Well there's been some discussion recently about the scarcity of aftermarket pipes for our bikes, and so, dear reader, I thought I'd share a little adventure I had on the weekend. Now while this story isn't specifically about SOHC4's, don't be put off just yet, this information can be used on just about any pipe, for just about any bike.
You see, over the last few months I've been building one Suzuki GS1000 (my other passion) out of two wrecked bikes, one with a good Yoshimura equipped 1100CC engine from an accident damaged bike, and a spare frame and forks, tank etc, that I had kicking around my garage.
Anyway, as much as I'd like to keep the bike, there are 7 or 8 other bikes crowding my garage, so my intent has always been to fix this bike up and sell it, so while the bike will be a reliable, fast road-burner, to make any money at all out of this build, I need to finish it on a very tight budget.
A problem that manifested very late in the build was that the excellent set of "Tranzac" pipes that SteveK0 found for me at a swap meet earlier this year that
looked like they'd fit, sadly didn't. The headers were about an inch too short for the engine, so the exhaust flanges on the headers didn't sit square on the engine's exhaust ports, and I couldn't get the headers to go into the collector, because the sump pan was in the way. Bugger.............
I thought about this dilemma for a couple of days, the budget definitely wouldn't allow $800.00 for a hand made "Megacycle" pipe like the one I had specially made for my Suzuki GS1000S "Wes Cooley replica", and even a "cheap" pipe would set me back 600, so with that in mind, I went to a steel supply place and bought a yard of 35mm OD thin walled tube (the "inner") and a yard of 38.5mm tube. (the "outer")
On the lathe, I cut off 4 x 1 inch sections of the 38.5mm outer pipe, and 4 x 3 inch sections of the 35mm inner pipe. You certainly don't need a lathe though, a nice straight(ish) cut with a hack saw or a drop saw will be fine, in fact a little "gap" is a plus for a good weld penetration.
I then drilled each header in two spots about 20mm apart on the straightest section, so I'd know where to line up each half of the cut headers once I added each 1 inch "extension" piece. I cut each header in half, and installed the inserts, lining up, then "pop riveting" the pipes back together, so I could check that I had the angles right.
I then test fitted the pipes back on the bike, to make sure everything fitted as well as I hoped it would.
It all looked good, so I mig welded it all together, ground the welds smooth and painted it with etch primer, then K&H "Black Ice" exhaust paint.
Once it was nice and dry (not hard in this weather, it was around 90 deg F today, and summer in Oz doesn't start for another 3 weeks!) I converted the engine to exhaust studs using some BMW exhaust studs I had in a box, and installed the pipe with new exhaust gaskets. I'm pretty happy with it!
Now while I was "cutting and shutting" this pipe I realized how easy it was to make this pipe fit my bike, and also, how easy it would be to modify just about any pipe like this to fit one of my CB750's. While a lot of pipes for other big 4 cylinder engines (Suzuki's and Kawasaki's at least) are relatively close fits, the biggest barrier to swapping pipes around that I've encountered, has been either the length of the headers, or the angle that the headers go into the engine.
So using this method, both problems can be addressed relatively easily and cheaply. (the two 1 yard lengths of pipes only cost me 11 bucks) While I decided to go the cheap route and just paint my headers, the fit was so good that I could have had them chromed, if I'd wanted to. I'll certainly be doing it again soon! Cheers, Terry.
