How To Rebuild Your Topend

well come to find out i take off me head and it has a hot rods rod and also an after market piston do you know how to tell i it is bored out or not?
 
well come to find out i take off me head and it has a hot rods rod and also an after market piston do you know how to tell i it is bored out or not?

There is a number etched into the top of the piston, what is it?
 
What exactly would this do... Just to check nothings gone?

Or does it help at all?
 
wow thanks man just in time i need to rebuild my top end i compression is 90 :/
 
What do you need to do when you rebuild your top end. Just dropped my blaster off and they said that I need a top end rebuild. Have not told them to go ahead, was wondering want type of money for the parts etc and what do you really have to do!
 
Is the compression were looking for supposed to be after 3 kicks? mine on the first kick is 90, after the 3rd kick its 120.

Also the number on my piston is 50, is this stock?
 
im rebuilding my topend on the motor i got yesterday but my piston doesnt look like that at all... no names or anything. it just has 9716F on top of it. and another number across the middle of it thats covered with carbon. im going to town tomorrow to get new rings for it the piston looks almost new. but the rings arent any good. it has low compression. and im going to start with the rings and go from there. if its not then im splitting the cases.

ok i got the carbon off and searched the other number and its a standard size wiseco piston.
what else can cause low compression? its down to 90 on a cold start. should a hone and new rings ring it back to life?
 
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I only got about 75 psi on my compression, i can get it to run but it runs like crap and wont idle and has no power. That was after 20 kicks
 
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First topend rebuild

I got it all taken apart, but I noticed that the cylinder is a little burred at the top. How can I clean that up or do I have to take it in and get it smoothed out. Thanks for any suggestions.
 
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how important are those pieces that look like they hold the fins apart or something? somehow 1 on each side fell off mine, and i know they came off because theres some marks there. it looks like fresher paint where they should be. do i need new ones?

and if you havent read my "major problem" thread in engines then do so and i need to know if this is possibly related to my engine problem.
 
You can replace those with the proper size wooden dowel cut to size and soaked in water for a few hours to soften them up. Then just tap into place with the head on the bench using a rubber mallet so you don't break any fins off.
 
Im gonna respond to a couple things.

1. you need to kick over your blaster a few times while checking the compression. once you reach the highest reading that is your #. 1 or 2 kicks will not give you an accurate reading

2. the wooden dowel things sounds like it would work. But if you leave them off no big deal. As they were only put there to lessen the noise of the fins vibrations like stated in a previous reply. And leaving them off might just give you a better idea if things start to go wrong as more sound will resonate, just an idea though.
 
Oh, and just go check out your local parts store or a Harbor Freight or something... I'm sure they'd have one cheap.
Just be careful buying tools just because they're cheap... You get what you pay for. There's really never a reason to cheap out when buying tools. Unless you know it's going to get trashed.

But then again, that prolly just means you're using the wrong tool for the job.