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Dare Devil
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53 Posts
Discussion Starter #1
I am rebuilding my fuji 500 out of my 1990 polaris indy 500 because it blew the gasket between the crankcase and the cylinders...( see in photo ) when i took it apart i noticed some wear on the pistons and wanted some input on if i sure just change gasket and leave everything or changes rings/ pistons etc... the pistons say .50 mm on them? does that mean its been bored over 50mm over . Well any input will help .. tell me what you think of the pistons



 

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Rick
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3,070 Posts
yes thats bored that much. mine is .40 over and mine say that on mine. i was told .40 over is the most you wana go safely i that motor. how do the cylinder walls look? and are the pistons scored or just glazed? if they need to be replaced and even bored more you'll need to get new jugs or re-sleeved. and those for sure are not stock pistons. they look like my .40 over lite ones i just put in mine.
 

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Premium Member
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34,103 Posts
Normal scuffing and wash on top of the pistons.
How long ago was the last rebuild done?
If not so long ago, just put new gaskets on and go, otherwise, just new rings too.
 

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Dare Devil
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53 Posts
Discussion Starter #4
my uncle i bought it off had a friend screw with it all summer and his friend said he rebuilt it then... and no one used it till i got it three weeks ago ... i dont remember seeing if that gasket was pushed out or not .. or if it happened after.. the stud by where the gasket got pushed out came out with the nut and seems to be a little stripped so maybe it wasnt tightened enough? so i should just regasket and go?
i guess try the old stud and if it doesnt grip put a coarse bolt and tighted it with that?
 

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Rick
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3,070 Posts
is the bolt stripped or is the hole stripped?
 

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Rick
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3,070 Posts

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Rick
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3,070 Posts
lol i know that but was wondering where he came up with that.
 

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Dare Devil
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53 Posts
Discussion Starter #11
it was running pretty good before it blew out the gasket so im just gonna put all new gaskets and put er back together .. how much can gaskets cost $50 right.. then this summer i will replace the sleeves and pistons or get a used block with std size pistons and get it redone to .020 ... now my only problem is setting the carbs up
 

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Rick
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3,070 Posts
i just got a head gasket and it was 30 bucks. for the one that blew on yours i got silicone that is made for that. but it is like 25 bucks for a small tube. not sure on what a gasket is for it. and for the carbs if you didn't mess with nothing to much and it ran fine befor ethen try them out. if not there is a how to forum that will show you hot to set them up or even go to youtube for it.
 

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Dare Devil
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53 Posts
Discussion Starter #15
thats great :) if thats the case my engine is only .020 :D on my intake ports where the carb boots go on there is 020 stamped on both sides i didnt put 2 and 2 together ... so i guess ill just use them as is and then this summer ill rebuild and bore to .040 ok more questions and pics up next
 

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Dare Devil
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53 Posts
Discussion Starter #16
ok here is the my solution to the stripped hole .. the threads only go done about 3/4 of an inch and the hole goes down and inch or so so i rethreaded the hole deeper and used 3/8 threaded rod and pics will tell the rest



 

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Dare Devil
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53 Posts
Discussion Starter #17
ok waiting to go get gaskets but heres more questions here are two pictures of my carbs. carb #1 is not straight where the floats ride and carb #2 is straight .. how is it suppose to be

 

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Dare Devil
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53 Posts
Discussion Starter #18
and question 2 .. are the carbs suppose to be mounted a little side ways like in the pictures in the tabs ? .. ( dont make jokes lol thats how the carbs sit in the tabs )

 

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I just fix 'em...
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1,045 Posts
Threaded rod repair looks ok as long as you got good threads in the block. Carb float arms need to be level and the same on both sides. Carbs need to be straight up and down in the boots- your boots are wrong. Just cut off the rubber locating tabs or grind the locating protrusion off the carb and you'll be good to go.
Jerry
 

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Dare Devil
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53 Posts
Discussion Starter #20
thats what i thought ... i wanted a for sure answer thanks you guys appreciate it alot .. any one else please feel free to post your opinions too..
 
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