Engine locked-up, need advise.

[ozrivera]

Hello all
id like to thank you all for all the helpful information. im a new member but been trolling for some time.
Ok, so i made a stupid mistake for not paying attention. i only premixed half of the 2cycle that i needed on my sons blaster and rode on soft sand. which created lots heat and seized the engine.
i took off the crank cover and the bottom looks good. put it in neutral and tried to free the piston by rocking it back and forth but still locked.
i have 4 other ATV's but this is the only 2 stroke engine. i have tools and am mechanically inclined. so with that said here are my questions.

how do i remove the top end with the piston still seized?

i dont know for sure till i remove everything but, im pretty sure i will need a bore kit. the blaster is stock with boyesen reed valves.

what bore kit would you recommend?
im not looking for a racing kit. just something that works and is reliable.

i wont know the extent of the damage till i take everything apart but, any suggestions up until this would be greatly appreciated.

just thought it would be helpful to mention, that the blaster orginally shut off while driving it. i was able to use the kicker a few times before it just got locked. it locked up during the kicking and not while driving.

thanks

Ozzie

 

[Awk08]

i'd say it locked up as it cooled down, ie......heat things up to expand them, cool things to contract them
your gonna need to get some type of lube, penetrating oil or pb blaster in that cylinder to help break the seizure free from the cylinder, and slide the cylinder up off the piston
if you get lucky the crank will be on it's down stroke, allowing you to push (stand) on the kicker so the crank is pulling down while trying to wiggle the cylinder up and off,
not positve if you could use a small propane torch to carefully, and evenly heat the cylinder to expand it and help with removal ????

once on a ktm144 i had to actually pound wood wedges under the cylinder while a buddy stood on the kicker and finally broke it free

pics of the carnage will allow us to further guide you

 

[ozrivera]

awk, im guessing based on your answer, that im gonna have to free up the piston before i remove the top. i was really hoping to get the top off with the piston still in it. once out i could remove the top cover and bang the piston with a piece of wood and a hammer. pics will come soon, so far i havent opened anything thats visibly damaged. im gonna remove the top cover and pour some break free in there and see if i could break it loose. more to follow

thanks

oz

 

[Awk08]

not gonna happen, the only way to release the piston from the connecting rod is to remove the circlip and wristpin, and that is buried inside the cylinder right now

you must get the cylinder off, then remove piston from rod
(and shove some clean rags around the crank where it enters the bottom end, so you don't drop a circlip or anything else down in there)

i'm assuming you don't have the manual ???
if not, here's a link, after opening, click file/save as, and save to your puter,
the engine disassembly starts on page 75

http://www.rydindirty.com/blastermanual.pdf

 

[ozrivera]

awk, thanks for the manual. well i guess i have some work to do. worst part is that christmas is around the corner. it couldnt have happend at a worst time. LOL

 

[Awk08]

fear not brother, you'r prolly looking at around $200 to rebuild a 2 stroke top end.
find a reliable shop in your area to look at the cylinder and they will tell you what size overbore piston to get
then put a piston and factory or cometic top end gasket set <(only) on your x-mas list, (no green base gaskets, they will leak)
maybe santa will hook you up,

if you don't trust or find a reliable builder in your area, call the number in my sig pic, and get hooked up as professional as it comes !!!!!!!!!

 

[ozrivera]

havent really had a chance to work on the top end but, will this weekend. in the mean time ive been doing some research and pricing. since im gonna rebuild the top end im really considering going with a .040 overbore. i noticed that there are many kits and pistons. whats the difference between the wiseco piston that looks much like stock one and the one that looks to be about half the length of the stock (looks like a couple of big washers stacked on top of each other)? seems like a performance piston but there not much difference on the price. i also might as well replace any seals and bearings while im at it..
trying to keep everything under $300. to end up with a 240cc engine. what kit would you guys recommend? also if i put a 240cc big bore kit, will i need a new carb or modify my existing one?

thanks

Oz

 

[StrokedTater244]

i dont know what "other piston" you are talking about. but i would suggest to use a wiseco piston. best on the market IMO.

 

[ozrivera]

Dont have any pics of the carnage, so im gonna post some pics of my setup

 

[ozrivera]

ready to ride in south Texas

 

[Painthehouse]

No hope of getting a 240 for under $300.
The vitos 240 kit alone is $500.
Plus you would need atleast a 30mm carb.

Vito's 240

LA Sleeve 240

 

[ozrivera]

there both wiseco, take a look.

 

[ozrivera]

there both wiseco but they look much different. whats the difference? or is it even a piston that can be put into a blaster? sorry havent done engine work on a 2 stroke in about 25 years, hehe.

 

[Painthehouse]

The one on the right is probably a stock image, it is a 4 stroke piston. Post up a link of where you got that pic.

 

[Awk08]

a lot of ebay sellers will just use any old pic available for all piston kits they sale,
look down on the page further, most of them say............
"stock photo used - you will receive the proper kit for your application"

as stated above, the wiseco pistons are cream of the crop, as they are forged, instead of cast, which can and do shatter/break

and i see you posting going to .040, that will be determined how far overbore you need to go by the shop doing the work, only go as far as needed to preserve cylinder life, you only get so many bores out of a cylinder, to go bigger is a waste, overboring adds negligent power

 

[ozrivera]

good info guys thanks.

yeah i was a bit confused, i thought there were 2 different wiseco pistons that i could have used. but, as it turns out it looks like theres only one type for the 2 stroke. i got the pics from ebay.
heres a link
Wiseco 67mm 1mm 40 Over P4 Piston Ring Blaster YFS 200 | eBay
well i was originally thinking that if i was going to spend $200+ on a rebuild kit, i might as well spend the extra to go for .040 kit regardless of whether it needed it or not (if it wasnt going to be that much more). but hey thats why im here asking the questions. after you guys response im beginning to think that its not worth it.

awk, i dont really understand what you mean by "negligent power" can you please elaborate? thanks

 

[Awk08]

good info guys thanks.


awk, i dont really understand what you mean by "negligent power" can you please elaborate? thanks

going from stock to .040 or even .080 overbore does not add enuff cc's to increase power that can be felt
it takes considerable cc's to add power, such as the 240 kit, or a stroker crank will add some too
overboring these does not

it's a common misconception, as everyone knows over boring an auto engine adds power, thats because your doing 8 cylinders, and the cubic inches add up much faster than the cc's on these little single cylinders

 

[EvilElvis]

If you are going with a new topend kit I strongly recomend this seller on Ebay he is the cheapest and fastest in shipping and a new member to this site rj_atv heres an example but he has all the bores you need depending on what piston you need, you can also call and order

Yamaha Blaster Wiseco .050 Piston Gaskets Bearing Kit | eBay

 

[EvilElvis]

comes with everything gaskets needle bearing all you need to do the topend

 

[Blaaster]

That piston you mention that looks like a couple of washers stacked up is prolly for a 4 poke, they dont need as much skirt as the dont house any holes for air mix transfer.