Coolant leak

[peski111]

Bike is 2012 yz125.  Did top end and don't think I torqued the left front cylinder bolt enough.  About 6 hours later, Bike did some serious smoking and finally would not even start .  Found some coolant leaking slightly from right below that bolt/stud and from underneath powervalve where cylinder meets case.  Only lost small amount of coolant was lost, looked in radiator when cool and coolant is just even with top of fins so I would guesss 3-5 oz.  So now I guess there is coolant in my case and cylinder.  Another message board said to take top end off and rinse and drain the inside of the case with kerosene, and then rinse with some 2 stroke oil.  Does this sound pretty accurate?  Is it possible that my piston and ring are still ok?  Also, is there anywhere else that the coolant may have gotten into, that I need to check out?  Have not taken it apart yet, using spare bike for next few races.  But already ordered top end parts just in case. 

[zotis777]

It should be fine, do like the others said and take it. Apart and rinse and clean it, also use brand new oem gaskets & a torque wrench to get the correct torque specs every time

[peski111]

It should be fine, do like the others said and take it. Apart and rinse and clean it, also use brand new oem gaskets & a torque wrench to get the correct torque specs every time

Sounds good, new torque wrench already ordered.  Old one apparently not working properly. 

[zotis777]

Sounds good, new torque wrench already ordered. Old one apparently not working properly.

Well if it undertorqued one bolt out of 4 that pretty had haha, how much less was it than the others? Significant?

[peski111]

Well if it undertorqued one bolt out of 4 that pretty had haha, how much less was it than the others? Significant?

this specific bolt sits in the recess of the cylinder and needs the adapter.  I did not have one, so I just torqued it with a combo wrench while I was torquing the other one.  When the wrench clicked, I stopped turning both bolts.  A little of my own warped and demented engineering thoughts.  Ordered a new wrench and adapter as soon as we got home from the race. 

[zotis777]

this specific bolt sits in the recess of the cylinder and needs the adapter. I did not have one, so I just torqued it with a combo wrench while I was torquing the other one. When the wrench clicked, I stopped turning both bolts. A little of my own warped and demented engineering thoughts. Ordered a new wrench and adapter as soon as we got home from the race.

I see, I hate those bolts, in that case I don't think it was your torque wrench in particular just maybe your guesswork haha, never too many tools though, and I was lucky, my dad had some other adaptor for it I used, along with the formula provided with my torque wrench

[peski111]

Tore top end off and getting ready to unbolt case from frame.  Checking out the crank and I see some slight discoloration on the crank itself on both sides of the connecting rod.  Does this indicate a problem of some kind?    I circled it for clarification. It matches up perfectly when the piston is TDC.  

Edited September 20, 2013 by peski111

[zotis777]

Tore top end off and getting ready to unbolt case from frame. Checking out the crank and I see some slight discoloration on the crank itself on both sides of the connecting rod. Does this indicate a problem of some kind? I circled it for clarification. It matches up perfectly when the piston is TDC. 004.JPG

Is that black? Or is the crank blued, I got a hotrods crank in my bike and I think its blued where the big end bearing is but I'm not positive, it may be caused by the leaky coolant, but I see no particular reason it would get discolored in that one region

[peski111]

Is that black? Or is the crank blued, I got a hotrods crank in my bike and I think its blued where the big end bearing is but I'm not positive, it may be caused by the leaky coolant, but I see no particular reason it would get discolored in that one region

Blued.  Surface is still super smooth, no buildup or anything. 

[zotis777]

Blued. Surface is still super smooth, no buildup or anything.

Its normal, It was the same on my crank, did you put that crank in? If so was it blued when you put it in? Or did you have someone else do it? Or is it the origional crank?

[peski111]

Its normal, It was the same on my crank, did you put that crank in? If so was it blued when you put it in? Or did you have someone else do it? Or is it the origional crank?

original.  Bike only has about 20 hours total so far. 

[zotis777]

original. Bike only has about 20 hours total so far.

Yeah its normal don't worry