Horizons Unlimited - The HUBB

Horizons Unlimited - The HUBB (https://www.horizonsunlimited.com/hubb/)
-   Yamaha Tech (https://www.horizonsunlimited.com/hubb/yamaha-tech/)
-   -   XT600 engine rattle (https://www.horizonsunlimited.com/hubb/yamaha-tech/xt600-engine-rattle-78303)

etsihel 21 Sep 2014 17:15

Another update...decided to take cylinder off also.... :eek3:
It was over 8 months in workshop and this is what I get...
https://dl.dropboxusercontent.com/u/...921_184907.jpghttps://dl.dropboxusercontent.com/u/...921_190138.jpg
pretty.....

I checked the old head and new one and both pistons... Valves and piston seem ok, no hit marks and at old head they were restored when I got engine back from repairs.

xtrock 21 Sep 2014 18:15

Wow thats really sad, end of story for that engine with parts of the piston all over...

Jens Eskildsen 21 Sep 2014 18:47

Its just plane sad what a lousy mechanic can do to an otherwise good engine.

beagle scott 22 Sep 2014 01:51

:censored: thats got to hurt !doh
Good luck .
Its looking like versions No 2. Too much oil may have hydraulic-ed the piston. As piston went to bottom of stroke it may have hit the overfull oil level and cracked ?

jjrider 22 Sep 2014 02:48

Quote:

Originally Posted by beagle scott (Post 480364)
:censored: thats got to hurt !doh
Good luck .
Its looking like versions No 2. Too much oil may have hydraulic-ed the piston. As piston went to bottom of stroke it may have hit the overfull oil level and cracked ?


It's because the cylinder is bored oversize and a standard piston was used. Each firing slaps the piston as in his video(it was worse there because the skirt was already gone).Piston had .01" clearance which will always end the same way. Notice which side skirt is broken ,the side that would hit on combustion.

Hydrolocking would most likely cause the piston to break around the wrist pin (or blow the top off it)and bend/break the rod, maybe crack the cases around the crank bearings. By looking at an XT motor it would take probably close to 4 quarts to stop the piston.

I see that the picture that shows the .25 on the top of original piston wasn't posted here, but on ADV, so Beagle is probably not seeing what some of us others have. It's where I got into the too small piston problem. https://dl.dropboxusercontent.com/u/...tud/piston.jpg

beagle scott 22 Sep 2014 23:30

:oops2: !! Yes that is it alright to sloppy from day one ! I haven't been on the other sight. he should stand by his mistake but as already said I wouldn't trust him much at all ! Good luck

etsihel 6 Oct 2014 14:21

Little update.

Got the cylinder checked out and those are minor scratches, no need to rebore. Piston should be 95,25 like it was before the repairs and finally got in touch with the mechanic and when he saw that broken piston, he told that he is going to get new piston kit. Everything went smooth.
I don't know if it is true, but he told that cylinder size was checked out by local motoclub....although I think you can see that piston is too small when you put it into cylinder...

Most people told me, that there's no point to split the cases. I kind of think the same. Going to fill it with diesel and get metal dust and all the pieces out(already found most in the clutch area).

Also found this thing in other topic about KTM:
Quote:

On a Japanese bike? Flush it out and put another 50,000 miles on it.
That bike? Tear it apart.
The metal dust should not be the problem, cause oil filter is going to catch most of it and even when you brake in new engine, you get metal dust anyway.

In 100-200km oil change, then at 1000km. But all of this will be in about 2015 march/april cause of winter is coming and can't ride with icy roads+snow.
Under oil pump gear, theres a hole with some skirt pieces. You can see 1 piece there if you look closely.
https://dl.dropboxusercontent.com/u/...tud/engine.jpg

xtrock 6 Oct 2014 14:28

What size is the piston that cracked? if you dont need rebore you need to do some hone of the cylinder, good luck.

etsihel 6 Oct 2014 14:48

Quote:

Originally Posted by xtrock (Post 481850)
What size is the piston that cracked? if you dont need rebore you need to do some hone of the cylinder, good luck.

95.00 size, should had been 95.25. Yeah, will hone it.


All times are GMT +1. The time now is 07:01.


vB.Sponsors