Australian FJ1200 carburetor specifications

[JaJa]

Hi All.
Looking for some help with carburetor specs.
I am looking to purchase overhaul kits to solve over-fueling problems, but am unable to verify correct jet sizes.

All information refers to either US or UK models, but my bike is a 1988 OCE model with engine number 3BC 000xxx.

I have removed the tank and examined the carbs but have been unable to find any identification marks, except that they are Mikuni.

I suspect they are BS36 Mikuni with #110 main jet, #155 air pilot jet, and #42.5 fuel pilot jet, but am unable to verify this without removing carbs which I dont want to do at present so I can continue riding while awaiting overhaul kits.

would be grateful for any info.

Regards...

[andyb]

I belive you can consider it to be a UK spec machine.  Pop the diaphram covers off.  If you know things are otherwise stock internally, the needles will be adjustable.

[racerrad8]

Here are stock jetting replacement carbs kits:88+ Carb Kit

You also might want to consider replacing all of the other o-rings within the carbs as well as all of the soft phillips head screws as well. You can do that with this kit; Carb O-Ring & S/S Allen Screw Kit

You can find any other carb part on the website as well; www.RPMracingCa.com

Randy - RPM

[JaJa]

I belive you can consider it to be a UK spec machine.  Pop the diaphram covers off.  If you know things are otherwise stock internally, the needles will be adjustable.

Thanks for that. I have since removed one of the needles, and it is adjustable, but the clip is set in the fourth slot from the top !
My CLYMER repair manual states that the setting for UK models from 1988 onwards should be second slot from top.

Is there any reason these would be set in fourth slot ?

Thanks

[andyb]

Because someone adjusted it.  That's the idea behind most items that have multiple settings, as it turns out.  Sometimes people use those optional settings.

[JaJa]

Because someone adjusted it.  That's the idea behind most items that have multiple settings, as it turns out.  Sometimes people use those optional settings.

Thanks. I kinda figured that. I was thinking possibly of a more technical reason like maybe something to do with air pressure at different elevations, or maybe for high speed highway cruising or something similar.

Regards

[flips]

Hi JaJa

Does your bike have after market exhaust and/or air filter?.Usually people find adjustment may be necessary after making these mods but I'm not sure if  no 4 slot on the needle is the way to go (I'm no carb expert but mine runs pretty well on no 2,no4 may be part of your over fueling issue..).If you type in carb jetting into the search box (up at the top of the page next to "news" if you havent found it already ) you will find a multitude of great info,carb tuning and carb synch are also great searches.Hell,a carb expert may even chime in! Hope this helps.

Cheers

Jeff P

[JaJa]

Hi JaJa

Does your bike have after market exhaust and/or air filter?.Usually people find adjustment may be necessary after making these mods but I'm not sure if  no 4 slot on the needle is the way to go (I'm no carb expert but mine runs pretty well on no 2).If you type in carb jetting into the search box you will find a multitude of great info,carb tuning and carb synch are also great searches.Hell,a carb expert may even chime in! Hope this helps.

Cheers

Jeff P

Thanks flips. As a matter of fact it does have 4 into one exhaust, maybe the reason for setting needles so high. I will conduct further research and will drop back to at least 3rd slot unless I find a good reason not to.

I had initially suspected the emulsion tubes, being the most common cause of over-fueling. However the diaphragm on the one i pulled out is not in the best shape either, so it appears I will have to strip them down for examination before proceeding further.

Thanks for your help

cheers

[JaJa]

Following my initial inspection of no. 1 carburetor, decided to pull them all out and dismantle.
Jets were as suspected i.e. #110 main, #155 pilot etc.
Diaphragms showing signs of wear.
Difficult to tell visibly if emulsion tubes are worn, but appears to be a fair bit of sideways movement of needle.
Spark Plugs are all sooty black (no surprises here)

Decided to bite the bullet and go the whole hog so to speak. Just ordered;

• 4 x new diaphram/slides http://www.rpmracingca.com/proddetail.asp?prod=Carb%3ASlide&cat=24
• 4 x carb rebuild kits http://www.rpmracingca.com/proddetail.asp?prod=Carb%3Arebuildkit3&cat=24
• 1 x Carburetor kit. http://www.rpmracingca.com/proddetail.asp?prod=carbkit&cat=24
  

Total cost US$544.00 (AU$510.00). Not a cheap exercise, but then is any love affair ?
If it all works out I will recoup a fair bit of the outlay in fuel savings over time. not to mention a more pleasant ride.

Now have to cool my heels for a week or so until they arrive. In the meantime I can clean up bodies and get everything spick and span ready.

[flips]

Hi JaJa.

A good carb clean/rebuild can do wonders

I can recommend this thread while doing carb rebuilds.....Pictures and everything

http://www.fjowners.com/index.php?topic=4281.0

Plenty of great info here too...

http://www.fjowners.com/index.php?board=21.0


Cheers

Jeff P