Big engine problem

[508blaster]

Hey guys I just did a top end in my blaster along with a shaved head. When I started it it ran awesome plenty of power and sounded great , after 10 mins of riding around it makes a banging noise in the top end and then dies out but before that you can see the cylinder shaking I have no idea what's goin on please help thanks guys

 

[josh519]

May have bad rod bearing.bottom end may be bad too.
Did you do heat cycles before riding it?

 

[508blaster]

May have bad rod bearing.bottom end may be bad too.
Did you do heat cycles before riding it?

No I didn't and the bottom end seem to move freely I had a hard time fitting the jug over the piston so I kinda lean towards something with that its weird because it ran awesome

 

[josh519]

Bad crank would make the banging in the top.
Pull head ,check piston and see if rings are in correct position

 

[508blaster]

Bad crank would make the banging in the top.
Pull head ,check piston and see if rings are in correct position

Will do thanks man I'm praying I don't have to mess with the bottom end again

 

[508blaster]

Bad crank would make the banging in the top.
Pull head ,check piston and see if rings are in correct position

Will do thanks man I'm praying I don't have to mess with the bottom end again

could using an old head gasket have anything to do with you think? Once I took the head off and put it back on it went away then came back

 

[josh519]

You should replace it every time,, but I've been ok before.

 

[Blaner]

I suppose the question here should be why you rebuilt the top end in the firstplace? If it was because of a piston failure, your bottom end will be littered with bits of metal you would have needed to get rid of. You could have damaged the crank etc. You could also have had a 4 point heat seizure if you didnt do heat cycles with it...

 

[508blaster]

Piston grenaded so my buddy split the case because the crank was jammed so he took out whatever was broken into the bottom end ( piston pieces) and put it back together it seem to move pretty smoothly after that then when I fit the jug over the piston it was super tight and I had to force it in then it eventually freed itself up because it would only go 3/4 up the cylinder so the heat thing could be right because once it was running hot it started knocking bad to the point you could see the cylinder shaking

 

[508blaster]

I'll be honest I got on it went easy for a bit then just went wide open the heat cycle prob would've helped big time

 

[508blaster]

I can't kick it over it just won't fire

 

[DUALSTROKE]

Sounds like to me that your buddy didn't line up the marks on the gears to align the balancer shaft and internal gears.
does 508 stand for your area code?

 

[508blaster]

Sounds like to me that your buddy didn't line up the marks on the gears to align the balancer shaft and internal gears.
does 508 stand for your area code?

That's definetly possible and yes it is

 

[DUALSTROKE]

Well to hell with you south coast massholes

On a serious note sounds like time to split those cases again and get it squared away. Hopefully you didn't mess up the bore.

 

[508blaster]

Well to hell with you south coast massholes

On a serious note sounds like time to split those cases again and get it squared away. Hopefully you didn't mess up the bore.

Hahaha I know we are a rare breed , yea I was afraid of that

 

[Blaaster]

Piston grenaded so my buddy split the case because the crank was jammed so he took out whatever was broken into the bottom end ( piston pieces) and put it back together it seem to move pretty smoothly after that then when I fit the jug over the piston it was super tight and I had to force it in then it eventually freed itself up because it would only go 3/4 up the cylinder so the heat thing could be right because once it was running hot it started knocking bad to the point you could see the cylinder shaking

Is there a possibility a ring was not lined up with the locating pins in the piston.

Very little pressure is needed to get the piston into the cylinder, by forcing it you may have broken a ring.