Author Topic: Drilling out exhaust bolts  (Read 541 times)

Offline max

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Drilling out exhaust bolts
« on: April 02, 2019, 12:00:33 PM »
After my rusty exhaust header bolts stopped me swapping my centre stand last summer, I've finally had enough and plan on drilling them out.

A few questions for anyone that's been there done that:

1. The bottom inside exhaust bolts look drillable insitu - has anyone done this?

2. The top outside exhaust bolts look like the frame will be in the way, but is it definitely?

3. I've seen suggestions of removing the head while leaving the engine still in the frame. Has anyone done this on an 06 and is it actually any easier than just dropping the engine?

4. How quickly can the engine be dropped (assuming all goes well)? I'm pretty proficient with other work on the bike but obviously nowhere near mechanic tier

Offline Kilted1

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Re: Drilling out exhaust bolts
« Reply #1 on: April 02, 2019, 03:55:28 PM »
"Just because you can, doesn't mean you should."  It may be tempting to drill the bolts out by hand.  Two of them are already accessible and the other two can be accessed by simply unbolting the engine and shifting it in the frame a bit.  But you're drilling into hardened steel that's surrounded by relatively soft aluminum.  One slip, or a less than perfectly aligned drill and you've got a whole different problem than what you started on.  At a minimum you should drill it with the head mounted in the vise of a drill press.  I'd suggest taking it to a machine shop and let the professionals ply their trade. 

That said, you should remove the head.  And since the head can be removed with the engine in the frame, there's no reason not to leave the block where it is (unless you have some other reason).  Just start with the breather cover and work your way down a piece at a time.  There's room for each piece to come out once you remove the piece above it.

Your bike, your rules.  But that's what I would do. 

Cheers!

Offline max

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Re: Drilling out exhaust bolts
« Reply #2 on: April 02, 2019, 07:36:49 PM »
Sorry I should have said that I "plan on HAVING them drilled out" - it's definitely not something I want to risk doing wrong.

The questions are to help me decide whether it's worth taking it to the local mechanic to see if they'll be able to have a go with it in frame, or whether I should remove the head/engine and take it to a machine shop instead. Opinions are welcomed.

My thoughts for not removing just the head rather than whole engine would just be not having to mess with gaskets and other potentially corroded fasteners that would risk starting any off any of the GS's infamous oil leaks.

Offline Kilted1

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Re: Drilling out exhaust bolts
« Reply #3 on: April 03, 2019, 01:47:28 AM »
Ah, that makes more sense.  It's probably still less work to remove the head than to remove the entire engine.  Yes, you'll need a head gasket at a minimum and maybe the valve cover gasket but that should be about it.  Unless you decide (while it's already apart) to go to the next level and replace the rings, hone the cylinders, and do the valves.  All of which is mostly labor you can do yourself.  At the end of which you have most of a new engine aside from bearings.  Of course this depends on mileage and how much you want to put into it just now.

You may wish to inquire with your machine shop if they'd even be willing to work on the whole engine rather than just the head.

Offline max

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Re: Drilling out exhaust bolts
« Reply #4 on: April 03, 2019, 08:10:25 PM »
...

You may wish to inquire with your machine shop if they'd even be willing to work on the whole engine rather than just the head.

Very good point actually, it does sound like head only may be the way to go then.

After calling 4 local garages and mentioning 'corroded exhaust header bolts', they all instantly said they wouldn't touch it. Surely it's something they must come across often?

Anyhow, looks like it's calling machine shops now and seeing how extortionate their prices are.

Offline herennow

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Re: Drilling out exhaust bolts
« Reply #5 on: April 04, 2019, 06:44:39 PM »
I removed my head and drilled the studs out with a left hand drill bit (to try to get the bolt to unscrew while drilling - did not work). Started fairly slow and small and ended up drilling about a 1/4 inch hole right through the bolt, then I used alum with a light bulb for heat to dissolve the rest of the bolt (really.. google it....) took about a week of stirring , adding alum twice a day.
« Last Edit: April 05, 2019, 09:32:49 PM by herennow »

Offline Kilted1

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Re: Drilling out exhaust bolts
« Reply #6 on: April 05, 2019, 03:56:03 PM »
I reoved my head and drilled the studs out with a left hand drill bit. Started fairly slow and small and ended up drilling about a 1/4 inch hole right through the bolt, then I used alum with a light bulb for heat to dissolve the rest of the bolt (really.. google it....) took about a week of stirring , adding alum few times a day.

Wow!  That sounds like an interesting process.  I'm going to have to read up on that when I have some time.  Thanks!

Offline tobyd

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Re: Drilling out exhaust bolts
« Reply #7 on: April 05, 2019, 10:26:17 PM »
on a '98 but i suppose once the fairing is removed its all the same...

I snapped 3 of the 4 bolts removing an old manky exhaust from mine. Briefly considered drilling but ultimately took the head + barrels to a local engineering shop and for 140 they drilled and helicoiled the head, honed the bores and shoved the bits through a parts washer. It was quite labour intensive getting to that stage but mine was a neglected engine.

its surprisingly expensive depending on what you need to go with all that.

The head can be removed in-situ but if anything causes trouble its easier to remove the whole engine. I say 'easier' the front engine mount seizes up easily. in retrospect its not hard to sort with the right approach but it took me ages to get to that.

involved for me (plus engineering shop time):

cutting off valve cover (ebay replacement) - 11
bolts for engine mount and front-most valve cover (oem) - 30
new rings and circlips - 90
tools - (dremel, piston ring pliers, 1/4" torque wrench) **investment anyway** (< 90)
gaskets (base + head + valve cover + valve cover 0-rings) - 70 (oem + pattern for valve cover)
50mm studs for exhaust - 10 (the Nissan 47mm ones are too short) - probably cheaper available but had problems so bought engineering ones
various oddments (seized front engine-mounting spacers, replacement stainless bolts for things) - 30

but I don't need my bike to get to work so I could spread out that over a few months (yes, i'm aware its economically stupid, but I like fixing things).

The engineering shop didn't even blink at the job, just phoned them with the circumstances, they said "bring it all in" and after a 1 second glance at it said "yeah, no problem; we get this a lot. you want studs and copper-flashed nuts once its helicoiled" - a week later (I was in no hurry) and picked it up.

regardless of how you do it i would absolutely swap to studs instead of bolts. bolts were a terrible idea Suzuki!

Offline max

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Re: Drilling out exhaust bolts
« Reply #8 on: April 06, 2019, 11:50:51 PM »
I removed my head and drilled the studs out with a left hand drill bit (to try to get the bolt to unscrew while drilling - did not work). Started fairly slow and small and ended up drilling about a 1/4 inch hole right through the bolt, then I used alum with a light bulb for heat to dissolve the rest of the bolt (really.. google it....) took about a week of stirring , adding alum twice a day.

Never heard of that before, will definitely be looking into it!


on a '98 but i suppose once the fairing is removed its all the same...

I snapped 3 of the 4 bolts removing an old manky exhaust from mine. Briefly considered drilling but ultimately took the head + barrels to a local engineering shop and for 140 they drilled and helicoiled the head, honed the bores and shoved the bits through a parts washer. It was quite labour intensive getting to that stage but mine was a neglected engine.

its surprisingly expensive depending on what you need to go with all that.

The head can be removed in-situ but if anything causes trouble its easier to remove the whole engine. I say 'easier' the front engine mount seizes up easily. in retrospect its not hard to sort with the right approach but it took me ages to get to that.

involved for me (plus engineering shop time):

cutting off valve cover (ebay replacement) - 11
bolts for engine mount and front-most valve cover (oem) - 30
new rings and circlips - 90
tools - (dremel, piston ring pliers, 1/4" torque wrench) **investment anyway** (< 90)
gaskets (base + head + valve cover + valve cover 0-rings) - 70 (oem + pattern for valve cover)
50mm studs for exhaust - 10 (the Nissan 47mm ones are too short) - probably cheaper available but had problems so bought engineering ones
various oddments (seized front engine-mounting spacers, replacement stainless bolts for things) - 30

but I don't need my bike to get to work so I could spread out that over a few months (yes, i'm aware its economically stupid, but I like fixing things).

The engineering shop didn't even blink at the job, just phoned them with the circumstances, they said "bring it all in" and after a 1 second glance at it said "yeah, no problem; we get this a lot. you want studs and copper-flashed nuts once its helicoiled" - a week later (I was in no hurry) and picked it up.

regardless of how you do it i would absolutely swap to studs instead of bolts. bolts were a terrible idea Suzuki!


Appreciate the detail there, good to know that the machine shop were more than happy to do the work. Costs shouldn't be too bad for me as I only serviced the shims a few months ago and put in new breather and rocker cover gaskets and a few new bolts and o-rings too. Also have most of the tools (although now's probably a good chance to buy Halford's new 6pt socket set to try to avoid rounding anything off).

What's the story behind "in retrospect its not hard to sort with the right approach"?


Offline tobyd

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Re: Drilling out exhaust bolts
« Reply #9 on: April 07, 2019, 10:41:01 PM »
If all that is under control I think you'll be alright to try and pull the top-end with it all in-situ. You'd likely only need a new head gasket - OEM was the cheapest I could find. A few people suggested to just take the whole engine to the machine shop but I can imagine that would piss the people off having to clamp up a surprisingly heavy lump with the GS (i'm sure my 4 cylinder yamaha engine is lighter). Don't break a LH drill-bit off in the head - they are incredibly tough and will be very difficult to extract.

The actual process of pulling the head and then putting it back is covered in excellent detail on this guys website - The cams need a lot of care when releasing and tightening so as to not strain them and tightening them back down into the right place is pretty harrowing but its not hard and doesn't need any special tools beyond a decent torque wrench.

If, however, you end up needing to cut the engine out the front as the front mount is seized solid then its possibly not obvious how to tackle that. In my case, dealing with this took a ages. Rebuilding the bike back up from a few boxes of parts from the bare, newly-painted, frame is doable in an afternoon.

its easy enough to grind or hacksaw or whatever the bolt head off the hacksaw through the spacer tubes (these are surprising expensive new, I went second hand) to free the unit from the frame. but you are then left with a sturdy, rusted bolt stuck through a very fragile piece of aluminium. Just smashing it with a hammer will break said aluminium (ebay used engines or posts on here for the results) and no matter how much heat or plusgas I applied the thing wouldn't shift. I tried drilling it but its tough metal that work hardens and keeping a handdrill dead-on just wasn't going to happen...

Bolt corroded into spacer...


turning the engine upside down exposes the middle-section of the bolt so very careful use of a dremel will let you cut out that section so you are only fighting 1 corroded surface instead of two - with the spacers in situ you'd be fighting an awful lot of rust hence sacrificing them. One side then freed off with a little heat, the other I drilled through and could then get a hacksaw blade through the hole and cut a slot in the bolt (to let it relax into the slot) and it popped right out (I suspect this is the 'best' approach). Hence seems simple in retrospect when you have spent quite a while soaking in pen-oil and cooking it with a blow-torch and getting no where it seemed effective enough.

I've taken to re-lubing the front mount every so often as a precaution.


Offline Kenner

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Re: Drilling out exhaust bolts
« Reply #10 on: April 10, 2019, 01:51:37 AM »
Max,

I successfully drilled mine out by hand and installed a Time-Sert thread repair. It was not too hard. I documented it in my thread here http://gstwins.com/gsboard/index.php?topic=72148.0  titled "Kenner nurses a neglected 04F back to health". I center punched the busted bolt. Then I drilled it out with an 1/8" drill then I continued with larger and larger drill bits until I had it to the correct size to thread the Time-Sert (Helicoils also work fine). I did it with the engine still mounted to the bike. I just removed the front tire and fender for better access. It is holding up just fine.

Try it yourself, it's not too hard to do.

Ken

P.S. How do you insert a link into a post rather than just the web address?

Offline Ted

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Re: Drilling out exhaust bolts
« Reply #11 on: April 10, 2019, 07:12:29 PM »
Ya know, it's stories like this that keep me from trying to remove my pipes and hit them with some black header paint. My experience with Suzuki bolts is they corrode at the merest hint of humidity, so they probably will sheer right off if I so much as wave a wrench in their general direction. Not to mention the fact that some of the bolts (bike is still in storage, so I can't say if it's one or two) are blocked by the frame.
Ted
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Offline max

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Re: Drilling out exhaust bolts
« Reply #12 on: April 10, 2019, 11:04:17 PM »
@tobyd
The cams are the only aspect that puts me on edge, but maybe that's just because it's new to me. Will need to buy a low range torque wrench though looking at those specs.

No need to google used engines to see a broken front motor mount, look at my attachment to see what mine is(n't) being supported by... At least the bolt shouldn't be stuck :icon_eek:


@Kenner
I remember reading your thread a while ago, notably Yellow Bird's ever increasing score counter!

You've reminded me that it might be worth a go welding a nut onto the stud first. I'm thinking that my bolt heads are corroded so I'll drill those off, then hopefully there'll be some hidden strong-enough stud left that I can weld a nut onto from there.

Got to be worth a go before taking it to the machine shop at least.

Potentially very nooby question, but I've only ever welded mild steel (stick welder). If I'm removing the head and doing the welding on that at a bench (/ pile of bricks), can I just clamp my earth leads onto any of the aluminium as there won't be room to get the clamp onto the remainder of the bolt?

Code: [Select]
[url=kennerswebsite.com]Any text you like[/url]

@Ted
I was wincing when I thought of it too, but the functionality of being able to remove the exhaust leads to so much more possibility (including giving the pipes a proper clean and spray).

Offline The Buddha

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Re: Drilling out exhaust bolts
« Reply #13 on: April 11, 2019, 12:09:56 AM »
Ya know, it's stories like this that keep me from trying to remove my pipes and hit them with some black header paint. My experience with Suzuki bolts is they corrode at the merest hint of humidity, so they probably will sheer right off if I so much as wave a wrench in their general direction. Not to mention the fact that some of the bolts (bike is still in storage, so I can't say if it's one or two) are blocked by the frame.

Someone on here a few yrs ago was just shocked at all the carb issues on the bike seeing tons of carb threads and decided that leaving the carbs alone was the best strategy.
Of course if the carbs ever got plugged from something, that strategy would have come to a "not running bike for sale $100" event.

So if you have rusty headers, either fight this smaller demon now, likely get a handle on it, or atleast cut it down to size or well, wait till the exhaust blows a hole form the rust, and you can fight a rustier header bolt set then plus the rest of the header which may still need to be sourced and bought from someone here or ebay or junkyard.

Cool.
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Offline Cincykz

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Re: Drilling out exhaust bolts
« Reply #14 on: April 11, 2019, 01:19:05 AM »
I had to drill out 1 of my 4 header bolts when I painted my pipes. If you block the frame and pull off the forks (6 bolts including the caliper) it's pretty doable. Use sharp drill bits and go small to big, finish with a tap. The original threads were perfect.

Offline The Buddha

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Re: Drilling out exhaust bolts
« Reply #15 on: April 11, 2019, 03:08:30 AM »
I had to drill out 1 of my 4 header bolts when I painted my pipes. If you block the frame and pull off the forks (6 bolts including the caliper) it's pretty doable. Use sharp drill bits and go small to big, finish with a tap. The original threads were perfect.

Yea I had to do this as well, on 1 out of 17 GS'es I owned and maybe another dozen I worked on for others.
Its not as common as the plague in the 1600's. Its about as common as a virgin in the kardashian clan.

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Offline tobyd

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Re: Drilling out exhaust bolts
« Reply #16 on: April 13, 2019, 09:41:45 AM »
The worst thing I found with the cams was undoing the bolts and tightening up the exhaust cam at the end. I assume as the bolts are under stress from the valve springs below as you slacken them off they make a pop noise and every time they did (just once per) I thought 'thats the cam snapped then...'

I think I went a quarter turn at a time in a figure of 8 over the caps until they were loose.

Putting the exhaust cam back in so its correctly timed was the big scare as you have to tighten down against a valve bucket on one side whilst keep the timing position right. The cams on my Yamaha have a hex extrusion so you can turn the cam once its seated but my GS ones don't and it will try and slip out a tooth or two and you'll have to start again... Its not hard but is stressful (for me).

Bit of chemical metal on that and it'll look better than new!
« Last Edit: April 15, 2019, 10:31:04 PM by tobyd »

Offline max

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Re: Drilling out exhaust bolts
« Reply #17 on: April 15, 2019, 10:15:21 PM »
Good to know, I'll try not to brick it too much when I hear them pop into place then! Sounds like patience is key - we'll see how much I have left by the end of this...

tobyd you were right about the parts adding up though, new crush washers and o-rings alone are coming in at silly money, let alone 25 for the head-base gasket.

On the bright side, I ventured outside and cracked the 6mm front head bolt loose yesterday to test the waters before this weekend. It took some back and forth but I got it out no problem - step 1 of many complete!

Offline tobyd

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Re: Drilling out exhaust bolts
« Reply #18 on: April 15, 2019, 10:41:24 PM »
Its not a cheap endeavour - there isn't a lot you can substitute in in place of anything and if you end up doing the rings too its very uneconomical. Its very satisfying do yourself though and once its running again you'd think nothing of swapping a head gasket on something a bit more complex :)

Patience is definitely key - same with the 8 head nuts - little bit at a time in the undo-sequence (I think this is 8 -> 1  opposite of tighten but check the manual) until they are all slackened off. I re-used the nuts and washers on mine and it leaked a bit of oil for a while they gummed itself up (fixed!) but i'd definitely replace the washers and nuts if I did it again.

Oh and if you need to beat it with a mallet (wooden or rubber!) to free the head from the barrels don't hit the fins (even by mistake or in a blind rage) as they are very fragile, ask me how I know...


Offline ShowBizWolf

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Re: Drilling out exhaust bolts
« Reply #19 on: April 16, 2019, 12:31:33 AM »
I'm a little nervous about the condition of that front engine mount... looks pretty well gone in the picture. Anyone else feel that way or am I being paranoid?
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