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So the world’s slowest exhaust change is ongoing, been about a year or so in progress.
The exhaust on my c90 rusted and snapped just past the cylinder head. I’ve removed the exhaust, nuts and collar but the stub of the remaining exhaust is struck fast in the cylinder head. The bike is in our place in rural Ireland so I want to see what I need to take over next month in a bid to free it. Am I right in thinking that I’m probably looking at heat and a slide hammer of some sort to free this? There doesn’t to be much room to get a blade in to cut the stub but it may come to that if needs be
If so is there a heat source which is not a full on welding torch that would do the job and any recommendation for a slide hammer? Amazon seems to be chock full of cheap Chinese ones but the reviews are fairly mixed.
A slide hammer is only a heavy lump of steel with a hole in it. A house brick and a length of threaded bar can be used in an emergency.
Weld a length of studing/threaded bar to what's left?
Can you get a washer on the inside of the barrel against what's left of the 'pipe? Then slide hammer it
Cut a slot in it then drift the remains inwards?
Can you get an angled drift inside the cylinder bore to get behind it?
Boil the barrel in a pan of water / or heat in a pan of glycerine or oil for awhile then tap it out from inside?
It's worth soaking it in plusgas. A plumbers torch should get it pretty hot. Engineers picks and a wire brush could be handy to clean off corrosion. Maybe you could drill a hole through the stub to get some leverage. Take your time, little by little, and it should come loose. You might want to bung a rag into the stub to stop bits going into the head. A dremmel could be useful if you need to split or cut it. A controlled wallop with a cold chisel might move it.
Thanks all
Can’t, well not without going to a garage weld a bar onto it and getting to a garage would be a major issue. Was hoping to get an expanding internal bearing puller behind it. Plumbers torch may be as good as I can do .
big stilson wrench on the stub to twist it out? heat and penetrating fluid as well of course
Might be able to get vice grips on what's left. I think heat will be an essential
Hacksaw blade and cut lengthways through the exhaust and prise the exhaust away from the cylinder head with a screwdriver
Dremel, or cold chisel and hammer? Or both?
Like others have said lots of plusgas to start and then it's one of those jobs that has you rooting around in the tool box for all manner of odd tools. I'd be packing some fine drill bits and a drill - put a pair of small 2-3mm or so holes through the exhaust on opposite sides and then thread a wire nail through. With a pair of molgrips or similar you can then grip the nail and exert a fair amount of turning force on the exhaust without ripping it to bits or crushing it.
I had a very similar experience with a snapped stud at the exhaust port on my rd250. The remaining stud was basically a tiny sharks fin protruding from the head. I drilled a 2mm hole, threaded a wire nail through and lo! a hail mary moment.
For heat a hot air gun would also get things pretty hot.
Oh and definitely stick a rag in the port to stop any swarf getting in - first thing I would do
Rd250? Smashing! Air cooled or LC? If I had more time and space I would very happily embark on buying up all the bikes I wanted as a teenager but could never afford…. A mate of mine has done exactly this and has a very impressive collection of mid 70s kwaks, z900, z650, z1r to name a few.
Bizarrely I’d probably also have a Honda C90.
Hold on !
Are you saying it's just the stub of pipe thats cold welded to the port in the head ?
All the rest , flange, studs etc are all out ?
If so, then don't try and pull it out. Dremel it away . Very slowly and carefully but you'll do a lot less damage.
Can we have a picture of the Honda 90? I had a Honda 110, it was brilliant. I think about it much more than the Vespa or dual sport I had.
I recently found a product called Freeze & release. It sprays a mixture of penetrating oil and something at -45°C, the idea being to shrink the component and create a crack for the penetrating oil. Worked on a seized brake union and bleed nipple (I don't know how seized the nipple was, I only use limited torque on them)
If I had more time and space I would very happily embark on buying up all the bikes I wanted as a teenager but could never afford…
I'm assuming you've not looked at what 2-strokes are going for these days...
2 strokes are evil shitdog spawn of Satan.
Unless it's in a Lambretta obv.
I had an RD125 LC.
My first 125 after a painfully slow Honda MT50.
I only had it about a week. Put it and myself through a hedge. That powerband was something... 😅
GT250 Hustler here. Paid £40 for it from a scrapyard. Home ported it with some of my dads files. Stan Stephen’s I’m not! Power band was razor thin but boy did it shift when it was in it.
Or save your time and get a big bore upgrade with a kit like this: https://www.ebay.co.uk/itm/163250311065
During exhaust removal and with trailer
In normal state
And crappy photo of recalcitrant exhaust bit
With pensive owner in background
Tidy (the bike, not the owner, no offence)!
Could you make up a puller bar using the exhaust studs then lock something in behind the last bit of the pipe, or chain drill out the collar part of the pipe and collapse it?
Is this a better photo example of where you are at?
Dremel it away . Very slowly and carefully but you’ll do a lot less damage.
Will a reciprocating saw be too savage (I may be able to borrow one of those)?
That last picture shows where the stub has welded itself but there’s a bit of cylinder head missing in that one. You can see the internal lip the sealing brass washer and exhaust butt up against though. Big bore kit looks fun but judging on this debacle beyond my mechanical skills!!!
Will a reciprocating saw be too savage (I may be able to borrow one of those)?
Maybe.....and it may be too big for the hole.
Which is why I suggested a hacksaw blade way back when.
Some one said dremel it. I reckon they are right.
Yep dremel and try and fold the cut in
Loads of lube. Once it starts moving you've won!
Ahhh! Just spotted your eye!!!! Gave me quite a fright 😂
I reckon you might be able to tap round that with a hammer and cold chisel, or large old screwdriver…
So thread update. The wee bastard bit of exhaust is now out! Lots of heat from a newly purchased blowtorch and a few wacks freed it and Neely purchased mole grips wiggled it out. Now onwards to exhaust fitting nightmares. I also now have a newly purchased dremel and various blades to play with and already used it to remove a rounded cleat bolt! There’s a bit of a newly purchased theme to all this!!!
Thanks for all the replies.
newly purchased blowtorch 👍
newly purchased mole grips 👍
newly purchased dremel 👍
That's your complete Honda 90 toolkit right there 🙂
Ever since the start of this thread I've been idly surfing eBay for Honda Cubs. I've not got a motorbike licence or anything, but there's something about them that really appeals to me.
I hope I will one day return to this thread and see something like ...
🙂
Kongrats, kilo!
2 strokes are evil shitdog spawn of Satan.
I just came to post a more obscene version of this sentiment.
Dremel, or cold chisel and hammer? Or both?
Yep. Or douse it in petrol and set it on fire, then piss on it. Repeat until you feel better.
I was reading this and thinking "why has nobody recommended just hitting it from the side with a hammer"
I was reading this and thinking “why has nobody recommended just hitting it from the side with a hammer”
Yep. Universal remedy.
