Making Downpipes

[numark1]

Having a real real real hard time finding downpipes for a fzr400, sourced some exup 600 pipes but not sure if they will fit and charging over £200.

How easy would it be to make some? I was having a think and i don't think it would be too bad. 4 Bits of pipe, calcuate how it needs to be bent, get a garage or whatever to bend it, weld brackets on to secure it onto the engine then maybe extend the pipes so i can have an underseater.

Yay or nay?

[Gazdaman]

Why have I got images of you sitting there with a bit of plastic guttering and a lighter?

No mate, I wouldn't try it, just keep an eye on eBay or go looking round some breakers. FZR400s pop up quite a lot.

If you think, people buy micron or whatever full systems because they increase power over the standard pipework, and that's not the end can, it's the pipework aswell. It's not just the metal being bent, there's so much more in the equasion.

Gaz

[Kickstart]

Hi

Down pipe design is very important (far more important than some tatty old can on the end). As such you can't just lob something together (and also why an exhaust for an engine that revs to a far lower level such as the FZR600 is not the best thing to use).

There are people around who will make them up. Best if you have some to copy (full of holes should still be fine). Try Gazelle or OS Stainless.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[Ichy]

I made some for a street fighter I was building a few years ago. Spent about 10 quid on bits of pipe from a dealer and built them at work. Rather than bend the pipes, I don't know anyone that had a pipe bender big enough, I cut segments and welded it all together. Took about 2 months to finish them and they did look pretty good on the bike, very 'industrial' . It did restrict the bike though, lost about 20mph top speed but that was running stock carbs with K&n's so it probably would of helped if I rejetted.

On a 4 stroke most downpipes will work as long as the gases can flow freely.

[mchaggis]

[Brava210]

[Ichy]

Totally agree, which is why I said downpipes and not exhaust systems. I guess its why so many custom bikes have the same number of pipes as cylinders, saves a lot of hassle

[Kickstart]

Hi

Without connecting the down pipes you can probably wave goodbye to a load of power anyway as the pressure pulses from each cylinder cannot be utilised on each other.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[SoND]

When I made my exhaust the downpipe was a complete pain to make. Didnt have access to a pipe bender so I cut loads of slots into a pipe, bent it, welded it up and ground it down again. Took ages to do. This is only a small bit of what i cut.

https://www.bikechatforums.com/files/bend1.jpg

If you have 4 pipes to make it's going to take a long time and it's going to be difficult to get them bent properly. If they're sitting just a little bit off then the whole thing could look crooked.

It's going to be pretty difficult if you don't know what you're doing.
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Go back to bed - You have no rights - "Streetfighters ~ Mainstream motorcycling's crackwhore sister."

[Ichy]