No Start - Compression?

[gzed]

Hi All,

My 2006 GZ250 was having some issues starting before I winterized it. This weekend I put a fully charged battery and everything sounds to be in order but the bike does not start, even after some TLC.

The engine turns and turns with no results.

Cleaned the carb
Verified the air filter is clean
Verified the carb is getting gas from the tank
Put in a new spark plug, confirmed it is sparking


Compression is the only thing I can think of, but based on the sound of when it tries to start it has compression, as well as I can feel the pressure coming out of the exhaust.

Is there anything you guys and gals can think of that I should also check? Is there any way to test if the timing is off? Any advice is appreciated, thank you in advance.

[smakaho76]

Yesterday was the 1st time I started her this season.it took 2 batteries,3 recharges,an hour or 2 with the petcock on prime and a bunch of starter fluid lol.i sprayed started,ran,revved,died repeat til it stayed barely running for 10 seconds w hard throttle.had to back off the choke a Lil too.

[gzed]

After trying for about an hour, still no luck. The starting fluid did help it make it sound like it is about to fire. I am starting to think bad gas? I used a stabilizer but it did sit for almost 5 months. Though it still smells like gas.

I also hooked up the battery to a car one to have a solid charge. Throttle up and choke engaged, no dice.

Any other guesses?

[Vegas Street Rider]

I would drain the fuel tank and start with some fresh gas. It sounds like everything else has been checked by you. You said you were having some issues before you put it away? Can you elaborate.

[gzed]

I will change out the fuel and give it another shot.

Prior to the winter the gz250 was rather inconsistent on starting. I would almost always have to use some choke to fire it up, but considered it normal for the type of bike. I always figured the carb needed a cleaning but put it off, though when I pulled it this time it was relatively clean.

It also had a good amount of top end noise on the exhaust valve side even after an adjustment. I was reading around and saw that the TDC can be tricky to get right even if the marker is aligned. Also that he valves are meant to be set in spec on the compression stroke only. Since the bike was running, i did not revisit the above steps, but maybe I should.

It does worry me that the starter fluid did not turn it over once, but will try fresh gas. Or any other suggestions?

[gzed]

Compression it is :crazy:

Spent the money for a compression tester and not getting past 60 psi.

Debating if it is worth it to open the top or sell.

[chandlerbingfl]

Compression it is :crazy:

Spent the money for a compression tester and not getting past 60 psi.

Debating if it is worth it to open the top or sell.

I'm facing the same issue although I can push start my GZ and it'll start up right away. One thing I have noticed is my top end speed is limited, hence my thinking my issue is the gasket (?) between to top and bottom case...

chandlerbingfl

[gzed]

thanks chandlerbingfl, did you run a compression test? If so, what PSI did you get? I have not tried to bump start it, but will give it a shot.

The bike had a low top speed but didn't worry much since I only use it in the city, but on a highway test the top speed was around 55-60.

I just wish there was a way to know what component has failed without tearing it apart. Though my guess is the head cylinder gasket, since the last time I rode it was on a very cold day and was terrified to see a few poofs of white-ish gas shooting out of that area, as well as some oil seepage.

I do like the bike, so might take the time to bring it back to life. Any guess on the price of the worst case scenario? I mean at which part is it better to swap the engine? I see them on ebay for 500-800$

[Vegas Street Rider]

Sounds like both you(Gzed) and Chandlerbingfl have a tough choice to make. If you can do the work yourselves, you save a bucket of money in labor. That being said, how much money are you willing to invest to bring the bikes back to life vs. their value after the fact. Depends on how much you love your GZ, I guess.

[Water Warrior 2]

Just a thought here for the folks with more knowledge than me. Would a needed valve adjustment be part of the problem?

[blaine]

You can try this......Put a teaspoon of oil down the plug hole......Than take another compression test (Make sure throttle is wide open)......If readings come up sufficiently than the rings are worn/broke........If compression don't raise.than its a top end problem. :)

[gzed]

Just a thought here for the folks with more knowledge than me. Would a needed valve adjustment be part of the problem?

I could see this being an issue if they were too loose, though I remember reading the valves tighten over time on the gz. I don't know for sure, but will take another look at them when I take off the top.

You can try this......Put a teaspoon of oil down the plug hole......Than take another compression test (Make sure throttle is wide open)......If readings come up sufficiently than the rings are worn/broke........If they don't raise.than its a top end problem. :)

Hmm seems easy enough, will try this when I get home tonight. The bike only has 4,500 miles so I would hope its not the rings. The previous owner mentioned he almost always used some choke so I wonder if something overheated and was damaged from running too lean on a hot engine. Will report back. Thanks for the idea / help.

[Water Warrior 2]

Check all the valve clearances first before tearing into the engine. If the valves are too tight they do not close completely and will cause lack of compression.

[gzed]

Put a bit of oil in the spark plug gap and no change in compression. I guess that is kinda good news, since it means the problem is likely valves or head gasket.

Will take another look at the valve lash this weekend.

[Water Warrior 2]

Put a bit of oil in the spark plug gap and no change in compression. I guess that is kinda good news, since it means the problem is likely valves or head gasket.

Will take another look at the valve lash this weekend.
Just a reminder. The engine should be stone cold. Do not run it even for a minute.

[chandlerbingfl]

GZED: No, I have not run a compression test yet. As for my top speed a GPS tracking pgm I use states my top speed around the mid to upper 50's. I know I used to get more but then again I've put on a fair amount of pounds in the last year or so lol.

After I spoke to my mechanic he quoted me somewhere between $700-$800 to repair the gasket and hopefully do not find any other issues. I can probably save close to half that figure, if not more if I do the work myself. Looks like quite an undertaking but I take comfort in knowing my mechanic will pick up the pieces if I get into trouble lol. Even dropping and reinstalling the motor itself is probably a couple hours work (my guy charges $65/hr).

Due to my current situation trying to rebuild is in my best interest. Plus, I could not in good conscience sell or trade my bike due to the problem(s) it has.

Definitely between a rock and a GZ lol...

chandlerbingfl

[Water Warrior 2]

GZED: I could not in good conscience sell or trade my bike due to the problem(s) it has.



I salute you Sir, you are my kind of people.

[smakaho76]

I was wondering,I seen a video of a guy bypassing some mmm switch solenoid thingamajob under left side of seat of marauders.idk if its universal or just the bigger ones but his cranked w no boom,unplugged it the jumped the connector and it fired up fine.mines down too,hence the searching

[gzed]

Check all the valve clearances first before tearing into the engine. If the valves are too tight they do not close completely and will cause lack of compression.

This, the exhaust valve on the left side was almost completely shut. After putting them all back in spec, it fired up with some starting fluid on the first shot.

Also the comment from smakaho76 was right that the gz needs a freshly charged battery. The one I had in there was likely low from all the tries, had to hook up a tender.

However, I am not out of the woods yet. It looks like the head gasket is damaged as I see puffs of white smoke and a bit of oil seepage coming out from the area just below where the exhaust tube connects to the engine.

Would it worth it to try some kind of liquid gasket to seal that for now? Also I have see a good number of people mention on this forum to tighten the head bolts. How many are there on this bike? Is just the four sitting next to valve covers? Or all of them pointing down?

Thanks again,

[smakaho76]

Check ur oil level,mine did that after it had a lil too much in it,although it mightve been oil plus gas lol.when the bike is on it's stand the bubble shouldn't show oil,center the bike n don't go over the mark