This melt down just might have me stumped..

[Dartman]

Didn't yet!

Think we've narrowed it down to being lean,

but I'm gonna grab a small mirror so I can check the upper reeds without taking the mani off. The lowers are fine.

you still didn't check piston to wall clearance...
you cant make a decision until you check that

 

[Roseand]

you still didn't check piston to wall clearance...
you cant make a decision until you check that

I will once I have time.

 

[Dartman]

I've inspected it the best I possibly could and it looks fine from what I can tell.

But there has to be a chemical to use to flush the cases without splitting them and pulling the motor out..

go to home depot and get 100% mineral spirits
they sell it by the gallon can
blue and silver can
pour it full
spin crank
flip over to dump
add lots of 2 stroke oil into the crank bearing main holes and on the rod bearings right after it dries out

 

[Dartman]

This will hone out.... wonder if the crank is safe to use.

cast pistons will not tolerate mistakes
one BIG positive with wiseco forged pistons

 

[tor*p*do]

Tear it down

 

[waukie]

You cant narrow down and assume without knowing critical #'s. You have a thermal problem, cauased by what? ??? What does the underside/inside of piston look like ? See any shadows / streaks /dark spots? Do you understand what that will inform you of?
You also hav a choice: take apart and clean out what you can.... there may b no debris in bearings but its best way... or run and deal with "what if"

 

[Lumpy]

You also hav a choice: take apart and clean out what you can.... there may b no debris in bearings but its best way... or run and deal with "what if"

This ^^^
If you burn it down again without complete teardown and inspection expect to be receiving alot of atodaso's.

 

[CRJ]

Its not worth investing $100+ on a piston if you cant take an hr to pull the bottom end and split the cases. you dont need to replace the seals, just make sure the bearings arent licoriceed and theres no metal shavings. I normally will not use a crank that had a blown top end as ive found almost every time metal gets into them. motoseal is $6 a tube, but if you want to skip it, its your call. You dont even know if you have a broken reed, the new top end could melt down just a quick, who knows your cases could be cracked.

if its worth doing, its worth doing correctly.

Im not trying to be a dick, but half ass preparation give half ass results.

 

[Roseand]

Yeah I'm gonna tear it down. I feel like it'd be a good idea to do seals too. It's only an extra 40$ or so on oem seals and ensures no leak upon reassembly. You're right. I would be devastated if a crank took out my ported cylinders.

 

[Roseand]

Thanks for all the advice guys. I really appreciate it.

 

[Lumpy]

Should be able to re use your seals

 

[Big Kahuna]

FYI, that pic is not my ski. Local kid picked up a WRIII and it had low compression..............

 

[DAG]

please dont reuse seals.. jesus people. cutting corners is not worth it. How does the old saying go? penny wise dollar foolish

 

[Roseand]

Yeah I'm picking up new seals for sure.

 

[BruceSki]

please dont reuse seals.. jesus people. cutting corners is not worth it. How does the old saying go? penny wise dollar foolish

A cheap man pays twice.

 

[VXSXH20]

A Cheap Man will Pay Twice..

-we really don't need a " why did my excellent condition used seals fail after my top end was replaced thread "

we're not trying to give you a hard time here Andy, just use common sense. I cant fathom why an aspiring engineer as yourself would take a analytical approach to everything ( which is absolutely ok and acceptable ) consider all the variables from torque values to octane ratings.. yet consider "cheaping out" on a rebuild. We know money is tight these days for most all. even on a students budget. But fix it right and enjoy it dude!

 

[SXIPro]

He already stated he is buying new seals......

 

[Sparkplug]

That's from the yamaha manual. They are to be inspected and replaced if damaged or worn. An engineer doesn't replace parts just cause. They go by spec.

It also has the proper answer to the greasing the seals and silicone debate. But to each their own. I've reused seals before. And put 100 of hours on the engines.

 

[CRJ]

on a motor that didnt melt, id re-use them. On a melt down its good to replace all variables, gaskets and seals included.

 

[SpaceCowboy]

Well I can give up two lap dances for some new crank seals...may just have to hit up amateur night instead


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