Engine screw

[Yamaha]

I got a problem.

old bikes got screws which r old and rusty. when u try to unscrew them(crosshead), they are very tight and when u use force, the screwhead become round :cry:
in the end u cant unscrew them.
is the anything to fill up the hole and make a new crosshead or what can u do to unscrew it???

[Yamaha]

and if the screw is from the crankcase right hand cover.......r they very tight???
can i unscrew them myself or need special tools.......

[FingerZ!]

ok 2 ways of going about this

1. go out and buy some fairly decent screwdrivers, buy a few different sizes and evetually you will get the one that fits the screw head really tightly. Spray some penetrating oil on the thread if you can get to it, or just between the head of the screw and whatever its holding on. Then, with the screwdriver fitted into the head of the screw, tap the screwdriver in tightly with a hammer. Once in nice and tight, hit the screwdriver hard with a hammer - this helps to break the rust and the locktight that is holding the screw in the thread so tight. Then push as hard as you can against the screwdriver and slowly try and turn the screw with as much force pushing into the head of the screw as you can, That should do it.

2. If you have ruined the head on the screw, get a chisel and hammer a large flat head screwdriver shape into the screw/bolt. then go and find the biggest flat head screw driver you can and turn it out with that. - if that fails, its time to hammer the chisel into the edge of the bolt head and try and get it to turn out if you see what i mean.

:)

[djbadger]

Here's my two penneth.....

You could try using an Impact Driver (I got mine from a local motor accessories dealer for £12). That should simplify the job a bit.

You could also try stud extractors, but ive found that they are generally pretty crappy.