Author Topic: ESR Power Valve (Read 16204 times)

tylermx71 · « **on:** February 29, 2016, 05:05:23 PM »

Im looking to get a more broad power band out of my ESR 310 with trx9 port(without esr port work), It seems to be mostly topend or nothing. My cylinder has a powervalve option but is currently blocked off, ive seen lots of threads back from 2010 and 2011 that ESR PV were failing and dropping down onto the piston. Now that its almost been 6 years from those posts does anyone know if ESR ever fixed these problems? Im used to my yz250 style power with a PV and would like to get my TRX there but not at the expense of my top end.

etccb · « **Reply #1 on:** February 29, 2016, 06:30:19 PM »

The power valve will definitely help address this area and desire. Clean it now and then and use locktite and you wont have a problem. Ignore it forever and at some point in time down the road it may mess up in some way.

kb250r · « **Reply #2 on:** February 29, 2016, 08:43:18 PM »

I'm not sure of the price of buying just the PV.. But maybe close to same price maybe a little more and just try and have it re-ported low-mid trail ported if the port timing isn't too high and avoid the PV...I've spoke to a few engine builders and they we not having much luck with eddies PV.. I run a lot of of eddies stuff from cranks,cylinder and pipes but his PV just ain't one..jmo good luck

Michael88R · « **Reply #3 on:** February 29, 2016, 11:13:39 PM »

I was in the same boat as u. Had 310 trx9 port, trx5 pipe, and pump gas. Sold the 310. Went with 330 trx7 port on race gas. 10 times better for my style of riding. The 310 was probably faster in a drag race but my 330 is way easier to ride and has the power where I want it. Higher compression helps the low end torque. The larger displacement and trx 7 port helps as well. My 330 has the PV but I don't feel like it contributes that much.

rablack21 · « **Reply #4 on:** March 01, 2016, 05:28:57 AM »

I had a 310 pv and raced it for several years. Never had a problem. Not saying that someone didn't, but I think it was blown out of proportion by a few. I never loctited mine either, although it wouldn't necessarily hurt if you did. I cleaned mine once or twice a year or so. Never an issue. With that said,to a certain extent, ANY power valve requires a little maintenance from time to time, doesn't matter what style or brand.

tylermx71 · « **Reply #5 on:** March 01, 2016, 12:46:21 PM »

The power valve runs about $140 on ESR's website. I also live in PHX and Jerry Hall is right down the road from me. Im not sure how much he would charge for a port job though. The problem is I ride alot of different terrains, so one minute ill be hauling through a sand wash and the next minute ill be in a really tight technical section or out at the MX track. So the real question would be which is going to give a better more usable powerband, almost like a 4 stroke. I like the price of the PV, ive never gotten anything ported but I feel like it will be triple the price.

tylermx71 · « **Reply #6 on:** March 01, 2016, 12:50:56 PM »

Quote from: Michael88R;65059

I was in the same boat as u. Had 310 trx9 port, trx5 pipe, and pump gas. Sold the 310. Went with 330 trx7 port on race gas. 10 times better for my style of riding. The 310 was probably faster in a drag race but my 330 is way easier to ride and has the power where I want it. Higher compression helps the low end torque. The larger displacement and trx 7 port helps as well. My 330 has the PV but I don't feel like it contributes that much.

Id love to go up to 330 but its just not in the bank for me right now. It might be possible in the next year or two hopefully

dem3500 · « **Reply #7 on:** March 01, 2016, 12:51:15 PM »

ive run an esr pv on two engines. i never had a problem with either of them. i used loctite on both. i run amsoil dominator with 110 and have checked the pv on both engines periodically throughout the year and they were never dirty at all, not even a little bit.

Michael88R · « **Reply #8 on:** March 01, 2016, 04:14:19 PM »

What pipe are u running? An mx pipe will also help.

tylermx71 · « **Reply #9 on:** March 01, 2016, 04:36:32 PM »

I just bought a trx5b centermount off a member here (I had a FMF which sucked) and it helped abit but still wanting more bottom without sacrificing too much .

Robsessed86 · « **Reply #10 on:** March 01, 2016, 05:12:09 PM »

Mx or esr 7 pipe will help for sure. What carb are you running?

tylermx71 · « **Reply #11 on:** March 01, 2016, 05:34:51 PM »

I bought a 38 keihin air striker for it shortly after purchasing the quad. Strange thing about the jetting is that I'm running a very small pilot jet compared to everyone else. I've heard people recommend anywhere from a 48 to 52. I'm running a 42 and afraid to go smaller. I'm using the idle technique to figure out the jetting. Is it because I'm not using genuine keihin jets? Or because I'm running avgas? I was the impression that avgas makes you have to have fatter jetting. My plug still reads rich, is there something that would cause this? I also have a good amount of oil sitting in the intake tube after I ride. Possibly the reeds leaking?

Jerry Hall · « **Reply #12 on:** March 01, 2016, 07:45:14 PM »

Set the pilot jet size and air screw setting to where I runs the best. Reading the spark plug is not the proper approach to selecting the best pilot jet size.

tylermx71 · « **Reply #13 on:** March 01, 2016, 08:38:28 PM »

Hey jerry, I was going off idle speed to tune for the pilot but stopped at 42 because I feel like that seems a pretty small pilot for a 310

Grande huevos · « **Reply #14 on:** March 01, 2016, 10:57:26 PM »

I would use Kehin jets only and ditch the av fuel and get good race fuel. What is your compression? If you have a ESR dome even the "race" domes I was informed by a couple different engine builders that they are very conservative to help keep people from blowing engines and don't really require race fuel.... You could by a blank dome for around $40 and have a builder cut it for under $75 and really boost your compression up by close to 50 lbs that alone would help a ton!! If you have another $250-350 you could have same builder do a more extensive port job. Also what gearing do you run? What reed setup?