Honda TRX250R Forums banner

1 - 20 of 107 Posts

·
Registered
Joined
·
83 Posts
Discussion Starter #1
I recently bought a 1988 250r from a buddy that he was having trouble getting it to kick start it came with a 1988 310 engine and the engine on it is suppose to be a 1986 with a 265 kit I tore the engine down and the exhaust side of the piston was missing I was thinking that it had a blowed head gasket and it caused it to melt the piston but I’m not sure the engine has a spacer plate under the cylinder so I’m assuming it has the long rod in it but I’m not sure I cleaned the cylinder up and it seemed to clean up nice so I was gona put a new piston and rings in it but I’m not sure what year piston to get I googled the numbers on top the old piston and came up with a 68 mm wiesco 1986 piston but I was just wanting to try make sure that was the year piston I needed and the reason tgat it broke or melted was not because someone had the wrong piston it any advice would be greatly appreciated
 

·
Registered
Joined
·
83 Posts
Discussion Starter #3
K I have put the 310 kit on it right now I will try to tear the engine back down this weekend and get some pics of the rod thanks for your reply
 

·
Registered
Joined
·
83 Posts
Discussion Starter #4
This is the piston that came out of it and the cylinder that came off of it and the rod
 

Attachments

·
Registered
Joined
·
1,607 Posts
that is a short rod crank Justin posted from an 86 ATC TRX 250R if it says HB9 on crank it is from an 87-89 Honda TRX 250R and will be long rod and if it said KA$ that would be from an 85 ATC 250R also short rod.
Not very familiar with hot rods cranks but post any identification number that are on crank. I am sure Carlos will chime in he know a great deal about these bikes!!
 

·
Registered
Joined
·
83 Posts
Discussion Starter #6
Since this is a short rod is it suppose to have the spacer plate on it or not have one it had one on it
 

·
Registered
Joined
·
83 Posts
Discussion Starter #8
Are the cylinders the same for the 86 through 89 wonder y they had the plate on there just not knowing what they was doing when they put it together or something
 

·
Registered
Joined
·
4,142 Posts
that looks like a long rod crank with a short rod piston.do you have a picture of the other intake side of the piston.long rod piston has a square hole and a sr piston the bottom of the skirt is a u shape.from left to right.sr stock piston..sr big bore piston long rod piston. and all cylinder are a touch different but a spacer plate isn't needed unless a stroker crank,or 70mm+yz250 piston
 

Attachments

·
Registered
Joined
·
83 Posts
Discussion Starter #10
I will post that pic when I get home from work when I set the cylinder and head on there without the spacer plate the piston hits when it gets to the top I appreciate all the help I would be lost on what I have without all of the help
 

·
Registered
Joined
·
83 Posts
Discussion Starter #11
Also I’m pretty sure my piston is like the one on the left of the pic u posted. I will make sure this afternoon though
 

·
Registered
Joined
·
4,142 Posts
yeah thats a sr piston and you have a lr crank.if you lookat my picture i have the wrist pin in them to show the 4mm piston height difference.
 

·
Registered
Joined
·
4,142 Posts
you can only buy a longrod piston up to 68mm.anything bigger than that you have to buy a sr piston and use the spacerplate.
 

·
Registered
Joined
·
83 Posts
Discussion Starter #15
So I need to get the 86 model piston and does the piston I posted in pic look like it melted or broke I thought it had melted and if so what causes them to melt so I don’t have this issue when I get it rebuilt
 

·
Registered
Joined
·
83 Posts
Discussion Starter #18
I’d like to order some parts tommorrow but I’m still not 100 percent sure exactly what I need I also need a good gasket set any help would b greatly appreciated and if anyone knows where is a good place to get gaskets and stuff I could use some guidance thanks
 
1 - 20 of 107 Posts
Top