piston is busted, i cant find the piston anywhere HELP!
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Factory recommendations on piston to cylinder clearance is .0014"- .0016". Wiseco recommends .0022"
Even that difference isn't enough for me to run a cast piston. When they blow, they just disintegrate.
Even that difference isn't enough for me to run a cast piston. When they blow, they just disintegrate.
You should run a compression check immediately after you finish the break-in on a new top end. Then once a month (or if you don't ride your quad that much) twice a year check your compression. Over time it's natural for the rings to scrub themselves and lose their gas tight seal. As they do, it's an indication that your top end needs refreshing.
You can pull the top end off and measure the piston to cylinder clearance and if it's still within a decent spec (it should survive on a single bore several years as long as there is no catastrophic failure) you can hone the cylinder, re-ring the piston and stick it all back together. Do the break-in once again and retest for compression as a "constant" to check future readings against.
You can pull the top end off and measure the piston to cylinder clearance and if it's still within a decent spec (it should survive on a single bore several years as long as there is no catastrophic failure) you can hone the cylinder, re-ring the piston and stick it all back together. Do the break-in once again and retest for compression as a "constant" to check future readings against.
yeah, i tried ebay, is 040 over the same thing as 73mm? i only found one website it it looks kinda sketchy
Vito's Performance Products from Lakes Motorsports ATV Accessories when you click on any piston it shows the same picture
i have your piston laying around but it's a wiseco and i'm living on an other part of the world so it's not a cheap piston for you
If the machine shop told you you can re-use that piston with the ring land deformed, you need to run away from that machine shop. His brain is deformed...
You may be able to re-run that same bore (not have to over-bore to 73mm) but you cannot re-use that same piston.
Look up la sleeve 240 piston on Ebay. If you can use a 72.50mm piston, they are available for about $145.
Blaster 240 Big Bore Piston Yamaha 200 72mm 72.5mm - eBay (item 350310401239 end time Feb-21-11 21:15:55 PST)
Or the vito's cast 240 piston is less expensive but if it comes apart again, it might be the end of your bottom end.
YAMAHA BLASTER CAST 240 BIG BORE PISTON KIT - eBay (item 200275618306 end time Mar-03-11 23:48:32 PST)
Either way, pistons are available, just have to know where to look.
Also, you could take bonzaiking up on his offer. Shipping would be high, but the deal could be mututally beneficial for you both.
You may be able to re-run that same bore (not have to over-bore to 73mm) but you cannot re-use that same piston.
Look up la sleeve 240 piston on Ebay. If you can use a 72.50mm piston, they are available for about $145.
Blaster 240 Big Bore Piston Yamaha 200 72mm 72.5mm - eBay (item 350310401239 end time Feb-21-11 21:15:55 PST)
Or the vito's cast 240 piston is less expensive but if it comes apart again, it might be the end of your bottom end.
YAMAHA BLASTER CAST 240 BIG BORE PISTON KIT - eBay (item 200275618306 end time Mar-03-11 23:48:32 PST)
Either way, pistons are available, just have to know where to look.
Also, you could take bonzaiking up on his offer. Shipping would be high, but the deal could be mututally beneficial for you both.
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The good news is, once you get a new piston back in it, you've got a 240BBK with a rechambered head. It looks to have been ported too. Once you've got more than 30PSI of compression it should run like a raped ape!
ok, say i get this one
YAMAHA BLASTER CAST 240 BIG BORE PISTON KIT - eBay (item 200275618306 end time Mar-03-11 23:48:32 PST) its smaller (72mm)the one i have is a 72.45 i can buy that one and take it to the machine shop and they will make my cylinder smaller to fit the 72mm one? i know nothing! i thought i had to buy a bigger one :-/
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No, you have to buy a bigger piston (or at least the same size if the machine shop said you don't have to overbore)
I just posted links to show you there are pistons available in the sizes you need.
I just posted links to show you there are pistons available in the sizes you need.
Ok, even 72.45 piston is not anywhere. the link you put is 72mm so the .45 doesnt matter?
A quick lesson about big bore kits. All engines have a specification for the piston to cylinder clearance. For stock yamaha it's ~.0015" or .05mm
Either the piston has to be the stated size and the cylinder has to be slightly larger than that or the cylinder has to be the stated size and the piston slightly smaller.
When Wiseco made big bore kits they decided to make the cylinder the stated size 72mm exactly and then print the exact size of the piston on top of the cylinder. Most manufacturers make the pistons .05mm smaller than their stated size because they don't want to confuse anyone.
Your cylinder should measure exactly 72.5mm (it's already been overbored by .5mm) and the piston will say 72.45mm.
If the machine shop measured the current bore size and said it was ok for re-use, you need to order the 72.5mm piston.
If the shop said it needs to be overbored, you'll need to order the 73mm piston and take the piston to the machine shop to have them bore the cylinder to match the piston.
Either the piston has to be the stated size and the cylinder has to be slightly larger than that or the cylinder has to be the stated size and the piston slightly smaller.
When Wiseco made big bore kits they decided to make the cylinder the stated size 72mm exactly and then print the exact size of the piston on top of the cylinder. Most manufacturers make the pistons .05mm smaller than their stated size because they don't want to confuse anyone.
Your cylinder should measure exactly 72.5mm (it's already been overbored by .5mm) and the piston will say 72.45mm.
If the machine shop measured the current bore size and said it was ok for re-use, you need to order the 72.5mm piston.
If the shop said it needs to be overbored, you'll need to order the 73mm piston and take the piston to the machine shop to have them bore the cylinder to match the piston.
Search banshee super cub pistons.
Don't take my word for it but they might come in that size because a super cub comes stock with a 72-ask a builder.
Maybe Twister has them them.
I know for fact that some 421cc Banshee kits use 2 68mm big bore Blasty pistons.
Don't take my word for it but they might come in that size because a super cub comes stock with a 72-ask a builder.
Maybe Twister has them them.
I know for fact that some 421cc Banshee kits use 2 68mm big bore Blasty pistons.