MB - Exhaust Developments

This was first written for our facebook as information to a winters Saturdays over time...................

The weekends come and go and I'm juggling my work time with free time. Me and Alice usually get away from it by walking the hills in the winter, but this year we have been slack! I get to walk to work most days so I don't get the need as much. And with the big bike in the garage we like to get away from it and ride all over.

Looking at the weather it was going  to rain on Saturday so I decided to have a day at work and try to get through some of the exhaust mods I need for a up and coming dyno mayhem session due. And did it rain, what a miserable day or it would have been out on the hills or on the bike. So with time on my hands I cleared the old workshop welding area and set about a few jobs, which by the end of the day I had the new pressed pipe nearly ready for testing. I've still to name this one, it's something I've been working on for a couple years. The pressing tool is done and I have samples to play with, which is what I've been doing. The pressings are based on our popular Stainless Dev-tour, but I've modified it so on a right hander there is more clearance with a flat side. The idea is; a new pressed main body, made in steel with 2 or 3 down pipes varying in length to give different power outputs, all interchangeable with different cylinders including the RB. This is not easy our pressing manufacturer Dep Pipes says it's impossible! It's not, but it's not easy. I've started with two U bend sizes and I need to do a tapered one as well.
 



This shows the new pressed pipe in place.



This shows the flat designed into the pressing, so ground clearance improves on what is already a high up pipe


But this pipe is for the future, so all I'm going to do is test against the existing Dev-Tour and develop it and improve it. If you read the latest Scootering, Sticky used our Dev-Tour as the baseline test against all the modern pipes. I've had a quick read and saw the article before it went to press. To say the Dev-Tour was never made as a high horse powered pipe it really does compare very well and for its age it shows how good it is. I designed the pipe to fit easy, have good ground clearance, be reliable and perform. So an engine is in its element at sensible revs, which it does. It's a great touring pipe and customer feed back is really good, which I know as I've done hundreds of miles testing it. What Stickys article fails to say or point out is; An exhaust pipe/expansion is not just about how much peak power it develops. It's about fit, rideability and power spread. Indeed there are a few pipes which now shine, some I've tested myself....... BUT these are big fat ones that don't let you go round corners! What's the point? The last rally I did was using the Franspeed race pipe, its works great but I ground it on the first right hander and again on the next left hander and thats before i got off our estate. I was shitting my self on every corner it was so low and some of the others are even lower. For me fat pipes are not always the best, its a compromise, power over practicalities! And also I find these bigger pipes only suit a certain port timing range, drop out of it and they don't work as good, which Sticky does say. The beauty of our Dev-Tour is; it works on every type of cylinder at any port timings. It is so versatile, it was designed with many hundreds of hours of testing. It was never done to produce power as I've said it was design to fit and work on anything.... one pipe fits all. Obviously I've got better pipes but they may work on one engine and not as good on another. I've seen 30bhp with 25Ibs torque on my Carbon IOM bike with my Dev-Tour but with a different pipe it produced 36bhp! Showing the Dev-Tour is not a race pipe, but the touring power spread is great. I went to Skegness on it once and I didn't need to change down from top gear with GT200 gearing! 25 Ibs torque is really good fun on country roads, I was passing other Scooters like they were not moving.
 



We think about these things, it's shaped so it's easier to get to a center plug head, we may alter this area a little to get the U bends right




And as it looks from under neath, smooth sexy lines, we find blown/pressed pipes perform better. Our old out blown pipes always came top in test years ago.


By swapping down pipes you can kid the engine to work in different rev ranges, most of this work has already been done in many previous tests, its just a case of doing different U bends to hopefully give low down power, mid range power and top end power. By doing it this way you can buy one pipe and which every U bend you want to suit your style of riding. The hard part is finding companies to produce U bends in different angles and shapes, which is my limiting factor. It's easy doing one offs but you have to think about production and costs. Anyway, until I run the new pipe vs the Dev-Tour I have nothing to report, I do expect to have to tweak it again. All I need to do now is finish off the tail pipe area, which is going to be adjustable in diameter so I can tweak it right, as I want the silencer to be shorter than the end of the bike to make it neater. We do have a new design silencer with an oval shape to bring it closer to the panels. And that's what I do on a free Saturday and looking at the pile of pipes in the que. I'm going to be doing this for months.

I did get time on the dyno with results elsewhere. This pipe with the original chosen U bends didn't do as I wanted. It produced loads of bottom end power similar if not better than a Taffspeed/JL3 pipe. To be honest I ran out of time to develop this pipe. After many visits to Dep pipes for spares and bits and bobs, it was like hitting your head against a brick wall, even though I turned up went round the stores and workshops and found what I wanted they couldn't be bothered to post them for development! After 3 years of chasing you get bored with a project and I moved on. I have been developing this as a lobster back pipe with a new manufacturer, but I've just been too busy, I will update when I do more.

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mark@mbseriousoutdoors.co.uk