Ok, i always wondered if that caustic trick realy worked.
Only way to be sure would have been to cut it open after the event which rather defeats the purpose of soaking it anyway--but we'd all know then for when our time comes.
May depend how bad it's clogged too i guess.
Not steel & not exhaust but Boiling water & CausticSoda with alloy gets going madly.
I dropped my BSA crankcases in & left them boiling & bubbling, fizzing etc & then the main bearing fell in the holes with clearance. Bugger.

As a kid, once read a test in motorcycle mechanics magazine. They weighed a blocked silencer and filled it with caustic.  After 24 hours they weighed it again and refilled it.
It removed so many ounces a day. 
Cannot recall what amount, but a fair bit.
The longer you left it in the more it removed.
This was in the day of chrome  silencers and burning them out was not an option.
caustic does not dissolve carbon. It breaks down the burned oils that bind the particles together so it can be washed out.

I had a good idea that my new exhaust had little use and was not in any danger of blocking. But sticking it in the bath would not hurt . As for the rear silencer. That had less than 2000 road miles. So no danger there either.

Sears used to sell it here to clean carbon off stove and grill grates.  Pretty sure the active ingredient is Sodium Hydroxide.  You'd mix a powder with warm water in a large bucket and submerge overnight.  Worked good.  I did use it on a silencer once...  cleaned it up great by took a few days.  I think the mix they have you use is relatively weak.

Sears still sells it:  www.sears.com/kenmore-gas-grate-cleaner/p-02240080000P

Yep. The paint stripper would be stronger. The modern paint stripper bath we have, you can put your hand in without problems as long as you wash it off afterwards.  It is only heated to 40C.

You would not be wanting to do that with the lye tank though.  You would pull out a stump without a hand.

As with all things though, not as good as the old bath. Like everything else, the good stuff is banned and the modern stuff does half a job.

Like the hot Trike (Trichloroethylene) baths when I was an apprentice. That took everything off. It was like a hot mist in the bottom of the vat. Took off paint, oil, grease, carbon and just about everything else. Engine blocks came out clean bare metal.

We apprentices used to hang our heads over the rim of the vat and breathe in the fumes. Gave quite the buzz.... and if feeling a bit congested, cleaned out the tubes...

It was banned because it may have been linked to cancer....

Same here, I just tried to buy ethylene chloride stripper like always.

NOT AVAILABLE-any where.

I tried some airplane stripper at 100/gal and it's OK but evaporates fast.

Damn the tetra-hydro-furan is far worst on the user.


cliff

Easy off yellow can has sodium hydroxide

New exhaust fitted after about 8 coats of heat resistant paint and looks far better than the old. The old one was very badly corrosion pitted.
These days patina like that is prized, but it did not fit my idea of how I wanted the bike.

I wanted it almost identical in condition to the bike I had brand new when I was 17, albeit the one I had was the later model with the box section swingarm and red.

Exactly like this un.  Sure mine had yamaha in big white letters on the seat sides though.  Memory can play funny tricks.





It was a friend that had the blue 1979 model and I always thought it was a far nicer looking bike. More classy looking somehow.


Anyway. Pic of exhaust fitted.



Just small items to attend to now.. Or so I thought.

So summer goes on. I actually get out and ride the thing (only when the weather has been sunny and dry for a fortnight and forecast to be sunny and dry for a fortnight hence).
I add about 180 miles to the speedo and decide to get a professional classic bike appraiser in to value the DT and my 25 year old VFR750 that has had the same treatment as the DT, but despite being 10x more complex, had no heartaches waiting in the wings.

Upshot was that the DT was the lowest proven mileage, genuine UK bike with matching numbers he had ever seen or heard of.  He waxed lyrical about the restoration  If it was to be stolen, it would be irreplaceable and his valuation would reflect that.  Twas worth a LOT of money.  I was gobsmacked.
He made a big deal about what I considered normal finishing touches.  I never thought much about it at the time, my constant searching for bits n pieces had unearthed them and I just thought "oh they will look nice and keep it original as it left the showroom".
He said they were the difference between show judges picking it out as a show winner and coming third place.

Since I have no intention of taking it to shows, it's all a bit Meh.  Good job I did not tell him about the KYB stickers on the insides of the forks legs covered by the wheel hubs, he would have fallen over into a swoon.

NOS Stickers.  Show winners apparently.

Headstock E and model number


Battery vent tube sticker under sidepanel.  It still had the original fitted, but I found that one in a deep dive on ebay, and knowing I was going to have to have the tank and panels repainted, snapped it up.  Good job because Barry said it would not have peeled off without tearing, adhesive was too dried out.


So I am feeling cock a hoop about it all.  Yippee!  Then came the end note in his email.  Of course, this is the devil bike, it was not good reading...

Basically, if I rode it more than a few dozen miles a year, I would remove one of its reasons of rarity - the low mileage and slash its value.
Bllocks.

So I have spent all this money and time on a horror of a bike that I cannot ride.

Just feckin great.



 

wadda ya need laddy?


cliff

A good cry, or being British and owning a stiff upper lip..  Several cases of a premium lager.  That would sort me right out.