can some kind person explain to me relationships

[hillsy]

Don't ride with the tank open. You want to bring the problem on, THEN open the tank and see if it goes away.

Plus you don't want to die in a fire - guaranteed fuel will slosh out of your tank while you are riding.

Also there is very little vacuum coming from the manifolds to open the tap - your hose will not collapse.

 

[Boriqua]

Plus you don't want to die in a fire - guaranteed fuel will slosh out of your tank while you are riding.

Yea .. when your young going out in a blaze of glory its kinda crazy James Dean Cool. " Oh man did you hear .. Alex just blew up .. yup one minute there and next poof"

when Your old .. like I am ..and you set yourself ablaze ... you just look pathetically stupid like you had an AARP moment! " Guess he forgot about the whole gas combusting thing .. good thing he had life insurance."

 

[Boriqua]

Well I didnt get it to run right but I am encouraged because I was able to eliminate alot. I pulled the airbox and re attached everything and checked and double checked my boots. I must admit I was a bit more thorough. I installed new plugs and a new air filter. I had turned the mixture screws down half a turn to Richen but it didnt seem to like that. It wouldnt hold idle at all. I tried to run the bike with the gas cap on or off and to no effect so it isnt a vent issue. Came back and took off the tank again and turned the mixture screws up one half turn and I plugged the vacuum line and put the petcock on prime. Started right up and held idle at 1500 beautifully. I may have a petcock issue even though I just installed a new one but I will need to do more testing. Had it idling with a fan on it for about 5 minutes and during that time did the leak test with starter fluid and no air leaks. Idle speed didnt change.

I checked the plugs I pulled out which looked fairly new so I wasted 15 bucks on new plugs and they were all Tan and dry with no damage.

Figured lets try a ride and as I was backing it out of the driveway the minute it hit about 208 on the dash gauge .. Stall! *&$^#%%$@

Now I have had a couple of air cooled bikes over the years and I know 208 isnt nearly overheat temp so I am pretty sure I am not overheating .. But .. I am pretty sure I have eliminated everything from gastank through combustion. The carbs are good, mixture and adjustment while not perfect is pretty good and when the bike makes spark it runs well. So .. at least I can stop sweating the delivery system. Now ...??

Coils? I just don't see the connection though between being able to run it home with a partially open choke and the coils?

 

[chuck hahn]

The vacuum comes off carb 2 and goes to the small nipple on the petcock If thats not hooked to the petcock the petcock will not function right. Secondly if the vacuum from carb 2 isnt capped in such cases as the petcock is a manual operated one .....such as a Pingle... then youve got a massive vacuum leak and the bike wont run right either..follow me???

 

[tom203]

Let's rule out the new petcock as a problem.....
There have been reports of new petcocks not functioning right, so test yours. Get some vinyl tubing to fit on petcock's vacuum fitting (the little guy). With petcock in "on" position, disconnect fuel line and using jar underneath outlet, suck on the vinyl tubing, fuel should flow. Stop sucking, fuel should stop flowing. Now move petcock to "pr" spot, fuel should flow without sucking.
I'm confused about where you left your mixture screws ... Two turns out from gentle bottoming would be my minimum to start.

 

[Steve]

I had turned the mixture screws down half a turn to Richen but it didnt seem to like that. It wouldnt hold idle at all.

If you turned the mixture screws IN, you did not richen the mixture, you LEANED it out. This was explained in post #12.

Also mentioned in that post: the bike will run much easier on a rich mixture than it will on a lean mixture. Set the screws a bit rich just to make sure that a lean running condition is not your problem, then diagnose from there. Three full turns out. That is three full 360-degree turns. I have to say that because I was trying to help a member several years ago who insisted that he was doing "three turns out", but his running symptoms still sounded lean. I hopped on my bike and rode about 2 1/2 hours to his place to see what was going on. Started turning the screws in, counting as I went. Got to 1 1/2 turns in, they bottomed out. He was thinking that a "turn" was one "flip" of the screwdriver without changing your grip. Turned the screws out three full turns, it purred like it was supposed to.

.

 

[Boriqua]

Ugh .. I know it was laid out but I obviously still didn't get it. But ... I spent about 20 years designing and building things and have created hundreds of cad drawings for others to build from and know the difference between 180 and 360 degrees so they are at a true 2.5 turns out. Not trying to sound smug because I would rather say I figured it out and all is well but just want to eliminate that as a possible trouble spot.

Right now they are at 2.5 turns and it starts and runs beautifully ... right up until it gets to 208 degrees temp as measured by the gauge. I dont know that making the mixture more rich will help that but I will try it in the AM.

I have eliminated the petcock and for the most part the carbs as an issue since it starts and idles well .. right up until it gets warm/hot

My wondering now is tight valves or coils... but I will admit I dont have a damn clue so thank you to everyone for your input. That epiphany is going to come from someones post and I am thankful for the comments.

 

[JJ]

I have eliminated the petcock and for the most part the carbs as an issue since it starts and idles well .. right up until it gets warm/hot

My wondering now is tight valves or coils... but I will admit I dont have a damn clue so thank you to everyone for your input. That epiphany is going to come from someones post and I am thankful for the comments.

I don't think the valves will cause the problems you described, but if you haven't adjusted them, you should. Actually, that should be the first maintenance item you do on these old bikes.

I'm thinking either the coils or igniter box failing when they get warm, but I'm surely no expert on them.

 

[Steve]

I will agree on the valves not being likely suspects. The valves almost always tighten up on these bikes. The 16-valve bikes like yours are the occasional exception. Once in a while, a locknut will come loose and who knows which way the valve will adjust itself then. Anyway, tight valves make the bike hard to start when cold, then easier when warm. That is not your reported problem, so I do not suspect valves, at least not tight valves.

If your bike is running well with the mixture screws out at 2.5 turns, then 3 turns won't help much. You can test the mixture when the bike is warm by blipping the throttle and observing the response. If it revs quickly and cleanly, then returns to idle, that's great. If lags a bit on the way up then hangs there, not wanting to come back down, it's running lean, turn the screws out about 1/4 turn and test again. If it revs rather readily, but drops below the set idle speed and comes back up to it, it's running a bit rich, turn the screws in about 1/4 turn and try again.

.

 

[hillsy]

Sounds like it might be coils breaking down as they get hot, but I'm not sure you've totally ruled out the fuel delivery issues.

Take off the tank and sit it up on a bench. Get a length of fuel line and attach to the tap, then route this into a bucket or fuel can. With the tank full (or close to), turn the fuel tap to prime and let it drain out with the cap sealed. If there is a venting problem the fuel flow will stop after a few minutes. If it doesn't, and the flow is fine then move on to checking the coils / igniter.

 

[chuck hahn]

If it deosnt stop flowing fully at least monitor it for any noticable slowing of fuel flow.

 

[Gorminrider]

Have to ask but Hopefully your oil supply is ok! Does the red light come on when key on and then go off when bike runs? That's pretty basic but your symptoms make that important.

If a single coil is dropping out at 200+ degrees, the engine would sound a lot different, running on just two cylinders per dead coil or three cylinders per bad lead and plug (check the plugs was mentioned maybe clean up the internal suppressors in the cap too)

Having to use the choke/enricher to limp home suggests mixture is too lean without it, but dumping more gas into a partially running engine also gives a little more power because the engine is "lugging" ....you might want to check the timing too. These have mechanical advance?


Troubleshoot this when it's running bad - when it's hot. Take your tank off and run it from an auxiliary tank so you can get at stuff better..coils, carbs wiring. be sure to plug the petcock vacuum tube if using an auxiliary tank OR use the bike's tank with longer fuel lines and petcock vacuum hose...Either way, keep these tanks about the same height as it is on the bike .

valves set really too tight aren't going to close! a bit of tappet noise ensures that they will. A compression check will show if this is the case and other stuff too.

 

[Boriqua]

Alright .. I did the test where I filled the tank with about 4.5 gallons and secured the new cap and then turned the petcock to pri and it drained the entire thing in little under 8 minutes with no interruption of flow as far as I could tell. I bought clear hose for the test so I could see if I started to see air bubbles like it was choking off but it was smooth and steady.

The oil light goes off the second I start the bike and before I started it for the first time I did an oil and filter change so I dont think its oil pressure or temp.

The coils look beat to hell and the spot where the wire actually goes into the coils looks like it was secure with a glue gun. The spark plug caps and wires look new though. So ... if my research was right .. and it has been spotty .. Dynatek 3 ohm coils?

Kind of exciting in that I think I have eliminated gas delivery or oil delivery so all that can be left .. I think .. is electric. Down side is .. the electric looks like a mess with wires going everywhere and many just cut with no explanation. There are also some 5 wires attached directly to the battery and I know that aint right!

 

[Gorminrider]

look new though

I've got a ton of new looking stuff that doesn't work.

spark plug caps

these actually come apart on stock ones. A small slot-head screw driver undoes the brass plug-tip connector. Behind it, there's a suppressor-resistor, tiny springs, tiny contact discs, so do it over a white cloth if you are interested. The idea of this contraption is to allow 5k ohms along the lead while using straight wire in the plug leads.

and the spot where the wire actually goes into the coils looks like it was secure with a glue gun

oh oh..These were originally made "factory permanent" with very strong glue. If so, ( if somebody's been at 'em) that's a thing to look at with jaundiced eye. Plus I'd put new or decent-used coils on your list. HOWEVER it's unlikely to be the problem specific to a warmed up bike except for the harm it may have done to the coil. any unconnection there will be a spark and fail entirely pretty quick IMO

I would have said to you or the Previous Owner- Do NOT futz with the connection between coil and the lead unless you are an aspiring surgeon with a nice dremel kit and some spare coils to use if you wreck it. Not impossible to repair if you must get back from Mars but time for replacement.

 

[Boriqua]

I ordered new coils with wires and caps and will report back. If I have one coil dropping out when it gets hot then that can certainly be what is going on. The outside of them is blistered as if from the heat. Looks like lizard hide. I got the bike for $1300 and have put in time but in actual funds I have only added maybe another $300 with much of that being consumable like the bucket o carb cleaner and the tow home from the seller. The coil set up is another $130.00. If I can get a fun, mostly reliable standard style motorcycle that I loved in my youth for around 2 grand done .. I will be more than satisfied. When we set about getting an older bike we set an imaginary figure of 2500.00. In about 3 weeks it will be five million degrees here and not fun to ride unless its 5 am so I have plenty of time to get her going.

When it runs it is still everything I loved about motorcycling. It has the same uprightish position of my Triumph but is far smoother at speed.

 

[Gorminrider]

yes, if someone was futzing with them,(or the bits in the cap even) perhaps they caused a burnout.
...I usually hope to limit $ input to a third of original price but expect it to be half, and even if the "Truth-I-Can't-Handle" works out to be 100%, it's still a deal.

 

[Boriqua]

This has been an invaluable thread. Thank you all!
Unfortunately I have developed new symptoms/clues. I ordered and received new coils. I then got the nastiest flu and was on my back for some 6 days and hadnt touched the bike in about 10-14 days when you add waiting for the parts and such. All that time I was concerned about new varnish in the carbs since I had removed the tank and I think had run the float bowls dry and it has already broken 100 degrees here.

So before I got sick the bike ran and idled fine and when I blipped the throttle it would jump and immediately return to idle until it hit about 208 on the temp gauge and then it would stall and be done. I was able to limp it home on enricher/choke. I assumed I was losing one of the coils and by enriching it I was limping home on 2 cylinders. I have no proof of this just speculation. I just replaced 2 ignition coils in my cars with the same symptoms and it was the fix.

Also before the coils change when I started on choke it would run up to 5000 rpm immediately and decrease as I released.

Today I finished the install of the coils. Dynatek 3ohm. New wires, new caps and new plugs.

Started on Enricher/choke and it only jumped up to 2500 rpm. When I blipped the throttle it jumped up to 5000. Took off with the choke partly engaged and went about 1/2 mile and pulled the clutch in and dead. I can start it on choke but it wont idle more than a few seconds before it stalls. but now .. when I blip the throttle it hangs. It wasnt hanging 2 weeks ago. I give it a little twist and it shoots to 3000rpm and stays there a bit and then slowly decelerates.
I have gone through a bottle of starter fluid looking and listening for leaks.
Its seems the more I fix the bike the worse it gets!!

Here is where I am
New oiled air filter
New coils, plugs (gaped.025) and caps
Cleaned rebuilt carbs
cleaned and lined tank
new fuel line and vacuum line
new petcock
new gas cap
oil and filter new

Am I destined to spend this weekend pulling out the carbs and recleaning or is there anything else left to look at?

 

[hacri]

My 83 gsx750es startes fine (a little rough) would run fine, after a few minutes it was starting to drop cylinders.
I had to change the ignition box (ignitor). If you have a service manual there will bee ? check procediere. This is how
I found out on my bike.