Adjusted Valves, rebuilt Carbs and the bike wont stay on, what's going on here??

[Quade614]

YO! So heres the deal-About a month ago I had the valves adjusted and main valve cover gasket replaced. This got the bike running-sorta. So I decided to take off the carbs clean them out and rebuilt them. Got it all back together and finally got it started but sometimes it will start and sometimes it won't. Once it starts and is running it sounds decent and will idle for a bit but eventually just dies and won't restart. I had to adjust the idle a few times and finally got it to stay at a decent idle for a bit. Before this it would die if I tried giving it gas. Last night I had it running and was able to drive it up and back on the driveway a few feet but eventually it died again and wouldn't start. I have no idea what might be causing this. The only solution I could think of was to stick a rag in the gas tank and light it.......(not really but I was getting frustrated). Any Ideas or suggestions guys? I've had some good help on here before and really appreciate any advice or ideas you've got!

Thanks
-Quade

[WillyD]

How much carb experience do you have? When you say rebuilt them, what exactly did you do? Did you pull pilots out and check/clean them? Idle mixture screws out (needle, spring, o ring, tiny washer)...Did you set them properly? Are you sure you got all the ports and passages clean? flushed and back flushed with carb clean? Are the carbs stock? Needles have shims? Did you set the float heights at the correct setting? Is your tank vent system working? How did the valve adj get done? What clearances?

Is your tank clean? Is your petcock stock? Is it in good shape? You can flawlessly clean and set carbs and turn on the gas and get crap right back in them?

There are lots of reasons that could be...Can you give us a little more info? I am not trying to say anything was done incorrectly but all this stuff has to be right or it will not run right...It can be simple...

Willy

[rs2000]

try putting the petcock on prime = free flow , to rule out the vacuum part of the petcock, if that doesnt work then it sounds like you have a problem with either gas flow, or dirt in the carbs :-(

[WillyD]

Some things I forgot to ask...

Prior to the valve adj and carb rebuild, was the bike running? Is this a bike you have had and ridden in the past? What lead to the valve adj and carb work?

[Quade614]

How much carb experience do you have? When you say rebuilt them, what exactly did you do? Did you pull pilots out and check/clean them? Idle mixture screws out (needle, spring, o ring, tiny washer)...Did you set them properly? Are you sure you got all the ports and passages clean? flushed and back flushed with carb clean? Are the carbs stock? Needles have shims? Did you set the float heights at the correct setting? Is your tank vent system working? How did the valve adj get done? What clearances?

Is your tank clean? Is your petcock stock? Is it in good shape? You can flawlessly clean and set carbs and turn on the gas and get crap right back in them?

There are lots of reasons that could be...Can you give us a little more info? I am not trying to say anything was done incorrectly but all this stuff has to be right or it will not run right...It can be simple...

Willy
OK heres a bit more info to help out. To start everything is stock on the carbs and airbox. As far as taking it apart I took the carbs off, took the float bowl cover off them and took the pilots and everything out of there that I could. I put the carbs and pieces through an Ultrasonic cleaner at work twice. Flushed out with air and cleaner and put everything back together. The rebuild kit came with a new float bowl gasket and the air mixture screws and parts that have the little plug over them(which had to be removed). I've worked on carburetors on ATV's before and Took this bike apart once before and cleaned everything out and it worked after I did that. I turned the air mix needles out 2 1/4 turn as suggested.
However-the floats I didn't think to reset to a certain height-Not sure how thats done actually. Everything went back in as it came out. No shims either.

Valve adjustment was done at a local shop-thats all the info on those.

As far as the tank and petcock-Stock. I guess I could try cleaning it out and taking the petcock apart to check. I did put it on prime and can see gas flowing through though.

Vent system working-How do I check that.

I hope this helps and clears it up a bit- any more questions ask away and I'll try to get as specific as possible.

[Quade614]

Some things I forgot to ask...

Prior to the valve adj and carb rebuild, was the bike running? Is this a bike you have had and ridden in the past? What lead to the valve adj and carb work?
I've had this bike for 5 years now- It used to run when I first got it, then sat for a bit-but would run untill last year or so. I had it running last summer but it sounded like one of the cylinders was sticking and eventually just wouldnt start. After sitting through the winter I tried starting it and never got it going- Took it in and had the shop do a look over and thats when they said the problem was most likely the valves-Plus the bad valve cover gasket. Once they finished and I got the bike back it ran but didn't Idle well and sounded like there were carb issues- and they had never been rebuilt so I figured it would be a good Idea.

[WillyD]

Here is what I would do....

On your carbs where the vacuum lines connect (this will be small ports on the top on the front side of the carb) I would disconnect the line(s) there. Should be one going to the petcock and one going to the air suction valve (that one might be a "T") and plug them with vacuum caps....Then put your petcock on "prime"....Open the fuel cap....

Try to start the bike...Will it start? Will it idle? if it starts and idles I would let it run and warm up good...Then close the fuel cap but don't push it down and latch it closed...Then see if it will run enough to drive it...

Tell us what happens...

If the bike still won't start or idle too long, do this...

Put your petcock on "on" and disconnect the gas line at the petcock and put a piece of 5/16" fuel line on it long enough to run into a gas can...Turn your petcock to "prime" and see if you get fuel flow out of it..It should flow steady and pretty fast...if not, you need to pull the tank and pull the petcock out and check it...

What you are doing by doing all of this is making sure your gas flow is good out of the tank to the carbs and eliminating vacuum leaks that could be causing a problem...

[Quade614]

I'll try the vacuum line idea once I get a chance later this evening and let you know the results.
I do know that the fuel will flow out of the petcock on prime pretty fast. I drained the tank this way the first time but pulling it off the bike completely and setting it over an empty can on prime in order to drain it.

[golddrakul]

If gas is flowing, would be worth checking Igniter, they can go bad and you can end up only running on two cylinders. Had this happen on a 900 last weekend; was running, got hot while adjusting carbs, puked anti-freeze out of bottle [conveniently located by Igniter]. Let bike cool until next day; wouldn't restart. Went through all the above, including tearing carbs apart again, before it dawned on me what was going on. Best part was that the "dead" cylinders [in my case, 1 & 4] still had a weak spark. Swapped Igniter and fired right up.

Not saying this is your issue, just posting it for what it's worth. Sometimes someone else's problems apply to yours. :)

[WillyD]

If you drained the tank through the petcock on prime and had the fuel lid latched down tight then that should indicate that your tank venting is ok.

It is possible that the vacuum control on the petcock is bad and the diaphram could be ripped...that could give you two problems..1. vacuum leak and 2. you could be sucking gas right into the carb vacuum port..

are you running an in line filter?

[WillyD]

Good point golddrakul....

[ZLrider]

i'm no mechanic, but know you have to set the floats when working on carbs. on my kz the **** thing could not be dialed in until i finally got the floats right. it took me several tries using both the dry and wet method. when both tested correctly the bike ran much better for it. i had to fab up a stand and also made some tools to be able to do this. dunno about anybody else, but i found this a bit challenging.

[WillyD]

The ZL floats are not hard to set the height...and you don't need to put them on a stand...the hardest thing is to feel when the tension is sitting on the tab or being push a little past...

[ZLrider]

The ZL floats are not hard to set the height...and you don't need to put them on a stand...the hardest thing is to feel when the tension is sitting on the tab or being push a little past...

do you like to set them wet or dry? i built a device out of tubing and glass then graduated it. stand is necc to hold the rack fast while seeking fuel level. i only did this to confirm the dry settings (measurements) were correct. this pertains to a KZ btw, but would think ZLs are similar. took me several tries and spent more than a little time on it.

[kawboy]

i built a device out of tubing and glass . . .

Yeah so did I . . . back in the '80's . . . I think . . . memory's a little fuzzy :hippy2::detective::occasion16:

[Quade614]

I do have an in line filter on the bike. I can take the petcock and check it- what would I be checking on it though?

[Quade614]

UPDATE:
Took a few days off from working on the bike, went out last night and hooked up a jumper to the battery to start it. The bike started right up and stayed on for a while. I switched between prime and on and there didn't seem to be much difference in either although at times it seemed as if it were going to stop running on "on". The bike drove up and down the drive a bit but i noticed what sounded like kickback in one side of the carbs. It would idle then a "popping" like sound would happen. I took the spark plug cap off of the # 4 plug and the bike died immediately-Same thing happened with #1.

Other than my battery being useless I'm still unsure as to the problem.-Thats the latest. Unless getting a new battery would help- Ill just have to try it and see.

[zlMark]

When they backfire(spit) back into the carb it's from a lean condition like an air leak.

[furchin]

[quote=Quade614;109391]UPDATE:
Took a few days off from working on the bike, went out last night and hooked up a jumper to the battery to start it.

Word of caution, do not ever put more than 10 amps of charge into your system for jump starting. You will fry your cdi. costly mistake for a quick start. Not saying you did this but beware.