Snapped head of transmission level screw

[nudedaytona]

I've sort of cocked this one up, so need a bit of advice as to what to do.

The bike is a 1996 aprilia rs250
I replaced the transmission oil, all good. But then I checked the transmission oil level by removing the level screw and seeing if oil came out (which it did). But I applied to much force when I put the screw back in and snapped the head off. The long bit of the screw is well stuck in there. A bit hard to describe, I guess a photo would help, I will try and put one up later.

I am worried that without the head of the scew oil will leak out, or worse, the screw will work its way into the transmission and cause a major problem.

I noticed a bit of oil around there before, but it might have been from before when I changed it. I tipped the bike over and nothing came out. I suppose I could drain the oil and measure it, see if it is about 700ml, which I put in just the other day.

I'm not that keen on removing the engine and taking screw out from the inside, its a major job for me as I'm a beginner mechanic. What do you reckon - should I leave it and watch it, see if it moves over time, or is there another way to get it out?

[vifferman]

It's possible that if you can get a bit of a notch or similar carved into the surface of the remaining bit of screw you could undo it with a screwdriver. Something like a Dremel or similar to cut a bit of a slit.
Alternatively, if the top isn't smooth, get something pointy like the corner of a fine-bladed screwdriver tip against one edge of it, and tap it gently with a hammer and see if you can get it to rotate anticlockwise.
Another option is a special drill bit with a reverse pitch on it. You drill into the screw shank (with the drill set to reverse), and as the drillbit bites, it tries to unscrew the shank. If this fails, at least you have a hole to use an Eezy Out on.

[bungbung]

I sheared the head off a bolt recently (chain tensioner bolt, seized in hole).

In your case, different options are available (depending on screw size)

1. Screw extractor

2. Slot the visible end of the screw so you could use a screwdriver. (Dremel type tool with thin cut off disc)

3. Drill out centre of screw and use a thread tap to clear remaining bits of screw from threads. It's possible you'll need to go up one size if you damage the original thread.

Number three runs the risk of introducing metal fragments into your motor, if you're not in a position to remove the cover/part from the motor first.

(too slow, what vifferman said)

If you don't want to remove it yourself, keep an eye on it. It doesn't sound like it'll cause an issue until you next want to check your oil level.

[nudedaytona]

Another option is a special drill bit with a reverse pitch on it. You drill into the screw shank (with the drill set to reverse), and as the drillbit bites, it tries to unscrew the shank. If this fails, at least you have a hole to use an Eezy Out on.

What's Eezy Out??

[bungbung]

Ezy-out also known as screw extractor:

http://www.mytoolstore.com/hanson/extractr.html

[nudedaytona]

I sheared the head off a bolt recently (chain tensioner bolt, seized in hole).

1. Screw extractor

2. Slot the visible end of the screw so you could use a screwdriver. (Dremel type tool with thin cut off disc)

3. Drill out centre of screw and use a thread tap to clear remaining bits of screw from threads. It's possible you'll need to go up one size if you damage the original thread.

Number three runs the risk of introducing metal fragments into your motor, if you're not in a position to remove the cover/part from the motor first.

(too slow, what vifferman said)

If you don't want to remove it yourself, keep an eye on it. It doesn't sound like it'll cause an issue until you next want to check your oil level.

Thanks for tips. Sorry don't really know all these big words, can you please explain?

1. What's a screw extractor?
2. What's a Dremel tool?
3. What's a thread tap?

[imdying]

1. What's a screw extractor?

Something that noobs use to fuck up a job so badly that it takes an engineer a few hours to do something he could've done in 10 minutes if he'd been given it in the first place to fix. A trade name you might recognise is 'ezy-out'. If you have to ask, don't go there.

2. What's a Dremel tool?

A rotary tool with a grinding bit, that spins around 15000-30000rpm. In this case you would put a tiny wee disc (about 30mm diameter) much like an angle grinding disc in it, and use that to cut a slot in the head, that you can then use a screw driver in. Great tools, everyone should have one. Buy a decent one.

3. What's a thread tap?

It's what you use to cut a new thread into a new hole, or you can use it to 'clean up' a damaged thread in an existing threaded hole.

Google is your friend.

[imdying]

Oh yes, on that particular location, you don't want any swarf getting into your motor, so best take it to someone who knows the tricks for avoiding that. Of course, it it's in a side cover, you can just take them the side cover

Or attempt it yourself, but really, I wouldn't if I were you. Having said that... they can always repair what ever you bugger, they'll just weld it up, redrill and retap it.

[vifferman]

Thanks for tips. Sorry don't really know all these big words, can you please explain?

1. What's a screw extractor?
2. What's a Dremel tool?
3. What's a thread tap?

Ezy-Out = Screw Extractor, as bung bung said (check out the link in his post).

You drill a hole, and screw an appropriately-sized Ezy-Out into the hole, anticlockwise. The Ezy-Out is tapered, and has spirals cut into, so as you screw it in, it bites/wedges itself into the hole. As you keep turning it, it (hopefully) turns the snapped off bolt/screw too, and undoes it. (If you're unlucky, it snaps off in the hole, and you've got a bigger problem).

Click this to find out about a Dremel tool.

[vifferman]

Google is your friend.

Cue: "what's a Google?"

[nudedaytona]

Cue: "what's a Google?"

Nice one, fortunately for you guys I do know what that is.

[imdying]

Google kicks arse, and it's faster than waiting for us to reply (sometimes )

[nudedaytona]

Update: I went for a ride on the RS250 bike on Saturday night. It was my first proper ride on it.

And before any pc shitstirrer says that I shouldn't be riding an unregistered bike at night after 10pm on my learners licence, I'm glad I did it then 'cos the weather was crap on Sunday.

I headed out on to upper harbour highway then out to westgate. It went all-right, although even at that time of night there was a bit of traffic, which is a bit frustrating and I think the bike finds it frustrating too. The bike doesn't seem to like first gear unless you're revving the shit out of it.

I pulled into the mobil station up there, and checked the gearbox level screwhole, oil was oozing out of it. Not sure how much had come out, so I bought half a litre of synthetic 10w/40, and put that in, and stuck some chewing gum over the screwhole, not that it would do much good but at least it was something.

But I got my first comments about the bike from two pisshead westies at the servo who loved it, especially when I told them it was a two-stroke.

Then headed back, it had started to rain lightly so I was a bit nervous. I stalled it shortly after at the lights, and couldn't get it going for a while. Not sure what it was, might have been that I just ran out of gas. I fiddled around with the idle screw, put the choke on. Thought I might have fouled the spark plugs. Tried push starting it. Eventually got it going with the kick start. One of the things I did was turn the fuel cock over to reserve so that might have been it, I haven't yet checked the fuel level now that I'm home.

On the way back the traffic was lighter and it stopped raining so I thought I'd wring it out a bit more. I passed a ute on the motorway, first time ever passed anyone the bike it just goes for it and turns out there's a cop just in front of the ute, but he's pulled over someone else, too busy to notice unregistered bike hoon pass. T

Thought I'd ride my luck and rode quite aggressively home, which was fun. Back in the subburbs started to practice cornering, ended up taking one corner a bit too fast and went about a foot into the other lane, luckily nothing coming the other way. Got home safely.

On Sunday I had a go at getting the broken screw out. Turns out it wasn't that hard. I bought a precision tool kit from the warehouse and etched a notch in it, then used a tiny screwdriver to unscrew it. Now I just have to find a replacement screw, and change the gear oil (again) and should be able to register the bike this week.

What do you guys reckon I should use for gear oil? The manual for the 98 version of the aprilia rs250 says 75w-90, but that's really thick stuff, the guys in the bike shop say synthetic 10w-40. I've stuck the 10w-40 in it, its got esters in it which would give you a headache if you sniffed it too hard.

[xwhatsit]

Ah, but that's gear oil, not normal engine oil. So it would be thick. 2Ts have separate gear and engine oils.

[imdying]

I wonder who would know better... the factory that wrote the manual, or the yobs at some NZ motorcycle store... hmmmm... Go search/ask on rgv250.co.uk