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Discussion Starter · #1 ·
Im going to be building a 150ccm x18 and I really want to have a straight side pipe. I was planning on getting a universal GP pipe on ebay and just welding my own on there. I know exhausts need back pressure, and that may be an issue for a straight pipe not even going half way to the tail. what should I do?
 

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Well it needs some back pressure but not much. Only two strokes really need back pressure.
 

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Well make the pipe smaller or make it like a stroke and go small to big and then small. Why are you worried about back pressure this is a 4 stroke???
 

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Discussion Starter · #5 ·
Most of the pit bikes I have seen that go straight pipe loose their bottom end. I figured back pressure had somthing to do with that.
 

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You will shorten the life spand of the motor. Not to mention annoy the hell out of the neighbors.
Plus could affect the running. Gonna loose some low-end torque. Not worth it in my book.
 

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Discussion Starter · #7 ·
You will shorten the life spand of the motor. Not to mention annoy the hell out of the neighbors.
Plus could affect the running. Gonna loose some low-end torque. Not worth it in my book.
"It's not a two stroke" lol this guy. I found a gp pipe with a muffler. It should add enough back pressure to have the look, and still keep the performance. Obviously If it was an inline four, a 4 into 1 straight pipe would be fine but 1 cylinder there's literally no back pressure.
 

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"It's not a two stroke" lol this guy. I found a gp pipe with a muffler. It should add enough back pressure to have the look, and still keep the performance. Obviously If it was an inline four, a 4 into 1 straight pipe would be fine but 1 cylinder there's literally no back pressure.
LMAO! dude I know it's not a 2stroke! I have that same motor.lol You didn't know the even 4strokes need a certain amount of back pressure to run efficiently? Well they work off of the scavenger affect also. And yes back pressure plays a part in this process also. Lol
And I know exactly what pipe your talking about also.
 

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Discussion Starter · #9 ·
LMAO! dude I know it's not a 2stroke! I have that same motor.lol You didn't know the even 4strokes need a certain amount of back pressure to run efficiently? Well they work off of the scavenger affect also. And yes back pressure plays a part in this process also. Lol
And I know exactly what pipe your talking about also.
I was quoting the dude who was telling me before.
 

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I was quoting the dude who was telling me before.
Ah OK cause it look like you were quoting me. I didn't understand you were also responding to another person.
 

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Well the heat can be created from the leaned out effect of an open exhaust.
I just didn't want to drag this out with all the scenarios.
 

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Discussion Starter · #14 ·
Well the heat can be created from the leaned out effect of an open exhaust.
I just didn't want to drag this out with all the scenarios.
I already have it all planned out. I wanted to see if I could go straight pipe, but I didn't think so because of the back pressure issues. The one I found on eBay has a muffler, so it's all good. Thanks for you guy's help. Braap on!
 

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How? If it's engine heat, I'm getting a oil cooler.
Even with an oil cooler, take the bike for a ride then feel the pipe it will be hot, now think about convection, the heat needs somewhere to go!

But this is the internet and it is your bike so do whatever you like. I just happen to help run an automotive / diesel program and have learned a couple things while teaching the kids.
 

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Discussion Starter · #16 ·
Even with an oil cooler, take the bike for a ride then feel the pipe it will be hot, now think about convection, the heat needs somewhere to go!

But this is the internet and it is your bike so do whatever you like. I just happen to help run an automotive / diesel program and have learned a couple things while teaching the kids.
If my gsxr will do it straight, or even my 83 kz750 bbk to 950 with literally air cooling, I think a 150 will do just fine
 

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I never ran an oil cooler till I got the yx motor, up till then the 146 had nothing
just riding was fine but racing it would get real hot, and that's where the synthetic oil really helps
not saying it don't help just saying the 125 base dosent require a cooler
the yx 150/160 motors had to run a cooler and came with the hookups stock, and mine does get tons hot even with the cooler
 

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Discussion Starter · #19 ·
I never ran an oil cooler till I got the yx motor, up till then the 146 had nothing
just riding was fine but racing it would get real hot, and that's where the synthetic oil really helps
not saying it don't help just saying the 125 base dosent require a cooler
the yx 150/160 motors had to run a cooler and came with the hookups stock, and mine does get tons hot even with the cooler
On $50 more so **** it
 

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You can run the cheaper in price oil coolers. I have 1 on my 110 and one on my 150 bike.
When riding the 110 hard plus It will puff a little smoke. I also notice I little power loss after a few laps. So I put an oil cooler on to help combat against these symptoms,worked perfectly.
 

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