Changing down pipes and removing seized fixings

Last week I changed the down pipes on my mate’s ageing Honda VFR. Knowing my friend rides in all weathers, I knew the pipes were going to be “hanging” and I was so right.

After taking off both side fairings, I then saw how bad the down pipe fixings had corroded. I needed to change the pipes because they had rusted completely through, I think they were the original pipes and I knew the nuts and studs had not been touched since the bike had been originally assembled. With optimism, and after a generous soaking of WD40, I used a single hex socket and extension bar on the down pipe nut that looked less corroded than the rest. Nope, not a hope in hell.

At this point I want to advise you that if there is a slim chance the nut will round off, always use a single hex socket or spanner. Multi hex tools are great for tight spaces but they do not grip as well on the faces of a nut or bolt and the chance of rounding off a fixing is increased if you use one.

To loosen and remove seized nuts or studs takes patience. I soaked all eight nuts with a whole can of WD40 and left it over night. The following morning, it was time to turn up the heat. I used a hand held blowtorch (the type plumbers use) and heated up the nut on the stud. Heat makes metal expand and also burns the WD40 oil which has soaked into the thread.
Whilst the nut was still “cherry red” hot, I used my single hex socket again and with slow, constant pressure the nut started to move. After a few turns you must then tighten the nut half a turn, this cleans the thread on the stud and minimises the risk of shearing the stud. Once the nut had been removed, I repeated the whole process on the remaining seven fixings.

If one of the studs start to loosen rather than the nut, don’t worry just remove it totally. When all of the fixings are removed and the new down pipes are ready to be fitted, take my advice and replace the nuts or studs with brand new fixings. By renewing the fixings, time and hassle will be saved later on in life should you need to remove the pipes again. Personally I also brush the treads on the studs with copper grease. This type of grease is heat resistant and again will help should you need to loosen the exhaust nuts in the future.

In conclusion, although this is an “exhausting” (pardon the pun) and time consuming task, you will save yourself quite a bit of money in labour charges by giving it a go yourself.

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