View Full Version : Head gasket, head stud question
Working on a buddies 400ex, I rebuilt engine less than 10 hours of ride time ago. 416 Wiseco 10:1, cometic gaskets, crf450 timing chain ect ect.
It recently blew head gasket. I just took apart today and thought it pulled a stud. But I took studs out and they all look fine, the one that was by where it blew gasket came out hard but threads all look good and so does stud. This nut on this stud was loose though. I know it was tightened down properly, I double check all torqued bolts every time.
Question is, can studs get pulled and threads look ok? And can gt thunder studs be installed with cylinder on bike? I really don't wanna take it off because it's so fresh and broke in.
Yes they can pull out and not screw up the threads, just like sparkplugs can.
Id do the GT Thunder head studs, have them install them for ya, its well worth it.
thats the rought i'm headed, just wanted to make sure the stud can pull without screwing up studs. I have had gt thunder do another cylinder for my 460 but just did it as insurance, never actually seen a pulled stud before on one of these.
Chances are the jetting was off causing the cylinder to heat up along with the header which makes the studs pull out on the exhaust side.
Jetting was actually a slight bit rich. I jetted quad when I rebuilt it. I left it on the safe side for him, I would have went a size leaner on the main for myself. I think the problem was detonation from low octane gas. I talked to him and he said he just runs 87 octane in it. I know I told him when I was done with it before to run 93 in it! The spark plug was lil loose and piston shows light detonation. I will double check jetting after I get it put back together. I actually just took cylinder off and is boxed up ready to ship to gt thunder in the morning. Just gotta order rings and gasket kit now.
OH MAN! He ran 87 octane???? Thats a huge no no, smack him upside the head for me lol.
I wont run anything less than 93 in mine.
He did say he was using some sort of octane boost stuff too, but really doubt any octane booste gonna raise 87 high enough to be decent
Originally posted by 78ta
He did say he was using some sort of octane boost stuff too, but really doubt any octane booste gonna raise 87 high enough to be decent
No way lol. Whats the big deal, pay a buck more a gallon and be safe. The octane booster had to cost at least 5-8 bucks for what 16 oz at most?
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