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Attempted to balance carbs today,86 fj1200

Started by Shane4371, December 06, 2015, 06:52:04 PM

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Shane4371

First time I really got deep in my bike today,got me a set of vaccum gauges.removed the tank.i see a vaccum line running from my fuel valve on the under side of my tank to a vaccum port on one intake,another vaccum hose running to my igniter.does this sound right,assuming this hose acts as a vaccum advance,correct?any way hooked up my gauges to far left  far right carbs.and christ they were all over the place but consistent in irratic fluctuation.right side was off got a consistent reading.proceeded to the inner card with one adjusting screw for two cards but 2 vacuccum ports on my Intakes.this threw me off.hooked gauge up.all said and done their way outta synch.lol.love this process.I'll figure it out.yep a newby

Arnie

Shane,

Do you have 2 or 4 vac guages?  It's easier with 4, but you can do it with just 2.

EACH carb manifold has a vacuum tap that has a rubber cap and a spring clamp on it.
Your year bike ALSO has those additional vac lines running to the fuel petcock and the Ignitor box.  Ignore these additional taps for the moment (except you may have to cap the one to the fuel petcock if you're using an external tank.

Anyhow, hook your gauges up to the (normally capped) taps that are on each manifold.
Balance the left side carbs (3 & 4) to each other, then balance the right side carbs (1 & 2) to each other. THEN balance the left pair to the right pair with the center screw.
If you're using just 2 gauges, then either of the right or left carbs will be fine for this last adjustment.
Do NOT leave ANY of the vacuum taps open while balancing.

If you want to be extra good with this, then do the balance at 1100, then at 2500, then re-check that they are still all in balance back at the 1100 rpm.
Make sure you have a fan helping to cool the engine while you're doing all this.

Everybody starts as a newby.  Some stay that way. :-/
 

Shane4371

OK.however,im curious does the idle screw adujust the #3 carb.and the other screws are for 1-2-4 ?

Pat Conlon

The idle speed screw is on the bottom, meaning you access it from underneath the carbs .

The 3 balance (sync) screws are on the top.

As you sit on the bike, the left balance screw balances carbs #1 and 2 ....the right balance screw balances carbs 3 and 4

The center balance screw (you do this last) balances the left side carbs (1/2) to the right side carbs (3/4)
1) Free Owners Manual download: https://tinyurl.com/fmsz7hk9
2) Don't store your FJ with E10 fuel https://tinyurl.com/3cjrfct5
3) Replace your old stock rubber brake lines.
4) Important items for the '84-87 FJ's:
Safety wire: https://tinyurl.com/99zp8ufh
Fuel line: https://tinyurl.com/bdff9bf3

Shane4371

Taking the walk of shame on the carburetor project,sent them to RPM for a complete rum threw,let ya know how they turn out.thank fellas for all the advise.gotta let the pro's do what pro's do best.

CutterBill

There's no shame in realizing that you're in over your head.  I'm the best engine guy you ever met, but don't let me fix your computer... 
Bill
Never Slow Down, Never Grow Old.

Current Stable:                                                     
FJ1100                                              
FJ1200 (4)
1999 Yamaha WR400 (street-legal)
2015 Super Tenere
2002 Honda Goldwing

chiz

Quote from: Shane4371 on December 08, 2015, 05:52:23 PM
Taking the walk of shame on the carburetor project,sent them to RPM for a complete rum threw,let ya know how they turn out.thank fellas for all the advise.gotta let the pro's do what pro's do best.

"Rum threw" Actually get yourself Bottle of Old Brigand , Cockspur or Mount Gay SUGAR CANE BRANDY rum from Barbados and sip it as you go.

Shane4371

Received clymer version of repair manuals for my 86 fj,and i must say,the majority of advise givin on this sight is dead on.how ever the manual lacks.carb synching, and air fuel mixture adjusting procedures. The front and rear suspention sections were priceless.just wanted to say to the tech guys who advised me on repairs,keep up the great work on passing on the the knowledge your truely irreplacable.thanks again.