blueovalboy50 Posted March 30, 2008 Report Share Posted March 30, 2008 O.K. guys I have got everything I need for the rebuild except pistons. I have measured them to be 64.5mm and the are not stock pistons. First teardown after purchase of bike and not sure what size i need to buy. What I need is what size pistons I have and what size I need to buy. Like I said the piston measures 64.5mm. Please let me know. Thanks Brian Quote Link to comment Share on other sites More sharing options...
Bansh-eman Posted March 30, 2008 Report Share Posted March 30, 2008 then your going to need a 20 over piston. you want to have the cylinder honed while you have the piston so you can get the correct tolerances. Quote Link to comment Share on other sites More sharing options...
blueovalboy50 Posted March 30, 2008 Author Report Share Posted March 30, 2008 then your going to need a 20 over piston. you want to have the cylinder honed while you have the piston so you can get the correct tolerances. So I have 10 over roght now? Quote Link to comment Share on other sites More sharing options...
Bansh-eman Posted March 30, 2008 Report Share Posted March 30, 2008 So I have 10 over roght now? no you have 20 over. you want to get a 20 over piston and have the tolerance set to that piston. you dont want to just assemebl a motor without setting the tolerances. So if you took the jugs and had them bored or honed before having your piston you did it wrong. you want them to bore or hone it with the piston in hand so they can messure it and set the tolerances then Quote Link to comment Share on other sites More sharing options...
blueovalboy50 Posted March 30, 2008 Author Report Share Posted March 30, 2008 no you have 20 over. you want to get a 20 over piston and have the tolerance set to that piston. you dont want to just assemebl a motor without setting the tolerances. So if you took the jugs and had them bored or honed before having your piston you did it wrong. you want them to bore or hone it with the piston in hand so they can messure it and set the tolerances then O.K. I havent had it bored or honed yet I was waiting to see what size I needed. I blew it up last week and destroyed the left piston, rod and rod bearing so I have all new stuff just trying to see what size I needed. the left jug looks pretty bad so I am pretty sure I need to get them bored. So do I go 30 over or 40 over???? Quote Link to comment Share on other sites More sharing options...
blueovalboy50 Posted March 30, 2008 Author Report Share Posted March 30, 2008 no you have 20 over. you want to get a 20 over piston and have the tolerance set to that piston. you dont want to just assemebl a motor without setting the tolerances. So if you took the jugs and had them bored or honed before having your piston you did it wrong. you want them to bore or hone it with the piston in hand so they can messure it and set the tolerances then O.K. I havent had it bored or honed yet I was waiting to see what size I needed. I blew it up last week and destroyed the left piston, rod and rod bearing so I have all new stuff just trying to see what size I needed. the left jug looks pretty bad so I am pretty sure I need to get them bored. So do I go 30 over or 40 over???? Quote Link to comment Share on other sites More sharing options...
blueovalboy50 Posted March 30, 2008 Author Report Share Posted March 30, 2008 no you have 20 over. you want to get a 20 over piston and have the tolerance set to that piston. you dont want to just assemebl a motor without setting the tolerances. So if you took the jugs and had them bored or honed before having your piston you did it wrong. you want them to bore or hone it with the piston in hand so they can messure it and set the tolerances then O.K. I havent had it bored or honed yet I was waiting to see what size I needed. I blew it up last week and destroyed the left piston, rod and rod bearing so I have all new stuff just trying to see what size I needed. the left jug looks pretty bad so I am pretty sure I need to get them bored. So do I go 30 over or 40 over???? Quote Link to comment Share on other sites More sharing options...
Scuba_Shteevo Posted March 31, 2008 Report Share Posted March 31, 2008 no you have 20 over. you want to get a 20 over piston and have the tolerance set to that piston. you dont want to just assemebl a motor without setting the tolerances. So if you took the jugs and had them bored or honed before having your piston you did it wrong. you want them to bore or hone it with the piston in hand so they can messure it and set the tolerances then So what if he buys the 30 over piston and say the bore doesnt clean up at 30 and needs to go 40 know hes out 180 bucks, for the pistons... to me if you bore and hone before you buy pistons your better off cause most machine shops should have a dial bore gauge and be able to hit size with or without the piston IMO Quote Link to comment Share on other sites More sharing options...
crustydemon Posted March 31, 2008 Report Share Posted March 31, 2008 No,No,No!!!! Take the cylinders to a machine shop and let them look at them. The machinist will be able to tell you how far he will have to go to clean them up. Then buy the pistons and take them in and have the jugs bored. To do it properly you have to use the piston manufacurers recommended clearances. Quote Link to comment Share on other sites More sharing options...
brugal Posted March 31, 2008 Report Share Posted March 31, 2008 Take the juggs to the machine shop thats gonna bore them,they will tell you what size pistons you need.Then when you get the pistons go to the shop n have them start work on the juggs. Quote Link to comment Share on other sites More sharing options...
crustydemon Posted March 31, 2008 Report Share Posted March 31, 2008 Yeah, what he said. Quote Link to comment Share on other sites More sharing options...
Scuba_Shteevo Posted April 1, 2008 Report Share Posted April 1, 2008 so every piston company has a different set of tolerances? Quote Link to comment Share on other sites More sharing options...
gregrob Posted April 1, 2008 Report Share Posted April 1, 2008 No but every piston you get (regardless of manufacturer) will have different tolerances beacuse nothing is "perfect". You take the cylinder to the machine shop so they can measure the bore (in mm) or measure it yourself and order a piston kit that fits. Then let them do the final bore based on what that piston actually measures. make sense? Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.