XR650L blown head gasket - could head be warped?

Hey Guys-  been away along time... ( was Exdirtbiker before I had to re-up ) .... playing with a 80 GS1000G

Today my Nephew showed up with a 2000 XR650L with no head gasket visible on front left corner of motor. bike starts instantly, big puff of smoke from that corner.

Before we rip it apart, what are the chances of the head being warped?  I really hope to make this a one day project, not have XR bits all over my garage for a month.

Highly unlikely , but not impossible. It may not have been torqued correctly or a bolt could have come loose or stripped a hole.


OK, we cleaned the garage and ripped the bike apart.

PO staid it just had a new 101mm piston and hot cam... he wasn't lying. 

Looks like they forgot to torque the head bolts ! Popped them off with one turn of my weak wrist.

I can't find anything else to complain about.  

Buying new OEM gaskets, and borrowing a good torque wrench.

Stock size OEM head gasket is OK for a 1 mm overbore, yes ???


Edited by Pete Morley

I used an OEM gasket on my bike without realizing a PO had installed a 101mm piston. I had no issues, but that's not a guarantee it'll be 100% fine.

The stock gasket is OK.

By looking at your picture of the cylinder it doesn't look like the proper head gasket was installed. Does your old one cover the two exhaust transfer ports?



I think Steve is right.looks like they may have used a XR600R headgasket instead of an XR650L..

I`ve seen that here before..:lol:



Oh, BTW...


If in fact there was a XR600 gasket in there what you thought was a blown head gasket was in fact the cylinder to head emission passageways venting to the atmosphere since they were not sealed by the gasket.



Thanks for noticing that Steve... I was so happy that nothing got warped that I didn't notice the holes.

I've been away so long that I forgot all about the smog stuff.


1 hour ago, mcma111 said:


Seems like the right thing to do in this case.

Here's two for you !

giphy.gif giphy.gif

Quite refreshing...




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