Suzuki RM250 2007 - Did a topend and after 10h engine noise appeared

[MX_Peter]

I bought the bike used and it had aprox 40h of ride from new. 10 hours ago did a topend rebuild (Used Mitaka piston with RIG rings, changed bearing and piston rod). After the last 2 hours I started to noticed that the bike started to be noisier and noisier . I stoped riding and the vibrating sound came like from topend and bottomend. Today I decided to take it apart. I took off the cylinder and checked for conrod play. It had it side to side, but not up and down. Weird thing was that that 10h piston had more play if you tried to rotate it left and right than previous used piston. I split the cases to see the main bearings and it was like somehow burned inside, little bit noisy (like shhhhshhshhhhhshhhh) but no play. Is this normal? Still couldn't find the source of that vibrating sound. Does someone has any clue what could be the case?

I'm just pissed right now and don't know where else to look. Thanks in advance

[scotty dog]

What does the small end area of the rod look like? Maybe it was a dodgy small end bearing. What were your tolerances like between bore size and piston size, maybe the bore is like A size and a C piston was fitted?
Shouldnt really be any noise from ya mains, is the ssshhhhhhh very quiet? or is it very noticeable?
If youve got it apart, might aswell replace mains anyway and if you can afford to do the big end, if the piston looks good and the tolerance is acceptable it should be good to go.
Hope i helped 

[cnrcpla]

Piston slap? Maybe the piston and bore aren't compatible with each other like scotty said. What kind of fuel do you run in it?

[TotalNZ]

When you say you changed piston rod, do you mean you replaced the conrod and bigend bearing?
If so the crank may not have been balanced properly when it was pressed back together.
I'd take the 40hours running time with a grain of salt too, thats not much for an 07 and without an hour meter there's no real way of keeping track.

[scotty dog]

When you say you changed piston rod, do you mean you replaced the conrod and bigend bearing?
If so the crank may not have been balanced properly when it was pressed back together.
I'd take the 40hours running time with a grain of salt too, thats not much for an 07 and without an hour meter there's no real way of keeping track.

Good point, wouldnt the vibration be there straight away though? Maybe it was done rough, but it shouldnt get out of balance after its been run should it.

[TotalNZ]

When you say you changed piston rod, do you mean you replaced the conrod and bigend bearing?
If so the crank may not have been balanced properly when it was pressed back together.
I'd take the 40hours running time with a grain of salt too, thats not much for an 07 and without an hour meter there's no real way of keeping track.

Good point, wouldnt the vibration be there straight away though? Maybe it was done rough, but it shouldnt get out of balance after its been run should it.

Na you wouldn't think so. And yeah you'd think it would vibrate from the getgo.
I was thinking of some sort of alignment issue between the 2 crank journals puttin hell strain on the mains causing the noise the burnt look and really accelerated wear.

[scotty dog]

When you say you changed piston rod, do you mean you replaced the conrod and bigend bearing?
If so the crank may not have been balanced properly when it was pressed back together.
I'd take the 40hours running time with a grain of salt too, thats not much for an 07 and without an hour meter there's no real way of keeping track.

Good point, wouldnt the vibration be there straight away though? Maybe it was done rough, but it shouldnt get out of balance after its been run should it.

Na you wouldn't think so. And yeah you'd think it would vibrate from the getgo.
I was thinking of some sort of alignment issue between the 2 crank journals puttin hell strain on the mains causing the noise the burnt look and really accelerated wear.

Yeah, which would cause vibration after 10 hrs 

[TotalNZ]

When you say you changed piston rod, do you mean you replaced the conrod and bigend bearing?
If so the crank may not have been balanced properly when it was pressed back together.
I'd take the 40hours running time with a grain of salt too, thats not much for an 07 and without an hour meter there's no real way of keeping track.

Good point, wouldnt the vibration be there straight away though? Maybe it was done rough, but it shouldnt get out of balance after its been run should it.

Na you wouldn't think so. And yeah you'd think it would vibrate from the getgo.
I was thinking of some sort of alignment issue between the 2 crank journals puttin hell strain on the mains causing the noise the burnt look and really accelerated wear.

Yeah, which would cause vibration after 10 hrs 

Shit we're good.

[MX_Peter]

I meant by piston rod, that I changed Piston pin, piston, piston pin bearing,...whole kit. The sound of bearing shhhhhshhhhshhhh is quite noticeable, I applied some oil and it was quieter, but still no play in the bearings. From where that vibrating sound still don't know. Crankshaft has some play left to right (which is normal) but not up and down.

And forgot to add that crankshaft weight had some little rust spots?

[SachsGS]

Are you sure it just wasn't loose motor mounts?

[MX_Peter]

Are you sure it just wasn't loose motor mounts?

I'm shore because I checked them all...this is how the bearing and crankshaft looks like  " title="Roll Eyes" class="smiley">

[cnrcpla]

What is all the rust from? Did you spray some oil when you did the top end instead of exposing those parts to air? If you didn't than that is where the rust came from, and the bearings could be rusty. Maybe that isn't causing the vibration, but it isn't good having rust in there.

[Recovered]

in the picture of the crank it looks like it wasn't aligned back up when pressed back together shouldn't the crank journals where the black area then the polished areas are on the two journal halves lign up? the bearings in the case look burnt i'm guessing that the crank journal that has the burnt look to it is the side that goes with the burnt bearings. that could possibly be the crank journal that is out of alignment not pressed back on correctly and putting more stress on that bearing and causing it to burn and causing your shhhhhhhhhhhhhhh noise.

[MX_Peter]

What is all the rust from? Did you spray some oil when you did the top end instead of exposing those parts to air? If you didn't than that is where the rust came from, and the bearings could be rusty. Maybe that isn't causing the vibration, but it isn't good having rust in there.

I had pre oiled conrod, and this rust was before I changed the piston. The previous owner hasn't ride the bike for some time before he sold it. The bike before me has newer been opened from new, so I'm the first one to do it. 

[scotty dog]

Looks like new bearings for the RM to me, I would get a new crank or get a new big end and rod, if theres rust like that on the crank and rod it will be on the bearing aswell. Check your piston/cylinder clearance and start buying new parts, Good luck