Update Pictures of engine case hole

thomas-ralph

New Member
Jul 22, 2011
135
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South Wales , United Kingdom
Sorry pictures is not the best!

htb66u.jpg


The hole is around a 10mm to 12 mm socket.

24bq1bl.jpg


1ghgcy.jpg
 
that looks to be in the crankcase area of the bottom end, i see the rear lower motor mount behind the drain plug, so thats cleary right under the crank............

busted piston skirt down in there and pushed out thru by the crank
or you hit a big pointy rock and blew up in ?????
 
get a skid plate, that will prevent the rock problem, your going to have to see what did it, then possibly have it welded up
 
It could possibley be a rock awk as i was in a bumpy lane with loads of small rocks.
Quadboy i have allreaddy checked for 1 and soon as i sort this out that the first thing im gona get is a skid plate.

I coverd the hole up to see if it would start , And it did and reved ok.

So what the plan?
should i have the engine spilt? - I havent got a clue where to start.

Theres a place close to me that welds broken caeses so fingers crossed that can be sorted.
 
if u have the place to weld up go for it just make sure u dont keep running it without atleast looking in topend,also see if u got all them metal chunks out of lowend or u will have more problems than that my nephew just went threw that on his with a broken piston skirt!! i just replace a engine half
 
i have bad news, that looks to be right on the split of the case halves, and welding it is gonna make it tough to get the 2 halves to seal properly, which will cause an airleak and go boom again
you can't just weld a piece over it or you'll never be able to split them cases
i'd say new cases are in order,
you still need to pull the intake and pipe to get a look inside to see if the piston skirt broke, or if it was caused externally by a rock or whatever ????
 
You will need to split the case to remove all the debris in there and it looks like both cases need welding/replacing. May pay to get a known good second hand bottom end. The piston could have damaged the bore, you will possibly need a rebore as one the causes of skirt failure is a sloppy bore.
 
Yes it is on the 2 halfs
so best thing to do is go with new case each side.

Does the cases have to be matched or can you use 1 half from a engine and another half from another

And whats a piston skirt
I will need a new piston will i?
 
Repairs can be made in that area by a skilled aluminum repairman. I've done it and I wouldn't call myself "skilled" but more "proficient". It does take a bunch of time and effort to get the case halves to match again and not for the faint of heart but a professional welding operation should be able to handle it. Depending on prices of used parts "across the pond" it may or may not be cost-effective to have it repaired.... absolutely has to come apart and either be repaired or replaces though.

P.S. from the look of the break, something came "out". Look for a broken intake skirt...
 
Skirt is the lower half of the piston, imagine a woman's skirt with the waist being the top of the piston. If it was caused by the skirt breaking off then you will possibly need a bore as well.

Skirt breakages are usually caused by cracks appearing in the piston from rattling around in a loose bore, happens mainly with cast pistons.
 
these are the piston skirts, you should be able to see them thru the intake and exhaust to see if (usually) one right or left side is missing from the intake or exhaust side

piston.jpg
 
Ahhhhaaa now i no.
I had a rougth idea but was not sure.

So im looking at - New cases , Piston and more than likely a fresh bore.

And then i should also change the crank bearings and seals right?

yep on the parts, and i'd do crank bearings and seals to prevent having to do it twice
 
You can check piston skirt through the intake and exhaust ports but in order to split that bottom end, you have to pull the top end off anyway. Go ahead and plan on doing that.

You can mix two halves with relative security. They're not line bored as a pair or anything silly but occasionally some case mating surfaces are lower than others. You may need a dab of silicone under the base mounting gasket during reassembly to take up the little "dip" where two case halves meet.
 
Thanks for all the help guys.

I now planning on tearing every thing down and rebuilding every thing.

Is there a manual or manuals out there that i can buy that shows how to take every thing apart and rebuild after.


Starting with changing breaing in the axle carrier , swing arm.
Then spraying the carrier and swingarm.

And work my way to the front of the quad.

Is there any good sprays or any thing to remove old grease , dirt and so?



Also gona need alot off help these next couple of month now guys so THANKS in advance.