grandfatblanc Posted January 1, 2009 Share Posted January 1, 2009 Just bought a 90 fj1200 it didnt have the airbox. Only #2 exhaust gets hot I checked compression about 130 in all four holes.Spark plugs have spark when touched to head. I have the CLYMER Manual I have removed the carbs and I will clean them all. It has stock pipes on it. My Question is if i put pods on it because I dont what to find or mess with the air box how should I jet it meaning what kind and size. And will I have to put an exhaust on it. I have another new bike for riding but I wanted another fast bike. This one was cheap. Thanks Grandfat Link to comment Share on other sites More sharing options...
Madison Motorsport Posted January 1, 2009 Share Posted January 1, 2009 With an OE exhaust system, you shouldn't need to re-jet the carbs. You will, obviously, need to adjust mixtures, etc. when you re-build. I presume by pods, you mean individual cone filters such as K&N? TBH, cheap unbranded ones (of the K&N red colour) will do the same job - they are all made in the same place in China anyway, just made under liscence. I would recommend fitting an air box if you can source one, then use an aftermarket panel filter. Using cones can offer set up difficulties to the less experienced if you have unbalanced compression as each carb will have to be set up more precisely. If you do wish to work on carbs, one essential piece of kit I would really recommend is a set of vacuum gauges - you cannot set carbs up reliably without them. Link to comment Share on other sites More sharing options...
FJ12SP Posted January 1, 2009 Share Posted January 1, 2009 If you intend to use pod filters you will have to re-jet the carb, this is a specialist job as the FJ carbs are not suited to pod-filters and have to be drilled to take an oversized main jet, this will preferably be set up on a dyno tester. It sounds very much like your carbs are gummed up or that the diaphrams are holed. Carb balance is pretty critical on an FJ if the carbs are out you will get plenty of strange symptoms. Look HERE Adam. Link to comment Share on other sites More sharing options...
Madison Motorsport Posted January 1, 2009 Share Posted January 1, 2009 If you intend to use pod filters you will have to re-jet the carb Not quite true. Only with an aftermarket exhaust. I have converted many air filters on XJ12s and other Yams of that era to cones without an issue. With an OE exhaust, all it requires is careful setting up. Link to comment Share on other sites More sharing options...
Rich_B Posted January 1, 2009 Share Posted January 1, 2009 Sorry Grandfat but just had to comment on Adams pic of his FJ, what a great looking bike Link to comment Share on other sites More sharing options...
grandfatblanc Posted January 1, 2009 Author Share Posted January 1, 2009 If you intend to use pod filters you will have to re-jet the carb, this is a specialist job as the FJ carbs are not suited to pod-filters and have to be drilled to take an oversized main jet, this will preferably be set up on a dyno tester. It sounds very much like your carbs are gummed up or that the diaphrams are holed. Carb balance is pretty critical on an FJ if the carbs are out you will get plenty of strange symptoms. Look HERE Adam. Thank you for your replies Adam and Mad. Adam I see you have a aftermarket exhaust so you had to drill the carbs for different jets? I ask this because all I had to do to my 05 zrx 1200 was put in new needles on a certain clip height. My abilities are limited I was able to jet my last bike only because the zrx owners site had many excellent posts that walked me through the process. Mad there is a drag racer in Ohio Just south of my state of Michigan I think I can buy an airbox from him. I will clean and reinstall carbs tomorrow fingers crossed it will fire on all cylinders. Will I be able to tell without any airfilters on it I would not run it more then a minute to see if all cylinders are firing. If not all cylinder fire I will look at new plugs and wires the spark was white on all plugs not blue as manual states.The wires may be original and if they are 18 yrs old it would need new ones anyway. I will update when this is done thanks for your knowledge. Link to comment Share on other sites More sharing options...
wild foamy Posted January 2, 2009 Share Posted January 2, 2009 white spark plugs may indicate lean running (too much air, not enough fuel) which may be the reason it is not firing. if the airbox has been removed then this may cause it to run lean as it can now take in more air and is less restricted, but the fuel intake has stayed the same i suggest you reset your carb and set it up to the correct mixtur before trying again Link to comment Share on other sites More sharing options...
grandfatblanc Posted January 14, 2009 Author Share Posted January 14, 2009 Just an update I cleaned carbs put them back on would not stay running. I looked at the mixture screws on intake side they were so stripped I could not move them in or out it just got worst. Tried different easyouts then tryed to drill.Hmm Well I went on ebay bought 4 carbs from racer in Wisconsin. He installed 120 mains 40 pilots and stiff springs for better thottle response 155 air jets needle set at 3rd pos. I installed the carbs it fired right up I just had to turn idle up a little and it idles and responds quick with a flip of the thottle. I will sync them and put pods on it I feel I was lucky to find someone so helpful thank you Dano In Wisconsin Oh bye the way he has More engine parts and carbs. Link to comment Share on other sites More sharing options...
Recommended Posts