Seized engine mounting bolt - How do i get it out!?

killerbanjo · Renault 5 Driver Joined: 17 Jun 2013 Karma :

Hey all, I have a CG125 engine that I want to slot into my XL125RC because the 200 Chinese engine in it shat itself (after 2 bottom end rebuild I cant be fucked to split the cases again... dont get me started on them...). The CG engine is from my old CG that I retired and I personaly put about 12,000 miles on the engine before removing it and it was running fine. The only problem is, when I went to undo the nut on one of the mounting bolts, it sheered off and the bolt head did too when I was trying to release it. I have oiled it and heated it and beat both ends until I
am blue in the face but can't get it to move.

Any suggestions?

https://i.imgur.com/4JaNJ6o.jpg

https://i.imgur.com/9izjxKB.jpg

https://i.imgur.com/Sia7Dql.jpg

https://i.imgur.com/luUsQDf.jpg

gavcarter · Could Be A Chat Bot Joined: 28 Mar 2009 Karma :

Drill the ends off both side, just a little way into the casing and try and knock it out with a punch.

Use a soft punch, such as brass rod, and try and get the punch to be a tight a fit in the hole as you dare, otherwise you can "flare" out the end of the bolt and jam it in more

pdg · World Chat Champion Joined: 15 Sep 2012 Karma :

Both ends of the bolt remains look mullered. I'd wager you're going to have to drill more than a tiny bit past the end of the casting.

You said you've applied heat - if you didn't put the heat onto the casting (i.e. you heated the bolt) then you did it wrong.

Do what was suggested with the brass (or similar) drift but heat the casting first and do it while it's hot.

Edit to add -- if you have drilled into the bolt you will have a concave surface on which to apply the punch, using something close to the original diameter of the bolt will be more likely to cause it to swell and jam more - I would say to use as small a drift as will stand up to the battering.
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gavcarter · Could Be A Chat Bot Joined: 28 Mar 2009 Karma :

killerbanjo · Renault 5 Driver Joined: 17 Jun 2013 Karma :

Thanks for the information lads. Taken on board and I will try and sort it within the next few days. As for anti seize... if I assembled it, I assure it would have not seized but I did not remove the engine once while I had the bike up until I retired it (frame started to rust badly, wheels buckled etc)

Thanks!

CBRMAN94 · Nitrous Nuisance Joined: 09 Jun 2013 Karma :

Had this problem, Tried everything, Massive amounts of heat, punches, drilling. Nothing worked. Ended up having to take a thin cutting disc and slot the mount horizontally and through the bolt too and with the extra clearance the bolt could be knocked out.

This was a last resort option but still seems to be solid enough in the frame.

Common problem on the CGs apparently.
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bikenut · World Chat Champion Joined: 21 Nov 2011 Karma :

a friend had a similar problem ( identical as it goes but on a chinky 125 twin)

he successfully drilled it out .

with a new drill ( much smaller than the bolt size which is 10mm? ), some oil, electric drill and lots of tlc and patience, he successfully drilled thru with a small dia drill ( 6mm ) first.

he was only half a mill out when the drill appeared at the other side so did a really good job.

it was in the summer about 3 years ago in his back garden.

the bike was stood up safely with no wobble or danger of it falling over.

he was sat down comfortably with the engine in the frame, the front bracket was still in place.

the mangled ends of the bolt where prepared flush with the bracket and centre popped.

I was sitting on the other side making sure the bike was safe etc.

he took his time, with regular checking that the drill was going in square, in line in all directions as the possibility of bursting thro the casing ( and into a void ) as well as breaking the drill was very high.

he regularly cleared the drill of swarf and lubed it. he also took breaks....

re drilled at 8mm.....used water as a lub and flushing agent.......got the remains to move, the rest was more patience.....the remains where really corroded but it was out!

he was successful and gained a huge boost in confidence from this experience.

most workshops locally would have told him to f off.

is your engine out of the frame??

consider welding a big bolt to one end ( after preparing the "riveted in " sheared bolt ) to the remains, heat and a twisting turning action....water as a lub and flushing agent..........and patience.........take your time and be very careful.

you still have the drilling option as a fall back.....

I used this method ( welded ) on an upper crank case after removing the engine and splitting it (as it needed internal repairs which Is why I took it out ) ....still have the bolt some where if you want to see.

you have a pillar drill??
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swampy · World Chat Champion Joined: 04 Aug 2004 Karma :

Dremmel a slot in the thick end, use some angle iron or flat bar as a lever and add heat ? Can still drill if needed..
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