My rebuild went wrong, head gasket blow


14 replies to this topic
  • akiraone

Posted December 21, 2008 - 10:15 AM

#1

I need help with rebuilding I have just done it but I have do it again, because my head gasket just blow :thumbsup: to high pressure in water system the water is boiling to fast. I don’t know exactly what I did wrong I was keep going with manual. I used go quality torque wrench. But I didn’t like specification for torque the head bolts this 30Nm then lose and retighten to 20Nm and the up to 180 degree in two steps. Do you always do in this way ? I think it’s a little bit to tight don’t you think its even really hard to lose those screw :smirk: … Anyway what I could done wrong ? Please any advice would be appreciated…

I don’t want blow new one gasket again. I use OEM Yamaha Gasket , all surface are clean and flat. And should I tight the cylinder first then the head ? or first head and then cylinder ?

Regards
Eryk

Sorry for my English :-(

  • KJ790

Posted December 21, 2008 - 10:35 AM

#2

So you are saying that you did not torque the head bolts to spec and you are wondering why the head gasket failed? Torque the head bolts as the manual says and you shouldn't have a problem.

  • akiraone

Posted December 21, 2008 - 10:45 AM

#3

eh my english :-( ... Nop. I did like manual say everything like in manual. But I think it to much in my opinion....

  • brad the best

Posted December 21, 2008 - 11:02 AM

#4

did you do them in the proper sequence ? did you replace the head gasket ? i personally replace the bolts as well you probably don't have to on this engine but its never a bad idea .

have you checked to see if its warped ?

  • akiraone

Posted December 21, 2008 - 11:05 AM

#5

Maybe after the first ride I should , retorque my head ? Can I do this ? retight the screws ? or this is not the solution, if I can how I should do this relase them all and set again how is in the manula writed ?

  • akiraone

Posted December 21, 2008 - 11:13 AM

#6

yep all new gaskets, base one and head one, also on the clutch cover and ignition. I did not replaced the screws. Its a first rebuild on this bike (wr450 2006). I dont want to blow it again :-( new one. Should I replace the base gasket aslo under the cylinder or only under the head ?

yes I checked if its not warped with filler gauge on the flat surface, everything was look ok.

  • akiraone

Posted December 21, 2008 - 01:00 PM

#7

Or maybe Im wrong and this is not the faulty head gasket ? When I should know when this is a blown gasket ?

I stop the engine after it idle 3-4minutes its come pretty hot, and the coolant startet coming from connecting hose that is comming to the water pump, I was think that is meaybe the faulty o-ring inside but I dont think so, how about you guys ?

But now everytime when I start the engine even cold I can see when I take the cup from radiator that there are comming bubles a lot of them just after 10 second of start.

Maybe I should mention that after replacement I start the engine and everything was look allright then I hit the road for 3-4km and came back home, and after its come cold I start again and the problem show up.

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • jhmotard

Posted December 21, 2008 - 01:07 PM

#8

is coolant seaping from the head gasket?? how do you know you already have a blown head gasket??

maybe you have an air pocket in the cooling system?? did you run the bike without the radiator cap to eliminate this?

  • akiraone

Posted December 21, 2008 - 01:39 PM

#9

Nop I cant see any coolant seaping from head gasket, just when I take the cup I can see just after few second a lot of bubble not like before. And how I mention before the coolant found the way to escape on the conection hose where is going to the water pump (there is oring I guess - maybe I have bad luck and this is just circumstantce that the oring get faulty and the same time that I finish rebuilding). I have a boysen water pump, and I never found that my engine is so hot after just 2-3 minutes in idle. But maybe it have something to do that I replaced new piston and rings now is bigger compression etc. ??? ahhh dont know what to do help please

  • Just_a_trail_rider

Posted December 22, 2008 - 12:42 AM

#10

Nop I cant see any coolant seaping from head gasket, just when I take the cup I can see just after few second a lot of bubble not like before. And how I mention before the coolant found the way to escape on the conection hose where is going to the water pump (there is oring I guess - maybe I have bad luck and this is just circumstantce that the oring get faulty and the same time that I finish rebuilding). I have a boysen water pump, and I never found that my engine is so hot after just 2-3 minutes in idle. But maybe it have something to do that I replaced new piston and rings now is bigger compression etc. ??? ahhh dont know what to do help please



More compression will mean more heat. This is why your water is boiling so fast.

Did you change the jetting. It could be running a little lean which may cause more heat.

  • akiraone

Posted December 22, 2008 - 05:26 AM

#11

More compression will mean more heat. This is why your water is boiling so fast.

Did you change the jetting. It could be running a little lean which may cause more heat.


Nop I did not changed the jetting, should I ? when I take it for a small ride 3-4km it runs great.

More compression will mean more heat, hmm I putted oem yamaha piston std new with new rings is that so much different ? is there any way that I could recognize that my head gasket is damaged without taking the head out ? please any advice. Now I dont know what to do, I read in some threads if there is start bolining just after the start without the cap on radiatior its mean that head gasket is blow. and its getting pretty hot, just after two minutes I never notice it before rebuild. I was could idle it for 4-5minutes without any problems.

and why the coolant just came out on the connecting house to the water pump, just bad oring or to much pressure in the radiators....

  • matt4x4

Posted December 22, 2008 - 05:31 AM

#12

Here's what you should be doing, and just so you know - it does NOT sound like you have headgasket issues...just a bad oring or connection.

Once you have your system put together, you fill it with antifreeze through the radiator cap (I think you call it cup)

I generally crank my bike 20-30 times without starting to get the fluids pumped through, you can't get an air pocket in the cylinder head since the upper rad hose continues up to the rad so there is no extra bleeding required at the head since your highest point is the rads.

If your leak occurred at the head where the hose connects, you may have had some dirt in where the oring seats, or your oring got pinched on install, or the oring is simply bad and needs replacing. I tend to replace all those orings upon rebuild - it's cheap insurance.

you should run your bike to make sure fluid is being pushed to the overflow - anything more than 2-3 minutes of idling without moving and you WILL boil your coolant - you NEED to have air moving through the rads, these bikes do not like sitting still.
Once you have gone through a full heat cold cycle, check your overflow in the rear, make sure it's on the full cold line (lower of the two once your bike is cold) and make sure it stays there after a number of rides.

Once other word of warning, make sure your overflow line to the reservoir is not getting pinched - if you routed it through an area where it can get pinched by the tank or seat, it will push the coolant to the reservoir when hot, but be unable to suck it back when cooling and this can collapse one of the rad hoses and make your rad look low as if you've lost fluid - but the fluid is actually in the reservoir.

  • akiraone

Posted December 22, 2008 - 01:20 PM

#13

ok, I have replaced my oring on the hose that comes into water pump. I start it and idle for 3-4minutes. no signs of leak. then I turn it off I let it cool down and I start it again without the cap on radiator and just after 10-15seconds I could see a lot of bulbs is this maybe normal ? when I have a boysen water pump I was try to compare with my friend with his wr250 2008 with stock water pump, I could see similar effect only when I run it in higher RPM, on ilde it was just bulb bulb :-) not bulblbulbbulbbulbbulb like on mine :-)...

ok I putted the cap on radiator and take if for 5 min spin everything was run great no leak only when I cam back head,cylinder and radiator are came very hot :-( . right now dont know is there everything ok or not. maybe im just getting insane because it was just my first rebuild :-) ....

still sorry for my english

  • jhmotard

Posted December 22, 2008 - 04:27 PM

#14

i think you may be okay as far as a blown head gasket.

but you may be running a little too hot because of lean jetting?? just a guess.

what is your current jetting/altitude/modifications done to your bike???

  • matt4x4

Posted December 23, 2008 - 05:22 AM

#15

Also - when you rebuilt, you must have checked your impeller on the water pump so it should be fine - really the only other reason I can see that it would boil over.....
If you're not losing fluid, then you don't have a leak.

What coolant are you using - I only use high quality coolant - and that can make a difference too when it comes to the boiling point.

If everything is pretty much the same heat after your ride (head, cylinder, rads and hoses) then you are likely fine for coolant circulation.

The movement (bulb bulb) you see could be the force of the water pump - yours might circulate more volume thus creating more disturbance.

here's a little test you can do to compare.
Ride your bike for a certain preset amount of time at certain revs, shut it off, drop a meat thermometer into the rad lid and read the temperature at 30 seconds.
Do the same on your buddies bike and compare, if they are within 5-10 degrees then everything is fine.




 
x

Join Our Community!

Even if you don't want to post, registered members get access to tools that make finding & following the good stuff easier.

If you enjoyed reading about "" here in the ThumperTalk archive, you'll LOVE our community. Come join ThumperTalk today!

The views and opinions expressed on this page are strictly those of the author, and have not been reviewed or approved by ThumperTalk.