Removing Exhaust Header Bolts??

[Dazbo666]

Removing Exhaust Header Bolts??

Do I put WD40/penetrating oil on a hot, warm or cold engine
and before or after running the engine??
...or is it just a matter of "all of the above"??


Basically I'm making preparations to replace the connector pipe on the exhaust collector box, but when I take the exhaust off I'm also going to be replacing the existing header bolts with better quality stainless ones.
Well, I made a tentative attempt to loosen one or two of the header bolts yesterday, but absolutely NO movement from them.
If possible I'd obviously like to avoid having to drill and re-tap them, so I'm going to be giving them an intermittant dose of WD40 or similar over the next few days
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1st bike (Sept'06 - May'10) : 1991 GPZ500S / Current bike (since Nov 2009) : 2003 Suzuki Bandit 600N
Word of the day : DILLIGAF

[dodgydog]

Plusgas is better than WD40. just keep soaking the bolts in it.



Dog
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I know that you believe that you understood what you think I said, but I am not sure you realise that what you heard is not exactly what I meant

[neil.]

I did this recently on my YBR. The screws looked pretty rusty and the bike had covered 2 and a half winters and 31'000 miles.

I started my penetrating oil routine a week before attempting to remove the bolts. The stuff I used is called 3-in-1 penetrating spray. When I got in from work, I immediately sprayed it all over the screws whilst the engine was hot (but turned off!). It smoked a lot but don't worry about that. The heat draws the stuff into the threads aparantly. Before bed, when the engine had cooled, I gave them another dousing so that more spray could have the chance to seep in overnight.

I carried on with this for 5 days and then, using a proper hex head socket, NOT an allen key, I tapped it in with a small hammer, in hope that the shock would help loosen things up and centre the socket bit in to the screw properly. Then I carefully used my breaker bar and slowly applied pressure until the screw cracked loose. After that, I sprayed it with more penetrating spray, gave it a moment and turned it a bit more, then turned it clockwise 1/4 turn and repeated the process until the screw became easy to unscrew. Then repeated with the other one and then removed both. Whatever happened I did not in any way, shape or form want the head being rounded out or, even worse, snapping off leaving a stud in the engine block! The key is patience.

Also, with penetrating oil you can make up a plastacine 'well' around the screws and effectively submerse them. I didn't do this but it sounds like a good tip IMO, especially if the screws face downwards.

+1 for not using WD40, use a proper penetrating oil. Also when you put it all back together, use loads of copper grease on the exhaust gasket as well as the new screws and a torque wrench because they are easy to overtighten and chances of stripping the soft threads of the alloy engine casing are high.
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CBT February 2008 | A2 June 2008 | Yamaha YBR125 (written off) | Honda CBF125 (current)

[DrDonnyBrago]

Even if you do all of the above, I still wouldn't be surprised if you snap at least one. Probably one in the middle, so it's harder to get at.

Good tip when you finally get them out though is to run a tap down the holes to clean them out, copper grease the F out of them, and even consider using brass nuts. The brass shouldn't corrode and should strip before the stud snaps next time - I got the idea courtesy of Stinkwheel, and used them when I did my CBR downpipes a while back.

[Bezzer]

Take it this is for the infamous Bandit collector rot
Use Plusgas for a few days or any other penetrating spray, anything is better than WD40.
When you have a go at removing them give the allen socket a good whack as this can help to shock the corrosion apart, if they haven't been done for a while you will round off a few of them.
The best method then is to get a 12mm multipoint socket and hammer it over the allen head, stick a ratchet on and it should undo. This method usually works, if it doesn't and the bolt breaks then it was beyond redemption anyway.
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I used to be indecisive but now I'm not quite so sure.

[Dazbo666]