DEP vs RomeuHenriques
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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.
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@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.
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@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
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@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.
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@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
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@irongamer727 Pipes needto be suited to the engine. But athena is quite common. Ask him, he's pretty knowledgeable.
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@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 " .
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@irongamer727 Hhmm, it seems like he and I share the same opinion of the Athena kit it would seem.
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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.
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@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.
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Here is the link I found when browsing.
http://www.125ccsportsbikes.com/forums/index.php?showtopic=100859
Years ago now mind you.
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Just wanted to update this thread and say I got my romeuhenriques exhaust.
My DEP has a small hole near the cylinder head, so thought I'd treat myself.
Before hand, I was struggling to get 60mph in 6th out of my bike with the DEP on. With the new exhaust I'm in 4th gear at 55-60.
The powerband is a lot more prominent and you can feel it actually pull you back.
The bike also comes up in 1st 2nd and 3rd with no clutch, just raw power.
Thought I'd update this thread incase anybody is sitting on the wall debating if they should get a DEP or spend the extra money and get the better exhaust.
