Hi there,

 

I've just dragged my '94 Yamaha RXS100 out of the shed where it's been lying for about 20 years unused. I was going to replace the footrests because I snapped the right one off when I decked the bike, so I started to remove the exhaust to make it easier to get at but one of the bolts holding the exhaust sheared when I tried to remove it!

 

So I've got a sheared bolt sticking out of the engine block by about 7mm. I've tried just using pliers to rotate it but it is stuck solid, no doubt firmly rusted in.

 

Now the same thing happened many, many years ago and my uncle got the sheared bolt out for me by heating it but I didn't see him actually do it so I'm not sure what he used to heat it as he owned a garage so it could have been anything but I'm guessing he just took a blow torch to the engine block.

 

Any suggestions as to how I can get this beastie out of my engine block? Should I try to heat it or should I use some sort of rust remover first down the thread or something else entirely different?

 

Thanks for any help.

Heat the block around the bolt. Gently with a heat gun, no blowtorches!

Then get a good set of mole grips on it and try and work it back and forth. Some good penetrating oil might also help.

Patience is key here! 

Thanks finnerz89. Good advice about the heat gun as I definitely would have gone at it with a blow torch!

The thread is pointing down so will I have to upend the bike to get the penetrating oil to seep into the thread? And any suggestions for what to use as penetrating oil? I used DOT4 to separate a core bit from its shank but that took a good two weeks of soaking before it would budge!

Plus gas is a good penetrant. Or WD40. 

Another option is try and weld a nut onto the sheared bolt and use that to wind it out, but that depends if you have access to a welder

Actually that answers what was going to be my next question which was what should I use to stop this happening again? Apparently Plus Gas is meant to be used for that very purpose.

I just use copper slip

Carlube Xcg500 Multi-Purpose Grease, Copper https://www.amazon.co.uk/dp/B004HPER6M/ref=cm_sw_r_cp_apa_lWFHzbD7DTCAZ

No point that stuff will get fried. Then the crap will jam the threads.

If you are rebuilding a bike thats been stood 20 years you really want to give the engine a seals and gaskets rebuild with new crank and output shaft bearing.

While its split give the barrel to the engineers that will probably be reboring it for you anyway and they will have it out quick smart for little or nothing if their doing the bore.

 

Hi

something I found dealing with a solidly seized swing arm bolt is to make your own penetrating oil out of 50% automatic transmission oil and 50% acetone

put it in a metal oil can shake it up to mix,

worked an absolute treat its like the acetone pulls the oil in somehow

 

The acetone probably thins down the oil making it penetrate easier then evaporates leaving the oil in place.