Missing Bolt

[Leines]

I started to teardown this soon to be project of mine..and when i went to start taking nuts off the top of the engine.. i noticed there is one bolt missing on the head...and also there wasnt a head gasket there...

two questions..

can i assume it wasnt running recently because there is no head gasket there..

also will one of those bolts and nuts missing cause a big effect on the seal etc? and if so..what part am i looking for.. top end i assume??


sorry about the rookie questions... just getting started..


Cheers

 

[scotj77]

yes you need all the bolts and if someone was running it with no headgasket it wouldn't have ran long at all especialy without a bolt. those bolts need to be torqued to 18 foot pounds so that you don't have a leak by being too loose and don't pull the studs out of the jug by over tightning. sound's like you will have quite a job ahead of you.

 

[Leines]

apon further inspection... there was a head gasket there.. but still im missing one of those bolts... it looks like i could get one rethreaded in there.. because it didnt break out... almost looks like it was screwed out.... is it possible to remove and replace just the bolt... or am i after a whole top end now??

Cheers

 

[scotj77]

no you don't need a top end. what you need to do is take the head off. that isn't a bolt it's a stud. it is a rod that is threaded on both ends. you can pick them up at any ace hardware store or small mom and pop hardware store, homedepot usually doesn't carry have them in stock where I live. you will want to take one of your old ones with you. while you are at it might as well replace all of them and the nuts. to get them out take two nuts and screw them on to a stud when the head is removed. then take two wrenches and tighten them against each other really tight. after that put your wrench on the bottom nut and unscrew the stud from the cylinder jug. to get the nuts back off of the stud, leave it screwed in to the jug alittle then use the two wrenches again to loosen the nuts from each other. hope this helps. order a new head gasket too. it's worth the money to avoid an airleak that will ruin your motor. ok just noticed your post said "cheers" so you have no f'n clue what an ace hardware is sorry. you might need to order the studs from bikebandit.com or something. they have all the yamaha origional factory parts there.

 

[Leines]

Im canadian.. but i know what ace hardware is cause i watch nbc,cbs and fox.... abc i guess is okay too..... Ill check out home hardware or one of the local engine shops..

Cheers

 

[brandoz28]

the studs are M8x1.25 if you're going to the hardware store after one, its pretty common for those threads in the jug to strip, but that doesn't mean its time to throw it away!

you can time sert those holes (or a machine shop can) and you'll have a stronger setup than what was there before, i had to do all of my head studs when i put mine together. and the holes for the exhaust studs...