1st Gen B12 Carb Synch How To

8/8/2019 1st Gen B12 Carb Synch How To

1/35

Member II

Karma: 0

Offline

Posts: 230

Reply #8 on: April 03, 2009, 07:57:58 PM

Sounds good. Can't wait to learn more.

Report to moderator Logged

'97 Bandit 1200s abs, Yoshi RS3, Jet kit, K&N, Streetfighter fairing and windscreen, more to

come!

jwray76Member II

Karma: 0

Online

Posts: 598

Re: 1st Gen B12 Carb Synch - How To With

Homemade Manometer Type Tool (56K Warning) Reply #9 on: April 03, 2009, 09:37:56 PM

Quote

Modify

Alrighty, here it goes from start to finish with as many pictures as I

thought you could handle. I figure the pictures are worth a thousand

words but I will try to describe everything along the way.

The basic idea for the homemade tool is a simple manometer to measurepressure difference between the carb suction ports. When all liquid levels

are even heights then all pressures are equalized and the carbs have

been synchronized with equal air/fuel flowing to each. Here is a little

blurb and schematic from Wikipedia

0)

Page 4 of 441st Gen B12 Carb Synch - How To With Homemade Manometer Type Tool (56K Warning)

7/24/2010http://www.maximum-suzuki.com/forums/index.php?topic=72246.msg797399


2/35

Here are the supplies that I purchased, which included: 4' of 5/16" gas

line, 40' of 1/4"ID clear vinyl hose, 2 1/4" plastic tee connectors, and 1

plastic universal connector. Other than this I had everything else around

the shop and you can really improvise if you don't have something that i

did. Only tools you will need you can get from the bikes tool kit.

1)




3/35

OK, this is the state that you need the bike in to perform the job.

2)




4/35

Remove the seat and then unscrew the two bolts that held the back of

the tank in the holes seen below. After this pop out the side fairing tabs.

3)




5/35

Now on mine I have some aftermarket clips for the fuel gauge sending

wires that I can unhook to make for easy tank removal. Not sure what

comes stock but if there are not any connectors I highly recommend

splicing some in to make tank removal easy. In addition to unclipping

these wires be sure to pull the two hoses lose from the petcock (leave in

on run position). Also use a phillips head screwdriver to remove the

petcock handle. Now the tank can be lifted off the bike and placed to the

side.

4)




6/35

This is what things will look like at this point with the tops of the carbs

exposed. Note that the vacuum ports are located at the front right of

each carb and that all but carb 3 (numbered 1-4 from left to right) have

caps. This is because carb 3 had the hose connection to the gas tank.

5)




7/35

Place the tank on an adjacent surface that is higher than the carbs so

that fuel can flow by gravity to them.

6)

Page 10 of 441st Gen B12 Carb Synch - How To With Homemade Manometer Type Tool (56K War...



8/35

A fan should be placed in front of the bike to help blow air across the

engine to keep it cool during the process since it will take about a half

hour and the bike is running at high idle speeds.

7)




9/35

Now hook the 4' piece of fuel hose to the top left petcock connection on

the tank.

8)




10/35

The other end should be connected to the universal plastic connector and

joined to the fuel line coming from the carbs

9)




11/35

Now you have fuel back to the carbs and are pretty much all set up until

the manometer is built. Of course you can chose to build the manometer

before you do any of this.

10)




12/35

First step to building the manometer is to cut the 40' of hose in to 4 x 10'

sections with cut ends like this.

11)




13/35

Now connect the 4 separate hoses to the plastic tees like the below pic.

Note that you will also need to cut a short piece from one of the tubes to

connect the two tees together in the middle. Don't worry about cutting

off some of one of the tubes as they do not need to be exactly even.

12)




14/35

Now it is time for the professional pneumatic test. Now things are

starting to get fun.

13)




15/35

Now chose the fluid that you would like to fill the manometer with. I

would chose something with a good color and has a decent viscosity to it

to help dampen the pulsations. You can pretty much chose anything but I

chose some ATF that I had laying around. I put one of the free tube ends

in the oil, threw the ends with the tees on the ground and held two

others up in the air and then sucked on the fourth free end to help fill

the tubes with fluid. Doesn't take but a little bit of suction and then it will

siphon. You don't need much fluid at all, I went for a couple of feet in

each tube so that it was at a good height for me to read during the synch

process.

14)




16/35

and here it comes

15)




17/35

this was a new bottle of ATF, you can see how little it takes to fill the

small tubes.

16)




18/35

OK, now you gotta find something to mount the tubes to. I had this scrap

of wood around that worked well for me but anything will work even the

wall in your shop. I also chose to just mount my tubes with some duct

tape so they would be temporary and after I am done I can just pull the

tubes back off and store them.

17)




19/35

Here is a close up of the tees at the bottom and the fancy duct tape

work. I really don't think that a job is complete till some duct tape has

been involved.

18)




20/35

Now place the tubes vertically and next to the bike in a place where you

can easily read them while synchronizing the carbs.

19)




21/35

The 1/4" tubing is a little lose on the carbs vacuum ports so I put some

small zip ties on each free end of the tubing to help hold them tight. Now

the tool is all done and you are ready to start the actual synch process

20)




22/35

The first step is to warm the bike up to operating temperature so that it

is idling with no choke. In order to do this you need to close off the

suction hose on carb 3. I have this nice little hose clamp that comes in

handy but you can use a bolt or golf tee or something.

21)




23/35

Now turn the petcock to prime so that the fuel can flow to the carbs.

Note that the standard run position will not work because the suction line

from the carb is no longer hooked up to the gas tank to create pressure

difference to open the petcock.

22)




24/35

So this is what she should look like when you start it up to warm up.

23)




25/35

Once warmed up adjust the idle up to 1750rpm with the adjustment knob

under the carbs.It is the gold/brass knob in the middle if you aren't

familiar.

24)




26/35


27/35

Now it is time to hook up the 4 suction ports on the carbs to the 4 clear

tubes. I recommend keeping with the reading left to right order to keep

things straight in your head. Now this is really starting to look like a mad

science experiment but it really is still very simple and straight

forward.

25.5)




28/35

I again used my fancy hose clamp to clamp off the four manometer

hoses so that when I start the bike back up you can blip the throttle and

get things all set up without having to worry about sucking the fluid up

into the carbs. This is not a necessary step but I thought it made things a

little easier to keep an eye on.

26)




29/35

Make sure to start the fan up and then go ahead and start the bike and

make sure that it is still at the 1750rpm (this may need to be adjusted

during the process if your synch is pretty far off to start with)

27)




30/35

Now the entire time you have probably been wondering what you really

do to synch the carbs. Well you only adjust three screws...yep thats it

folks. The screws are located between each pair of carbs. If you look

closely at the front area between carbs 1 and 2 you can see a gold

looking screw head down kind of low below the little copper line. There is

another screw just like this in the same spot between carbs 2 and 3 as

well as 3 and 4.

27.5)




31/35

Well this is where my carbs started off. As you can see there is quite a

big difference between the fluid levels.

28)




32/35

You start the synch process by adjusting carbs 3 and 4 using the screw

between them to make them even heights to each other. Note that the

screws are quite sensitive and I found that you have to overshoot the

equalization point by about an inch and then let them levels settle back

down. Here are my carbs 3 and 4 after synch

29)




33/35

Now it is time to synch 1 and 2 with each other using the screw between

them. Here is the pic after 1&2 have been synched to each other

30)




34/35

Finally it is time to sych the 2 pairs of carbs 1&2 with 3&4 using the

screw between carbs 2 & 3. Here is my final product. It may look like

carb 3 is off by a bit but that is less than a half inch and its the best that

it was gonna get. At this point you don't want to go back to try and get

something like carb 3 any better because it will throw the others all out

of whack.

31)




35/35

And thats it folks. You could really hear how the bike smoothed out as

each bit of the synch was happening and the end result is a very nice

constant idle tone and a tach that doesn't move at all. Feel free to ask

any questions because obviously I didn't spend the time doing this for my

own good.

P.S. it is late and I am beat so please excuse that there hasn't been any

proof reading yet.

Last Edit: Todayat 05:55:40 PM by jwray76 Report to moderator 24.125.179.116

ACDNateLegendary

Re: 1st Gen B12 Carb Synch - How To With HomemadeManometer Type Tool (56K Warning)


Documents

1st Gen B12 Carb Synch How To