250r low end port???

[beak7707]

I am wanting to get a low end port on my R motor. I mostly ride wooded and trail areas, but every now and then go to the open areas and want to rip. I have heard with low end port that the 250r motor will just fall on its face when you try to let it rip, is this true? I defiantly want low end power but i do not want to lose any top end. The motor is stock now so its not like i have tons of top end, and i don't use top end much but i don't want to lose any of what i have.

[Bean]

well, get a midrange port, with a decent pipe (LRD ajustable), then just ajust the pipe till you get what you want

[beak7707]

so will it lose all its top end then, with a low end port? I was just told that with low end it will pull like a train then when it gets to higher rpms it will just lose it all.

[250rpilot]

all depends on who ports it. some guys port a low end motor to pull real hard up to about 5-6k, then they just fall on their faces. other guys will shift the power curve so it pulls hard up to about 7k. a midrange motor wont pull off the bottom as hard, but they would pull up to about 8500 real hard. a top end port wont start pulling until they hit about 6-7k, then will pull super hard up to about 9-9500. i am in the process of building an esr powervalve motor, with the lowend port trx7, and from what i am told, it will still pull like a rocket all the way up to about 7-7500 rpm. i dont think i have ever revved my motor up past about 8k anyway, its just not necessary in the woods if you are geared right and your pipe is what you need. unless you ride sand, then i guess you would want that thing to rev to the moon!

[wilkin250r]

So, what you're saying is, you want your cake, and be able to eat it too?

The powerband in a two-stroke is almost always a compromise. You can't have stump-pulling low-end power, and still scream up top. If you increase your low-end power, you lose your top-end power, and vice-versa. If you want good all-around power, it won't be very strong on either end.

Only two strategies will increase power all around. A little bigger bore will increase power all around, up to a certain point. Beyond about 310-330cc, the piston gets too big, and you lose top-end to vibration. Or, a powervalve. A powervalve will increase low-end without sacrificing top-end.

There is a lot of power to be found in porting, but that's because it robs power from other areas. Now, it is possible to increase power across the entire RPM range, but it won't be stellar performance in any one area.

[beak7707]

No i never said i wanted both, i know if you get low end you lose top. All i said was i didnt want to lose the top end i have now in stock form. I just dont want it to be slower on top than what it is now stock. I have heard stories from people with low end port that wont even harldy pull them selves in 6th on top. I'm sure those are junk port jobs, but i just wanted to make sure all low end porting didnt do this.

[airheadedduner]

Depends on who does it. My buddies R has the PTR low end port. It had a PTR woods pipe on it too. It had killer low-mid but fell flat on its face fast. We ditched the PTR pipe for an LRD and it revved out much better. It did loose some of its low end punch but overall was more rideable. Porting is huge to a 2 stroke, but the pipe is the number one factor in determining the power curve. First, find the pipe you want to run and stick with it. When you are ready to port work from where you still see weakness in the motor. Personally I don't like low end ported motors, I find a more midrange setup more rideable and enjoyable.

[beak7707]

airheadedduner how would mid range be when you do ride in the woods. Is there still plenty of low end or for woods would you get a mid port with low end pipe. Right now i have a esr trx5 pipe and silencer and i think its a dog on bottom end.

[AndrewRRR]

If you can't afford a powervalve, go for a MX type port from LRD or Sparks or PT. It has plenty of bottom and mid and will still pull on top. All the decent port jobs i've seen are stronger than stock over the entire powercurve. Low end ports will have a power peak much lower and fall off quicker on top but should still be as strong as stock on top. Top end ports shift the peak higher up the RPM curve but lose power on the bottom. Unless you go really extreme one way or the other it should be fine.
Good porting= better flow and more air in the cylinder= more power.
A good pipe tuned for the motor will help too.
Give LRD or Sparks a call (or any other reputable shop).