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-   -   No Start - Compression? (http://www.gz250bike.com/forum/showthread.php?t=7694)

blaine 03-18-2016 07:53 AM

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 03-18-2016 03:57 PM

Quote:

Originally Posted by Water Warrior 2 (Post 85673)
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.

Quote:

Originally Posted by blaine (Post 85674)
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 03-19-2016 12:21 AM

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 03-22-2016 02:19 PM

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 03-22-2016 11:37 PM

Quote:

Originally Posted by gzed (Post 85687)
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 03-23-2016 08:58 PM

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 03-24-2016 01:43 AM

Quote:

Originally Posted by chandlerbingfl (Post 85697)
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 03-25-2016 01:40 PM

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 04-13-2016 03:48 PM

Quote:

Originally Posted by Water Warrior 2 (Post 85679)
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 04-20-2016 03:07 PM

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


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