if it works once ill be happy with it, i just want to see where i stand with this old beat up blaster i bought, see how soon i need to think aobut rebuilding
How To Rebuild Your Topend
- Thread starter 01blaster_freak
- Start date
Yeah, but what about next time you need a rebuild? On any of your toys? Meh. Up to you.
Good luck, man. I hope the rebuild goes well.
Good luck, man. I hope the rebuild goes well.
Just a question? anyone have a special way to stagger there ring gaps? I neve do on the thrust side, but have on the two non thrust sides opposed 180 degrees from eachother. Re ringing this weekend and going to inspect for wear please hit a post on this.
Wiseco pistons have notches in them that line up with the ring gaps to get the proper stagger... I am pretty sure most of the aftermarket ones do.
when you rebuild dont you need to bore it out every time?
just asking because i have barely any compression ,wont even start
just asking because i have barely any compression ,wont even start
You put the piston back in the jug very carefully!! Some pistons don't have the little pins that keep the rings in the proper orientation...so keep in mind you don't want the gaps right on top of each other!! If there aren't the pins, 180 degrees from each other is a good idea. So to get the piston back in the jug, with a new base gasket already on the bottom (yes, you need new gaskets every time you take the head off!!!) you just slowly lower the head down onto the piston (bearings, pin, and C-clips already keeping the pisotn on the rod) and compress the first ring as best you can until it will slide into the cylinder, then do the same with the next. Don't force it, be gentle!!
Most people recommend atleast doing rings once a year. As long as you keep a clean air filter and haven't run really hot or really lean a lot, the piston shouldn't be all that bad. You can check the piston and cylinder for spec with a micrometer. If everything is within spec, you'll want to at the very least do new rings. A new piston is cool, but if the stock one is still in spec, and you're not made of money, honing the cylinder and doing rings will bring back lots of life for less money!!
So, any time you put in new rings, you need to have the cylinder honed. You can do this yourself with a honing tool or bring it to a shop and have them do it...it takes 5 minutes!! I've seen two types of honing tools, they both do the trick, but basically honing just puts a cross hatch pattern back into the cylinder bore which is needed for the new rings to seat properly. If you don't hone and throw new rings in there, you're wasting your time/money. So you throw the honer on the drill, work in in and out of the cylinder a few times, clean it up real well and it's done!! Wipe it as clean as you can get it. Here is another advantage to using a machine shop, they will usually give it an acid bath or atleast in parts cleaner so that there are no fine metal particles hanging around. May be worth a little extra over buying your own tool....but some shops don't do this, so ask.
If the cylinder/piston are out of spec, take it to a shop and they will bore it out to the next size over. They usually go in 0.020" increments...that is two hundredths of an inch..., which is roughly half a millimiter (0.508mm to be exact). If it's gouged bad, they may have to bore it out 0.040. You're really not gaining any displacement by boring it out here...you're just fixing the surface that the piston and rings ride on so that you have good compression, so it doesn't matter how much you bore it out...you want to go as small as possible.
Oh yeah, I forgot to mention that you probably don't want to order your piston until the shop has finished doing their thing!! Give it to them and they will know how much to bore it. They hone it after it's bored. You'll notice a cross hatch pattern in the cylinder, this is what you want!
If you want, you can have the machine shop order a piston for you, and you can have them polish it up a bit, match it to your cylinder perfectly. It should match pretty well, but they can just knock off burrs and such and maybe do an ever so slight porting job...still basically stock, just cleaned up. Depends a lot on what kinda shop you have near you. I'm lucky enough to know a guy who works at a shop that specializes in motorcycle machine shop work....so they work on bikes of all shapes, sorts, and sizes all the time and know every aspect of your bike way better than you, which is good.
Also, the OP didn't cover this but when you put the cylinder and head back on, especially the head, there is a specific torque sequence, kinda like putting on a tire in a star pattern. However, with a head you usually torque in a star pattern (or whatever specific pattern the manual for the bike says) first to one torque setting, then to another final setting. Oh yeah, you do need a torque wrench for this!! Too loose, you're gonna have leaky gaskets, too tight, and you can break one of the studs as they expand and contract....so yeah, it's very important to have them torqued in the proper order and to the proper spec. Oh, and before you put the head on it doesn't hurt to pour just a tiny dab of 2stroke onto the piston. the idea is for it to fall down into the rings in the time it takes you to finish putting everything back together. Also, it doesn't hurt to dab a tiny bit of oil on the rings themselves instead of pouring just an ever so small dab of oil onto the piston. Hopefully you pre-lubed the bearings too...
Cliffs:
-Rings about once a year is ideal, although you can obviously get away with less
-Need to hone a cylinder before putting in new rings, or else you'll be worse off than before
-Need to use new gaskets...you can only tighten them down once!!
-Follow the manual for torque specs, it's very important!!
One more after-thought...while a new aftermarket piston is nice because it is fresh and will be slightly lighter than stock, running the same piston that is not out of spec but a little looser than brand new is helpful!! The looser that piston is the less friction, yada yada, more power. The rings need to be tight, but the piston being a little loose is a good thing.
Most people recommend atleast doing rings once a year. As long as you keep a clean air filter and haven't run really hot or really lean a lot, the piston shouldn't be all that bad. You can check the piston and cylinder for spec with a micrometer. If everything is within spec, you'll want to at the very least do new rings. A new piston is cool, but if the stock one is still in spec, and you're not made of money, honing the cylinder and doing rings will bring back lots of life for less money!!
So, any time you put in new rings, you need to have the cylinder honed. You can do this yourself with a honing tool or bring it to a shop and have them do it...it takes 5 minutes!! I've seen two types of honing tools, they both do the trick, but basically honing just puts a cross hatch pattern back into the cylinder bore which is needed for the new rings to seat properly. If you don't hone and throw new rings in there, you're wasting your time/money. So you throw the honer on the drill, work in in and out of the cylinder a few times, clean it up real well and it's done!! Wipe it as clean as you can get it. Here is another advantage to using a machine shop, they will usually give it an acid bath or atleast in parts cleaner so that there are no fine metal particles hanging around. May be worth a little extra over buying your own tool....but some shops don't do this, so ask.
If the cylinder/piston are out of spec, take it to a shop and they will bore it out to the next size over. They usually go in 0.020" increments...that is two hundredths of an inch..., which is roughly half a millimiter (0.508mm to be exact). If it's gouged bad, they may have to bore it out 0.040. You're really not gaining any displacement by boring it out here...you're just fixing the surface that the piston and rings ride on so that you have good compression, so it doesn't matter how much you bore it out...you want to go as small as possible.
Oh yeah, I forgot to mention that you probably don't want to order your piston until the shop has finished doing their thing!! Give it to them and they will know how much to bore it. They hone it after it's bored. You'll notice a cross hatch pattern in the cylinder, this is what you want!
If you want, you can have the machine shop order a piston for you, and you can have them polish it up a bit, match it to your cylinder perfectly. It should match pretty well, but they can just knock off burrs and such and maybe do an ever so slight porting job...still basically stock, just cleaned up. Depends a lot on what kinda shop you have near you. I'm lucky enough to know a guy who works at a shop that specializes in motorcycle machine shop work....so they work on bikes of all shapes, sorts, and sizes all the time and know every aspect of your bike way better than you, which is good.
Also, the OP didn't cover this but when you put the cylinder and head back on, especially the head, there is a specific torque sequence, kinda like putting on a tire in a star pattern. However, with a head you usually torque in a star pattern (or whatever specific pattern the manual for the bike says) first to one torque setting, then to another final setting. Oh yeah, you do need a torque wrench for this!! Too loose, you're gonna have leaky gaskets, too tight, and you can break one of the studs as they expand and contract....so yeah, it's very important to have them torqued in the proper order and to the proper spec. Oh, and before you put the head on it doesn't hurt to pour just a tiny dab of 2stroke onto the piston. the idea is for it to fall down into the rings in the time it takes you to finish putting everything back together. Also, it doesn't hurt to dab a tiny bit of oil on the rings themselves instead of pouring just an ever so small dab of oil onto the piston. Hopefully you pre-lubed the bearings too...
Cliffs:
-Rings about once a year is ideal, although you can obviously get away with less
-Need to hone a cylinder before putting in new rings, or else you'll be worse off than before
-Need to use new gaskets...you can only tighten them down once!!
-Follow the manual for torque specs, it's very important!!
One more after-thought...while a new aftermarket piston is nice because it is fresh and will be slightly lighter than stock, running the same piston that is not out of spec but a little looser than brand new is helpful!! The looser that piston is the less friction, yada yada, more power. The rings need to be tight, but the piston being a little loose is a good thing.
ok my blaster just come from the shop for jetting changes and helicoil job. My friend who is the mechanic at the dealership said he mic'd my specs. and said that the bore was 66.37 and the piston was 66.20 . He also that was pretty loose but the compression was at 150 but i still need a top-end soon what do you guys think needing advice
hey man check out my piston, i started a thread because i was having issues, compression was 60 psi, i pulled the head, and well... both skirts cracked
this ones a sticky and you cant be any of kens videos
http://www.blasterforum.com/engine-13/how-install-cylinder-31635/
