Was working on a simple oil change this week, and today was putting everything back together when I snapped two of the four sump plate bolts. Wow. I wasn't even torqueing them very hard. Anyway, before I undertake some very awkward drilling out and re-threading of these bolts, has anyone else every done this before and are there any pitfalls you can help me avoid? Ugh, this sucks...

Craig

Drill a hole and braze a nut around it and use a cutoff bolt (1/4 inch)as a sump plug.Take care it's clear of pickup.

Strange that the bolts snapped? Usually the thread in the ally case gives out first. Bloody awkward job with the engine in the frame. I think you will have to drain the petrol tank and lay the bike over on an old mattress or similar to give yourself a chance at it. I would drill a small hole through the centre of the bolt with the drill bits getting slightly bigger each time till you are nearly at the threads. You might just be able to peal out the remains of the bolt or you could try an 'easyout' at an earlier stage, (but they hardly ever work for me!) If you do muck up the threads, then you will need to put helicoils in or re-drill and tap out to 5/16" (not ideal). You can get them removed by spark erosion.....but nut in the frame I wouldn't think. Ron

email (option): ronpier@talk21.com

Hi Craig, I frequently find these studs snapped off in crankcases..in fact when I have an engine to rebuild it's a bonus if none of them are. It is quite easy to do and care should always be taken not to overtighten them. I rely on tightening them with just a light 'pinch' and use a shakeproof or spring washer under the nuts to keep them in place. A dab of thread lock would work just as well I imagine but the stud might unscrew from the case the next time they are undone.
The repair is a fiddly one due to the small size of the studs and the difficulty of drilling on center and square. Another thing I frequently have to deal with is the results of attempted repairs going wrong!
Personally, although I think a repair in place is theoretically possible I wouldn't attempt it myself, preferring to set up the crankcase half on a milling machine to tackle the job.Chances of a successful repair are under 50% at best I would say. If you have snapped off two studs on the same side of the sump plate I would be more inclined to drill and tap another hole between them, with a corresponding hole in the plate etc. and fit another stud as a temporary repair. This can all then be rectified correctly the next time the engine is stripped.
If you have broken them diagonally opposite to each other then use some silicone sealant and refit as is...you will find it will most likely seal OK.
If you have broken both studs at one end of the plate add the additional hole adjacent to one of the two studs. You will find it will seal fine on three studs.
These solutions really come under the heading of 'temporary lash up' to avoid an engine strip down...If you attempt the repair in place be prepared to get into deeper water ....Ian

email (option): ian@wright52.plus.com

Hi Craig, If you have a mig-welder I would clean the broken stud and carefully aim the torch and built it up with small welds till you can grab it. (or then weld a small strip on it which you can carefully hit with a hammer or grab with a bahco). Much easier and quicker then drilling and fussing with a lefthand tap. It is also less risky, because when the drill breaks you are in deep trouble.

Worth trying, works always for me. think it also helps that the heat from the spotwelds expands the stud a bit and when cooled down it is less stuck.

Good luck. Michiel

email (option): m.wijbenga@hotmail.com

Thanks, I appreciate the good suggestions everyone, and I'm actually glad to hear these studs are somewhat prone to failure. I too was surprised the threads didn't go fist.

I snapped both studs on the lefthand side, so Ian's suggestion of a new hole/stud as a temp fix is something I hadn't considered. I think I'll try to carefully drill and/or tap out the studs first and see how it goes. The welding idea is interesting, but my welding skills are more likely to make things worse than better!

Thanks again, fingers crossed...

Don't come crying to me.. ..Let us know how you get on.....Ian

email (option): ian@wright52.plus.com

Will do. Out of town for a couple of weeks, so will probably tackle it in Nov.

Hi dave

All is not lost, there is always a way

You need to get a left hand tap of a smaller diameter than the bolt and then drill a suitable hole in the stud. But only drill it part way so that you have a blind hole. Then thread the left hand tap into the hole until it reaches the bottom and then you carefully continue to twist as you unscrew the bolt.

You know they are not seized as you have only just put them in. So this should work just fine.

Job done!

Darren

email (option): dwrudd@lineone.net

Laser 3744 Combination Screw Extractor & Drill Set will do the job from Amazon, used with great success and is a concept similar to that described above by Darren.
Good luck.
Julian

email (option): 79aust@sky.com

Hi Craig,

I had 2 studs broken in my sump plate when bought the bike.

I drilled it in the middle (Gradually, up to some 4mm drill) and took it out with “Easy out” tool (left hand tap)
I came out very easily and effortlessly.
Did it on the bike.

You can then use a 1/4 hex head screw to fasten it back, or a screw with a nut on it:
You can put a spring washer on the plate, Screw in the screw with a nut bolted all the way on it
(On the screw, before you screw the screw into sump..),
and then undo the nut to some extent, to press the plate in place.

I think that this system work even better than the studs.


Good luck,
Noam.

email (option): noam10@gmail.com

Well, it took long enough to get around to it, but I told the group I'd let you know how the snapped baseplate stud repair went, so here you go...

Went surprisingly smooth. Propped the front tire up on a pickup bed, drilled a small hole in each snapped stud, and after a fair amount of fiddling I finally got both broken studs out with an easy out. No thread damage at all! Cleaned things up, and per Noam's suggestion, used bolts this time instead of studs. All seems good so far.

On an unrelated note, also had the first test-ride with the new 21 tooth engine sprocket (swapped out the old 19 tooth, running an 18 on the gearbox). Runs real well, and a little lower RPMs at top speed. No real issues on hills either. So far so good. Now onto that pesky wet-sumping issue...

Sound like you have done the usual things to check for wet sumping, mine did the same about 4 years ago, tracked to a distorted pump body. I fitted one of the better anti sumping valves the one that screws into the crankcase made from stainless, no need to shorten the oil pipe. Think they are about £37 dont buy one of the cheeper in line as they do restrict the flow. Works great with full return ( no restriction) Have picked a good pump up now but will not fit it till i do the next full strip down, which could be a long long time as its running so well. I run mine with 21 tooth front and a 19 gearbox. Still pulls out in top.

Tim W

email (option): t.j.walker@btinternet.com