Carb Rebuild

[cedmund00]

Greetings fellow FJer's,

93 FJ 1200 ABS
28,00 miles

I am having a few issues with my 93 1200 that I think are carburetor related. its very hard to keep the bike running when its warming up. When I start it with the choke out, it runs like it should but after the choke is off it takes a long time before it will idle on its own or close to normally.  I end up putting the throttle lock on to keep it running.

Also, When it is hot out and the bike is warmed up, when I stop the bike will idle at about 2100rpm.  Intake leak? no increased rpm when I spray carb cleaner around the boots.

Never done a rebuild. never owned an old bike before. 4 carbs, syncing, I am a bit apprehensive about doing this myself.

Thoughts, suggestions, it is easy, things to look out for, avoid, all that jazz.

Thanks a ton

Craig

[wheels]

hey craig you wanna pick racerrad's brain about carbs he's the man for that .chhers darren

[SILVERGOAT]

  I had the exact same problem with my '89. It was my daily ride and I did not know it's service history, so to save down time, I purchased a set of rebuilt carburetors off eBay from a seller known as "oldskoolcarbs". As I posted before, his claims are truthful. I did not have to adjust ANYTHING! It starts cold, idles at EXACTLY 1,000 rpm when warm. He currently has a set on eBay for $345 including shipping.
  Now, when I was taking my old ones off, I found that someone had in fact been there before. The throttle and choke cables had no slack in them. The bracket for the choke cable actually has a stop built into it to allow for slack in the cable when the choke is off. These would be the things I would check first.
  With the new carburetors installed, I just did 220 miles yesterday using only 4.0 gallons of fuel. 55 mpg ain't bad. With that being said, that was with my girl on her Bandit S and we were just cruising(i.e. short shifting). Still, I have no issues or complaints about how my FJ runs. If I'm on it, it drops into the lower 30's for mpg.
  If you decide to go with a rebuilt set, older ones have a dual 8mm inlet system, yours has a single 6mm inlet. You will need to fabricate a tee'd set up for the fuel feed. Either get a 5/16"x5/16"x1/4" brass tee, or I found a three  way 1/4"  tee and STRETCHED 1/4" fuel line over the two 8mm(5/16") inlets.

[andyb]

Couple things to work at here.

Sounds to me like it's about due for a synch and possibly a valve lash check, ya?

Is the choke working on each carb properly?  Is the cable stretched, or slipped out and not activating properly?

What do the plugs say?  Black?  White?  Worn?

Idles high when warm, or only when it's hot out?  The idle's adjustable, turn it down if ya need


Sounds a bit like the choke (enrichment, really) isn't working properly, and possibly some of the pilot circuits are having issues (so it takes eons to get fully warm).


It's not the hardest job to do. The big bastard is that you need the proper tool to do the synch.  You can fake it to a degree with clear tubing and ATF, but it's not as accurate as a proper gauge is (beats nothing, mind you).  I can't think of any special tools required to clean the carbs, just a selection of screwdrivers, hammer, punch, ruler, maybe pliers to help get hoses off and on.

The absolute best thing you can do is replace the original screws in the carb assembly with the stainless steel version.  SlowOldGuy is the gent to speak with there.  He'll likely chime in here shortly, listen to him, he's quite adept at getting FJ's to do silly things like idle and run cleanly.

[Arnie]

At only 28K miles, its unlikely that anything is worn out on your carbs.  May be some jets and passages are dirty or varnished a bit.  You're also at 7000 ft there so you may be running a bit rich due to altitude.

I'd clean and adjust your carbs while replacing all the screws with SlowOldGuy's kit.  He provides a great set of step by step instructions too.

Then follow the rest of AndyB's suggestions re syncing the carbs, checking the valve clearance and adjusting the idle.  It'll run like a new bike again. :-)

Cheers,
Arnie

[cedmund00]

Thanks for the info. I am definitely going to opt for the rebuild myself, save money and gain the knowledge as carb's are not my specialty. I adjusted the throttle and the choke mechanism "seems" to be working properly.

I hope I get that kinda mileage.

Thanks, this forum is awesome.  

[cedmund00]

Sounds like SlowOldGuy's kit and a thorough cleaning should be the answer. If not then I am sure it needs it anyways.  Anyone have a suggestion for a good syncing gauge, loaners from bike shops? that's on my list after the carb clean. Likely need valve adjustment after 28K miles? is that easy on this bike?

To answer a few other questions:

The choke seems to be working right.

Plugs are whitish.

It only Idles high when it approaches 90 F or so. Otherwise it holds a smooth 1,100rpm at idle when nice and warmed up warm.

Thanks a bunch guys.

[andyb]

Morgan Carbtune, best synch tool I've used.

Valve adjustment may or may not be needed, but a quick check definitely should be on your todo list.

[oldskoolcarbs]

  I had the exact same problem with my '89. It was my daily ride and I did not know it's service history, so to save down time, I purchased a set of rebuilt carburetors off eBay from a seller known as "oldskoolcarbs". As I posted before, his claims are truthful. I did not have to adjust ANYTHING! It starts cold, idles at EXACTLY 1,000 rpm when warm. He currently has a set on eBay for $345 including shipping.
  Now, when I was taking my old ones off, I found that someone had in fact been there before. The throttle and choke cables had no slack in them. The bracket for the choke cable actually has a stop built into it to allow for slack in the cable when the choke is off. These would be the things I would check first.
  With the new carburetors installed, I just did 220 miles yesterday using only 4.0 gallons of fuel. 55 mpg ain't bad. With that being said, that was with my girl on her Bandit S and we were just cruising(i.e. short shifting). Still, I have no issues or complaints about how my FJ runs. If I'm on it, it drops into the lower 30's for mpg.
  If you decide to go with a rebuilt set, older ones have a dual 8mm inlet system, yours has a single 6mm inlet. You will need to fabricate a tee'd set up for the fuel feed. Either get a 5/16"x5/16"x1/4" brass tee, or I found a three  way 1/4"  tee and STRETCHED 1/4" fuel line over the two 8mm(5/16") inlets.

thanks for the kind words