Meanwhile: Exhaust pipes

I had not been fussed about exhausts so far, safe in the knowledge that I had a fine selection hanging from the rafters of the garage.
As previously mentioned, my objective with this build is to keep the bike as original as possible. The “as possible” clause leaves me a bit of leeway, but I had decided that expansion chambers would be a last resort.
That said, let’s evaluate, or at least enumerate the expansion chambers in the garage.

  • A pair of Swarbrick pipes suitable for 250cc swept volume, from my Suxuki X7 earlystocks racer, in decent usable condition albeit a bit dented in places.
  • A pair of JL Lomas pipes marked specifically for an RD350LC, in excwllent undented condition except for paper thin downpipes, which will not last through another winters corrosion.
  • A pair of TZ 250 pipes, which I believe to be from an “Exactweld” racer of the mid 1980s. they have been chopped in half and then rewelded… badly, but are in usable condition.

The OEM Yamaha pipes I have collected in the last 40 years, do NOT include a pair of 4L1 pipes.

  • 1) Right 31K 14721 : Fair condition, battered
  • 2) Right 4L0 14721 : Section 2 rusted through. the rest, fair
  • 3) Left 31K 14711 : Fair condition
  • 4) Left 31K? : Downpipe good, terrible repair welds
  • 5) Right 31K : Downpipe poor, poor repair welds, Dents repaired with filler
  • (6&7 are the TZ Pipes listed above)
  • 8) Left 31K? Header rusted through, Terrible repair welds
  • 9) Left 31K 1471 Downpipe rusted through
  • 10) Right 31K ? : Final section cut off for repair, needs welding

…and finally, the pair of YPVS LC2 pipes which were on the donor bike… filthy, dented, but probably the best condition OEM pipes I have.

So with a bit of effort, some welding and cleaning and painting, and a following wind I could probably rustle up a pair of 31K pipes for my 4L1 RD250LC.
Alternatively, I could clean up the LC2 pipes and stick those back on.

Rejecting all of these options I went straight onto ebay and secured a pair of de-restricted German 4L2 pipes which appear to be minimally dented and with good downpipes. I’m not sure why they were half the price of all the other options on ebay. I guess I’ll find out when they arrive.

The 4L2 pipes I ordered from an ebay seller have arrived, and they are really OK!
They are sound, don’t have anything rattling inside, have decent, barely rusted down-pipes, and have been de-restricted, (4L2 being German restricted pipes).
I’m happy that I can use something looking original, even though it was made for the German market.

They do have one section of one pipe which has taken a bit of a battering. Eventually, I may cut this out and weld a good section in. it would give me an excuse to use the MIG for the first time in about 5 years.
In the meantime, I’ll clean up the downpipes and dented rusty area with the trusty rotary wire brush, and give them a coat of paint.
After a vigorous brushing it was clear that there was still some rust in little pits which the wire couldn’t get to.
A couple of treatments of simply brushing 30% Phosphoric acid on and leaving to work for 15 minutes did seem to make a difference. I sponged the acid off ecah time with a couple of gallons of water before leaving to dry in the sun.
Paint was applied the next day.

The XHT paint which I used was randomly picked from the dozens available.
I requires curing by heating once dry to the touch.
I don’t have an oven that big, and the one which I have is used for food preparation. the presence of bits of motorbike in it would need to be carefully planned to happen when the user of said oven was to be away for an extended period of time.
The best way I could thin of to cure the paint on the pipes was to fit them to my runaround LC and take it, and them, for a ride around the Sussex countryside.
The freshly de-coked baffles were fitted to the pipes, and the pipes in turn, fitted to the bike.

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