What sleeves does this 61x motor use ?

[XZF]

Hello everyone,,
bought me a freestyle ski a while ago,, came with 61x engine guess the owner did not give the engine proper care
as the pistons have experienced a lot of detonation,, probably because he ran an r&d head 82mm on a 85 mm bore.
tapping the head too clearly seen by the marks left on the wiseco pistons

now I would like to order some new sleeves and pistons for the engine as one has a deep scratch in ,but i cant figure it out ...
are these like blowsion 785 sleeves, just 780 sleeves in a 61x cylinder or something else I have no idea
what would be the best option could I bore them to 85.5 or just put new 84 mm sleeves in ?
don't know what type i should order

thanks in advance

 

[TheBuzzard]

If it's a 61x cylinder and it's at 85mm it's clearly had big bore sleeves installed. More than likely you are never going to find replacement sleeves for that and since you have to bore the casting for big bore sleeves, you can't use just any sleeve. If it can be bored will depend on how thin the bottom of the sleeve is. If there's not enough thickness left it can't be bored. I have a 61x that I couldn't punch out to 86mm. Too thin at the bottom and the bit chattered down there. I've ran worse looking piston tops than you show

 

[Big Kahuna]

Gonna say those marks on the head came from someone trying to cut the domes, not from the pistons hitting it.

 

[XZF]

Allright guys thanks ,, i see where u going to I don't think they cut the domes as its 82 mm and bore 85 .. could be tho ,, see on the piston a clear line from the head ,, anyway will take the cylinder off within a few days and measure the outside of the sleeve at the bottom ,,

 

[WFO Speedracer]

There are not that many places that make those big bore sleeves if you have the dimensions, you can probably call around and find some replacements.

 

[TheBuzzard]

I just looked closely at those dingers on the piston tops. Those are not from detonation. Something went thru the motor. Probably the crank bearing cage going away. Motor needs to be ripped apart and checked

 

[fastgtfairlane]

+1 definitely recommend taking bottom end apart for close inspection. Nothing worse than seeing your new top end grenade just after having it done

 

[XZF]

I could wait to get into it .. so i found out some good and bad news, the sleeves are outside 91mm at the bottom in a61x cylinder . so good news i can bore out the sleeves even a couple of times,, and found a pair of wiseco 85.5 pistons super cheap, the sleeves will be bored and honed. now sunshine never last so when i open up the cases dirty and little metal flakes.

the crank rod and bearings.... to start a horrible sound .one in the middle the side of the stator is ok . the rod on the side of the coupler has to much play on first sight,, will try to find to correct specs. also checking the tolerance for the case as this one probably has seen better days

for the crank I suspect misalignment of the engine wich would cause the coupler side to have the most damage coming thru to the back... so yeah next mission source myself some bearings and find someone here in my country that can rebuild a crankshaft

 

[WFO Speedracer]

Misalignment of the couplers does not take out rod bearings, no dice

 

[XZF]

Forgot mention the main seal, it did not seal from the coupler side . due to this a lot of rust on the bearings ,, the seal fell right off the crank when I took it out
could be a reason too. I am only guessing tho.