So I picked this bike up a few weeks ago from a barn. So far I have:
Cleaned the carburetors
Changed the plugs
Fixed a coil grounding issue
and looked for a few missing parts.
Now at this point I'm sitting with a bike that will 1. turn over 2. fire on two cylinders (I've tried them all independently) The two that fire are marked 2 and 3.
It will idle with the choke on full, very roughly, but will only rev slightly and the other two cylinders never join in on the fun. One thing I am missing is the airbox, I know this will affect the overall performance and cause it to run rougher but would it prevent two cylinders from firing on these bikes?
Also the petcock has two nipples sticking out, one on each side of the main fuel outlet, that I assume these are for vacuum. I've found that one connects to the second carb boot but I don't know which side nipple to use (hehe) and also I have no idea where the other one is supposed to connect?
Any ideas? I'm fairly stumped on this one. :dash2:
Ignition and/or cam timing? Faulty ignitor unit?
What year? By the sounds of it a pre fuel pump model?
Only issues I've ever had similar to this were a shorted spark plug cable or a bad plug.
A clue could be the numbers on the cylinders that fire... #2 and #3
Those cylinders 2/3 share the same coil (right side)
Cylinders #1 and #4 share the left side coil.
Quote from: Pat Conlon on June 21, 2016, 11:23:33 AM
A clue could be the numbers on the cylinders that fire... #2 and #3
Those cylinders 2/3 share the same coil (right side)
Cylinders #1 and #4 share the left side coil.
^This^
The bike is an 85 and definitely pre-fuel pump. See I thought that the coil might be it but I still have spark and if I squirt some gas into the cylinders it will fire. I'm thinking it is not getting the gas it needs so maybe a combination between a few areas I missed cleaning and the wrong petcock? I have been looking them up and only see petcocks with one vacuum nipple on it, is that the correct one? The one that came with the bike has two and I think that may be causing some starvation.
Quote from: Spudman on June 21, 2016, 07:23:54 PM
The bike is an 85 and definitely pre-fuel pump. See I thought that the coil might be it but I still have spark and if I squirt some gas into the cylinders it will fire. I'm thinking it is not getting the gas it needs so maybe a combination between a few areas I missed cleaning and the wrong petcock? I have been looking them up and only see petcocks with one vacuum nipple on it, is that the correct one? The one that came with the bike has two and I think that may be causing some starvation.
You need a 10MM fuel barb and a 4 or 5MM vacuum port. The 10MM is routed over and around the #3 carb top and splits to feed carbs 1&2 and 3&4. The vacuum line is connected to the #2 intake carb manifold. The petcock will have two positions. "ON" and "PRI. "ON" allows fuel to flow when engine vacuum is present and shuts off fuel with engine off, "PRI" will free flow fuel till the tank is empty.
Quote from: FJmonkey on June 21, 2016, 07:33:45 PM
....The 10MM is routed over and around the #3 carb top and splits to feed carbs 1&2 and 3&4....
Fuel line routing is important on the gravity flow bikes.
So....Just to be clear: the single fuel line that leaves the petcock runs *under* the 2 branch lines that feed the carbs.
It is counter intuitive until you see how low the petcock outlet is when the tank is bolted down.
If you don't run the fuel line this way, you will pinch either of the two branch lines, or the main line itself.
Don't ask me how I know.
So from what I'm gathering is my fuel line was definitely cut short as there isn't much before the tee. I'll have to pick up some more.
Quote from: Pat Conlon on June 21, 2016, 08:31:54 PM
Quote from: FJmonkey on June 21, 2016, 07:33:45 PM
....The 10MM is routed over and around the #3 carb top and splits to feed carbs 1&2 and 3&4....
Fuel line routing is important on the gravity flow bikes.
So....Just to be clear: the single fuel line that leaves the petcock runs *under* the 2 branch lines that feed the carbs.
It is counter intuitive until you see how low the petcock outlet is when the tank is bolted down.
If you don't run the fuel line this way, you will pinch either of the two branch lines, or the main line itself.
Don't ask me how I know.
I'll see if I can get a picture for verification tomorrow but I'm almost certain I have the incorrect petcock.... Looks like the part may cost almost as much as the bike did... :wacko3:
Quote from: FJmonkey on June 21, 2016, 07:33:45 PM
Quote from: Spudman on June 21, 2016, 07:23:54 PM
The bike is an 85 and definitely pre-fuel pump. See I thought that the coil might be it but I still have spark and if I squirt some gas into the cylinders it will fire. I'm thinking it is not getting the gas it needs so maybe a combination between a few areas I missed cleaning and the wrong petcock? I have been looking them up and only see petcocks with one vacuum nipple on it, is that the correct one? The one that came with the bike has two and I think that may be causing some starvation.
You need a 10MM fuel barb and a 4 or 5MM vacuum port. The 10MM is routed over and around the #3 carb top and splits to feed carbs 1&2 and 3&4. The vacuum line is connected to the #2 intake carb manifold. The petcock will have two positions. "ON" and "PRI. "ON" allows fuel to flow when engine vacuum is present and shuts off fuel with engine off, "PRI" will free flow fuel till the tank is empty.
$120 is chump change. Less than the cost of a new tire.
http://rpmracingca.com/proddetail.asp?prod=M%2FC%3A36Y-24500-01 (http://rpmracingca.com/proddetail.asp?prod=M%2FC%3A36Y-24500-01)
....and it's already safety wired for you.
A wet paper towel on the header is a good way to see which cylinder is hot or cold. If you got one that's cold or in your case you already know which ones are dead, drain the float bowl and see if you have any gas in that carb. That's how I did it and after setting my floats to spec I found that one of the carbs didn't really like that measurement and had the gas shut off. I can honestly say that I have pinched my fuel line off on my 90 model when the line fell out of the holder on the tank.
Update so far, carbs are getting a thorough soak with all the jets pulled and soaking independently. I've looked into the new petcock and will have it ordered soon. Should I separate the carbs off of the rack on this for any reason? I'm not sure if the plastic in between them will get soft or damaged?
Thanks for all the help and suggestions so far everyone.
Quote from: Spudman on June 23, 2016, 08:54:44 PM
Update so far, carbs are getting a thorough soak with all the jets pulled and soaking independently. I've looked into the new petcock and will have it ordered soon. Should I separate the carbs off of the rack on this for any reason? I'm not sure if the plastic in between them will get soft or damaged?
Thanks for all the help and suggestions so far everyone.
If I was in your position I would break down all the carbs and run each one through a sonic bath of vinegar solution then put new O rings on all the supply lines. They're probably hard and they're cheap to boot.Dont try and cut any corners in this area or you'll fight the gremlins on some back country road. I picked up an ultra sonic cleaner to do mine http://www.harborfreight.com/25-liter-ultrasonic-cleaner-95563.html (http://www.harborfreight.com/25-liter-ultrasonic-cleaner-95563.html) . It worked really well and the smallest of ports get scrubbed out which is why the pro's use them.
Make sure you remove the emulsion tubes as well and soak and clean them. When I took mine out they where full of nasty schmuck. I had a problem getting two of mine out and ended up having to replace them.
Well it is a little late but here are a few pictures of that old petcock. Do you think it came off of one with a fuel pump? It does have the on/prime/on options but the two nipples throw me off.
Quote from: Spudman on June 27, 2016, 07:32:25 PM
Well it is a little late but here are a few pictures of that old petcock. Do you think it came off of one with a fuel pump? It does have the on/prime/on options but the two nipples throw me off.
That looks like a standard '86/'87 petcock, 10MM for fuel and 4MM for vacuum (goes to #2 carb intake boot). If it has a PRI position then it is an '84/'85. If it still works properly then add some safety wire, the 10MM fitting has been known to fall out spilling fuel on to a hot engine. Think fire ball...
This petcock has two outlets for vacuum though, which side should the line that runs to the second boot go to? and where does the other one go?
Quote from: Spudman on June 27, 2016, 10:02:17 PM
This petcock has two outlets for vacuum though, which side should the line that runs to the second boot go to? and where does the other one go?
My error, you do not have an FJ petcock. See the following links from RPM
84/85 - (http://rpmracingca.com/prodimages/large/M%20C%2036Y-24500-01-1.jpg)
86/87 - (http://rpmracingca.com/prodimages/large/M%20C%201TX-24500-02-1.jpg)
89/93 - (http://rpmracingca.com/prodimages/large/M%20C%2089-93petcock-1.jpg)
Not sure what the extra port is used with.... :pardon:
Mark,
You keep saying the petcock vacuum port should go to the second cylinder. That's not technically correct. Although it can go to any cylinder, it originally went to the first cylinder vacuum port. The ignition vacuum when to the second cylinder vacuum port.
Quote from: FJ_Hooligan on June 27, 2016, 10:42:25 PM
Mark,
You keep saying the petcock vacuum port should go to the second cylinder. That's not technically correct. Although it can go to any cylinder, it originally went to the first cylinder vacuum port. The ignition vacuum when to the second cylinder vacuum port.
Fair enough, I may be in error on the exact port. Thank you for the correction. :good2:
Looking at the pictures I definitely have the wrong one. I found this one on eBay that is reasonable but it does not utilize a vacuum port. Would this work well given it is still a gravity feed? I believe the vacuum just helps shut the fuel off on these, yes?
http://www.ebay.com/itm/171642705025?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT (http://www.ebay.com/itm/171642705025?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT)
Quote from: Spudman on June 28, 2016, 07:02:33 AM
Looking at the pictures I definitely have the wrong one. I found this one on eBay that is reasonable but it does not utilize a vacuum port. Would this work well given it is still a gravity feed? I believe the vacuum just helps shut the fuel off on these, yes?
http://www.ebay.com/itm/171642705025?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT (http://www.ebay.com/itm/171642705025?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT)
The vacuum control is a safety feature in my opinion. When the engine stops, vacuum drops out and fuel stops flowing to the carbs. It also prevents a stuck float valve from draining all the fuel from the tank, which may end up in the crank case or in a puddle on the ground where it is parked.
That manual petcock has an 8MM barb for the fuel, our GF feed units are 10MM. However, some here have ridden home after bypassing a failed fuel pump and that is 6MM hose. So it may work, just understand the risks/challenges that come with it.
If you don't want a vacuum shutoff on the petcock.... have you given any thought on how you plan on shutting off the gas?
Pulling off the seat and left side cover, reaching in to turn the lever every time you park?
Quote from: Pat Conlon on June 28, 2016, 10:43:04 AM
If you don't want a vacuum shutoff on the petcock.... have you given any thought on how you plan on shutting off the gas?
Pulling off the seat and left side cover, reaching in to turn the lever every time you park?
Very good point. My bike does not have a shut off, not sure if my petcock is stock or not but it does not have a vacuum shutoff and I wish it did. I've seen tiny puddles of gas dripping from the overflow tubes once or twice and I know full well where that road leads. As soon as I start the bike it stops leaking but the point remains, when not in use the gas should be shut off. Like Monkey said, the gas can all wind up in the crank case, My Yamaha Kodiak was notorious for that if it sat a little to long and you forgot to shut the gas off and I'm talking the entire tank of gas in the engine.
If you're lucky the fuel will end up in your crankcase.....often times it will end up on the floor of your garage.
By chance, you don't happen to have a water heater in your garage do you? :bomb:
....so for some extra $ (above what you would pay on FleaBay) you can get a proper petcock.
Well despite my best efforts, soaking the carbs, clearing every hole/jet/breather, replacing o rings the bike still does not want to run. It actually runs worse than before (not at all, really). This thing is the one of the most fussy bikes I have ever worked on. I checked the bowls for gas, which they do. Checked spark again, does. Plugs were wet so it is getting fuel in the cylinders. and it still have compression. From what I've learned all I should need for at least it to fire is fuel, spark, and compression. Is there something I am missing with this bike?
Quote from: FJmonkey on June 27, 2016, 10:51:39 PM
Quote from: FJ_Hooligan on June 27, 2016, 10:42:25 PM
Mark,
You keep saying the petcock vacuum port should go to the second cylinder. That's not technically correct. Although it can go to any cylinder, it originally went to the first cylinder vacuum port. The ignition vacuum when to the second cylinder vacuum port.
Fair enough, I may be in error on the exact port. Thank you for the correction. :good2:
Sorry, meant no ill. It's just much easier to disconnect/connect on cyl 1.
SHE LIVES! The bike took a lot of extra work and battery charges but she screamed to life, literally. Now all I have to do is fix all the other little mechanical problems (clutch doesn't fully engage, brakes need to be bled) and get a proper petcock as you all suggested. Any other things I might want to look out for before taking her on the road? The tires are fairly new so those are good.
Quote from: Spudman on June 29, 2016, 07:49:54 PM
SHE LIVES! The bike took a lot of extra work and battery charges but she screamed to life, literally. Now all I have to do is fix all the other little mechanical problems (clutch doesn't fully engage, brakes need to be bled) and get a proper petcock as you all suggested. Any other things I might want to look out for before taking her on the road? The tires are fairly new so those are good.
Awesome!!! Happy to hear that she roared to life. :good2:
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 :good:
Quote from: Tuneforkfreak on June 29, 2016, 11:50:50 PM
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 :good:
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.
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.
Quote from: Spudman on June 30, 2016, 06:17:26 PM
Quote from: Tuneforkfreak on June 29, 2016, 11:50:50 PM
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 :good:
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 (http://www.ebay.com/itm/like/262465180844?lpid=82&chn=ps&ul_noapp=true)
Quote from: Nova on June 30, 2016, 09:58:52 PM
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 (http://www.rpmracingca.com)
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.
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.
Quote from: Tuneforkfreak on July 08, 2016, 09:57:01 PM
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.
Quote from: Spudman on July 09, 2016, 09:20:17 AM
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.
Quote from: Mark Olson on July 09, 2016, 02:49:19 PM
....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.