Basic ignition troubleshooting

Wouldn't start in the fall just before I put it to bed, and will not start now. Engine turns over but doesn't fire. I'm reading and wanting to try what the forum searches are suggesting, but what's basic to others is not so basic to me.

1) It's been sitting all winter so I figure I'll have to put the petcock into the PRI position to fill the carb bowls (is this correct?). How long do I need to leave it on PRI before trying to start it?

2) I have some carb cleaner that I picked up (don't remember why... it probably was because everyone on these forums are obsessed with carbs). I've also read of people using this as some sort of starting fluid to help see if they can get it to start at all. Where would I spray this stuff in, and what would the fact that it runs or doesn't run with carb cleaner show me?

 

You can leave the tap on PRI indefinately, if the floats are shuuting down properly, but if the fuel is flowing ok 2 mins will be fine.
There is a snorkel that goes down into the airbox, shoot it in there.
If it fires with help, like that, your issue is fuel not spark..........

 

Thanks.

The floats" are another thing every talks about. Is there a way to check them without taking the carb assembly off the frame? I'm looking at a parts diagram now. Are "the floats" the float needle valve, float assembly, float pivot, float bowl, or something else?

 

It's the float assembly.
Test by putting a short piece of clear tube on the drain, hold it upwards & loosen the drain screw, the fuel will climb the pipe & stop at the level inside the bowl.

 

I've actually got the bike running. Yay.

I'm still trying to figure out the "starter fluid" tactic, though. If I shoot the starter fluid through the "snorkel" leading to my air intake wont it muck up my air filter?

(edit) also, is carb cleaner ok to use in the place of starter fluid?

 

I would use starter fluid (it's made for the job) & no it won't screw your filter.

 

Thanks! =)

 

So it started a couple days ago just fine after I put the new plugs and battery in, but this morning it refuses to start. It was never on for more than a few minutes when it started before. What could have happened with it sitting in the shed for a few days that would be preventing it from starting now?

 

Could be any of the following
1. Not enough power from the battery
2. Not enough fuel
3. Too much fuel/Flooded
4. Side stand switch ingaged/stuck on.

 

I left it out in the sun and topped up the battery and it started up. It was warming up quite a bit and probably went from 5 to 10 degrees outside.

 

Hello again.

Will not start again. Here's the run down:

Last week I changed battery and plugs and it started right up. This morning I gave it a go and it turned over strong but would not start. It warmed up outside a bit and I charged the battery and it still would not start. I tried starter fluid and still will not start.

I believe gas is flowing. Taking the fuel line off the petcock and running prime gives me good flow straight out of the tank. When I try to start I'm smelling a bit of gas... but please help a rookie: should I be opening the throttle a bit to help it start? Is that helpful? Not helpful? Hurtful?

I have a compression guage, but I'm confused how tight it should be. There's no way for me to do anything but hand-tighten it. My hand-tightened guage on cyl 4 went to 115 but my battery was low from turning it over so I couldn't test the rest. In my forum searches I've seen that anything over 100 is ok but the service manual says 128 psi is the minimum. It also says I should disconnect the head light fuse when I do the test... is this really necessary?

I'd like to test spark but am not sure how to do this. I've found lots of forum searches that say "I have spark" or "spark is bad" but how is this actually determined?

Please help...

 

I took off #4 plug and saw a spark... then much to my surprise it started with the plug OFF.

Yet, with the plug back on it still will not start.

 

You need to ensure your battery is topped off, trickle charge it until it is. Then have it load tested. You can get a bad battery to work first round but have it drop off rapidly after a few rounds. You might be experiencing this issue.
Compression test can't hurt and, if you find a bad hole, will tell you why the bike won't run. Go ahead and pull the headlight fuse and make sure to remove all of the spark plugs so the engine can spin freely. Disconnect the TCI so you don't fry the TCI if you don't ground all of the spark plugs.
Have you tried starter fluid? If it fires up on the fluid, you know you have a fuel problem. If you are smelling gas, you might have carb problems and/or are flooding the cylinders.
Best of luck!

 

Do those bikes have a choke(enrichment lever) ? Is it working correctly? Mine always needs full choke for starting.

 

Came home tonight and after a long warm day in the driveway it started up and I took it for a ride. It sure sounds sick, though. I've got to leave the choke on to keep it alive when idling and if it stops it's hard to start again. It sputters until I get the RPMs above 3k.

I'm going out there now to do the compression test and change the oil.

Given that it started and ran can I assume that my spark is ok?

I'm starting to think I'll need to crack those dreaded carbs.

 

Yeah, beginning to sound like float levels to me....check those first.

 

Changed the oil but didn't have time to do the compression test before the sun went down. The bike started right up and ran much better. I'm fairly certain I had overfilled the oil.

I think the carbs do need to be cleaned, though. That's still on the list.

 

I'd start at the top,
Oil and filter change,
Compression test,
Check and adjust valves,
Clean the carbs out (I know this sounds hard and it is... the first time), clean again and sync.
Given the bike started, I'll agree odds are you are not suffering from lack of spark. Get those carbs cleaned up.

 

I did the compression test. The threads closest to the outside of #1 are stripped so the longer spark plug has something to grip but the compression gauge just slid in/out so I couldn't do it.

#1 ?? psi
#2 98 psi
#3 105 psi
#4 112 psi

Can someone please interpret this for me?

 

Any suggestions/analysis on the compression test? I realized I didn't have the throttle open when I did the test so I guess I'll have to redo it...?

I'm about ready to brave checking the valves. How long should this take me?

 

checking the valves will only take 1/2 hr, but if you have to change some shims, it will take some time. You should get the valves in spec BEFORE checking the comp & you must get #1 hellicoiled otherwise the testing will be inconclusive.

 

"checking the valves will only take 1/2 hr" ... I assume that's the case if you've done it a couple times. I probably spent 4 hours on it by the time I got all the shim sizes figured out.

Here's what I got:
#4 exhaust 0.006/0.15 280 intake 0.002/0.05 290
#3 exhaust 0.006/0.15 280 intake 0.004/0.10 290
#2 exhaust 0.006/0.15 275 intake 0.002/0.05 290
#1 exhaust 0.006/0.15 275 intake 0.002/0.05 290

Big question about this: the service manual states the following clearances are in spec:
Intake: 0.11 ~ 0.15 mm (0.004 ~ 0.006 in)
Exhaust: 0.16 ~ 0.20 mm (0.006 ~ 0.008 in)

So my question is whether I should go by inches or millimeters. Everything is tight, but if I go by millimeters every shim is out of spec, if I go by inches then just #1,2, and 4 intake are out of spec. What is the best way to go?

(edit: fix the typo on #3 intake)

 

Just looking quickly I see half of your shims will interchange.

 

0.15mm is out of spec for exhaust, but 0.006in is not... 0.10mm is out of spec for intake, but 0.004in is not... thus my confusion.

 

I will listen to fitz (http://www.xjbikes.com/Forums/viewtopic/t=24581.html) and go by the metric measurements, thus I'll be changing all 8.