Ported stock cylinder -vs- ESR 310 kit

[SARON81]

About to re-do the top end on my 86 R, and I'm having a difficult time deciding which way to go with the rebuild. I'm torn between sending my stock cylinder to be ported -vs- ordering the TRX-9 ported ESR 310PV ready kit. It's looking like it should be pretty close cost wise, so that's not a deciding factor. Any opinions either way? Is there a even better option I'm missing (under $1000?) I do mostly woods/MX stlye riding, and am looking fo something with a good mid/upper mid range.
The rest of my setup is a stock 86 short rod bottom end, Paul Turner Type 6 pipe, 38mm air striker, K&N, and a CR250 rad valve.
I'm likely leaning towards the 310 kit, as it's ready to bolt on, and I'll have zero down time. With porting the stock cylinder, I'd likely be down for a few months waiting on it to return, missing prime riding season. On the other hand, I've heard mixed reviews on the ESR kit's reliability, though they seem to be on the older engines/kits. I do not want to sacrafice reliability for a little more power. I've also heard that a good ported stock cylinder will run with most 310's. What should I do?

[Rupp250]

Ported stock cylinder, several good builders on here to choose from.

I don't like the bolt-on 310 kits. The cylinder sleeve doesn't extend down into the cases.

[etccb]

Thats the 330 bolt on cyl kit that you are thinking of rupp.
That pv ready 310 kit could give even more in the future vs the maxed oem and more displacement as well.

[Rupp250]

I was corrected^^^^^^^^. Then yes go with the ESR setup.

[aberegg05]

Ive ran both ported oem and esr's 310 pv kit. Theyre both good but suprisingly the oem out ran the 310. Im guessing it all depends who ported the oem cylinder

[SARON81]

I was looking at a used LRD ported head, but never heard back on the email I sent Arlen to see if it would work with my setup.

[Tbone07]

About to re-do the top end on my 86 R, and I'm having a difficult time deciding which way to go with the rebuild. I'm torn between sending my stock cylinder to be ported -vs- ordering the TRX-9 ported ESR 310PV ready kit. It's looking like it should be pretty close cost wise, so that's not a deciding factor. Any opinions either way? Is there a even better option I'm missing (under $1000?) I do mostly woods/MX stlye riding, and am looking fo something with a good mid/upper mid range.
The rest of my setup is a stock 86 short rod bottom end, Paul Turner Type 6 pipe, 38mm air striker, K&N, and a CR250 rad valve.
I'm likely leaning towards the 310 kit, as it's ready to bolt on, and I'll have zero down time. With porting the stock cylinder, I'd likely be down for a few months waiting on it to return, missing prime riding season. On the other hand, I've heard mixed reviews on the ESR kit's reliability, though they seem to be on the older engines/kits. I do not want to sacrafice reliability for a little more power. I've also heard that a good ported stock cylinder will run with most 310's. What should I do?

If you have a reputable builder port both the ESR 310 and OEM 250 cylinders, the 310 will come out on top. There is no replacement for displacement

Now if you're using ESR's cookie cutter porting......then it's a different story

Look at ESR's "Engine Builder" cylinder kits. They come with no porting work, so you can send it out to your builder of choice. I think that's the best option

http://www.eddie-sanders-racing.com/category_s/137.htm

[SARON81]

I don't see a power valve option for the engine builders kits though.

[rsss396]

IMO dont go with the poweralve, but go with the ESR 310 (which is only 295cc on the first bore)

[Bowtie316]

My buddies trx9 port match esr 310 runs real strong but for the riding we do (trail, woods, dunes), the trx7 might be better.  Also it tends to run a bit hotter than the stock jug, so you might plan on upgrading the radiator.