SXR Engine Death and Autopsy Report Part II

[djkorn1]

Completely blew up my engine in Gananaque, Canada on the St. Lawrence River. I can't figure out what went wrong, but I pulled the head and one piston is just destroyed and parts of it are wedged into my head. I know there is a hole in the cases somewhere because exhaust was coming out of the bottom of the the front right corner of the engine. I am sure that I am out for the season. No more money to rebuild the engine for the 3rd time this year. I am not sure what happened. It was running perfect. I was letting friends ride it around on their knees (none of them were going passed half throttle) and I would ride it inbetween them. One guy fell off and went to start it and it wouldn't start. He kicked it in and it was completely f'd. Would barely run. I immediately stopped riding it, but it was too late. I am probably going to need:

SXR Cases (are they the same as SXI and SXI PRO?)
Crank (got one from Unclehulka)
Top End kit
Gasket kit
Bore (Cyllinders seem allright)

Mostly I want to know why it blew. I will rip it apart in a few days after my vacation. Can't order anything for at least a month. :banghead: :bad3:

[djkorn1]

Head is toast too. I will need one of them.

[MADMAT]

OMMFGHSTSA!!!! ******** Korn!! WTF!!??

[ski4]

dude seriosuly more like part 7 in your case
you need to go see a witch dr or something to get these evil spirits out of you
you are possed to destroy motors. so that is what5 or 6 in less than 4 yrs?
christ korn
well call me when you get home i have a phone number for you

so did it look like mine?

are those carbs still on tight????
maybe those wsm pistons are truely are trouble

[ski4]

:bigeyes:

uh huh

[Matt_E]

Uh yeah....I thought WSM pistons have the mark of the beast on them.

[Freestyleriverrat]

Head is toast too. I will need one of them.

Time to get roudy on the motor!!!!! :woot: BB, porting the whole 9 yards man. :biggthumpup:

[Marshj]

wsm pistons toasted mattdede's motor 2 weeks ago. skirt broke off on a 'new' rebuilt motor

[T-bone]

pro-x pistons only...

[Mouthfulloflake]

I had the EXACT same thing happen in my 750 sx engine.

new wsm pistons, about barely 10 hours of use, one skirt broke off.

pulled the head, it looked like "aluminum chowder" inside the engine.

cost me a head, and a lower case.

WSM pistons are NOT a bargain.
in fact I wont ever use them again.

[Matt_E]

Pro-X, Wiseco, Sudco, Art.

Nothing else.

[ski4]

OR..... vertex ( also produced by art)

you still got your stock head don't you korn?
will sxi pro cases work in this application?

[djkorn1]

I still haven't taken it apart...

Anyone know if SXIPRO Cases are the same as SXR?

[ski4]

where are you at on this korn, any word on cases? will 750's work?

[D Slicker]

I read somthing from group k that said that they would.


Rusty,
By the letter of the IJSBA rules, it's illegal to use a bored 750 cylinder in LTD or SS class racing (too bad). That aside, the 750 cylinder bored to 82mm is a better part than the stock 82mm 800 cylinder.
The steel sleeves of the bored 750 cylinder are much thinner, thus making a shorter heat path to the water jacket. The 96 and later 750 cylinders have port timing that offer lots better power than the stock 800 cylinder. Overall, installing a 96 or later 750 cylinder (bored to 82mm) on your 800 will give alot better power.
If you are running a stock inlet manifold with your carbs and pipe, I "strongly" recommend to block the crossover in the inlet manifold.

Respectfully, Harry Klemm


"rusty"WROTE:
Harry, Can you tell me about using a 750 Cylinder bored out to 800 cc on a SXR.
At the moment all I am running is a factory Dry pipe stock carbs & stock compression.
I read a thread about Super Stock Sxr's running this setup but would I gain any performance just using the cylinder?

Thanks

[djkorn1]

Thanks D, Thats interesting, but I am wondering about the cases, not the cyllinder.

:cheer:

[djkorn1]

BTW: Autopsy on Wednesday Afternoon. I will take lots of pics of the untimely demise of my 2nd motor of the summer... :boggled:

[Scorn800]

My best guess is you broke the front rod.

[djkorn1]

I am guessing the same... probably blew the lower rod bearing first...

[ski4]

well????????????????? what did ye find:dead1:

[Proformance1]

Sorry to hear that man! Hopefully it's not too bad. Keep me posted, and I'll keep my fingers crossed for ya!!!!

[djkorn1]

Had to wait till tomorrow... Too much ******** to do for the first day of school. I'll post pics late tomorrow night... I allready know its gonna be bad.
:frown:

[ski4]

yeah, but as bad as it is, you have a crank, 750 cases, just need to focus on the top end and getting a new head, or maybe jeffro can smooth it out at school like mine. and a gasket kit.
done up and running for maybe less than 2 bills

[djkorn1]

Bore $120
Top End $120 (hopefully)
Gasket Kit $50
Cases ? ? ? (750 Cases will work, but are a lot weaker, probably won't hold up.

[MADMAT]

This sucks:frown:

[ski4]

top end $115 with bearings ( if they stock kawi and the size you need)
tell the guy to give you a break on the bore, hell it's the 3rd this yr, mass discount, plus you have sent him myself and matt that should count for something.
tell him 40 bux a hole this time, hell that's fair considering YOU have to chamfer the ports after he is done anyhow
gaskets ? yeah will need those
f it ,use the cases. how much weaker can they be/ people have been building up 750s for years, don't much hear of case failure with those

[MADMAT]

Thats true I have never heard of case failure even on a SS 750.

I dont think that will be an issue.

[djkorn1]

I'm gonna check it out tonight... I will post a full report of my findings!

[djkorn1]

Its bad.... First and last pics are of the large hole in my cases. The second is my blown piston. The third is of the f'd up head (probably fixable) Fourth pic is the green corpse.

[djkorn1]

These are the pics that put the fork in me for sure...The second pic is the crank bearing that blew, (why it blew I have no idea, engine was running fine, Bearings were perfectly smooth and the crank was within 0.002 of being true) It actually blew up when it was just putting around. A bearing shot up and fired through my cyllinder as you can see in the fourth pic. A chunk of the cyllinder then shot up and into my head after bouncing off of and imbedding into my piston. Another chunk of the cyllinder then went down and blew through the bottom of my cases. The bummer was the cyllinder wouldn't even need a bore if it wasn't for this big chunk out of it.

So in total, I need:

Cyllinder
Cases
Top End Kit
Gasket Kit
Crank that will not blow up (anyone know of ones that will last on a modded SXR???)

Basically, I need an entire shortblock. I will be looking around November for a good strong reliable, fresh shortblock with a bulletproof crank.

[WaHoo_1]

damn dj.... that is some carnage there bro! Jeesh! Sorry for your troubles. I forsee a SJ in the Green dude's near future!




your refined avatar is too appropriate...

[djkorn1]

My new hobby...superjets blow up too.

[ski4]

ouch:bigeyes:

[Freestyleriverrat]

Oh no!!! :puke: What are your plans for the next motor?

[w-nut]

dam sorry to hear that dude , some off that is fixable have you thought about resleaveing your cylinder it could be a good time to go to over size sleaves and doind the big bore thing . get a stroker crank as well and have a 900

[MADMAT]

That really sucks Korn. I feel for ya man. That is depressing.

[djkorn1]

I tell ya what... I really just want the ski reliable at this point. Teachers don't make enough $ to keep blowing engines...

[D Slicker]

DJ, Is guess its time for a cylinder and port work....:Banane01:

[Scorn800]

Damn dude, You did a good job of blowing that 1 up.
Use new OEM crank and should get atleast 100hrs out it.

[Matt_E]

Korn, I feel for ya. I went through 1 topend and one crank (separate occasions) this year.
It sucks.

[kingnothing3]

:shocked: :pat: :smileeek: that sucks dj!!! Cant go wrong with reliability. I was really looking forward to heading down there and riding with ALL you guys again too. :starwars: never played but ill call you if i am down there.

[djkorn1]

Do you know someone who has done this????Never heard of it.


dam sorry to hear that dude , some off that is fixable have you thought about resleaveing your cylinder it could be a good time to go to over size sleaves and doind the big bore thing . get a stroker crank as well and have a 900

[Proformance1]

Have you figured out what went wrong yet?

[ski4]

korn
with your luck and ability to ruin things stick with stock componenets
stay away form anything that is gonna cost ya more to fix than stock stuff
you know you will ruin it soon again . it's in your genes:frown:

[djkorn1]

I break stuff...:shooter3::dunno:

[w-nut]

hi korn im not sure where you can get it done in the states (im in new zealand) but i know wisco makes over size sleaves for the 750 motors (800s shouldnt be that diffrent ) , ive got a set on the way for my 750 at the mo (820cc and still a couple off rebores left ) . leg drag pete has done the same on the motor in his x2 so you could proberly ask him where he got his done . or any good engine machine shop could proberly do it . they machine out your old sleaves and cylinder to suit the new sleaves then heat your cylinder up nice and hot and drop the new sleaves in and when the cylinder cools down it shrinks and locks the sleaves on place .
if you do get new cylinders i would be keen to buy your old one and fix it for my ski .
good luck and keep us up to date with the rebuild.

[w-nut]

http://www.lasleeve.cc/index.cfm?event=product.display&product_ID=1010
that should be a link to get new sleaves for you engine and if you go to the wesico website you can down load there catalog and it gives you all the piston kit details and stuff to rebuild your top end
hope that kinda helps

[Scorn800]

Replacing Kawi sleeves is expensive because the old sleeve must be bored out.

[w-nut]

true you do have to machine out the old sleave but form my experance it can be alot cheaoer than a new cylinder and from memory only one sleave need to be replaced if dj wont to keep it at the standard bore size

[doogiesux]

The 750 cases work ok ...Mike Delaire a racer from canada is runnign them on his sxr..I am pretty sure i have a set of bearings and a set of big pin cases here. If i have them around you are welcome to them for free I will even pay the shipping.

[djkorn1]

Thanks man, really appreciate it.

Especially since now I realize the crank from UncleHulka is no good. One of the center bearings is a little rough. I'm afraid to use it.

Bad news keeps hitting me like a 2x4. :banghead:

[douglee25]

Thanks man, really appreciate it.

Especially since now I realize the crank from UncleHulka is no good. One of the center bearings is a little rough. I'm afraid to use it.

Bad news keeps hitting me like a 2x4. :banghead:


Send it back:biggrin:

Doug