80 gsx750e dies in 5th gear

[Jackyl]

Ok, I thought it was an electrical problem, at road speed the bike would die out, like it wasnt getting fuel, I live in Wyoming at 7000' asl, so, I had it re-jetted, new air filters (K&N), it still happened, so, its electrical, bad stator & regulator, so I replaced them, now its charging just fine, and cr*p, it still happens, so now Im thinking maybe it needs new coils, perhaps the coils are over-heating, the tricky part is, in 5th gear this will happen every 1.5 miles or so, and if I let it drift down and down shift, about 30mph it will kick back in and run. in 4th gear at the same rpm's, same distances, it doesnt happen, so I am stumped. only in 5th gear at road speed does it seem to happen. Anyone have any ideas ?

I have checked this out further, at 5k rpm in 4th gear, 55mph, I can go all day long, no problems, in 5th gear, at 5k rpm, it dies. at 55mph in 5th gear, it dies. Please someone tell me Im not the only one to have this problem.

Yet more news, sorry, this is becoming a process, it finaly died on me in 3rd gear, I had only gone maybe a mile when it died and the only way to get it running again was to use the choke. I had riden it only about 2hrs before this, so it wasnt fully cold yet, and I did have to choke it to start it, but warmed and running it went about a mile, after choking it started again I had to push the choke all the way in to get it to idle, and it ran fine for about 10 miles until I was home. this is getting more perplexing as I go, but I am having to believe its a fuel problem now. it also now is seeming under powered quite badly. thanks for any help anyone can give me.

 

[arveejay]

Sounds like it's running out of fuel. If it were me I would carry a 10mm wrench with me and when it died I would pull the clutch lever in, shut off the key, come to a stop and take the carb bowl drains loose and see how much fuel if any is in them. Could be blocked petcock, kinked fuel hose, plugged fuel filter, defective fuel petcock, non venting fuel cap, just some things to check.

 

[focus frenzy]

Sounds like it's running out of fuel. If it were me I would carry a 10mm wrench with me and when it died I would pull the clutch lever in, shut off the key, come to a stop and take the carb bowl drains loose and see how much fuel if any is in them. Could be blocked petcock, kinked fuel hose, plugged fuel filter, defective fuel petcock, non venting fuel cap, just some things to check.

yep, starving for fuel.

don't forget the itty bitty fuel filter /screens on the float seats.

 

[arveejay]

Yes, I forgot these on my list, but very good chance of them being plugged also.

yep, starving for fuel.

don't forget the itty bitty fuel filter /screens on the float seats.

 

[Jackyl]

New info

New info

Heres the latest, it is definatly a fuel problem, I found I have a dead #1 cylinder as well, I did a spark test, the coils and plugs and leads are all good, the plug comes out dry after riding, I changed all the plugs as well, so I know that the #1 carb is not getting fuel, as for the other 3 dying out, I keep thinking the bulk of the problem has to be in the petcock, ok, if the float screens are bad, then one cylinder at a time should die away, that isnt whats happening, so it has to be before the carbs on 3 of them and in the carb on the fourth, so, what to do.

I will pull the carbs, the float screens are coming out, its been re-jetted and synced, so Im ok with the jets that are in there (as far as I know right now anyway), Im going to disassemble the carbs (all 4 of them) and clean them extremely well, set the floats about 2mm higher than they are (only because Im not positive this was done when it was re-jetted and the stock air-box was done away with). I put a filter on the hose that comes from the top of the cams (this originaly went in to the stock air-box) and Im going to pull the petcock, clean it extremely well and use an inline filter instead of the filter on the petcock now.

This is where Im not positive about what Im doing, I have to keep the diaphram in the petcock intact, I know that (could that be the problem?) so that fuel will not run constantly down through the bowls and flood them out or cause puddles of fuel under the bike when not running. Im going to use an in-line filter so the one on the petcock is also comming out.

Im not sure yet about the filter on the gas-cap itself, any ideas how to check that?

So all this should free up the fuel flow as much as I can make it and still ensure good clean fuel to the carbs and solve the dying out problem (I hope).

Thanks to all the folks here at GS Resources for letting me ramble and basicaly think outloud, and thanks for all the input both in this thread and all the others here I have learned tons from. You folks are the best.

 

[kalessin]

I would drain the tank, remove the petcock, and disassemble it. If you want, do some preventative maintenance and buy a rebuild kit. Take notes on which parts go in which orientation.

http://www.crc2onlinecatalog.com/petcock_rebuild.htm
http://www.crc2onlinecatalog.com/Index_Main_Frame.htm

You should be able to clean its filter. People have had lots of trouble with inline filters because they tend almost universally to be made for fuel-pump-feed rather than gravity-feed.

 

[Jackyl]

ok, more on the progress

ok, more on the progress

First, I did a compression test, #1 was 125, #2 was 100, #3 was 80, #4 was 120, I still have a dead cylinder on #1, as I got ready to pull the carbs, I found the K&N filter was soaked and dripping with gas, I had just ridden it and I wanted to pull the drain on the #1 bowl and see if it was dry, it wasnt, not by a long way, but no fuel is going in to the cylinder at all. when it was rejetted and switched to the pods, it took a lot of hit & miss getting the jets right, and finaly I thought it was worked out, but it still died at high speeds and under a load, it did this when I bought it, and I remember the reason we switched to the pods was that the stock air-box wouldnt seal on the back of the carbs, so I guess its doing what it has always done, I thought this was due to a bad charging system not powering the coils correctly under a load, it was bad and the stator & regulator have been replaced.

The biggest concern I have is the pod air filter is soaked with fuel, but none is going in to the cylinder, ok, Im getting pretty frustrated here and about ready to hit e-bay and find another bike I dump money in to (lol). The problem is, I like this bike, and I am finding myself more and more determined to get it running right just because I cant. anyway, if anyone has an idea, I'll be waiting to do much of anything until I have a better idea what to do, I am going to clean the petcock, and pull the carbs and check the floats and needle jets, to make sure they are closing, but even if it is flooding the #1 carb, why is no fuel at all getting to the cylinder?

Ok, Im starting to repeat myself even more than normal, thanks for all the help. any ideas would be greatly appreciated, thanks.

 

[arveejay]

If filters are wet theres a good chance the float valves are not stopping fuel flow. If bowl has gas but not getting to cylinder jets are probably plugged. Don't get discouraged and give up as long as someone is trying to help. Have you seperated the carbs and attempted cleaned everything? Sounds like low rpm system is blocked.

 

[Jackyl]

Im pulling the carbs today in fact and cleaning them. It just is so baffling that there can be so much fuel that I have to wring out an air filter and not one drop of it is even accidentaly drifting in to that cylinder. Im going to also check the boots very carefuly while the carbs are off. I have learned so much from this site, I have been reading hour after hour of threads that are pretty similar to my problem, though I havent seen one yet where the bike starves out at high speed to the degree mine does.

Im trying not to get discouraged, this has been a 2 year process and I thought I was finaly ready to ride

 

[Jackyl]

Used bike for sale ? LOL

Used bike for sale ? LOL

Ok, I got the carbs cleaned, the slide in #1 was stuck, got it freed up, cleaned everything, HOOORAYY ! ! ! ! all 4 cylinders are firing and it is running GREAT ! ! ! ! right up to the point it runs out of fuel ](*,) . now it runs good, but instead of just high speeds (60mph/100kmh or higher) it loses power anytime its under a load, going up a hill, accelerating, whenever, whatever speed, it chugs, hesitates, sputter, sputter, and then I have to decellerate and shift down and ??(wait for the bowls to re-fill)??.

after all I have done to this bike in the last 2 years, I feel Im so close to having it now, there has to be something I have overlooked in this process.

After reading a few other threads, I cleaned the petcock, but didnt use the in-line filter, I made sure there were no leaks around the induction tubes (between the carbs and the manifold if I understand what is meant by induction tube). ANyway, Im stumped, its almost to the point Im just gonna shave off all the hair so I cant pull it out anymore . Thanks for all the help, any ideas would be awsome and Im going to keep trying to find threads from others with similar problems.

 

[arveejay]

Stumbling under power is usually an air leak somewhere. The diaphrams are lifted up by vacuum generated in the cylinder, if there is a leak in the intake it won't lift the diaphrams properly. A wrong spring on top of diaphram will cause this, were they replaced. Did you check diaphrams for cracks. Did you take the fuel cap apart? if it is plugged it won't siphon gas to carbs. Is vac hose from carb # 2 cracked, collapsed or kinked from heat? Is there at least half a tank of fuel in it(not by the gauge,) look and see, Try running it with petcock set to reserve.

 

[Jackyl]

I feel like such an idiot

I feel like such an idiot

Ok, after 2 yrs and a new charging system, re-jet, pods, a year w/o riding, 3 times in the shop, kicking, screaming, cussing, and hair-pulling, I checked and cleaned everything, twice ! ! So there I am trying the last couple things suggested, I have the fuel cap off, still does it, vent lines off, still does it, turn the petcock to pri.

fixed.


If you see me out riding, please be so kind as to not point when you giggle, snicker or laugh. Thanks.

thanks Bob, I really couldnt have fixed it without your help, sometimes I guess I just dont see the chain because of the links

 

[arveejay]

Excellent, it lives, feels great doesn't it. You're very welcome. But, there's always a but. If there is any seapage in or around the float valves it will over flow into you're oil. If you have the vacuum hose from front of carb 2 and it's attached to the smaller nipple on the petcock and it won't work on run or reserve the petcock needs replaced. It's pretty much standard procedure to replace the petcock. It has dried out and will cause problems jut like the brittle orings in the carbs. If you want the factory Suzuki Petcock it can be found at www.bikebandit.com . Others have used other distributors. I always buy the OEM Suzuki petcocks from Bandit, 50-60 bucks, but others like the Pingel brand of which I have no experience. Either way, you should never run it on prime. In the tips area there is a How to Test a vacuum operated petcock thread. Read that and if it fails, replace it.

 

[Jackyl]

pingel vs. OEM

pingel vs. OEM

I looked at the pingel valve, and I do like it, its $90, but I ordered a rebuild kit from oldbikebarn.com ($45 for a diaphram and a cpl o-rings lol). I am planning to repaint the bike this fall and may switch to the pingel valve then, after reading the info from pingel, something they said made a lot of sense to me, since I switched to pods and much larger jets (90 to 110 miles on a tank now in town) making sure it has enough fuel flowing through the valve is important, that has, after all, been my whole problem all along (aside from some electrical/charging issues). Kieth says he turns his on/off every ride, Im doing that until I can rebuild the petcock anyway (in fact I only switch to 'pri' when I hit the highway or long high-speed backroads and then back to 'on' for riding in town on city streets). I have a feeling Im going to end up something close to educated at least on this whole petcock issue as far as the '80 GSX750E's go anyway. I can only hope the learning curve doesnt out range the power-curve. lol

 

[arveejay]

I looked at the pingel valve, and I do like it, its $90, but I ordered a rebuild kit from oldbikebarn.com ($45 for a diaphram and a cpl o-rings lol). I am planning to repaint the bike this fall and may switch to the pingel valve then, after reading the info from pingel, something they said made a lot of sense to me, since I switched to pods and much larger jets (90 to 110 miles on a tank now in town) making sure it has enough fuel flowing through the valve is important, that has, after all, been my whole problem all along (aside from some electrical/charging issues). Kieth says he turns his on/off every ride, Im doing that until I can rebuild the petcock anyway (in fact I only switch to 'pri' when I hit the highway or long high-speed backroads and then back to 'on' for riding in town on city streets). I have a feeling Im going to end up something close to educated at least on this whole petcock issue as far as the '80 GSX750E's go anyway. I can only hope the learning curve doesnt out range the power-curve. lol

I hate to keep harping but if you're assuming that by turning the petcock to run that it's turning the fuel flow off lets go back to what you said earlier. You said that if you sat after it died that it would eventually fill the bowls and start and run again. If it did this when the lever was in the run or reserve position and the bike was not running then gas is getting by the valve and could still cause you problems. Make sure your float valves shut off the flow when bowls are full.

 

[Jackyl]

You said that if you sat after it died that it would eventually fill the bowls and start and run again. If it did this when the lever was in the run or reserve position and the bike was not running

Sorry for the confusion on this point, the bike always stays running, if I were to pull in the clutch and hold it in it may have died completely, but I never did, I decellerate and downshift down to about 30mph and that gives it enough time to refill the bowls and then runs properly again.

The only time this happened and I wasnt going fast enough to keep it running I had to use the choke to restart it, and it took a fair amount of cranking to refill the bowls.

 

[arveejay]

OK, ride safe, lottsa fools out there.