diy carb balancer - what have i done wrong?

[hillsy]

The idea behind the DIY manometer is that you are comparing the vaccum of the carbs to each other. You don't need to measure carb vaccum v atmosphere.

The biggest problem with the multiple connected versions is if you have a leak at one of the joins the whole thing becomes useless - and this is why the oil gets sucked into the motor most of the time (along with the carbs being WAY out of sync).

You can argue all you like about why it won't work, but I use mine and it DOES work.

Carry on.

[trippivot]

synchro voodoo

I beg to differ --- mechanical slides can be set to 5Hg 10Hg or 20 Hg -unless there is a stationary base carb (not all have one) - hence the amount of poor running GS's just off idle

C.V. carbs equalize to the atmosphere at a rate depending on the size of the vent in relation to spring pressure inside the carb body restricting the rubber diaphram and slide seperating hi-pressure from low-pressure at any elevation.

sorry to argue the point - actually ,I put more emphasis into making them equal at 3000 rpm and let the idle handle itself , as long as it idle drops properly on all cylinders and you'll get a better cruise

The idea behind the DIY manometer is that you are comparing the vaccum of the carbs to each other. You don't need to measure carb vaccum v atmosphere.

[hillsy]

Can you explain how you adjust the specific gravity of each individual carb independently in a bank of four?

[Tom R]

I had a similar looking 4' manometer using atf - though I hung the tubes about 8' up over the rafters in my garage for some extra height. It took a while to sort out, but I managed to balance the carbs at 3000 based on some info read hear - could have been trippivot's; but it don't really remember.
If you have any leaks in your system, it'll give garbage results and/or try to deposit all the oil in your engine no matter how high your tubing is.
I'll have to look further into what trippivot is saying, because i'm not quite sure if it's clicking yet - but is probably right.
My bike ran pretty good before I "synced" the carbs - so no surprise that it ran pretty good after - maybe better, but definitely not worse.

[hillsy]

The best way to start with one of these is the single hose 2 end one. Very little chance (or should be none) of there being any leaks through dodgy joins. If you have ANY leaks in the system, you'll be sucking oil into a cylinder or two.

Another thing with mine is the main tube is only 3mm ID - I have some larger tubing over the ends to slip over the carb balance ports. Not sure if that makes any difference but I've never had the oil get sucked into a carb (or at least there's been a fair bit of warning and I've shut the motor down). I guess it's a bit like putting restrictors in 6mm tube.

Also, if you "bench sync" your carbs at the start they will be pretty close and shouldn't suck the oil into one of the ports without warning.

But hey - it isn't for everyone.

[Road Rash]

I made one of the dual bottle ones someone mentioned on here, and it worked pretty decent. The nice thing is that the tubes connected to the carbs were NOT submerged into the fluid. Only the tube interconnecting the two bottles does. This way, if you have a major initial imbalance, the fluid isn't gonna get sucked into the carbs. Just make sure the level in each bottle is less than 1/2 it's total capacity. Worse case, all the fluid gets sucked into the one bottle.
I also made the simple single looped tube type, too. The bottle one was better and safer for general adjustments, whereas the single looped tube one had finer accuracy. The pain with either of these types is have to do only two carbs at a time. By the way, this was all done on my old bike, a 4time cylinder, CV carb'd Yamaha 650 Maxim. We'll see how they fair on the GS750.

[jeffasaurus2]

I've used this method:

http://faq.ninja250.org/wiki/How_do_I_synchronize_the_carburetors%3F#The_two-bottle_method

Just as described above, on my 450 Twin. Its always worked amazingly well and the total cost was less than $15. The water can't be sucked into the engine ever, only into the other bottle.

I don't see why one couldn't create this using four bottles and label them 1-2-3-4 w/corresponding cylinders. But then again, I don't, nor have I ever, own a 4 cylinder bike.

[Killer2600]

I've used this method:

http://faq.ninja250.org/wiki/How_do_I_synchronize_the_carburetors%3F#The_two-bottle_method

Just as described above, on my 450 Twin. Its always worked amazingly well and the total cost was less than $15. The water can't be sucked into the engine ever, only into the other bottle.

I don't see why one couldn't create this using four bottles and label them 1-2-3-4 w/corresponding cylinders. But then again, I don't, nor have I ever, own a 4 cylinder bike.

It's a nice idea but the accuracy sucks. Are you aiming to hit a bullseye or is anywhere on the dart board good enough for you?

The best way to start with one of these is the single hose 2 end one. Very little chance (or should be none) of there being any leaks through dodgy joins. If you have ANY leaks in the system, you'll be sucking oil into a cylinder or two.

Another thing with mine is the main tube is only 3mm ID - I have some larger tubing over the ends to slip over the carb balance ports. Not sure if that makes any difference but I've never had the oil get sucked into a carb (or at least there's been a fair bit of warning and I've shut the motor down). I guess it's a bit like putting restrictors in 6mm tube.

Also, if you "bench sync" your carbs at the start they will be pretty close and shouldn't suck the oil into one of the ports without warning.

But hey - it isn't for everyone.

Your homemade tool does indeed function but it's an absolute nightmare to adjust 4 carbs with. As stated you can not just do two at a time and have a single pass at it and everything stays good. But then again you've never seen what it's like when you use the right tool and making adjustments on one pair can and does throw off the sync of another pair that you may have already set.

Maybe you are anal and recheck them all to make sure they are all right on point once you finish making adjustments but short of that madness you can't say how great your method is without comparing it's accuracy against a good 4-cylinder manometer.

[hillsy]

Your homemade tool does indeed function but it's an absolute nightmare to adjust 4 carbs with. As stated you can not just do two at a time and have a single pass at it and everything stays good. But then again you've never seen what it's like when you use the right tool and making adjustments on one pair can and does throw off the sync of another pair that you may have already set.

Maybe you are anal and recheck them all to make sure they are all right on point once you finish making adjustments but short of that madness you can't say how great your method is without comparing it's accuracy against a good 4-cylinder manometer.

You're making a pretty big assumption saying I've never tried other sync gauges. I worked in a shop for a while and used a set of 4 vaccum gauges on many occasions. Of course they work well, but my homemade job works too.

Yes, it takes a bit longer to balance 4 carbs, but the thing cost me about $4 and has paid for itself many times over. I'm happy to spend a few more minutes in the garage for that price - especially for something I only use once or twice a year.