Blown top end??

blaster_01

blaster_01

New Member
Mar 30, 2013
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so i was out riding the other day when my quad started to bog down and it felt like it was misfiring so i stopped and checked my profire ignition wire was still attached (checked that first cause that fell off last weekend) then pulled the plug and swapped it out for a new one....it ran fine for about 5 more mins then after a big hill climb it died on me.....pulled this plug and then noticed there was ZERO gap left.... looked like my pistonn came all the way up and smashed it close....then i went to kick it and nothing....then noticed i could push the kick start down with my middle finger.....so what are possible issues?? completely blown top end ?? or maybe just piston rings??

i didnt think the piston could come up that high to smash the bottom of the plug..maybe broken piston rod?

and how hard is it to tear apart these motors....new to blasters
 
know that guy that was selling those air leak testers on here before still selling them?? or am i making a trip to homedepot
 
By any chance can you take pics? For a piston to close the gap on your plug sounds like your rod broke or a bearing exploded.. either way you will want to split cases because of all the shrapnal thats in the bottom. Any noise when this happend? Vibration???
 
i can take a pic in the am....and ya thats what i was worried about dont really wanna split the motor
 
I'd say there's no need to perform a compression or leak test first, if your plug got smashed and you can push the kick starter dowb with one finger there's no doubt that you blew your motor. Either the piston shattered or the connecting rod let go, in effect sending your piston flying into the head. Now don't get me wrong you should at the very least have a leak tester and perform leak tests regularly, but at this point there's no need to do one. Your next move should be tearing that motor down so you can assess the damage !
 
10 minutes you can pull your pipe and carb, 4 nuts off the cylinder base and DONE!
You know everything at that point, although it would have been good to do a leak test first.

There is NO way the piston can hit the plug on a stock or even modified head Blaster.
If a bearing flew apart some of the jetsam can pinch the electrode.

Good Luck!

Steve
 
here are pics of both plugs i went through....
5

jl45kp.jpg
 
Hmm.... have you pulled cylinder off yet? If not do a leak test quick. I'm interested to see what caused this. Keep us updated.. like best said there is no way for a piston to hit plug. The plug is recessed in the head. Unless you have something in your cylinder, did anything fall in there when you changed plug???? Something is definetly wrong obviously..
 
Nothing fell in there that I know..... Really hopin I didn't do too much damage.... There's been a ton of money put into this motor and Iam broke right now just spent $600 on headers for my car.... No haven't pulled anything apart yet waiting to leak test it first..... And I'll def keep you guys updated with pics too if needed..... I don't know much about the inside of motors usually just work on the outside and all around them lol
 
so finally started to take my motor apart and this is what i found....
2ugzdcg.jpg

2u62nbo.jpg

1elb4.jpg



soo my question is now... how do i actually take off the piston from the rod and can i just throw on a new piston and be all set or what should i do???
 
blaster_01 said:
so finally started to take my motor apart and this is what i found....

soo my question is now... how do i actually take off the piston from the rod and can i just throw on a new piston and be all set or what should i do???
Click to expand...

dude, thats horrible :eek:
there is chunks of piston missing. :eek::eek:
and i hate to be the bearer of bad news, but that needs much more than "throw a new piston in it"
that needs at least bored/honed to a new piston/rings,

and the bottom end checked for shrapnel and cleaned < but thats a huge risk just trying to clean the bottom end bearings, if 1 little piece is still in a bearing, it will fail and take out the new top end :(

i'd be doing a complete top and bottom end rebuild if that were mine
 
FOD - Foreign Object Damage, although in this case the foreign object was likely the rod bearings.
You need a complete engine rebuild. Case split, new crank and bearings (~$200), an oversize piston kit (~$100), Bore (~$50) and cylinder head rechambering ((~$70). Sucks man, but then what 4 stroke can be completely rebuilt for under $500?

Steve
 
Top and bottom end rebuild is definitely a must ! And it does suck but I had to do the same thing last spring and I can tell you there's nothing like having a brand new motor ! I got a Wiseco top and bottom end kit complete with everything ( piston, crank, bearings, gaskets, seals etc. ) for $315 shipped from Motosport.com. Also as mentioned your going to need a new/used head or have the one you already have rechambered/redesigned ... Considering the money your going to be spending on everything you might as well spend a little more to just have your head redesigned/milled and get some more performance out of it. Hopefully your cases wernt cracked from when that bomb went off in your motor !
 
I had the same exact thing just happen to mine. I ordered a .20 over piston vitos +3 stroker crank and new hot rods crank bearings with seals for just under 300. On ebay you can get a complete weisco engine rebuild kit with new stock crank and piston with all gaskets for 229
 
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