h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

I like to think I'm fairly proficient at most mechanical things on bikes - but welding is a black art to me.

Having taken the bike out today it was sounding a bit off and not pulling properly at high revs. Stopped at a mates to let it cool down but on the way back it was getting worse. Checked it over whilst running and couldn't detect any leaks so as 'nothing to lose' thing I took the exhaust off and checked it over - still nothing. Taped off the end can and 3 downpipes and taped a foot pump to the fourth. Filled the bath up and stuck the system under water and started pumping - copious bubbles started appearing from it.

It's a standard 4-2-1 system and the hole appears to be right in the 'v' of one of the 4-2 bits where the downpipes join. And it's covered by a reinforcing strut. Rest of system is ok - bit rusty in places but I've seen worse - and it is 15yrs old now!

So, anyone with experience of welding exhausts - is it worth it? Is it likely to be weldable? Only a small hole but it does notice.
I guess they'd need to cut away the bar and then grind round the hole. Which won't be easy because of the restricted access.

Seems a shame to junk the system for such a small hole, but then again maybe it is just too awkward to fix.

there is a molecular metal puty available

'jml' sell a leak stop putty that you may be able to use to plug the hole

yeah, but that's bodging it!
Not that I am averse to the occasional bodge, but the problem with that stuff (anyone else remember gumgum?) is that it does eventually come off and it doesn't stop the rust continuing. Especially as the location is hard to clean properly which such stuff also requires.

I mean I may well go down that route but I'd rather see if I can do it properly first

Or see if I can find a Two Brothers Racing system in the seconds anywhere

Perhaps it's just better to replace the pipes with new. No blow-by, no loss of power, and it'll last another 15-20 years.

B4idorenovationsonmyownbike

yeah, there is that as well.

I discovered this on ebay (a fateful phrase if ever there was one)
http://cgi.ebay.co.uk/Honda-CB1000-Big-One-Full-JMCA-Full-Gild-Exhaust-System-/220645251264?cmd=ViewItem&pt=UK_Motorcycle_Parts&hash=item335f7b58c0

which says it is a " Full JMCA Full Gild Exhaust System" which I've never heard, can't find on the web. Plus it doesn't look right - not sure what the two right angle pipes are (some sort of balancing process?) and unsure whether the end pipe is baffled or takes a slip-on.

Ah well, their UK spares warehouse is not far up the road from me - might pop up there and see if it is still about next week. Or give them a bell if I get a chance.

just enquiry back from my favourite honda spares place - they have everything ever made for every honda bike ever made - or so it seems!

Anyway:

"Downpipes and collector box : to order from Honda at 494.31 GBP plus VAT and postage."

eep!

Well, just bought the JMCA pipe after going to see it first and is now fitted.
It does indeed have an integral baffle. Fitted pretty well, one of the rear lugs doesn't match up so I may have to sort some sort of plate out to make that fit, seems to be about an inch out. And it clears the swing arm by about half a mil. Seems very well made, all the welds are good ones.

Started it up - seems quite reasonable, nice burble at tickover, nothing too offensive. So took it out - bobobobobobobRAAAAHHHHHbobobobobRAAAAAHHHHHpopopopop



Snarls like a good'un under load, pops a bit on overrun sometimes but quiet enough through town. Think it will MOT, but gonna check with friendly garage.
Think it has freed the engine up somewhat as acceleration is cleaner but keeping constant throttle in low gears is bit more sensitive.
Given that it pops on overrun as well I suspect there's less back pressure and the mixture is a bit rich now. Couldn't tell if it was running hot or not as fairly warm anyway today. Needs another coolant change as well.

And all for a lot less than the standard pipe

Anyone any experience of electroplating?

Mainly cos the new exhaust pipe has only a thin paint surface that is rapidly disappearing in vulnerable places. Was wondering whether I might be able to get the whole system nickel plated or something to reduce corrosion?

Or would I be better off powder coating it from a decent paint shop?

Or maybe galvanizing it instead

Not really sure where to go with this one, but the exhaust does look like it needs something to protect it from corrosion.