piston is to long

[LONG-ROD]

I just put my 310 back togather with a new piston and it sticks out past the top of the cylinder to where the top ring pops out, I never had a spacer befor so do I need one now or did the send me the wrong piston.

[Nac's22]

i think that if you have an aftermarket top end like alot of 310 kits are supposed to use an 86 style jug and piston. so if you were to have an 87-89 bottom end then you are going to have to use a spacer plate that should be supplied with the kit (i think they come with it but i have never bought a kit)

[bluetrx]

im not savvy on the 310 kits but i know the 86 had a diffrent wrist pin height than 87-89 (fount that out building my 86) so it would make sense for there to be two diffrent pistons for the 310. compare the shape and location of the transfer ports on the side of the piston with your old one. if they are the same a spacer plate might be a good way to go, a spacer makes more crankcase volume which makes better intake flow, more power. if the transfer ports are diffrent dont run that piston.

[Nac's22]

Originally posted by LONG-ROD
I just put my 310 back togather with a new piston and it sticks out past the top of the cylinder to where the top ring pops out, I never had a spacer befor so do I need one now or did the send me the wrong piston.

just read your other post in the horse power thread. you have an 87 which as you obviously know has a long rod bottom end. this means that you have to use the spacer plate to make up for having the longer rod. your piston and jug are modeled after the 86 style. hope this helps you out.

[LONG-ROD]

ya it obviously looks like it needs a spacer but I have had this kit on for a while and it's never had a spacer. I ordered the same size piston and now this and the hole on the new piston intake side is closer to the top of the piston and there is a larg curve cut out in it, which looks like clearance for the rod. the old piston does not have this. Is it possible they sent me the wrong piston

[Nac's22]

oh i got ya now sorry. then yes i believe that they must have sent you the wrong piston. i think

[LONG-ROD]

Ok got it now, called CT Raceing and this is what I found. I have an 86'R with an 87' crank the previous owner did a hack job on the rebuild and used some weird piston that fit the 310 kit 73.45mm but did not requir a spacer so I have the spacer on its way along with needle main and piolet jet, cant wait they said it will rip compared to what it was befor.

[250r__Ice]

Sounds like you have a long rod crank with an 86 style piston.
This setup does require the space plate.