[loco]

Raptor ran hot today in 50 degree weather fan was on the whole time and now run a high flow impellor and fluidyne radiator. Looked into the radiator and it was low, and also looked like soot was in it? Just checked radiator maybe a hint of fuel in the mix. Also looks like my oil dipstick is double what is should be and is a tan color. Another blown headgasket? That would be 5 in the last 2 years.

 

[loco]

Re: Soot in Radiator?

pulled the head off today, yeah it milkshaked. Here are a few pics. what can you guys tell me.

Head

Gasket side 1

Gasket side 2

Piston

Head #2

 

[firstraptor]

looks blown just to the right of the center intake

 

[rt]

Look into getting a copper racing head gasket, they are re-useable in most applications and are a lot better than the oem-cometic counterparts.

 

[firstraptor]

Look into getting a copper racing head gasket, they are re-useable in most applications and are a lot better than the oem-cometic counterparts.

5 in 2 years?
I think he has a problem with flatness or a torquing issue

 

[ajax660]

how do you blow 5 head gaskets in 2 years? :3question:

 

[loco]

Same issue. I always ran a stright edge on it, seemed true, this time its going to the machine shop. Also used new head bolts, and everytime I've taken it apart everything on that head is tight, nothing is loose. Every bolt is tight, every allen is tight.

 

[firstraptor]

Before you assemble it next time run the head bolts in each hole to be sure the threads are smooth and free running.

 

[loco]

Before you assemble it next time run the head bolts in each hole to be sure the threads are smooth and free running.

Do this to make sure........................? If I encounter some resistance then what?

 

[firstraptor]

Do this to be sure the bolts are torqueing the gasket and not fighting the resistance of the threads.
I had one that was tight, replacing the bolt was sufficient, the threads in the case were fine.
If the case seems to be the problem you'll need to find a tap to fit, if I recall it's a m9x1.25 which is an oddball. I may be wrong about the pitch, verify the size before you buy a tap.


Anyone have other ideas for fixing bad threads, is there a stud kit available?

 

[loco]

Who sells the copper racing head gasket?

 

[scholle]

No need to wory with a copper gasket unless your going to o-ring the cylinder/head or both. OEM yamaha works just fine. I have said this countless times THE HEAD AND CYLINDER HAVE TO BE FLAT. You cant get it true with a buffer/grinder or scraper. I see the cylinders just as warped if not more than the heads.
We have some 720's 14:1 running on nitromethane with YAMAHA OEM gaskets. So yeah they work. On our 794 we have an o-ringed cylinder with the copper gasket mainly because of the 106mm bore.
If you try running some super gasket or (goop) on the surfaces your just covering an underlying problem.
Get it clean and true both the cylinder and head.
Double check all bolts and bolt holes.
Use a tiny bit of oil on the washers between the head and bolts.
I use 30ftlbs with oem gaskets up to 102 bore. Start at 10 and work up 10,20,25,30 and follow the manual for sequence.

 

[loco]

took the head to a shop, said the head had some low spots. Taking in the cyclinder tomorrow.