Thumper Club Forum
Technical => Bike Problems/Questions => Topic started by: Bob on March 08, 2007, 09:06:00 PM
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...exhaust nuts to be exact. I'm running a Suzuki GN250 as a winter hack and it badly needs a new exhaust. The exhaust I can buy from Ebay but the problem is that the exhaust nuts & studs are really badly rusted.The nuts will round off as soon as I put a spanner to them and the exposed thread will strip if I try to put a new nut on. As they are only M6, there isn't a lot of metal to play with in the first place.
As I don't want to have to take the barrel off to get broken studs removed, can anyone give me some tips on the best way to get'em out!!...(apart from lots of heat & care)
cheers
Bob
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My method ,Not guaranteed !
Loads of WD40 over the offending stud for at least 48 hours ,the more rust more time and WD40.
Start bike to heat stud ,tap on a imperial socket that's to small for the nut and pray !
If your lucky the stud and nut will come out.
If your unlucky the nut will round off or the stud will break off or the stud will take the thread with it when it comes out .
All these can be fixed but cost time and money.....
WARNING :) WD40 is flammable ,
This can be proved by squirting it over a lit cigarette lighter in a large open space ,use the plastic straw or the nozzle melts ! :)
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If the hammering on too small socket doesnt work;-
I suggest investing in some quality molegrips (Irwin visegrip etc) Get the bike up to full temp and use the mole grips to try and undo the nuts, if the studs snap remove exhaust (hot so gloves at the ready) if enough stud showing try the molegrips again. If snap again cenre punch and drill up the MIDDLE of stud accuratey with 3mm drill bit (not cheap crap one) then drill out to 5mm, then re-tap to M6 if that is indeed the size, and fit new studs.
That is how I would do it, hopefully the drill/tapping wont be needed, if it is should be able to do in situe without removing barrel.
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I have a complete set of oversize taps and helicoil plus studs and brass screws that I used on my SRX with no problem (on the bike)
Where abouts are you (roughly)?
This is a set that I got from my local engineering company.
SteveD
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Best way is local heat. Small welding tip and warm the stud and head being carefull not to melt the alloy. Dont try while the stud is still cherry red. Pair of grips and rock the stud back and fourth very carefully it should start to move then increase the amount you turn it till if comes out.
Ken
...exhaust nuts to be exact. I'm running a Suzuki GN250 as a winter hack and it badly needs a new exhaust. The exhaust I can buy from Ebay but the problem is that the exhaust nuts & studs are really badly rusted.The nuts will round off as soon as I put a spanner to them and the exposed thread will strip if I try to put a new nut on. As they are only M6, there isn't a lot of metal to play with in the first place.
As I don't want to have to take the barrel off to get broken studs removed, can anyone give me some tips on the best way to get'em out!!...(apart from lots of heat & care)
cheers
Bob
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All are good options, I'm assuming you'd prefer not to disturb the studs and just swap the nuts if possible?
As has been said, lots of heat on the outside of the nuts, then a very close fitting socket, the best option if you can lay hands on them are wall drive sockets, saved me many a heartache!! Turn gently and if it starts to feel "plasticy and soft" (tm) then STOP!! So you're in trouble now...:o more WD40/duck oil/home made penetrating goop and more heat/cold cycles, give it some sharp taps on the end of the stud/nut and try again, consider a ring spanner so you can put a gentle turning moment on the nut while jarring the end of the stud.
Above all, BE PATIENT! If you're getting stressed with it go for a cuppa and calm down ;)
Now once it starts to turn, don't undo it all the way straight off, apply loads of WD40 or whatever and undo a little then back a little then undo a little more and back a little and so on and so forth. (and keep adding oil!)
Et Voila! (hopefully!!)
Now when you refit, take that LARGE tub of copper grease you bought and put it next to the bike along with the stainless metric bolts you're going to use to refit the exhaust... ;)
Nah, seriously, good luck, let us know how you get on, it can be a pig of a job!
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When I was a kid about 40 years ago banging around on old rusted together bikes and cars a guy gave me a can of pb blaster to use.
It is the single best penetrant I've run across, bar none, and should be substituted for WD40 when you run across a problem like this and need the best penetrant available.
Once you try it, you will never go back. Hopefully it is obtainable over there, but if not, go to www.pbblaster.com and get a can of it somehow.
I have removed studs and nuts from old Indians and harleys and fords that haven't turned in 50 years with it after a 24 hour soaking and a little heat, and a friend of mine that restores old airplanes swears by it as well.
Some of the things he works on are rare and valuable and almost impossible to replace, so he uses only pb blaster, in conjunction with all the good techniques the other good guys have suggested to you here.
If no one distributes it in Europe or the UK yet, there would be a good opportunity for someone over there to make a pile of money, because all the old motorheads I associate with swear by it, and only it, and its merits will become readily evident to anyone who tries it.
It is simply the best penetrant, and it has saved me many hours of labor, frustration,old parts questing, and the associated cash involved in all of that.
PS. I don't work for them, and I wouldn't make a nickel if you bought a boatload of it. Just trying to pass on some things that work.
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Just adding to the above and agreeing
On rebuild plenty of copper grease
On taking out - sometimes tightening a little first helps break the 'weld'
I have found loosing your rag and beating the crap out of it with a lump hammer does NOT work and tends to damage heads.
Surface drive sockets are great - if it is the right size even better - I have some Halfords ones - bought as and when and they are brill. HOWEVER in then past I had access to Snap-On surface drive sockets, and with these you could pretty much file the nut round and it would still come out. Good mole grips are wonderful, cheap copies are rubbish.
If there is much of the stud showing past the nut it may be worth chasing that portion of thread you can get at - either with a die, a thread chaser or a new nut - 6mm is a little small but you can sometimes run a rat tail up the inside of the nut to cut some cross cuts into the thread - helps to clear the dirt.
Final choice - cut the pipe off with a short stub, fit a slightly oversize tube over this and slot the new pipe in this - using springs to retain....
R
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nutcracker!
this tool has saved me many a time. it pushes a chisel into the side of the nut until it splits, then the nut can be prised open and away from the stud.
after this tidy up the threads and remove all the rust and road crap from the threads before putting on shiny new copper-slipped nuts.
this maximises you chances of leaving the studs and their threads intact. if needed i can take a photo of the tool and e-mail it. most good car accessory shops should know what one is, i think mine cost about £8.
350bullet
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Thanks for all of the suggestions chaps! It looks like some one has stuggled before as it current has 2 studs with extremely rusty nuts and 2 bolts also very very rusty. Plan is , if I get them out ok, to replace these with stainless.
I'll give it a try over the easter holidays when I've got a few days off and don't have to rush!
thanks again
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Just remember - heat.
If it all goes horribly wrong then a good dodge to get a stuck stud out is to weld a nut onto it and whilst it is still hot use a socket to wind it out.
Smudge is dead right, work it back and fore instead of just winding it out, say half a turn out, a quarter of a turn back (and fore).
And yes I know, some of you will be astounded to hear that I have any sense of mechanical sympathy :)
GC
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And yes I know, some of you will be astounded to hear that I have any sense of mechanical sympathy :)
GC
Ha Ha Ha Ha ! I've seen you working ! LOL
Jethro
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I just cut them off by slicing down opposing sides of the nut with a dremel and a small cutting wheel then run a die nut down the stud to save it, m6's are always a pain and I dont like hitting them as theyre so petit. If the studs too far gone, lots of heat into the alloy without melting it, and I use some handy small stilsons as its coming out anyway and it dont matter if it has big cuts from the jaws in it, I grip the stud as close to the head as possible. If it snaps, I cut it off flush, centre punch it and drill it out to the size of the tapping drill - say 0.4mm for the tapsize, using a left handed drill bit that I have a set of that have saved my neck a fair few times now. If the drill snags it tends to just unscrew the stud and the drilling vibration tends to loosen it anyway
http://www.northerntooluk.com/products.asp?partno=150272E
I thought the gn was 8mm, the gn400 lump in my sp is 8 and its only honda that use m6 exaust studs. Maybe I cut them bigger years ago and forgot about it :-)