Duncan CT or ESR?

[Fox250R]

So I'm looking into getting maybe a 310 or 330 kit and I wanted some of your guys options on who I should go with company wise. I was thinking either Duncan, CT or ESR. Any thoughts?

ESR has a 330 PV with pipe and Carb for around $1400!

Thanks in advance :)

[yaegerb]

IMHO I would get a blank cylinder from ESR or CPI and send to Jerry Hall, Arlen Lehman or Rob Selvy.

[ONEBAD350X]

IMHO I would get a blank cylinder from ESR or CPI and send to Jerry Hall, Arlen Lehman or Rob Selvy.

This is just what I was gonna recommend!

[250rRoostmaster]

I know you didn't mention him but, LED Performance all the way and he's local (Gresham)!

[yaegerb]

I know you didn't mention him but, LED Performance all the way and he's local (Gresham)!

I got Arlen in my three....look above.

[Fox250R]

LED is just down the street from me like a mile away.


http://i155.photobucket.com/albums/s313/Fox250R/IMG_0925.jpg (http://s155.photobucket.com/user/Fox250R/media/IMG_0925.jpg.html)

[yaegerb]

wait a tick....you have Arlen's shop a mile from you and you are asking about Duncan/CT/ESR....um, pretty sure I would be walking to Arlen's on a daily basis.

He can order CPI cylinders as well.

[atc300r]

LED has some good videos of Arlans work and of him working in his shop on Youtube.

[The_Steve_Man]

Arlen does some nice work with ESR cylinders.

[Fox250R]

I've heard mix reviews about Arlan but I dunno. I might go with the PC2000 cylinder and see how that works out.

[christph]

I have a PC 340 from Duncan. It's a high quality cylinder and I've had it for years with no problems. Here is a picture of it.

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[yaegerb]

I have a PC 340 from Duncan. It's a high quality cylinder and I've had it for years with no problems. Here is a picture of it.

227937227936

That is a gorgeous 250R!

[Fox250R]

I have a PC 340 from Duncan. It's a high quality cylinder and I've had it for years with no problems. Here is a picture of it.

227937227936

Always loved the 88s colors!

So ya, the 340 PV was the same one I was looking at? Can you still ride trails and stuff? I'll be doing both dunes and trials. How's the power feel? I don't need anything crazy. I was looking at the 310 at first but it's the same price as the 340! Did you have to machine your case?

[Fox250R]

Did some more research on this. The 305cc and 340cc motors are around $1800 and cases need machining. How much will that cost just for the case mod? Now the 265cc and 275cc are like what $100 less but no machining is required. I'm leaning towards the 275cc tbh.. Just not sure for $1800 how much faster will a 275cc be compared to my current motor? Need to think about this more I guess lol

[BOB MARLIN]

Bypass the 310 and go strait to the 330. The torque is better with the 330. Run a digital temp gage also. You will be shocked on how hot the big bores run in a trike. They run cooler in the quads- more room for air to move around the engine and bigger rads.
I think porting a stock cylinder will give you more performance than just going to a 275cc.

[Fox250R]

Bypass the 310 and go strait to the 330. The torque is better with the 330. Run a digital temp gage also. You will be shocked on how hot the big bores run in a trike. They run cooler in the quads- more room for air to move around the engine and bigger rads.
I think porting a stock cylinder will give you more performance than just going to a 275cc.


The 275 would be a PV tho.

[christph]

Always loved the 88s colors!

So ya, the 340 PV was the same one I was looking at? Can you still ride trails and stuff? I'll be doing both dunes and trials. How's the power feel? I don't need anything crazy. I was looking at the 310 at first but it's the same price as the 340! Did you have to machine your case?

Yeah, you have to machine the cases. Duncan does a great job doing that, by the way. He apparently has a jig and it comes out perfect--no free hand stuff. If you are going to be riding dunes and trails, I'd recommend the 340. It has tons of torque and is best from low end to 3/4 throttle. If you are looking for a motor that is a little quicker revving and loves 3/4 to full throttle, I would recommend the 305. Don't get me wrong, the 340 is a fast motor. It has a heavier piston, though, and doesn't like to rev to the moon like some of my 250s. I did do the "midrange" porting, however, so that may be part of it. I remember Duncan also offers a "top end" porting. I got it back in 2004 and haven't had any problems. Just replace the piston now and then and clean the PV.

[Red Rider]

Always loved the 88s colors!Indeed! This color scheme was the inspiration for my R.

[Fox250R]

Indeed! This color scheme was the inspiration for my R.

Dude I remember seeing your R like over 10 years ago! Love the 88 look to it. So what mods you have done to it these days ?

[Fox250R]

Nevermind I clicked your link lol :) looks pretty bad ass man!

[Red Rider]

Never I clicked your link lol :) looks pretty bad ass man!Thank you. Your's is looking sweet as well. I'm pretty sure my website shows it's current condition.

[RIDE-RED 250r]

I have an ESR 350 in one of my R's, with a 41.2mm PWK, ESR reedblock, ESR full ATC5 exhaust and Eddies trx9 porting. It runs great and has lots of power, really comes on strong in the mid-range and keeps pulling. Having the porting focused to mid-top is a blast, and the big bore displacement makes up for it on the low end.

Now, I have no personal experience with the other fine builders mentioned, but based on the pages and pages of info and feedback I have seen here and other forums you would be hard pressed to go wrong with any of them.

Some folks dog on Eddie a bit now and then, but I have zero complaints about his work and service. His only downfall is that he can be slow, but last I knew it is because he is working alone now. And he usually sends extra goodies at no charge. When I got my carb from him, he sent his new combo jet holder/carb wrench loaded with jets along with it. I didn't even ask for one. :) He's a good guy.

Side note: My brother and I are beginning to step into learning how to port our chainsaws. I know...dumb huh.. But it has been a great learning experience and seeing the results of your own mods is really satisfying. I bring this up just to emphasize the fact that porting a cylinder for a desired result isn't s simple thing to do. Chainsaws really are a 1-trick pony. They need to spool up quick and maintain peak RPM under a load. I would say they would be comparable to a mild drag port on a bike or wheeler engine. We have been learning alot about these... But let me tell you, I took an R cylinder off my shelf and had a look under it's skirt. You can tell that they are much more sophisticated in their layout and design. And I now have a much greater appreciation for what builders like Selvy, Lehman, Hall, Sanders, and others can do, and then be able to repeat it build after build. My hat is off to all of those guys for the time and resources they have invested in the process!

[250rRoostmaster]

2 stroke porting really is an art form

[Fox250R]

I agree with this completely !!......i think in the trike you want it to bark at the moon ......in a quad you can use the torque you get from the big bore to drag the extra wheel around ! If it ain`t red it`s dead ! ;);):Bounce;);)


Looks goods man!

[Fox250R]

Hey is Dammit still around?

[ceaserthethird]

Hey Bud, I have a power valve 275cc cylinder it's pretty awesome. Also have the pc 2000 cyl. 275cc but not installed yet.

If you want reliable go with Duncan PC 2000 275cc power valve it's the best... You already have the Duncan pipe and silencer!

[Fox250R]

Indeed! This color scheme was the inspiration for my R.

Do you have any videos man?

[Red Rider]

Do you have any videos man?I've popped up in a few videos before, but I don't have any links to them. They are definitely few and far between.

[Fox250R]

Hey Bud, I have a power valve 275cc cylinder it's pretty awesome. Also have the pc 2000 cyl. 275cc but not installed yet.

If you want reliable go with Duncan PC 2000 275cc power valve it's the best... You already have the Duncan pipe and silencer!

Any chance you know the bore size of your 275?

[ceaserthethird]

Sent you a PM with my number, send me a text when you get a chance. :w00t:

[Fox250R]

Sent you a PM with my number, send me a text when you get a chance. :w00t:

Hey bro I sent you a text a few nights ago

Maybe you sent me the wrong number?

[arlaunch]

There are 2 PC 2000's on ebay right now. Both used and both around 1100 bucks.

http://www.ebay.com/itm/Honda-TRX-ATC-250R-PC-2000-305cc-BIG-BORE-POWER-VALVE-Cylinder-Kit-/281942086341?hash=item41a50ed2c5:g:8~gAAOSwe7BWyle v&vxp=mtr

http://www.ebay.com/itm/Honda-TRX-250R-PC-2000-340cc-BIG-BORE-POWER-VALVE-Cylinder-Kit-/281942093948?hash=item41a50ef07c:g:DSwAAOSwll1Wylv M&vxp=mtr

You guys are awesome being able to ride these things with that much power.

My 250 has too much power for me.

I will always be a fan of the professionally ported OEM cylinder with the OEM cylinder head combustion chamber shape being set just right.

Quicker rev's, better over rev, room for the head stay and steering stabilizer blah blah blah.

Looking forward to hearing what your decision is and how long of a swing arm you are going to put on the Fox.

[Fox250R]

There are 2 PC 2000's on ebay right now. Both used and both around 1100 bucks.

http://www.ebay.com/itm/Honda-TRX-ATC-250R-PC-2000-305cc-BIG-BORE-POWER-VALVE-Cylinder-Kit-/281942086341?hash=item41a50ed2c5:g:8~gAAOSwe7BWyle v&vxp=mtr

http://www.ebay.com/itm/Honda-TRX-250R-PC-2000-340cc-BIG-BORE-POWER-VALVE-Cylinder-Kit-/281942093948?hash=item41a50ef07c:g:DSwAAOSwll1Wylv M&vxp=mtr

You guys are awesome being able to ride these things with that much power.

My 250 has too much power for me.

I will always be a fan of the professionally ported OEM cylinder with the OEM cylinder head combustion chamber shape being set just right.

Quicker rev's, better over rev, room for the head stay and steering stabilizer blah blah blah.

Looking forward to hearing what your decision is and how long of a swing arm you are going to put on the Fox.


I've been watching those for for weeks now. Just not sure about going the used route!

[BOB MARLIN]

I love my big bore, BUT- There is a few drawbacks. Fitment issues and running to dam hot are the big ones. I have to run a spark plug that looks like it belongs in a lawn mower because a regular one doesn't fit between the head and the frame. And I have to run oversize rads to keep it as cool as possible (220 deg.). And because the cylinder is so tall the rads hit my exhaust. And to check my coolant level I have to remove the right shroud.
Don't get me wrong, this thing make awesome power, and I love it. I think its worth the hassle, but if I were to do it again I would do a properly ported stock cylinder. I've seen dyno results from one of the guys that knows how to port 250r's and it's pretty darn impressive.

[The_Steve_Man]

I can tell you that I am extremely happy with my stock cylinder with a +4 crank. Bubba Ramsey did the work on mine and runs fantastic. Whatever you get, you need pipe, carb, reeds to work together to get the best performance.

[Outlaw #24]

It might be that your pipe is to small at exit. I have a big bore 72mm in Skeletor and It doesn't seem to have problem. Also Higher octane gas burns more completely and cooler (110). Have you tried a cooler Plug? I have cylinders if you want to change already ported and some with no port work. BTW the carb on my big bore is a 38 Mikuni milled to 42. What Steve said, everything has to work together.

[BOB MARLIN]

It might be that your pipe is to small at exit. I have a big bore 72mm in Skeletor and It doesn't seem to have problem. Also Higher octane gas burns more completely and cooler (110). Have you tried a cooler Plug? I have cylinders if you want to change already ported and some with no port work. BTW the carb on my big bore is a 38 Mikuni milled to 42. What Steve said, everything has to work together.

I assume this was a response to my post ?.
Anyhow, Yes I agree with everything you said, My FMF Fatty isn't helping the situation any. I want to try an ESR pipe. I've been told they run well with big bores, but my rads already hit my skinny fmf pipe and the ESR is a lot fatter on top than the fmf. I going to try going to 100 octane next season, but here in so cal. all our gas sucks-bad. Race gas can be a trailprotrailprotrailprotrailprotrailpro to get ahold of at times here. Having a digital temp gage is very useful. I can tell what changes did what. So far running strait distilled water with no antifreeze made a bigger difference than the oversize rads.

[The_Steve_Man]

The FMF pipe is a terrible pipe on anything but a stock or mildly ported cylinder. The neck that comes out of the exhaust flange is small and chokes it down. Great for all bottom end but nothing else. The stinger on a big bore is 1 1/4" . An ESR will be way better. I had to make a spacer to move the bottom of the radiator forward to clear my pipe. Waterless coolant also works to keep Temps down.

[RIDE-RED 250r]

Hmm... I'm running an ESR 78mm big bore on a std short rod crank (so no cylinder spacer is needed) with ESR's pipe. I have no clearance issues.

Are you guys running stroker cranks or long rods with spacers??

[barnett468]

Did some more research on this. The 305cc and 340cc motors are around $1800 and cases need machining. How much will that cost just for the case mod? Now the 265cc and 275cc are like what $100 less but no machining is required. I'm leaning towards the 275cc tbh.. Just not sure for $1800 how much faster will a 275cc be compared to my current motor? Need to think about this more I guess lol



So ya, the 340 PV was the same one I was looking at? Can you still ride trails and stuff? I'll be doing both dunes and trials. How's the power feel? I don't need anything crazy. I was looking at the 310 at first but it's the same price as the 340! Did you have to machine your case?

If you like to cruise when you are on the trails or they are fairly tight trails where you aren't going more than maybe 30 mph, you do NOT want a heavily ported 250 cylinder because you will absolutely hate life . If your cylinder is stock but you have a pipe and are fairly happy with it the way it is on the trails, then just some minor porting and possibly increasing the compression and some Boysen Pro Reeds is all I would do.

If your compression is around 160 or less, you can gain a little power everywhere by increasing it a little, but you definitely need premium gas . If you happen to run ethanol in it, you can increase the compression even more but you won't be ale to go back to regular gas.

The bigger the bore the more power you will have at a lower rpm, and a big bore that is NOT heavily ported will do fine on both slow trail and the dunes.

If you plan to keep the bike, and have the money and want a big increase in power without it all being above 5000 rpm, get a big bore kit.

I think they now have bigger rads for the ATC250R which will help with the cooling.

Also, running around 70% water with 30% antifreeze and 1/4 bottle of water wetter and a higher pressure rad cap will help it run cooler.

You also need to play with the ignition timing a little to see where it runs the best and the coolest so the temp gauge that Bob Marlin mentioned is a very good thing to have.

It is VERY easy to "over port" a cylinder and end up with something you are not happy with, so it is always safer to be a bit conservative at first unless you know that you want screamin power at 10,000 rpm . You can always port it more later if you want, and I have found that it is far more difficult to "unport" them.
.

[The_Steve_Man]

Arlen (LED) has a dyno sheet on his website of an ESR 310 with a +4 crank with around 60 hp and nice flat torque curve. I would at least go talk to him since he is so close. A lot of the quad use him and very happy. He has been building motors for a long time.