my motor bike ran fine and now it wont start

[CarlosFerrerJr]

I have a GT6 motor i bought about a month ago I also bought an aftermarket head high performance and the thrust muffler aftermarket its been running me great for about three weeks to a month I ride it everyday well now it won't start I tested spark I have spark carb is good but it is stock I did have a popping on start like air was leaking from somewhere but it always started and ran great I know there is plenty of compression WHAT COULD IT BE ????? Argh been messing with it about a week now I'm glad I have two motor bikes

 

[crassius]

1st thing to check is head gasket

 

[The guy]

hey, bud, don't freak. These engines are very simple. When you have 2 strokes, they really go to town on them selves, rule 1 is when you first set them up, you HAVE TO tighten ALL nuts and bolts, 2 stokes vibrate and heat up so so so fast, if things are loose you are loosing vacuum, which is significant, a few microns of space can warp the head, a loose carb looses vac. Poor oil mix = too much heat. Simple engines but never the less, they need love. Replace the motor, if you buy from gasbike, they usually have a warranty, but when you put it together, remember: heat is an enemy, vacuum is essential, and locktight is important. Solder your connections, clips vibrate out. Only three things make these bikes not work, so ask yourself them.
1: am I getting fuel, if not, why not?
2: am I getting spark? If not, why not?
3: do I have vacuum, is there a air leak, if so where?

Lastly, why did this problem occure? And what can I do to prevent it happening again?

I really hope this helped you man, don't give up.

 

[gasbiketommy]

Ask yourself three questions.
1: am I getting fuel? If not why?
2: am I getting spark? If not why?
3: is the motor losing vacuum? If so, where?
These are simple engines and these are the primary problems. Check your warranty, it might not be up yet. It is so important to tighten every nut/bolt right after assembly, then ride for a bit, then tighten again, new engines need to heat, expand, the settle. If things are loose, the may warp and lose compression/vacuum. Make sure your carb is on tight, exhaust, and head. Make sure you CDI and plug are working properly. I really hope this helps some people. These engines are very simple, but also can fail, if they aren't lubed and tight.

 

[CarlosFerrerJr]

1st thing to check is head gasket

my head gasket looks good

 

[KCvale]

What are you torquing your head to, and are you using a torque wrench or just guessing?
And a GT6 engine? Is that gasbike special or E-bay?
There is a Grubee Skyhawk GT5 engine and they are solid but they don't make GT6.

 

[gary55]

my head gasket looks good

When you pulled the head to inspect the head gasket did you make sure the cylinder looked good? Did you do a compression check, and if so what did it read? If you have fuel getting to the cylinder, spark, compression and the carb is on tight, their is the possibility of a leak from one of the crank seals. Sometimes if the fuel is left on and the float valve doesn't seal enough fuel can get into the crank to create enough pressure to pop a seal out. Usually they can just be pushed back in carefully and flush to the face of the case. Another possible cause could be be the woodruff key in the rotor came out allowing the magnet to move out of time. This will still show spark, it will just be at the wrong time thus the popping.

 

[CarlosFerrerJr]

don't know I bought my bike motor from gasbike.net they sell a gt5 gt6 gt7 and a gt8 I do not have a torque wrench so I just tightened them down nice and snug and no I don't have a compression tester anymore Yes the cylinder looks great I didn't even put 50 miles on this engine yet it ran good then just stopped

 

[Cozmik Mezzenger]

Take apart your carb and clean everything, making sure your main jet is clear.

 

[gary55]

Take apart your carb and clean everything, making sure your main jet is clear.

That's a possibility, but the popping when he tries to start it leads my thoughts elsewhere. Ya never know till ya try.