DEP vs RomeuHenriques



  • Hi all,

    I've just found a small hole on my DEP pipe where rust has began to form on one of the welds - as some point I am going to be replacing it/selling it to a friend.

    I've been looking at the RomeuHenriques exhausts that wrap around the frame rather than being underslung. Has anybody owned one of these? If so, how do they handle the weather over time? Did you see an increase of performance over your previous exhaust?

    With a small hole developing on my current DEP exhaust, would this affect the performance of the bike? The hole is where the pipe meets the cylinder so I'm guessing it would be losing a small amount of back pressure..



  • The more expensive pipes he makes are stainless so they would definitely last longer than any other aftermarket pipe out there.

    With the hole being where it is you could be running lean, but if it's only small then it probably won't make a difference



  • A hole in a two stroke pipe is going to have adverse effects, small or big.



  • Why would a hole cause the bike to run lean? What causes this?

    I thought that the pressure in the exhaust is higher than the atmosphere around it so air wouldn't be flowing back through the hole in to the cylinder right?

    Correct me if I'm wrong I'm just trying to get a better understanding of what causes the hole could have.

    I'll deffo be getting a replacement exhaust either way I reckon.



  • I've explained this enough times. Plenty of information on the web and I reckon this gif does it justice

    alt text

    If you want to know more, learn about how critical expansion chambers are on two strokes.



  • Cool, thanks for the info @Calum will be having a read later on.



  • @pjt95 Just imagine if there is a hole in your exhaust, that sound wave won't propagate properly. If it does it may push lost fuel and air out the hole, making the next ignition sequence lean. Since you can see the green (fuel/air) charge is usually pushed back into the combustion chamber. Back in the day, there was no such things as expansion chambers, the bikes were jetted accordingly. Yours is jetted to take use of that chamber. No chamber will mean less fuel/air.

    We're talking minutes amount at this moment in time. And of course it's all hypothetical. But you asked.



  • Thanks for the info @Calum , really do appreciate it and have a better understanding now! as for the RomeuHenriques pipes, would you recommend one or would you just buy another DEP?



  • @calum as a ball park figure how much could you expect to lose hp wise on my project bike I can put my hand over the exhaust and it will continue to run perfect the leak is that bad now the bike only has 2.9hp I’d expect to lose 2hp so I’ve only just been thinking this is most likely why it has zero torque/power



  • @pjt95 I went with a Romeu pipe myself, because no matter how hard I tried, the DEP insisted on rotting.

    @declan I'd expect the majority of the power to go if the pipe is that bad. But it all depends on where it is. On a bike with only 2.9 hp, I'd be surprised if the exhaust was even setup properly in the first place. But a decent exhaust on a two stroke, is the difference between naturally aspirated and a turbo engine. The two stroke pipe supercharges the engine. So it's imperative that it's working effectively.



  • @calum you think an underslug romeu would work with the 170 kit? Does this Romeu make "regular" pipes as well? Currently have an arrow pipe but it rots fast



  • @irongamer727 Pipes needto be suited to the engine. But athena is quite common. Ask him, he's pretty knowledgeable.



  • @Irongamer727 I have asked him about 170cc kit and the answer was " if you do not tune the Athena kit that exhaust must go good " .



  • @yegor the underslug?



  • @irongamer727 Hhmm, it seems like he and I share the same opinion of the Athena kit it would seem.



  • Have just fitted a Romeu exhaust and it is impressive, can't comment on durability or performance as yet. Have a new Dep exhaust that came with the boxed up 88 and was going to get it plated over to try and counter the rot problem. Anyone tried that or any other remedy? Personally would not purchase Dep due to reputation. The seller I bought the bike said he had rejected the first one sent as already had rust on joints.



  • @oldman so I had a rotten big one I sanded it down and painted it black now it’s like new but obviously you lose the shine but I love it all the same



  • @calum which is?



  • @irongamer727 My understanding is that the port timings for the 170 Kit was based off the DT200R. As such the ports are 3mm too low. People have shaved 3mm off the head and shimmed it at the base to correct this.



  • Here is the link I found when browsing.

    http://www.125ccsportsbikes.com/forums/index.php?showtopic=100859

    Years ago now mind you.