vibration after new top end

[bigjohn1895]

Well I got my 240engine together after waiting for the back ordered piston
And it vibrates badly with any kind of revs an has a rattle sound. Should I look for a bad bearing or can piston slap do this (my friend thinks its slap)
I don't think its slap I'm on my first bore and had to clean it with a ball hone no bore needed as the piston and head took all the damage when the ring blew I have checked clearances and they were acceptable don't remember the numbers

 

[Blaaster]

Either the balancer is out of timing or a bit of the old ring has migrated down a transfer port and is causing havoc.

 

[bigjohn1895]

I will have to check the balancer Sunday but I don't see why that would make it rattle
It almost sounds like a bearing is going out but clears up when you rev it I've never heard a bad bearing stop rattling when you rev it so I'm stumped


So what your saying is piston slap won't make it vibrate

 

[Blaaster]

So what your saying is piston slap won't make it vibrate

I never said anything of the sort.

I presume you had the bore measured and fitted the correct size piston, if that happened there will be no slap.

Vibrations and rattle can be caused by the piston clipping the head.

Balancer timing will make it vibrate and noise can be made by worn bearings and debris in the case.

Was the previous ring damage caused by detonation or a ring snagging a port edge?

 

[bigjohn1895]

Yes I had it measured and I also checked again after the piston arrived
As far as the ring goes it seems like a reed did the damage or at least started the chain reaction I did have to clean up the ports a tad but not too much

 

[Blaaster]

Did you just suck a reed in or was it a screw dropping into the crankcase?

 

[bigjohn1895]

It sucked the reed in

 

[bigjohn1895]

Ok the balancer gear was lined up
So now I know its a bearing what should I do next
Is there away to check them or should I replace them one by one
If I'm doing any thing that requires splitting the case I'll get a Vito s +3crank
Also

 

[B S]

any way to record the sound?

 

[bigjohn1895]

I can give it a shot tomorrow

 

[bigjohn1895]

Well my video isn't going to get posted today
My wife to be rolled her trail blazer (quad) and broke her arm this morning
And we didn't get back from the hospital and every thing taken care of till now 10pm


On a side note I'm thinking about using the bottom end out of the pink and purple blaster and putting it in my blue/new one. Wile on my ride I noticed that I can't down shift. I'm thinking the kid that blew it up was jamming gears and bent the shifting forks
Unless I jingle the shifter it feels like there's nothing attached to the shifter
The reason I bought the blue one was I wanted the plastics and the big bore kit for my purple one. now it seems better to use the purple one to rebuild the blue one since the blue one is in better shape . Later on I will rebuild the engine for the purple blasty

 

[dirtysquared]

That sucks about your g/f. Hopefully it isn't a break that requires surgery. Best wishes to her.

Your flip flop Idea isn't bad one. Hope it works out for you!

Fred