2006 gz turns but won't start.

[jonathan180iq]

I think you're sniffing the right dog's ass, about vacuum.

You alluded to bad timing on start, which can be marked off easily enough by checking the timing and doing a valve adjust if necessary. But, if that were the case, it would also be difficult to start when rolling it. (Harder than normal, I mean.)

Since she seems to run fine after you get her going, I still feel like it's vacuum. (You mentioned sputter and slightly off at low idle)

Drain the tank down to maybe 1/4 or 1/2 and run a high concentration of cleaner. Like you said, roll start and give her a good stretch. I would even pull those vac lines and blitz the inlets with a shot of the stuff too.

Once that variable is completely eliminated, if it doesn't solve it, you can move onto something else, like the timing.

[schooler94]

Try seafoam in the tank. And check the air filter, maybe it starts when its rolling because more air is getting in, but its too clogged when just sitting

[Road_Clam]

A quick test to see if you have a restricted fuel flow issue is to yank the air filter and spray some starting fluid into the intake. Start the bike, if the engine quickly starts, then dies, you have a fuel flow issue. I'm thinking you have a sticky carb inlet needle. Ethanol is notorious for causing inlet needles to stick.

[jomama]

Just a thought here. Is it possible the starter motor is drawing to much juice ? There may be enough juice to for the plug while ontside the engie and just laying on the block for a ground but not enough for it to fire under compression if the starter is drawing to much.

[Water Warrior 2]

Originally Posted by jomama

Just a thought here. Is it possible the starter motor is drawing to much juice ? There may be enough juice to for the plug while ontside the engie and just laying on the block for a ground but not enough for it to fire under compression if the starter is drawing to much.

Excellant thought. Get another plug and screw it in. Repeat the spark plug test with the hole plugged and creating compression. Do make sure the battery is fully charged for best results.

[BonChaton]

Here is an update.

Tried a million things.
Checked electrical stuff. Cleaned carb. Charged battery. Yada-yada.
Gave up. Took bike to repair shop that works on Suzuki's.
They traced the problem to the exhaust valves not closing.
Estimated lots of $$$ for a repair.
Decided to get a new bike instead.
Bought a new-ish 2012 Suzuki Boulevard S40. (It is awesome to ride!)
Was going to trade GZ250 in.
Went to finalize deal with pink slip in hand.
However suddenly found sales was not going to cover the repair costs incurred up til then.
Kind of made bike not worth trading in.
Decided to have shop fix bike and sell it myself later.
Will update again when I have precise info on the repair.

So anyway ...
Now I have two bikes! :rawk:

[Water Warrior 2]

Cool, the S-40 is a nice bike. Just a bit heavier than the GZ with a bunch more engine to play with. One nice feature is the belt drive rather than a chain. This makes things a lot more difficult if not impossible to regear the bike but Suzuki is pretty close with their gearing on most bikes. You will probably like it as is.
Have fun and post some pics soon.

[alantf]

Originally Posted by BonChaton

They traced the problem to the exhaust valves not closing.

So, did they say what might be causing the valves not to close? Did they even try to adjust them? There's a lot of "ifs & buts". Something doesn't smell right here. Is there another shop you can take it to, or even a friend who can help you to try adjusting the valves? :??:

[jonathan180iq]

Or do it yourself:

viewtopic.php?f=8&t=5061

[mrlmd1]

Why would the bike start with a roll start and run fine and not start with the ignition switch and starter turning it over if the "exhaust valves were not closing"? That makes no sense. Go to another shop and get the valves adjusted if they're out of spec, or do it yourself.
Or just go out and buy another bike.