Help! Bike cranks fine but won't start.

[DSmithjr]

Okay, I'm new to the forum and to the Suzuki GZ250. I just picked up a 2000 GZ250 with 12K miles a couple of weeks ago and I still can't get it running. The guy I bought it from told me it was running fine until he let it sit for a few months. I picked it up figuring all I'd have to do is clean out the carb and I'd be good to go, but that's not working out. Here's what I've done so far: put in a new battery, completely dissembled and cleaned the carb, changed the spark plug, adjusted the valves, added good fuel, and changed the oil. The bike will crank over just fine but it has never made any attempt to start. Not a sputter, not anything. The bike is getting fuel and spark. I've even tried spraying starter fluid into the back of the carb hoping to at least get a little sputter of life but I got nothing. I'm going to try to check the compression tomorrow, but after that, I don't know what else to do.

Assuming the compression is fine, what could I possibly be missing here? I've been able to bring several bikes back from the dead in my day, but this one's got me beat. I don't know what else I can do. Any suggestions?

P.S. Nice forum. I've never owned a bike that had it's own forum before. :2tup:

[Water Warrior 2]

Perplexing to say the least. Random thoughts here. Are you absolutely sure the bike is getting fuel. The petcock is normally pointing forward and is vacumn controlled. Pointing to the rear is reserve and also vacumn contrlled. Pointing down is PRIME and not vacumn controlled, just gravity feed. Yes I realize you stated a no-go with starting fluid. The only thing left is spark, how are you determining this ? Did you hold the plug against the engine(to ground it) and turn it over with the starter to visually verify a spark ?

[patrick_777]

Did you change the plug wire too? This sounds like it's not getting any spark whatsoever if carb cleaner (B12) or "starter fluid" isn't even firing...Remember, there's only three things that an engine needs to run - air, fuel and spark.

[DSmithjr]

I've had the petcock in PRI (prime) and ON most of the time. After I redid the carb, I left the petcock in PRI for awhile to get the carb refueled. I say it's getting fuel for two reasons. First, I know there's fuel in the carb (when I loosen the screw on the bottom of the float, fuel drains out). Second, if I hold the throttle open and let the bike crank over for awhile, when I remove the spark plug I can see fuel on it. Even if it wasn't getting fuel, I would think it should still at least sputter a little when I spray starter fluid into the back of the carb, but it doesn't show any signs of life.

And yes, I held the spark plug against the engine and watched it spark as I cranked motor. The spark seemed fine to me. Nice and strong. I've worked around engines for a long time and this spark seemed normal to me. I'm actually pretty frustrated with this thing right now. I download the manual in PDF format from this forum and I just working my way through it step by step.

I'm reading everything I can on this forum, but I'm lost here. :??:

[DSmithjr]

No, just the plug. I was thinking about changing the wire and the coil, but I'm not sure why it would be necessary if I'm already getting spark? Can you buy just the plug wire for this bike? I know most of my other bikes have the coil and plug wires as one unit. Hows does the timing work on these bikes? I'm assuming it's controlled by the computer...

The guy I bought it from also said he put a new rectifier in it. I'm not sure why, but it looks new to me.

[patrick_777]

Maybe you're actually getting too much fuel into the cylinder and you're drowning out the spark. What was your main jet set to when you had the carb off? Did you change it? Are your mixture screws drilled out where you can alter them and lean it out? Just spitballing here (mostly what I do), but if you've tried other known good plugs and they're all getting saturated with gas when you try and fire it, then it's taking way too much gas into the cylinder and literally drowning the spark out of the plug from the first crank.

[patrick_777]

Originally Posted by DSmithjr

I'm assuming it's controlled by the computer...

What computer?

[DSmithjr]

The CPU. Although, I guess the timing is set in the ignitor.

[DSmithjr]

Honestly, when I had the carb apart, I just did the normal dissemble, clean, reassemble. I'm going to look through the forum to see if I can find a really good carb cleaning how-to. I'll take a look at the jet size and everything else. I should also purchase the hotter plug while I'm at.

I guess I have more to try out tomorrow...

Although, I did walk out there not too long ago after the bike had been sitting for hours and all I did was spray some starter fluid into the back of the carb and crank the motor, I didn't give it any gas. Nothing. Not one little sputter.

[patrick_777]

Take a look at page 6-19 in the Service Manual. The Ignitor might actually be bad. There's a checklist there that includes voltage checking and other steps to take to verify that it's working correctly.