home made sync gauge

[TomRodgers]

oh boy.....

[RS Thornton]

One gauge works fine

The last thing you do is open up each valve in the gang valve one by one, and make sure all 4 vac levels are within tolerance.

I use a needle valve in the line in front of the guage to supress the bounce in the needle. You start with the valve closed and then slowly crack it open until needle starts to bounce, and leave it there. The whole assy shown in the pic is pretty easy to put together, is easy to store and can be hung off the bars.

The ATF system seems a bit bulky to me.

Scott

[gareth]

I use a combination of the simple and the slightly more complicated. I get an initial sych from carbs 1+2 and then 3+4, and then balance the pairs with a sych from 1 to 4. I do this with the single tube ATF manometer, which is nothing more than about 24 feet of pvc tubing with a couple of rubber taps on each end to attach to the sync ports. Its long, a bit unweildy, but its super accurate. The individual pulses from the engine cancel one another out and there is very little jumpiness when reading the level. Only if the sych is WAY out do I have to keep an eye on the ATF level in the tubes, which is the benefit of the 24' super-long setup. If I am feeling particularly picky, I can then hook up the four tube manometer, knowing that the sych is now so close that I am unlikely to pull fluid into the cylinders when I do a final adjustment.
The four tube manometer was way too sensitive to changes in sych to be used for initial setup. I made the 4-tube when I first started working on the bike and played around with restrictors for ages. I could never get it right and was always concerned that slight changes in the restrictors that I had put in the tubes was causing inaccuracies. I stopped using it for the initial sych and used the "big loop" to make things simpler at the start. There are no restrictors in the 4-tube either. I hardly ever hook up the 4-tube anymore. Big Single Loop does the job..




http://picasaweb.google.com/agfitz/S...eat=directlink

[daveyg]

Dang I need to get off my arse and make one of these ideas up. The 11 is still chillin in the shed and the 650s both need a sync to keep puttering along. Thanks for the link and pics gareth.

[vanhump]

I have found that it is hard to beat a good set of vacum guages hung on a bungee cord between the handlebars.

[skids]

I like the concept of the design. The cross tube allows for oil or water instead of Hg. If you didn't have that, the tubes would have to be tall.

[WMarshy]

Well, a few of you guys keep talkin about vac gages so...lets see one. Where can ya get one and how much are they?

[DGXSER]

You can buy a vacuum gage at harbor freight, or four of them if you go that route.

[Yahman]

Bingo!!! Give the man a prize.

I like the concept of the design. The cross tube allows for oil or water instead of Hg. If you didn't have that, the tubes would have to be tall.

That's the theory, and it works to some extent. There is a small restrictor in there that I added for dampening. There's just a slight amount of bounce to the fluid in the tubes.

Larry

[freak_leg]

After a little hunting this is the best deal I've found...
http://www.amazon.com/EMGO-VACCM-SYN...0819970&sr=8-2

I think I might just go this way, a time comes when its worth the extra $20 so save the head ache... And this way SWMBO wont look at me like a mad scientist when i'm in the garage with a huge length of tube and a bottle of trans oil...

[Ivan]

Come on now Ivan, you can't just take what I said and boil it down to something so simple. It takes all the mystery and wonder out of the whole sync experience. I mean it's just not scary when you don't use words like "hydro-lock" and "IMPORTANT", or phrases like "KILL THE MOTOR" and "shooting up the tube."

I didn't use those phrases because they weren't necessary. I have no clue how someone could hydraulically lock a 1 liter engine on two tablespoons of liquid. There's no way that much would kill the engine, but it would smoke for a bit. It doesn't shoot up the tube nearly as fast as some make it out to be, and if it does, no big deal. Normally you can get an idea of what needs adjusted before the engine even starts.

Or, you could just use a small drill bit or piece of straight wire to ste them statically and leave well enough alone. I ran mine that way for several months before I built my sync gauge. Then I had to turn the sync screws all of 1/16 of a turn. Like I said, almost too sensitive.

[DGXSER]

After a little hunting this is the best deal I've found...
http://www.amazon.com/EMGO-VACCM-SYN...0819970&sr=8-2

I think I might just go this way, a time comes when its worth the extra $20 so save the head ache... And this way SWMBO wont look at me like a mad scientist when i'm in the garage with a huge length of tube and a bottle of trans oil...

Be aware that despite the picture that is a 2 carb set, as in you will get 2 vacuum gages and the rest of the stuff for 2 gages only.

Here is the link to the 4 gage/4 carb setup.

[cywelchjr]

After a little hunting this is the best deal I've found...
http://www.amazon.com/EMGO-VACCM-SYN...0819970&sr=8-2

I think I might just go this way, a time comes when its worth the extra $20 so save the head ache... And this way SWMBO wont look at me like a mad scientist when i'm in the garage with a huge length of tube and a bottle of trans oil...

That's the set I have, and they work pretty well. Gave me a good sync and things run pretty smooth. I'd like someday to get something a little better, but those tend to be pretty spendy, especially considering that these do a good job.

[81xsproject]

I didn't use those phrases because they weren't necessary. I have no clue how someone could hydraulically lock a 1 liter engine on two tablespoons of liquid. There's no way that much would kill the engine, but it would smoke for a bit. It doesn't shoot up the tube nearly as fast as some make it out to be, and if it does, no big deal. Normally you can get an idea of what needs adjusted before the engine even starts.

Or, you could just use a small drill bit or piece of straight wire to ste them statically and leave well enough alone. I ran mine that way for several months before I built my sync gauge. Then I had to turn the sync screws all of 1/16 of a turn. Like I said, almost too sensitive.

I completely agree. It seems to me the bench sync is under emphasized and the dynamic over emphasized. After I do a bench sync on a set of carbs, they idle smooth down to 600 RPM or less.

[cywelchjr]

I completely agree. It seems to me the bench sync is under emphasized and the dynamic over emphasized. After I do a bench sync on a set of carbs, they idle smooth down to 600 RPM or less.

My figuring is that the sync on the bike is to account for any movement caused by installing. Otherwise why would we ever need to resync them? I agree that the bench sync is probably about 99% correct as long as the rack doesn't have any give to it when installing, but the dynamic sync will account for that, and I'm guessing that things shift a little over time as well, so syncing every so often is a good idea anyways.