Author Topic: sheared engine mount bolt, how screwed am I???  (Read 2504 times)

Offline xcolo1

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sheared engine mount bolt, how screwed am I???
« on: September 28, 2011, 07:46:02 PM »
I was recently torquing my bolts after a ride and accidentally torqued what I think is an engine mount bolt.  Its bolt 11 on the schematics.       However when I look at the schematic on the left its not the same bolt as whats on the top right schematic.  This is the bolt the bolt on the left goes through the top of the crankcase while the bolt that I snapped goes up through the bottom of the crankcase.  you can see on the bolt that it sheared right where the threads start.  So, whats next!? please any solid advice that will let me sleep tonight.  Oh by the way its 1997 gs500ev

Offline Big Rich

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Re: sheared engine mount bolt, how screwed am I???
« Reply #1 on: September 28, 2011, 09:15:03 PM »
Ouch. You said it's one of the longer bolts that run into the bottom side of the case, correct? Probably the best way is to split the cases and try to get the threaded end out that way. I believe you can take the bottom half of the engine off without even messing with the top end though. Just drain the oil and flip the whole thing upside down......
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Offline gtscott

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Re: sheared engine mount bolt, how screwed am I???
« Reply #2 on: September 28, 2011, 09:22:12 PM »
Yeah, u can split the case with the top end together, I messed up and forgot the dampners for the chain guide and only realised when the motor has cyliners head came and rocker cover on, yet was able to split the case without taking everything else apart you will ned to remove oil filter, clutch cover stator cover ignition pick up, clutch, gear shifter parts, sump, yet that's about it, pretty easy job, engin needs to be out of the bike, look at the manual for were all the bolts are so you don't miss any

Offline the mole

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Re: sheared engine mount bolt, how screwed am I???
« Reply #3 on: September 29, 2011, 05:54:13 AM »
1. Why were you retorqueing that bolt?
2. Did you back it off and then use a torque wrench to tighten it up again, or just turn it a bit more because you could?
« Last Edit: September 29, 2011, 05:56:01 AM by the mole »

Offline xcolo1

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Re: sheared engine mount bolt, how screwed am I???
« Reply #4 on: October 10, 2011, 04:33:53 PM »
thanks for the suggestions.  Is there any way i could possibly take the bike to the shop and have it drilled out?? I just dont have the time or the proper tools to take out the engine and split the crankcase.  Im still a little confused at how there are two "11" bolts.  The bolt that i sheared was under the engine next to the oil pan.  the picture shows #11 going through the top of the crankcase which this doesnt?? The more I look at this the more I think its not an engine mount bolt.  heres a picture of where the bolt came from off the bike, the view is looking towards the rear wheel.  Can someone please look at their bike and try and figure out exactly which bolt this is.  Buddha? 

Offline adidasguy

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Re: sheared engine mount bolt, how screwed am I???
« Reply #5 on: October 10, 2011, 04:58:52 PM »
Im still a little confused at how there are two "11" bolts.
Note that there are lots of duplicate numbers. The numbers are not an assembly diagram with each and every bolt having a unique number.
The numbers refer to what the part is. All parts of the same bolt, spacer or whatever will have the same part number. There are lots of #26 - because they are all the same size nut.

I've never taken that apart, so someone else can probably say of you've experienced coitus with your bike.

Offline sledge

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Re: sheared engine mount bolt, how screwed am I???
« Reply #6 on: October 10, 2011, 05:25:19 PM »
Want to know the easiest way to solve the problem??

Glue the bolt back in, sell the bike and say nothing, then buy another.......you wouldnt be the first to do it  :D

Offline CraiGDaniel

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Re: sheared engine mount bolt, how screwed am I???
« Reply #7 on: October 10, 2011, 06:01:58 PM »
Great advice sledge, no really.

Offline gs500e

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Re: sheared engine mount bolt, how screwed am I???
« Reply #8 on: October 10, 2011, 07:18:47 PM »
thanks for the suggestions.  Is there any way i could possibly take the bike to the shop and have it drilled out?? I just dont have the time or the proper tools to take out the engine and split the crankcase.  Im still a little confused at how there are two "11" bolts.  The bolt that i sheared was under the engine next to the oil pan.  the picture shows #11 going through the top of the crankcase which this doesnt?? The more I look at this the more I think its not an engine mount bolt.  heres a picture of where the bolt came from off the bike, the view is looking towards the rear wheel.  Can someone please look at their bike and try and figure out exactly which bolt this is.  Buddha? 

I don't see why not, it is only money.

(btw: i don't think it is an engine mount bolt; i have no clue what it does, but it looks important (my noob hypothesis is it has to do with the starter, but that is just a W.A.G.).  It does however look to be in same position as bolt '#11' of the top right schematic)
I keep forgetting to turn the petcock on before i bolt down gas tank. :(

Offline adidasguy

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Re: sheared engine mount bolt, how screwed am I???
« Reply #9 on: October 10, 2011, 07:43:46 PM »
For what its worth, it looks like this one.
If nothing is leaking, glue it back in. When it starts to leak, sell it and play dumb. "Previous owner must have done that. I never touched that bolt"

Offline xcolo1

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Re: sheared engine mount bolt, how screwed am I???
« Reply #10 on: October 10, 2011, 08:59:30 PM »
thats definitely the bolt Adidasguy.  Can anyone tell me the importance of that bolt and how easy it is to drill out.  Ive replaced the tires, rotors, rebuilt the carbs and rebuilt both brake calipers along with new chain and sprockets. I'm not trying to just ditch the bike to some schmuck cuz of one sheared bolt.  Can anyone give me some sound advice besides scamming someone.

Offline the mole

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Re: sheared engine mount bolt, how screwed am I???
« Reply #11 on: October 10, 2011, 10:15:59 PM »
Just looking at it, I'm 98% sure its one of the bolts that holds the top and bottom of the cases together. As its quite long, you're going to have to remove the motor and split the cases to get at it, no other way that I can see to get the broken end out.

I'd really like to know if a torque wrench was somewhere in the vicinity when you "re-torqued it"

Offline burning1

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Re: sheared engine mount bolt, how screwed am I???
« Reply #12 on: October 11, 2011, 12:27:36 AM »
Woah woah woah... This isn't a stud we're talking about here. Engine bolts are held in place by the friction between threads as the bolt tightens and stretches out. With the head of the bolt twisted off, the bolt relaxes back to it's original length. and often isn't much more than finger tight.

There's a good chance that an experienced machinist could remove the bolt with a screw extractor. You might even be able to twist it out using a screwdriver and friction.

Offline sledge

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Re: sheared engine mount bolt, how screwed am I???
« Reply #13 on: October 11, 2011, 02:15:19 AM »
Look at pic 25.9 in Haynes.

The bolt is there to clamp the cases together around the gearbox shaft bearings and support and hold them in position.

So worst case scenario......Bearing becomes loose in operation and spins in its housing or if it is the locked end of the shaft it it becomes loose and it starts to float. Either way it could result in  serious damage to the case set or gearbox internals. Alternatively there may still be enough compression between the case halves to hold the bearing and it may never come loose in the lifetime of the bike and never cause any problems. Its difficult to call either way but if there is no oil leaking from the hole or in the vicinity of the of joint and no additional noise or vibration its safe to assume the bearing is presently holding in position.

A good machine shop might be able to put a pilot hole down the axis of the remnant with a long series drill, then using a small screw-extracter thats been welded onto a length of stock bar to extend its length spin it out but again.........its an unknown.

The way I see it there are 3 options.

Cover up the damage and offload the bike.

Run with it as is, it might last it might not but if it does fail you will be looking at serious money to fix it, possibly a written off case set.

Bite the bullet, pull the engine out and deal with it now.

I would go with in this order but its your call  :dunno_black:








Offline twinrat

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Re: sheared engine mount bolt, how screwed am I???
« Reply #14 on: October 11, 2011, 03:16:26 AM »
get a small drill and have someone with a lathe drill end of broken bolt with this drill about 3/4 inch deep ,if you know some one who can gas weld get them to easy flow it together,cut head off bolt and fit in drill and drill slowly till you have drilled to a depth that will hold an easy out.   Then stick a rod about same diameter as bolt  down the hole and give the broken thread a good smack this will take the tension out of the thread now insert the easy out and remove broken bolt thread  if it dosnt reach do the same as you did for the drill.before you start remove petrol tank ,battery ,and oil ,then lay bike on its side on a cushion or carpet or some thing soft so it dosnt get scratched .YOU CAN DO IT YOU JUST NEED TO KNOW HOW  ..

Offline the mole

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Re: sheared engine mount bolt, how screwed am I???
« Reply #15 on: October 11, 2011, 05:19:24 AM »
Hey sledge, how can you give advice like that and still have +1 karma??  :dunno_black:

Offline noiseguy

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Re: sheared engine mount bolt, how screwed am I???
« Reply #16 on: October 11, 2011, 10:11:46 AM »
Sledge has karma to burn. Stuff like that is why my ears perk up anytime a seller tells me they've done their own maintenance. I immediately shift from inspecting the bike to inspecting the seller.

I hadn't thought of jamming a screwdriver in to remove this bolt... that's an excellent idea. If you have a spare flatedge driver, sharpen it to a knife edge, insert in hole, tap *lightly* with a hammer to set the edge, and try to twist it out.

Personally, I'd run down a set of long left-hand drill bits and try that (they drill in turning CCW). To Burning's point, these are not high-torque screws... #6, right? If so, 9 ft/lb or so. If you manage to drill through without extracting the piece, use a screw extractor on the new hole. Longer versions of these, essentially:
http://www.harborfreight.com/13-piece-left-hand-drill-bit-set-95146.html
http://www.harborfreight.com/12-piece-screw-extractor-set-40349.html

Careful not to drill through the case. I'm mostly concerned about your mechanical ability (not sure why you were torquing this screw in the first place.) If you know anyone handy that's done this operation before, I'd ask them to help. Otherwise take it to a machine shop and get it done. There are professional broken screw extractors out there... guys that travel and do nothing but this work. They are handy after you've broken off a cheap screw extractor into a drilled-out bolt (it happens.)

« Last Edit: October 11, 2011, 10:17:26 AM by noiseguy »
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Offline Dr.McNinja

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Re: sheared engine mount bolt, how screwed am I???
« Reply #17 on: October 11, 2011, 12:14:55 PM »
Sledge has karma to burn. Stuff like that is why my ears perk up anytime a seller tells me they've done their own maintenance. I immediately shift from inspecting the bike to inspecting the seller.

I hadn't thought of jamming a screwdriver in to remove this bolt... that's an excellent idea. If you have a spare flatedge driver, sharpen it to a knife edge, insert in hole, tap *lightly* with a hammer to set the edge, and try to twist it out.

Personally, I'd run down a set of long left-hand drill bits and try that (they drill in turning CCW). To Burning's point, these are not high-torque screws... #6, right? If so, 9 ft/lb or so. If you manage to drill through without extracting the piece, use a screw extractor on the new hole. Longer versions of these, essentially:
http://www.harborfreight.com/13-piece-left-hand-drill-bit-set-95146.html
http://www.harborfreight.com/12-piece-screw-extractor-set-40349.html

Careful not to drill through the case. I'm mostly concerned about your mechanical ability (not sure why you were torquing this screw in the first place.) If you know anyone handy that's done this operation before, I'd ask them to help. Otherwise take it to a machine shop and get it done. There are professional broken screw extractors out there... guys that travel and do nothing but this work. They are handy after you've broken off a cheap screw extractor into a drilled-out bolt (it happens.)


I always inspect the seller. People like sledge make me always want to buy off a dealer. The second anyone mentions they did their own engine work I immediately become suspicious and ask for a certification. I give a bike a pretty jackbooted-nazi inspection too. It probably takes me nearly an hour to get through the entire inspection before I ask the owner to turn it on so I can listen to it. If they ride the bike to the meet spot, I'll request to see it another day or later in the afternoon. That's another trick owners try to pull on you. Warm the bike up and ride it there to mask all the internal fuel problems.
« Last Edit: October 11, 2011, 12:15:55 PM by Dr.McNinja »

Offline Phil B

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Re: sheared engine mount bolt, how screwed am I???
« Reply #18 on: October 11, 2011, 12:27:44 PM »
First off, it really makes me sad, that a forum for "the community of gs500 riders" would advocate ripping off a FUTURE gs500 rider.

now, to xcolo1: there's even a video on how to remove this.
Titled. appropriately enough,
Broken Bolt Removal from Engine Block

http://www.youtube.com/watch?v=A7ftJTUbp4o

Offline sledge

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Re: sheared engine mount bolt, how screwed am I???
« Reply #19 on: October 11, 2011, 03:02:15 PM »
I always inspect the seller. People like sledge make me always want to buy off a dealer.

On the basis of that comment can I assume you believe that all dealers are as honest as the day is long and never ever ever pull tricks such as the one I suggested??

If so please excuse me while I.................

WWWWWWAWAAAAAHHAHAHHHHHAHAHHHHHHAAAAAAAAAA!!

You buy a used bike you take a chance, regardless of who takes your cash  :thumb:

Oh and BTW......

"Second question: how do I go about inspecting my chain and sprocket? I've never really seen a damaged/worn sprocket before."

Given this comment of yours from an earlier thread can I ask what you spend this claimed hour actually looking at?? If by your own admission you dont know what a worn sprocket........ perhaps the most obvious visual defect there is.......actually looks like why are you commenting on what to look for when buying a used bike???

 :D :D :D

« Last Edit: October 11, 2011, 03:14:11 PM by sledge »