Weekend Exhaust Woes

[turboferret]

Right, so this weekend I decided that I was going to fit my new y-piece and shorter paralever arm.

The paralever arm seemed like the simpler job, so I tackled that first, until I found that you couldn't access the front nut because of the big fat nasty cat

So onto the y-piece....

The bolts at the front were far from removable, being rusted to b*ggery with circular as opposed to hexagonal centres. Out came the trusty dremmel clone, which I broke so had to go and replace with a pukka version.

Off came the heads fairly simply, which left me with \/ this \/



As you can see, heads are off, circled using my best artistic skills in red.

However, the flange, beautifully marked in blue, (part not fixed to the cat) was not wanting to budge at all. It would appear as though the flange is threaded, which seems rather odd.

Can anyone confirm or deny if this is threaded? Logic would suggest that it ought not to be to tighten the exhaust to the cat, but maybe I'm not thinking Germanically...

My theory is that by giving the beast a god thrashing without bolt heads they might self loosen

Also, before this, I thought that loosening my downpipes would make things easier, although this was rather counter-productive, as the first tweak on the spanner removed the head from the stud



I am hoping that this won't present too much of a problem unless I want to remove my downpipes - rectifying this I suspect is a workshop job....

Any thoughts gratefully appreciated.

Cheers, Rich

[gus]

Hi
First get a big hammer and twat the cat until headers come away.The collars are not threaded and will slide along the headers revealing the broken/cut studs.I take it the cans are off at this stage.
Regarding the broken header stud.You will need to replace this before you run the bike.It will leak there and may burn a valve,something you dont want to happen.Arm your self with some new studs and bolts before attempting this,the other is bound to break.Use heat and plus gas and try and ease the other nut of header.Once off you can remove the header and get to work on removing that stud or studs as the case may be.Again plus gas and heat will be your friends here,oh and patience!If there is enough thread showing run a couple of nuts onto the stud.Lock one against the other and gently ease the stud out.Do Not use excessive force and snap it flush,it will them be a drill out and helicoil job.Not nice.Better to have some stud showing so a bar can be welded on and you can start with the heat and plus gas routine.
If you dont feel confident in doing this,then take it to a shop.Cause if things go tits up,its hard to rectify.
Good luck
gus
ps
use copperslip grease on the new nuts and bolts.

[julian]

As Gus said, release the cat collars with a good quality calibrated twating hammer.

For the sheared bolt - I've been there. Try and use mole grips or stiltsons as a first call - a stud extractor doesn't fit the available space.

My recomendation however is to whip the head off. It will cost 20 quid for a new gasket and approx 40 quid to have the stud extracted in a shop. This will save hours or even days of increasing humiliation and despair trying to release the stud using advanced Heath Robinson methods.

See stud extraction pics here.

and also here

[Jason M]

Rich - that's a GRADE A died in the wool nightmare. I HATE that "it's moving it's moving it' F**********************K" moment when the bolt shears and you see hours of pain and your wallet runs screaming into a dark corner

Like the boys say - a suitable twatting hammer - preferably rubber in my opinion - will move that collar, and then the double bolt trick or preferably a bolt extractor socket - one of those reverse grabby ones or ones with the ball bearing in - and as much pre plus-gas soaking as you can manage. I would even get some blue tack and form a little 'cup' around the header bolt then fill it with plus gas and just let it soak into the bolt for as long as poss before trying to remove it.

Patience is the key - I should know cos I've not got any and usually resort to a bout of 'drill/hammer/Mole grip rage' within 0.0002 seconds of the disaster occuring

Good luck

Jason

[turboferret]

Thanks for the info guys.

I haven't come across Plus Gas before, but it sounds like good stuff, and I'll certainly go and get some before proceeding any further. Is it normally sold in motor factors/Halfrauds?

I was tw*ting f*ck out of those collars on the cat, obviously not hard enough

I think I might whip the head off and get the studs removed in a shop, as I'm not really kitted out with all the necessary gubbins.

My only reservation is that my bike is my only form of transport, to that would mean stealing the other half's car for a while

I've had various heads off before, is the boxer a straight-forward one to do?

Cheers, Rich

[Jason M]

I'm not sure they sell plus-gas in Halfords... I got mine from a proper tool shop but it's not expensive when you find it

As for the twatting - as have the studs in the cat still it might be good to employ a 'twatting accessory' like a screwdriver or centre punch to twat into the gap and force the collar off the studs. There is a gasget in there though (a metal one I think) so be careful (my middle name NOT).

The head removal is quite straight forward - just don't remove any more bolts than necessary cos the rockers will fall off/out. Job 1 is to remove the little inspection panel at the back of the cylinder (black plastic patch) and you can see the sprocket on the end of the cam. In my experience this is 'SUPER F'KIN TIGHT' and I think I would maybe put the bike in gear on the sidestand to get enough resistance to undo it - the head bolts were easy in comparison.

As Julian said - he's done this pretty recently so he'll have all the details. I've removed the ones on a spare engine but not done it 'live' yet.

Jason

[turboferret]

Jason,

Found some PlusGas in the motor factors opposite Tescos on the way back from buying lunch, so sorted on that front.

I did have a big screwdriver in the tiny gap twixt collar and cat, and was getting a good belting with technical adjuster #1, but they weren't having any of it, and were staying put

Will give a liberal coating of this super penetrating stuff and see how it goes.

I'm currently running it with no heads on the studs, although I've got some lockwire around each assembly, so if they do magically self loosen, it shouldn't be too noisy

Probably aught to get a decent manual to assist engine stripping, although the BMW repair manual doesn't look too bad.

Cheers, Rich

[julian]

I've had various heads off before, is the boxer a straight-forward one to do?

Cheers, Rich

Should be no more than 1 hour including cleaning around the joins before stripping. The head is held on by 4 big nuts and a few smaller bolts underneath. My cam bolt sprocket bolt required heating to release the Loc-tite. Also make sure that the chain stays on the cam sprocket teeth (cable tie and mark with Tip-ex) to retain the timing and that the chain and sprocket don't fall into the sump. See my pictures above. Also the black air intake tubes have a self tapping screw underneath which needs to be removed to enable the tubes to be pushed back into the air box.

I can email or post you the BMW manual on disk if you require it. It is 26MB.

[turboferret]

I've spotted a couple of heads on eGay, which I reckon might be a straightforward way to go, to minimise time off the road - hopefully just swap straight over.

I can then look at having broken studs removed at my leisure without having my bike out of action mean-time.

I'd assume that swapping my valve gear onto a new head will mean I'll need to adjust my valve clearances too.

I've got the 26Mb BMW service manual on my computer, but thanks for the offer

Any obvious pitfalls of this route that I've overlooked?

Cheers, Rich

[air_cooled67]

I have in the past had succes removing studs with a mig welder. Just weld a bit of stud on the end of your stud then double nut to reove. Pleanty of plus gas first helps!

Disconnect the battery before welding!

[Dog Tyred]

So how much do you want for the Y piece ???:wink:

Only kidding. Best of luck..................................................................... I think your gonna need it

Greg

[theseadog]

Hello Rich

Been there done that, and it's a pisser when it happens, that sinking feeling as you realise that it's not the stud loosening but shearing is awful. Anyroads advice so far is sound, I'd add, squirt some plus gas up the hole in the collars where the remains of the bolts are and then wiggle the pipes whilst wedging a screw driver/ pry bar in the gap between pipe collar and Y-piece collar. That should see it free in a few minutes. From there either plsugas lots of heat and mole grips to remove the remains of the bolt or drill em out.


For the head stud, if you've a drill stand then drill it out yourself and helicoil it, else take ti to local machine shop who should do it for no more than 40-50 quid.


Good luck and any more probs come back and ask, someone if bound to have already done it.

Toodle Pip

[turboferret]

Thanks for all the advice, guys

Plan is to get the job done, one way or another this weekend.

I have purchased a couple of low mileage heads from the wonder that is eGay, which should turn up soon, which should mean time off the road is minimised, and I can swap heads without machining.

I am also told by the guys at MotorWorks that there is an oil gallery just behind the exhaust stud thread, so drilling a fraction too deep renders the head rather useless.

Apparently they send all their heads with broken/seized studs for spark erosion, at a cost of about £5 a thread, which sounds like the way to go

I am armed with a new blow-torch and some PlusGas, so hopefully the tears will be kept to a minimum

I'm gonna see if I can remove the headers using copious amounts of PlusGas initially without shearing any more studs, and hopefully remove remnants of studs without resorting to too much butchery

Welding is a possibility, but as I've run out of gas for my tig set, it'll be an arc job, which may not be pretty, although a little bottle of Halfrauds finest should do the job too....

If I can get studs out, all well and good, if not, then I'll whip the heads off, and swap them over for the new ones. Chances of this going horribly wrong, is I know, pretty high

With some loose headers, lots of PlusGas, and perhaps some heat, the collars should become mobile, and the prospect of fitting my Y-piece should become closer to becoming a reality

One other bizarre thing with my bike though, which emerged at the weekend after fitting my standard bars, is that the lock stop on the right seems to have changed, as the bar end weight can now touch the fairing just before the stop, significantly different to the left, which is slightly worrying - any thoughts

Expect more tales of mirth and woe in the near future

Cheers, Rich

[Jason M]

One other bizarre thing with my bike though, which emerged at the weekend after fitting my standard bars, is that the lock stop on the right seems to have changed, as the bar end weight can now touch the fairing just before the stop, significantly different to the left, which is slightly worrying - any thoughts

The lock stop won't have changed by chaging the bars will it? I can't think of any reason for that other than the obvious - might do to get the ruler out and take some left/right measurements. The only example of this I know is a bloke that threw his S in a ditch and pushed the front subframe a bit to the right - or - maybe the bar is slightly bent

[turboferret]

Bars looked immaculate, purchased from a Boxertrixer, surely I couldn't have been given dodgy goods

All seems a little strange, the old bars certainly didn't do this

I'm sure I'll find out at some point - I'll have all of her clothes off at the weekend, and I'll have a good shifty

Cheers, Rich