Rebuilding

[yo_boss]

First off I want to thank you guys for stopping in on my thread. I'm a new user to the forum and new to the rebuilding project of my Blaster which is 2005..

I have a blown piston and wanting to rebuild my engine..

Don't really care if the piston is aftermarket just trying to get her back to stock and running..

Ive torn my engine down and also wanting to get some new gaskets for it also why not right??

Here a piston kit with gasket im looking at on ebay thinking about ordering..

Namura .020 Over Bore Piston & Top End Gasket Kit 2005 Yamaha Blaster 200 66.5mm | eBay

I knoew very little of ATV rebuilds and need some direction remember im looking at more stock then anything else..

If buying this it should fit correctly with my stock heads?

 

[blasterdemon7]

I would not buy that kit. The green gaskets are crap. I prefer Wiseco piston and OEM gaskets. Make sure you watch the Ken O'Conner vid on installing the top end. Make sure you do a leak down test and proper break in.

 

[Prime]

You should talk to woodwardspecialties here about a wiseco forged piston kit. He normally charges $80 shipped.

You should take your cylinder to a machine shop or send it to a machine shop to have it measured, so that you know what piston size you need to take it to the next bore. (for ex. if the cylinder is stock bore now, you need a .010 over or 66.25mm piston to bore the cylinder to.)

Lastly, you shouldn't have to think about getting new gaskets. You need new gaskets if you want that motor to run free of air leaks. Don't use paper gaskets, (generally green) use Cometic or OEM gaskets.

 

[yo_boss]

well i want a stock piston size don't really want to take my heads to get them bored..

If i do get a slight bigger piston what performance will this help?

 

[yamaha28]

Alrighty, welcome boss! I appreciate you stopping by here on the forums before you embark on your rebuild there.

First off, get yourself a manual! Don't take another step before consulting with the manual. I will get you a link for it here, you can also buy a Clymer manual online which is what I do.
http://www.blasterforum.com/general-support-17/downloadable-yamaha-blaster-manual-17325/

I figured you haven't done this before because you gave using the same gaskets a second though. Rule of thumb, NEVER REUSE OLD GASKETS! Good rule to live by unless you want to rebuild your engine again.

How did you figure out your bore? You are able to bore the cylinder 8 times, each .20 every time. If yours has been rebuilt before there will be a bigger bore. I suggest if you did not measure it, take it to a dealer or local machine shop to have it measured.

Second option is sending it to Ken Oconnor Racing. If your cylinder has a nice scratch in it from the piston blowing, then he will have to bore your cylinder. He can measure the cylinder, get the right piston size for ya, then send it back to you ready to reassemble. Just give him a ring and tell him what's going on. Very helpful guy.

index

If you find it does not need to be bored, you can go ahead and order a piston.

I suggest this brand of pistons, one of the top piston brands out there. The lower end pistons that are cast like yours are known to cracking. Here is a link
Top End Rebuild Kit- Wiseco Piston/Bearing/Gaskets Yamaha Blaster 200 1988-2006 | eBay
Little pricier but worth it!

Let us know if you have any questions about rebuilding it!

 

[Prime]

well i want a stock piston size don't really want to take my heads to get them bored..

If i do get a slight bigger piston what performance will this help?

I'm assuming that the cylinder wall is scored or out of round, so that it will need a bore. Correct me if I'm wrong. It could just be that the top end was "tired" and just lost compression and will no longer run. If the piston is torn up, most likely so is the cylinder wall. Therefore it will need to be bored. The head will not have to be touched. Installing a piston that is .25mm larger in diameter will have no effect on performance.

 

[yamaha28]

well i want a stock piston size don't really want to take my heads to get them bored..

If i do get a slight bigger piston what performance will this help?

you have to get it bored if the cylinder has any deep scratches! Any little light ones you can hone, but if it has even one good scratch then it needs to be bored

 

[yo_boss]

I'll take some inside photos of the head tomorrow i believe there's a scratch but then again it might a line that belongs int here..

well what happen i flipped her upside down into a creek it swallowed water and when tearing her apart i notced the piston had a hole through it

 

[Prime]

If the cylinder has any vertical streaks in it, there is a good chance it needs to be bored. Run your fingernail across it. If you can feel it, it needs bored. If not, a hone and a piston of the right size will be fine.

 

[yamaha28]

interesting, hole in the top of it? It can't even run like that

 

[Quadrider10]

Alrighty, welcome boss! I appreciate you stopping by here on the forums before you embark on your rebuild there.

First off, get yourself a manual! Don't take another step before consulting with the manual. I will get you a link for it here, you can also buy a Clymer manual online which is what I do.
http://www.blasterforum.com/general-support-17/downloadable-yamaha-blaster-manual-17325/

I figured you haven't done this before because you gave using the same gaskets a second though. Rule of thumb, NEVER REUSE OLD GASKETS! Good rule to live by unless you want to rebuild your engine again.

How did you figure out your bore? You are able to bore the cylinder 8 times, each .20 every time. If yours has been rebuilt before there will be a bigger bore. I suggest if you did not measure it, take it to a dealer or local machine shop to have it measured.

Second option is sending it to Ken Oconnor Racing. If your cylinder has a nice scratch in it from the piston blowing, then he will have to bore your cylinder. He can measure the cylinder, get the right piston size for ya, then send it back to you ready to reassemble. Just give him a ring and tell him what's going on. Very helpful guy.

index

If you find it does not need to be bored, you can go ahead and order a piston.

I suggest this brand of pistons, one of the top piston brands out there. The lower end pistons that are cast like yours are known to cracking. Here is a link
Top End Rebuild Kit- Wiseco Piston/Bearing/Gaskets Yamaha Blaster 200 1988-2006 | eBay
Little pricier but worth it!

Let us know if you have any questions about rebuilding it!

LIsten to yamaha!!!!! he know what he talking about now! lol

 

[yo_boss]

hey yamaha do you the size of that piston that you linked me to ebay?

 

[yamaha28]

It is a standard bore, you can find others like that brand on ebay though.

All over the place

wiseco blaster | eBay

What is your bore at?