Scratching my head after an incident yesterday. I'll relate all the facts in hopes that someone can think of a solution.
1. Replaced the head on my 96. Set the valve timing, clearances etc, per the manual. Replaced old fuel lines with new. Found out PO had hooked the lines up wrong - had the line from the back of the petcock (the reserve feed) running to the carbs. Changed that to the configuration per the manual. Started it up and everything was running well, although the idle speed was off.
2. Added some Sea Foam to the fuel in the tank - about a half a cup, not entirely sure how much fuel was in the tank probably a couple of gals.
3. Took a short run. Running well, no issues except that once it warmed up the idle climbed to around 3000 rpm. Suspected a vac leak. I checked the intake to carb connection (sprayed some carb cleaner on the boots there) and the idle dropped back down. Tightened the clamps, and seemed ok. Reset the idle speed.
4. Took another, longer run. Accelerating up a gentle hill and it started to chug and hesitate as though it was running out of gas. Switched to reserve, and the engine died. Coasted to the side of the road, checked the tank... seemed to be more than enough gas in there. Cranked the engine on Prime, got a cough, and then nothing. No smell of gas, not flooding, not a hiccup to suggest that it was trying to start. Ran the battery down trying to get it to go.
5. Got it hauled home, added more (fresh) gas to the tank and put the battery on the charger. Next day cranks but won't start. Checked spark - yep. Checked compression - yep. Checked for fuel in the carbs (opened the taps on the float bowls) - yep.
6. Started taking things apart. Pulled off the tank and checked flow from the shutoff valve there - check.
Pulled the air box, and cranked the engine with my hand over the carb - getting suction. Getting pressure through the tailpipe, so the pistons are moving air in and out, and the valves are opening and closing.
Removed the carbs. Cranked the engine, and can see the intake valves opening and closing. Sprayed a little fuel into the manifold and she fired (briefly). So it seems the engine is capable... but not getting fuel.
Pulled the carbs apart, soaked and sprayed everything in carb cleaner and blew them out with compressed air. Diaphragms are good, everything seems to be moving freely. Mixture screws weren't set the same, so adjusted them in to seat, then out 2.5 turns each.
Reassembled, attached to the intake boots. Used a funnel to fill the float bowls through the fuel line. Capped the vac hose (to the petcock) and cranked the engine. It fired, ran briefly and I shut it down.
Reassembled everything. Turned petcock to Prime, and started the bike. It started, revved very high, couldn't adjust it down using the idle speed adjuster. Kept turning it out and the speed dropped off, and then the engine quit.
Now back to same issue as yesterday - engine cranks but won't start. No smell of fuel. It really seems like fuel starvation, but I'm at a loss. Petcock not working properly? Carbs still not right? Something else?
The thing that is really confusing me is the fact that it ran really well for quite a few miles (140 - odd km, or about 90 miles) before the engine quit yesterday.
Any ideas from the cognoscenti?
TIA
Griff
Um, the back side of the petcock is the vacuum line which is supposed to go to the carbs. That's a smaller hose than the 3 fuel lines (main, reserve and output to carbs)
Can you show pictures of the line you're saying was connected up wrong?
Yep... vac line was connected correctly.
Will try to get a picture up today, but here's a link to the parts fiche...
http://www.mrcycles.com/fiche_section_detail.asp?section=92749&category=Motorcycles&make=SUZUKI&year=1989&fveh=2103
On that image, #3 was connected to the reserve side of the petcock, #5 was connected to the carbs.
I connected the lines the way the diagrams indicate they are supposed to be connected, and the bike ran for 140+ Km ...
Not sure I'll have time to get to it today... its a real head-scratcher...
Griff
Check the height of the fuel in the carbs with a clear flexible tubing (aquarium line works well). Just attach it to the drain and bend it into a U shape and let the gas flow in to check the height. Gas should be the to the same level as the float bowl gasket. Turn the petcock to prime to test this, and then turn it back to prevent flooding due to weak needle valves. If the gas level is not correct, the tab that the needle valve hangs on needs adjusted, or you need new needle valves.
Thanks Bombsquad, will check that as soon as I can.
Griff
Ok... finally got into the barn to try to figure this one out.
Gathered up all the usual suspects, put 'em in the cells and then started to work through the case to see who's the guilty bastard... :police:
Charged up the battery and tried to start... same as before, turns over fine, not even the hint of a cough of life.
Checked plugs - not wet, grounded them and turned over the engine, nice pretty blue spark. Ignition system is released from custody. :police:
While I have things apart, checked compression - plenty in both cylinders. Cross that off the suspect list. :police:
Moving on to fuel...
Checked for fuel in float bowls per Bombsquad's post. Not very much fuel there on the left, a bit more on the right but still not much.
Removed tank, airbox, carbs - checked float height per the Clymer manual - in spec, needles and seats are good, floats are working.
Reattached carbs to engine, filled float bowls through the feed line with a syringe - bike started and ran fine until the bowls emptied. Carb seems to be exonerated as the culprit. :police:
Fuel in the tank, and there's fuel from the tank when the valve is open (from the long (reserve?) tube only, which makes sense, since there's not much fuel in the tank. Fuel tank side of the system is exonerated. :police:
Which leaves the petcock.
Detach the petcock from the frame, and run the lines to the fuel tank. Disconnect fuel line to carbs. Disconnect vac line. Check petcock in 'on' position and 'res' position. No flow. Check in prime - fuel flow. Connect Mityvac to the vac line and apply a small vacuum - fuel flow from the RES position, nothing from ON. Add a gallon(ish) of nice fresh, clean fuel, repeat, and fuel flows from both RES and ON when vac applied to petcock. Hmmm.... Petcock appears to be innocent too. :dunno_black:
Reassemble everything, turn the petcock to prime, and start the bike. Idle is a bit rough, but smoothes out and steadies at around 1500 rpm. Let it warm up and then adjust the idle down. Bike runs for a bit, then dies. Try to start... same symptoms as I had on the road, switch to prime, bike starts and runs... switch back to ON, bike runs for awhile and then dies.
When the bike dies, only way I can get it to fire again is with petcock in PRIME.
SO....
I think the problem is the petcock... (Seriously looking at replacing the vacuum petcock with a manual one).
It's also acting like it has a vac leak (rev the bike and it won't come back to idle), which could be (most likely is) at the carb boots - that's easily fixed. But MAYBE the vac problem is what's playing havoc with the petcock? :dunno_black: Had the vac leak symptom when I first put it together after changing the head, tightened up the carb boot connections and the problem disappeared... that was just before I made the run that resulted in this thread in the first place... hmmmmmmm
Anyone have any other ideas/suggestions?
Good news is it is running again - :cheers: :woohoo: :thumb:
Now to iron out the remaining bugs...
Griff
Dont think I seen it said....
Try starting the bike with the fuel tanks cap Open.
The fuel tanks caps vent might be clogged.
this happened to me before too.
Was almost No fuel getting to the carbs and i couldnt figure out why.
someone said to try that, I did and it kicked Right over!
I almost fell over laughing.
hope thats all it is! :thumb:
#5069
A vacuum leak? It might be the line to the petcock. You verified that the petcock works.
Check the vacuum line to the petcock. Maybe it has a crack or hole or is not connected correctly. On a '96 it connects to a brass tube from the left carb.
Mind if i ask why it was necessary to harvest innocent foam from the ocean to put in your gas tank?
actually, i was wondering if there was a chance that this could be the problem.
did you add an inline fuel filter by any chance? if so that could very well be your problem
Quote from: iclrag on July 15, 2012, 01:18:13 AM
Mind if i ask why it was necessary to harvest innocent foam from the ocean to put in your gas tank?
actually, i was wondering if there was a chance that this could be the problem.
did you add an inline fuel filter by any chance? if so that could very well be your problem
Cleaned out the tank and put fresh gas in... you're right, the sea foam may have dislodged some crap that buggered things up... I've cleaned and reassembled things and it runs, but there's still issues - going to start tracing all the vacuum lines and such to ensure things are tight and leak free.
Griff
Quote from: adidasguy on July 14, 2012, 09:25:19 PM
#5069
A vacuum leak? It might be the line to the petcock. You verified that the petcock works.
Check the vacuum line to the petcock. Maybe it has a crack or hole or is not connected correctly. On a '96 it connects to a brass tube from the left carb.
Looking at that today... going to do a vac leak test to check all the possible culprits. The vac line to the petcock is hooked up correctly, but as you said it could have a pinhole in it that I haven't seen that is causing the issue.
Griff
Quote from: Tombstones81 on July 14, 2012, 08:58:03 PM
Dont think I seen it said....
Try starting the bike with the fuel tanks cap Open.
The fuel tanks caps vent might be clogged.
this happened to me before too.
Was almost No fuel getting to the carbs and i couldnt figure out why.
someone said to try that, I did and it kicked Right over!
I almost fell over laughing.
hope thats all it is! :thumb:
Will give that a try... thanks!
Griff
Quote from: Tombstones81 on July 14, 2012, 08:58:03 PM
Dont think I seen it said....
Try starting the bike with the fuel tanks cap Open.
The fuel tanks caps vent might be clogged.
this happened to me before too.
Was almost No fuel getting to the carbs and i couldnt figure out why.
someone said to try that, I did and it kicked Right over!
I almost fell over laughing.
hope thats all it is! :thumb:
This happened to me also... my bike kept dying and chugging just like yours. I had read about fuel starvation before, but I was baffled when there were still problems with it in Prime and checking over everything and finding nothing wrong. I finally looked at the gas cap and there was just enough crud in there to maybe be a problem, but it didn't seem like a lot of crud. So I cleaned it up thinking that couldn't the problem... but it was. I haven't had the fuel starvation issue since I cleaned the gas cap crud. Go figure! I sure was relieved, though.
Ok... Cleaned a VERY small amount of spooge from the cap vents... tightened all the carb boots etc, started the bike, warmed it up, did the "carb spray around the likely spots" thing... no vac leaks detected. Adjusted the idle, went for a ride - all seems ok, bit of a flat spot, and seemed not very eager going uphill, but that may be that I'm used to the FJR and pretty much ANYTHING seems like a laggard compared to that. Ran the bike for about 20 miles, highway and city, and then back to the barn.
I will still replace the stock petcock with a manual one (on order), but I think we can close this ticket... thanks to all for the suggestions and support :thumb:
Griff
UPDATE
Ran the bike for a bit, and the issues returned. I replaced the vac. petcock with a manual one - and now things are worse than ever. Pulled the carbs apart, soaked them, boiled them (twice), reassembled everything - still not running right. Doesn't have enough power to climb the slope of my driveway (which isn't very steep). Everything suggests a vacuum leak.
SO...
Checked everywhere for leaks. Replaced manifold rubbers and clamps. No leaks (that I can find). Pulled the carbs apart again, cleaned and checked - everything appears fine.
Checked the float heights per Kerry's directions - one is a bit higher that the other, but both are pretty close to the top of the bowl (one is a bit above the bowl line)
Checked the valve clearance and timing... all in spec
Checked for spark and compression - plenty of both
Put the vacuum petcock back in - no change.
My brain says it HAS to be a problem in fuel delivery, and everything points to the carbs, but for the life of me I can't think of anything else to do. This is really frustrating me...
Griff
Did you check the gas jet that is mounted inside the bottom of the float to feed the enrichment system? Also use some carb jet spray and guitar strings and verify that all your passages are completely clear. This includes carefully taking out and cleaning the emulsion tube. Unscrew the main jet and push it out from the bottom with a long screw with similar threads to the main jet.
If you are convinced clogged jets are not the issue, then it's probably inconsistent fuel flow the carb bowls. Get some new needle valve sets from an OEM source. Ronayers.com has them. They aren't cheap, but it's better than banging your head on a wall.
Quote from: bombsquad83 on September 17, 2012, 01:36:36 PM
Did you check the gas jet that is mounted inside the bottom of the float to feed the enrichment system? Also use some carb jet spray and guitar strings and verify that all your passages are completely clear. This includes carefully taking out and cleaning the emulsion tube. Unscrew the main jet and push it out from the bottom with a long screw with similar threads to the main jet.
If you are convinced clogged jets are not the issue, then it's probably inconsistent fuel flow the carb bowls. Get some new needle valve sets from an OEM source. Ronayers.com has them. They aren't cheap, but it's better than banging your head on a wall.
Jets are very clean... although I haven't poked wires through them. Had a look with a magnifying glass and a very strong light and insides of the pilot and main are clean. Pulled and cleaned the emulsion tubes as well.
Also shined a bright light through the port where the mixture screws live... can see the pinprick of light in the carb throat, so that seems ok too.
Should have mentioned that the mixtures are at 2 1/2 turns from a light seat.
When you say 'needle valve sets' I assume you mean the float needles? Or do you mean the needles jets that the slide rides on?
I wish there was a complete rebuild kit for these things available... all I can find are 'economy' kits with float bowl gaskets, float needle/seat and a few other small parts. Being in Canada, our parts sources seem limited, and the dealers sell every o-ring and spring individually. Would be cheaper to buy new carbs! :mad:
Just wondering what it could be if it ISN'T the carbs... and why the problem seems to come and go almost randomly.
Yes, I'm referring to the float needle and seat. They come as a set with the o-ring as well from Suzuki. Based on what you are saying about the cleanness of the passages, I'm willing to bet the gas level in the bowl is the issue, and you need to replace the float needle valve sets. Also make sure all o-rings are flexible and not rounded, and you are not missing the small oring under the diaphragm cover that seals off the sync port.
Had this issue once. Turned out to be the CDI Ignition box.
EVERYTHING and I mean everything said fuel starvation. Not sure if this is the case for you or not...I doubt it is since you have nice spark.
Quote from: jestercinti on September 18, 2012, 09:10:46 AM
Had this issue once. Turned out to be the CDI Ignition box.
EVERYTHING and I mean everything said fuel starvation. Not sure if this is the case for you or not...I doubt it is since you have nice spark.
I'm going back to square one and working my way systematically and methodically through everything again. Air...compression... fuel... spark. I've missed something, somewhere... and I'm sure I'm going to go "DOH!!!" when I find it.
These bikes aren't that complex...
Will post up as this saga continues...
Griff
Quote from: jestercinti on September 18, 2012, 09:10:46 AM
Had this issue once. Turned out to be the CDI Ignition box.
EVERYTHING and I mean everything said fuel starvation. Not sure if this is the case for you or not...I doubt it is since you have nice spark.
I've seen this too, even having a good spark (tested with plugs grounded outside the engine), but after running on the street for an hour or more, or 5 minutes with another ignition box, symptoms of 'fuel starvation' appeared.
Quote from: bigfatcat on September 20, 2012, 04:25:29 AM
Quote from: jestercinti on September 18, 2012, 09:10:46 AM
Had this issue once. Turned out to be the CDI Ignition box.
EVERYTHING and I mean everything said fuel starvation. Not sure if this is the case for you or not...I doubt it is since you have nice spark.
I've seen this too, even having a good spark (tested with plugs grounded outside the engine), but after running on the street for an hour or more, or 5 minutes with another ignition box, symptoms of 'fuel starvation' appeared.
I'll have a look there also. Haven't looked, but assume the Haynes/Clymer manual has a test procedure for the CDI box?
In too deep to quit now! ;)
Griff
Ok... time for an update.
I had a look at the CDI box, good spark, so that seems to be eliminated. Put new plugs in anyway, since I had them on hand.
Tore the carbs apart, cleaned them again, this time with an ultrasonic cleaner. Some spooge came out, but not really very much.
New gaskets and o-rings, new float needle and seat. Adjusted idle mixture to 2 turns to start. Bench-sync'd.
Put everything back together, fired up and seems to run... still not very smooth. Rode around the block, seems much better than it was. Shut down, let it cool, and fired it up again. No choke, started easily but revs climbed up to about 4000. Settled down to about 1200 (per the tach).
Seems to be getting closer to being solved. Going to check the carb linkage to see if something is hanging up and causing the revs to be high. Will also check for vac leaks.
At least it's running again :)
Griff
Is you carb vent tube clear, no kinks, and out of the wind? Search for crosswind engine stumble.
Kinked and it mimics plugged gas cap. Directly in wind mimics fuel starvation at high speed.
Sent from my iPhone using Tapatalk
Quote from: jestercinti on October 15, 2012, 08:07:39 PM
Is you carb vent tube clear, no kinks, and out of the wind? Search for crosswind engine stumble.
Kinked and it mimics plugged gas cap. Directly in wind mimics fuel starvation at high speed.
Sent from my iPhone using Tapatalk
Ahhh carb vent in wind sounds like my issue, still replacing tank and cleaning carbs though