Honda-SOHC

SOHC.co.uk Forums => CB350/400 => Topic started by: taysidedragon on June 05, 2018, 03:05:09 PM

Title: 400f downpipes
Post by: taysidedragon on June 05, 2018, 03:05:09 PM
I saw a new CB650F the other day and had a good look at the downpipes on it. They are obviously designed to look like the old 400 Four pipes.
Without a chance to take basic measurements I was wondering if anybody had looked into the possibility of modifying a set of these to fit the 400?
With the problems with aftermarket sets and the dire shortage of originals is it worth the cost of doing this?
Title: Re: 400f downpipes
Post by: hairygit on June 05, 2018, 03:12:51 PM
I'd say probably not, the 650 engine looks a LOT taller than the 400/4 motor, so it would mean lots of cutting and shutting and messing about, plus the top of the downpipes will probably be a larger bore than the 400's ports/clamps could accept. And no doubt, very expensive to buy!
Title: Re: 400f downpipes
Post by: K2-K6 on June 06, 2018, 11:21:42 AM
Without ready access to both the pipes and a 400 I'd guess they are probably too far apart to make sense.

Obviously, anything can be made to fit but if you have to modify so much it starts to cost more than it's saving over scratch built.
Those newer four valve heads have the exhaust ports close together and central to the cylinders because the spark plugs are centered in the head, as opposed to the SOHC motors that have the plugs facing forwards with the exhaust ports effectively splayed out to accommodate this head architecture.
It's not clear if the newer pipes are double skinned either,  which just increases the difficulty of cutting and rewelding.

[attachimg=1]

The above image seemed quote impressive to me as a one off modern take on those original curved pipes. I know it's a 550 but just shows what can be done.  I've no idea of the source or cost of the above, but there are some pretty good pipe bending skills around to make it worth researching I think.

It really does set a bike off so well to have a good looking pipe installed.
Title: Re: 400f downpipes
Post by: Rozabikes Tim on June 06, 2018, 12:58:56 PM
Real eye candy that! ;D
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