Blaster blown gasket twice any opinions, dropped sleeve?

[bigo]

ok so im never good at diagnosing carnage i brought wb2 760 when i got it it was down 30psi in the rear i popped the head and put an aftermarket head gasket on and compression was spot on again went for 20 min ride and retorqued off i went again for maybe 15min before this happened.

any opinions
chit aftermarket gasket ?
dropped sleeve?

 

[Carbon Blaster]

A bit hard to see in the pic, but a head gasket will usually blow for a few reasons, especially so quickly after you've just changed it:
Head bolts not torqued correctly
Sleeve dropped
Head warped
Cylinder deck surface not flat
Insane compression
Detonation
Surface of head has corrosion pitting
Quality of gasket
Thread in cylinder for head bolt is starting to strip & not holding torque
You will need to clean the head & cylinder surface right up & place a straight edge accross the head surface & check if the sleeve has dropped with a thickness guage or if you can see light. Sometimes you can obviously see if it has dropped, or feel a step.
If it hasn't dropped, it is worth checking how flat the cylinder & head surface is. As you've just bought the ski you don't know the whole history, it may have overheated badly at one stage.
OEM gaskets are always a safer option, sometimes you do get what you pay for with oem versus aftermarket.

 

[waxhead]

A 760 will always be down in the rear. The head was machined like that from the factory.
Its not normal for the 64x cylinder to drop a sleeve its more of a 61x thing so I would not be suspecting that at all.
The 760 head also is a stronger casting compared to 61x heads.
My money would be on the aftermarket head gasket. But it would be a good idea to check the head before you put it back on for warpage.
You can also spray the head gasket with hylomar it helps them seal up.

 

[SUPERJET-113]

LOL, thats a rusty stainless old corroded 760 gasket. How could it get rusty and corroded like it is after 20 min?
Look at the major rusty sleeve and piston head too..

Whats up with these pictures?? :crazy:

 

[JetManiac]

LOL, thats a rusty stainless old corroded 760 gasket. How could it get rusty and corroded like it is after 20 min?
Look at the major rusty sleeve and piston head too..

Whats up with these pictures?? :crazy:

That is what I was thinking! A new head gasket wouldn't rust up like that after a couple rides. Hard to tell from the pics but it looks like piece of metal is missing from one of the layers of the gasket?

 

[Freakrider]

#1 you need a oem gasket, # 2 before installing it spray WD 40 on some fine sandpaper, place the sandpaper on a flat piece of granite or glass and check the head for low spots....sand carefully until it's clear of low/high areas...

 

[bigo]

yep the gasket was only 20min old.

 

[bigo]

ps sat for a week that's where the rust came from salt water.
click on the pics to go bigger and yes theres metal missing from that gasket.

 

[kevbo]

ok so im never good at diagnosing carnage i brought wb2 760 when i got it it was down 30psi in the rear i popped the head and put an aftermarket head gasket on and compression was spot on again went for 20 min ride and retorqued off i went again for maybe 15min before this happened.

any opinions
chit aftermarket gasket ?
dropped sleeve?

You MUST make sure the head and cylinder are perfectly flat anytime a metal gasket or O-ring style head is used. Stock fiber gaskets will seal irregular surfaces a lot better. Im surprised to see as many people getting by without lapping their cylinders.

 

[JetManiac]

You MUST make sure the head and cylinder are perfectly flat anytime a metal gasket or O-ring style head is used. Stock fiber gaskets will seal irregular surfaces a lot better. Im surprised to see as many people getting by without lapping their cylinders.

Stock 760 gasket isn't fiber gasket but 3 layer metal gasket. Definately needs to be checked for surface problems and lapped.

 

[LegDragger64]

Also with metal gasket , head should be re tourqed after first heat cycle .