blaxmax
Well-Known Member
tinman22, I see that. In the video he states not turning on the digisync until after the bike is started. Also the last line "one carburetor is fixed and not adjustable" would be carb #2.
06VMAXIMUS
Well-Known Member
Like Danny stated, you probably have a spring out of place somewhere because the readings shouldn't move around once set. Remember to give the throttle a little "blip" after each adjustment is made and let it settle back to idle before taking a reading.
Redbone
Well-Known Member
I see where you are thinking I've gotten my # mixed up. I start with carb 2(left front) by checking for zero and making sure idle mixture is correct. As this is the base carb then like I said at the beginning I bring carb #1 inline with 2 . That's how I go from 2 to 1. I m making sure #2 is correct before I try and set everything else up to iincorrect carb. at 7:19 in the video he says to turn the digisync on before the bike is started to calibrate the digisync to atmospheric preassure. At 7:37 he says if you do it backwards I.e. Start bike first "it (the digisync) will detect that and give you an error code"
I don't know why they are upside down sometimes. I've actually started taking pictures upside down so they post right side up.
I don't know why they are upside down sometimes. I've actually started taking pictures upside down so they post right side up.
I'll leave it for now. I only have two other passenger worthy bikes . I loaned one to a friend for a bit until he gets his cylinder head back and the other lost its primary belt on Sunday (the one on the table) and I won't have parts for about 12 days. As soon as I've got something else to ride I'm sending them off to Danny. I'm sure it's a mechanical issue and I could figure it out sooner or later but it would probably be worth it to have them done right. It's my go to bike every time someone says "let's go for a ride" knowing they're done right would be worth it.
Traumahawk
Well-Known Member
When I sent my carbs to Danny, I actually had a bent tab on #3. I could just barely get it to sync, and never could figure out why. Danny fixed it. Danny had said that the tabs are so sensitive that you can drop the bike, and actually bend the tabs. I hadn't dropped it, but no telling what the PO did.
I'm sure it's something along those lines. I bought every set I could find in the area for parts to make a complete set and none of them were assembled so I'm kind of guessing on how they REALLY go back together. I spent hours looking for detailed pictures or diagrams for reassembly but found nothing that was either clear or detailed enough. I've actually got 2 complete sets,stage 7 and stage 1 Ill probably send both out and bag the stage 1 set and put it on the shelf. Having them done right And knowing it would be worth every penny.
B.t.w blaxmax I sent a p.m. The other day not sure if you got it. Anyway pegs I've got but the trans went with the motor. Send me a good address and I'll send Em to you . I'm going to a local guy here who has a venture/vmax fettish for a swing arm and trans parts I'll see what he has. He won't usually sell me anything but he likes to trade. I'll see what I can get.
B.t.w blaxmax I sent a p.m. The other day not sure if you got it. Anyway pegs I've got but the trans went with the motor. Send me a good address and I'll send Em to you . I'm going to a local guy here who has a venture/vmax fettish for a swing arm and trans parts I'll see what he has. He won't usually sell me anything but he likes to trade. I'll see what I can get.
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