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99 RM250 Broken Crankcase Bolt

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So I had a leaking crankgase casket from replacing my right side crankcase which was toasted in an attempted to retap my oil drain plug.. I split the cases and bought a manual and yatta yatta im doing everything by the books and I come to realize I don't have a 1/4" drive torque wrench or any wrench that goes down to 11nm which is what the crankcase bolts are specced at. I borrowed a 3/8 drive wrench from my neighbor that he uses on his motorcycle (much bigger) but it goes down to 11nm so I figure okay I slap an 8mm socket on it and start tightening in a crossing pattern 1/4 turn at a time just as the manual suggest I'm getting to the final pass and some of the bolts are making the wrench click - great.  I get to the bolt next to the swingarm engine mount and the bolt keeps turning with no clicking with a torque wrench this big (handle is about 1 and a half feet long maybe longer) its hard to tell how tight the bolt is getting because the wrench makes it feel easy.. anyways.. bolt breaks about 3/4 the way down the shaft of the bolt.. tried using a screw extracter to no avail and a little light drilling - didn't want to do too much damage.. Since the broken bolt hole is surrounded by a bolt on the lower perimeter of the case and one on the upper perimeter both torqued and the swingarm engine mount would it be safe to just do nothing at all? If anything just fill the hole up with some gasket maker? My brother in law told me that he had a couple of crankcase bolts stripped out one time and he just left them out and it was totally fine.  What would you do?

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I would re-split the cases and fix it properly. The engine is already out and on the bench so why not just fix it right?

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Say I do resplit the cases... then im left with drilling out the stuck bolt.. and retapping soft aluminum with not much padding on either side and then if i'm slightly offcenter I end up with a bigger mess than I already had.. I mean if it was a bolt on the perimiter i can see it being really important to fix.. but it's only an intermediate bolt..

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has anyone had any sort of success extracting a bolt like this without splitting the cases... I'm thinking of using a homemade bushing in the hole as a guide for my pilot hole that i drill with a small bit then using a left hand bit to bring it back out if I can

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So I had a leaking crankgase casket from replacing my right side crankcase which was toasted in an attempted to retap my oil drain plug.. I split the cases and bought a manual and yatta yatta im doing everything by the books and I come to realize I don't have a 1/4" drive torque wrench or any wrench that goes down to 11nm which is what the crankcase bolts are specced at. I borrowed a 3/8 drive wrench from my neighbor that he uses on his motorcycle (much bigger) but it goes down to 11nm so I figure okay I slap an 8mm socket on it and start tightening in a crossing pattern 1/4 turn at a time just as the manual suggest I'm getting to the final pass and some of the bolts are making the wrench click - great. I get to the bolt next to the swingarm engine mount and the bolt keeps turning with no clicking with a torque wrench this big (handle is about 1 and a half feet long maybe longer) its hard to tell how tight the bolt is getting because the wrench makes it feel easy.. anyways.. bolt breaks about 3/4 the way down the shaft of the bolt.. tried using a screw extracter to no avail and a little light drilling - didn't want to do too much damage.. Since the broken bolt hole is surrounded by a bolt on the lower perimeter of the case and one on the upper perimeter both torqued and the swingarm engine mount would it be safe to just do nothing at all? If anything just fill the hole up with some gasket maker? My brother in law told me that he had a couple of crankcase bolts stripped out one time and he just left them out and it was totally fine. What would you do?

If it didn't break off right at the threads it you could maybe split the case and get a pair of vice grips on it and spin it right out. It will defiantly be easier to split the case to get it out either way.

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Split the cases and fix it right.  It'll suck today but if you don't fit it and it leaks your future will suck even worse.

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If you don't feel confident drilling it out yourself, split the cases and take it to a machine shop. Even if it's $100 to remove it it's still cheaper than a new set of cases.

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It broke below the start of the other case I think so I don't think any is sticking out. I talked with a couple people from work about it and got some suggestions.. I think I'm going to make a bushing to slide in the bolt hole with a hole in the center for a drill bit for a pilot hole in the center of the broken bolt.. the bushing would act as a guide keeping the pilot hole straight and then I'm going to spray it down good with penetrating oil and try to use a slightly larger left hand bit to back it out and just replace the bolt.. plan on doing this Sunday will update with pics after I complete

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I like the idea of using a left hand drill, also see if you can find the right size "transfer punch".  Even one that's standard (not metric) will work if it's close, then you will be able to hit the center of the bolt with a punch mark before drilling.

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Update (Sorry no Pics): I got sick on friday and decided not to do anything saturday but I did try to work on it sunday.. I got about half of the stud drilled out and got too nervous that I was getting off center.. local hw store didn't have any left hand drill bits and I did get a good pilot hole started by using a plastic bushing as a guide.. Since i had no left hand bits I tried tapping a torx bit driver into the pilot hole and turning out to no avail as well as trying a flathead screwdriver.. I dropped it off at a machine shop yesterday.. they seemed to think it would be no problem to drill the remaining 1/4" of bolt out with a carbide bit and retap the hole without splitting cases.. they also assured me that if they could not drill it they could edm it which is the process of electrically shocking the bolt - making it break away in small pieces leaving the threads undamaged since the bolt is steel and the case is aluminum.. EDM is the safer method but it is much more costly so I'm waiting to hear today from the shop to see if they were able to drill and retap.. will post with updates.

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Got the lower end back from the shop and they were able to drill it out and retap and put in a helicoil so it's back to original size.. cost $45 but im fine with that for peace of mind knowing its fixed correctly and it's not going to leak.  Cleaned the exhaust valves last night and I'm going to reassemble the bike tonight after work will post a pic of it when its up and running

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Got everything back together minus the rear tire.. im changing the wheel bearings in it saturday so i'll put it back on and let you know how it goes.

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