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Snapped cam cover bolt on Harris ELR
Posted: Tue Jun 30, 2009 9:42 am
Author: Magnum1
Well, 23 bolts cam out nice, but one was tight so I stuck some penetrating oil on it and tried easing it backwards and forwards, but it snapped. Now I'm Donald Ducked. The broken end is down in the hole. Any ideas on what the best remedy is? Would be really grateful.
Rod
Posted: Tue Jun 30, 2009 11:43 am
Author: Taffus
spark erosion is probably the way to go......
Posted: Tue Jun 30, 2009 12:02 pm
Author: Magnum1
What's spark erosion?
Posted: Tue Jun 30, 2009 1:37 pm
Author: GEZ635
Ive had lots of these break. I always drill and tap mine or sometimes use a helicoil. You will need to mask everything off if the head is staying on the bike so you dont get any filings in the engine but its pretty easy if you are careful. Which bolt is it? Some are easier to get to than others so you could end up taking the head off if its too hard to get too??
Posted: Tue Jun 30, 2009 4:28 pm
Author: Magnum1
Hi Gez,
Here he is mate, just above no 2. Tried a 2.5mm drill and snapped it! Now its stuck in there. What a right ol mess! Also, tried heat and Bessy grips in vain.
Posted: Tue Jun 30, 2009 4:37 pm
Author: Steve R
Now you have a drill bit stuck in there definatly go for spark erosion, you will probably need to take the head off, though you may find someone thats mobile see below. Ring round your local engineering shops.
It will get that out and should not even damage the threads. I have had it done on a bleed screw that had an eazi out snapped in it, no damage to thread or seat of caliper. Its some sort of engineering magic
http://www.edm-products.com/Dielectrics ... fase_1.htm
http://www.sparkeroding.co.uk/
Posted: Tue Jun 30, 2009 4:37 pm
Author: Taffus
Posted: Wed Jul 01, 2009 7:22 am
Author: Magnum1
Hi Lads,
I dont have time to take the head off, there's too much to do to get ready for Mallory. But I have managed to get the drill bit out and I'm just off to get a new drill bit (better quality). If I knacker the thread, could I just use a longer bolt and stick a nut on the end?
Cheers,
Rod
Posted: Wed Jul 01, 2009 7:46 am
Author: kev edwards
I'd go for a 4mm drill bit first , then if the hole is nice and staight drill with a 4.5mm using a thin oil like 3 in1 , this may loosen the bolt and enable you to remove it without damaging the thread , if this fails drill out to 4.8mm then re cut the 6mm thread . though as said in previous post's spark erosion would be the best option with the motor in situ , good luck.