FJ1100 Won't run on all Four Cylinders

[Spudman]

Just an FYI check your oil ( pull a sample)If you've not changed it yet. sometimes when they sit for a while the gas can get in the oil and it makes them really fussy to start. If your oil is thinned down that's bad too if it does start. Glad you got it running, what a great feeling

I will be sure to check/change the oil. It does seem to start a little hard right now so maybe that will help it out a bit. As it was missing the air box when I got it I was thinking about buying some pods, has anyone done this with success? Or am I better off with the whole air box unit? I know some bikes are a bit more temperamental when it comes to this.

[Tuneforkfreak]

I think pods would be fine ( I was thinking of doing that too) but If I'm correct I believe you have to re jet if you switch to them. Your bike will tell you allot just with a pull of the choke or twist of the throttle when trying to start. If its lacking fuel the choke may give you the answer or to much fuel and a little air from throttle. One thing is for sure, my bike is temperamental when its cold,spitting and bitching at me, once it warms up it purrs like a kitten though.

[Nova]

Just an FYI check your oil ( pull a sample)If you've not changed it yet. sometimes when they sit for a while the gas can get in the oil and it makes them really fussy to start. If your oil is thinned down that's bad too if it does start. Glad you got it running, what a great feeling

I will be sure to check/change the oil. It does seem to start a little hard right now so maybe that will help it out a bit. As it was missing the air box when I got it I was thinking about buying some pods, has anyone done this with success? Or am I better off with the whole air box unit? I know some bikes are a bit more temperamental when it comes to this.

A bike with CV carbs will always run better all around with the original airbox and jetting. If you use podfilters you need to rejet the carbs. Ideally, you should get slide carbs if you want to use pod filters. About here people will jump in and say "You can run pod on CV carbs and they work fine!" Notice I didn't they they won't work. I didn't even say they won't work well... or well enough. I said they will run *BHEH-TURR* with the original airbox that the engineer (who went to school for many many years) designed for it.

If you like the idea of modding your bike for looks or whatever reason go for it. You'll spend a lot of time and money chasing different problems to get it tweaked right. Plenty of guys here to help you out with that if that's the way you want to go. But if what you want right now is a properly running bike for not a lot of extra expenses, get an original airbox cheap off fleabay and tune it to the original specs. You can always fit it with pods or go full streetfighter with carbon-fiber farkle knobs and a 12 inch subwoofer later.

http://www.ebay.com/itm/like/262465180844?lpid=82&chn=ps&ul_noapp=true

[racerrad8]

A bike with CV carbs will always run better all around with the original airbox and jetting. If you use podfilters you need to rejet the carbs. Ideally, you should get slide carbs if you want to use pod filters. About here people will jump in and say "You can run pod on CV carbs and they work fine!" Notice I didn't they they won't work. I didn't even say they won't work well... or well enough. I said they will run *BHEH-TURR* with the original airbox that the engineer (who went to school for many many years) designed for it.

The above underlined statement is just not true. The logic that the "engineers" designed the best "air box & jetting" combination just does not make any sense either.

If that logic was true, then why would the factory jetting be different for the different countries the FJ was imported to. All USA FJ's came with a 37.5 pilot jet, where all of the UK & Australian FJ's came with 42.5 pilot jets. The Candians got all three jets, 37.5, 40 & 42.5. The main & air bleed jets are also different. The main jet needle was also different from country to country. But, they all use the same air box. All of them are the base carbs, but they are jetted differently based on the emission requirements of the import country.

The air box is also designed around the emission control and noise reduction requirements placed onto the manufacture. The air box is a closed loop system designed to ingest the crankcase vapors instead of allowing them to vent to the atmosphere. Any performance engine builder/tuner will tell you gases, contaminated with (oil) severely affect the performance of any engine.

If the engineers could design something exclusively for performance, it surely would not be the stock FJ air box configuration.

The other part of this that just does not hold water is, if there was a performance advantage, we would find an easier way to keep them and work on the carbs. But there is no advantage and the carbs are easily jetting for better performance with pod filters. The air box is not designed for any reason other than it is to be a closed loop PCV system that does not generate significant induction noise based on emission/noise requirements.

Now, jetting and the need to adjust it. I can make any FJ run better by properly jetting the carbs for use with an air box. The jetting that came stock with the bike is not the best jetting for anything other than the required emission regulations Yamaha was required to meet. If I can make a FJ run better with jetting adjustments with an air box, just think what a "engineer" could do if given free rein to design the optimum air box & jetting combination.

Finally, the true benefit of the CV carb is the ability to perform well in a wide range of air temps & densities. Can you get one jetting that is the best for everything, no. But you can easily make it run the best for the majority of your riding conditions. I ride regularly from sea level to the 9,623 of the Sonora pass. Yes, my bike is definitely lacking some power at the higher altitudes, but it runs great where I do the majority of my riding. I also do that for more than 200 people annually for their FJ or their race cars.

The best thing about the FJ that most other bikes to not have, is the fact the engine is used in the Legend race car. That means people, like me, have been tuning on this engine to increase power & performance for more than twenty years now. The FJ production stopped more than twenty years ago and the engineering was over way before that.

I assure you I can make any FJ run "BHEH-TURR" with pod filters and proper jetting. Plus, with my experience I can get you in the ball park on the first try based on information provided about where & how you ride.

After building the FJ CV carb bank for more than twenty years, I can say with the utmost certainty, the FJ will run better with pod filters and properly jetted when compared to a stock FJ. Will some tweaking be required, possibly. But then again most people are satisfied with the improved performance they never make other adjustments.

Spudman, we can get you dialed in for pods & jetting, but first you need to get the petcock sorted.

Randy - RPM

[Spudman]

Well today the pods came in the mail. Bike has been sitting pretty much since I had it running and now the dang thing went right back to being a pain in the butt. Something is still not right in the carbs I fear but the petcock issue has been resolved.

[Tuneforkfreak]

Not sure if your bike has a fuel pump or not? If it does have one, do not over look it as a problem child, put a pressure gauge on it and make sure its up to the task. If it dont have the pump make sure your floats are properly adjusted and that the needles are not sticking in the seats. I had no start issues and both of these scenarios plagued me. I finally tossed the crappy Chinese fuel pump and installed an Airtex auto pump, bike has never ran so well.

[Spudman]

Not sure if your bike has a fuel pump or not? If it does have one, do not over look it as a problem child, put a pressure gauge on it and make sure its up to the task. If it dont have the pump make sure your floats are properly adjusted and that the needles are not sticking in the seats. I had no start issues and both of these scenarios plagued me. I finally tossed the crappy Chinese fuel pump and installed an Airtex auto pump, bike has never ran so well.

Sadly it does not have a fuel pump on the bike. I do wish it did however as this gravity system seems to not exactly be ideal for a 1100cc motorcycle.

[Mark Olson]

Sadly it does not have a fuel pump on the bike. I do wish it did however as this gravity system seems to not exactly be ideal for a 1100cc motorcycle.

If your fuel line is routed correctly and gas cap vents as intended you will have plenty of fuel with gravity feed . It uses a larger fuel line already and larger seats in the carbs.

The 1200 FJ engine runs just fine with gravity feed fuel.

If you wish to convert to fuel pump , it is posible with a later set of carbs and some minor modifications.

[Pat Conlon]

....If you wish to convert to fuel pump , it is possible with a later set of carbs and some minor modifications.

You can keep your existing carbs, just change the float needle seats to the smaller size used on the fuel pump carbs.

As Mark says, gravity flow delivers the fuel just fine (w/proper line routing and tank venting)

It's just that the gravity flow vacuum petcock sucks (get it? vacuum/sucks? I just crack myself up)
....and with a fuel pump you can install a REAL fuel filter. Our steel tanks are not getting any younger and with E15 gas on the horizon, it will get worse.