89 fj 1200 carb sync

[courtsdaddy]

help I am trying to sync my carbs and I have the motion pro sync tool and it says to sync the tool before use. what carb is the master carb?hooked it up to the number one carb but motion pro said thiis was worng? help!!!!!!
I have

[fj1289]

What type of synch tool is the motion pro tool?  Is it 4 separate vacume gauges?

If so, I'd think you could use a bunch of T's (3 anyway) to hook them all the the same vacume source at the same time to check they all read the same.  Wouldn't matter the vacume source - could be one carb from the bike, a vacume port on a car intake, your 5 year old with a silly straw...just so they all read the same for the same vacume. 

Chris

[andyb]

Think it's #2 that's the "master" carb?  Think last time I did it I did 1+2, then 3+4, then matched the two sides. 

[SlowOldGuy]

#3 is the master

[andyb]

Ah, well, there ya go.

[courtsdaddy]

Thanks for your help when my refill kit from motion pro gets here I will let you know how it turns out.  When I was setting up the tool for use it sucked all the fluid right out of it.  You have to sync the tool before you can sync the carbs and I was using number one cyl for that.  But just so I know does the third carb have less vacuum

[Dan Filetti]

They all *should* have the same/ similar vacuum -that's the point of the sync. But to run at all, or at least reasonably well,  they need to be fairly close.  I'm guessing the reason it sucked the fluid (mercury probably) into the motor, is that you goosed the throttle.  Vacuum increases dramatically as the engine runs back down to idle quickly. 

Sync the carbs at ~3,000 rpm with a box fan blowing on the motor to keep it cool. And if you're performing the 'blip test', do not do it with the sync tool attached! 

PS: if you buy one of these: http://www.carbtune.co.uk/inst.html, you'll not have this issue, you can blip all you want.  Although they are pricey, it's a fine, well made tool.

Dan

[courtsdaddy]

I have the tool with the blue fluid and no I didnt even get that far, as soon as I start the motor it sucked all the fluid out(i was still trying to sync the tool) only had one carb hooked up!

[fj1289]

If you're not going to hook up all the hoses, I THINK you'd need to cap them off.  You applied a vacuum on one tube (like a straw) and the others had atmospheric pressure "pushing" on the reservoir (like an open cup).  You're engine then "drank" the koolaid!  Did it do it without the annoying slurping?!

[andyb]

Never had to synch the gauge myself.  Seems like if there's liquid in it and the same gravity on each with the same restrictors in it, you'd be done, eh?

You'd absolutely have to cap the others off if you put vacuum on one or it'll just suck it right out.  it'll still go up a bit, from the trapped air behind the fluid and the tubing collapsing a bit.

[jack02]

I got two,individual vacuum gauges very cheaply from a local hyrdraulic trade suppliers. I hook them up (using 5mm ID tube) to carbs 1 and 2,leaving the blanking caps on 3 and 4. To damp them I put a pen top (!),into which I've made a tiny hole with a pin, in each tube. This gives a very nearly flicker-free reading,and makes balancing two carbs a sub-minute affair. Put caps back on 1 and 2,then repeat on 3 and 4. When they're done,attach tubes to 2 and 3 to balance both sides. Works an absolute treat and it's all done and dusted in five minutes. Before that,I'd been down the road of using oil and about half a mile of tube,but could never get past the stage of having it all getting sucked up one of the tubes and into the engine in the time it took me to reach the kill switch!

[Coronet]

 Hate to tell you this but the motion pro sync gauge Sucks    -- I know I own one. But it can be made to work and yes you will suck the fluid out every time if you are not very carefull.
The old mecury sync gauges worked a lot better but I guess to many people were drinking the mercury (go figure) and it was outlawed so now they use what looks and acts like colored water.
First make sure all the sync gauge adjustment screws are backed all the way out, remove one of the vaccum port caps on the bike (don't matter which one) and hook up the tee fitting that came with the gauge to the port then hook up all four sync hoses to the tee fitting and cap any fitting on the tee that don't have a hose stuck on it. Note > (Make SURE you have the vaccum restrictors stuck in each hose (4) from the sync gauge)
Start the bike (do not touch the throttle or you can say goodby to the fluid) and let idle. Adjust sync gauge so all 4 are reading the same. This is a must do with this gauge or you are wasting your time. Once this is done you can procede as normal and sync the carbs. just remember to do this everytime before starting the sync process.
>>>A few things I have learned trying to keep the fluid in the gauge.
>>>Do not blip the throttle.
>>>Do not try and sync the cards above about 2500 rpm or you can almost count on sucking the fluid out.
>>>If you raise the rpm above idle always close the throttle very slowly or say goodby to the fluid -- due to the vaccum spike caused when the throttle plates are closed fast.
>>>Make sure the vaccum restrictors are in the sync gauge vaccum lines. I even made a second set of restrictors and installed in the vac. lines.
>>>Keep a supply of the blue fluid on hand as it seems to go bad and start getting stuck in the vaccum gauge collum - all the blue fluid needs to be in the bottom of the gauge before you start. Seems like I have to flush out and change the fluid everytime I get the gauge out.

Hope this helps.

Mark H.

PS - anyone want a vaccun gauge cheap!   

[andyb]

^ I think I've still got the motion pro one in the garage.  Out of mercury.  Isn't available anymore, either, and I didn't want to piss with getting it from a specialty place (and shipping and such is a bear with it).


Now have a Carbtune and wish I'd have skipped bothering with the motion pro in the first place.

[SlowOldGuy]

It also might help to warm up the engine first.  This way it will start easier without throttle and you need to be off the choke anyway to get an accurate sync.

DavidR.

[courtsdaddy]

Thank for the tips, I got hte fluid today and used the number 3 carb like they said and it worked.  Not for sure if I didnt let the bike warm up fully before but it worked.  So I now have the carbs synced and I am very happy with the outcome so far.  Smooth acc and it might be in my head but I think its accelerates faster too?  Cant believe I waited so long to so this.  It sounds like a diiferefnt bike at idle and I am not kidding.  It used to pop just going down the road, that is long gone.  Sounds great.  I must say it was way out, as I got 1,2 matched to 3,4 the rpms went from 1100 to around 2800, so I had to stop and turn the idle down and start all over.  When I heard the difference in idle I couldnt wait for the test ride and that was even better.  Thanks for the help!!!!!!!!