Author Topic: ESR Power Valve (Read 14483 times)

rablack21 · « **Reply #15 on:** March 01, 2016, 11:11:02 PM »

Quote from: dem3500;65075

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.

Exact same set up here. Mine were never dirty, but I sprayed them with brake cleaner anyway and gave them a wipe.

rablack21 · « **Reply #16 on:** March 01, 2016, 11:19:21 PM »

Quote from: tylermx71;65050

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.

You're going to get a lot of answers that lead you all over the place. So back to your original post and questions: if you want to broaden the power of what you CURRENTLY have, you either need to get the power valve and put it back in there, get the cylinder re-ported to get the power range to fit closer to what you are wanting, or bump up your compression with a race dome and run race gas. Yes, the higher compression with boost your bottom end some. But keep in mind that your porting is still aimed at higher rpm power. So it depends on your goal.
If your goal is to keep your top end power the same, but add some bottom end, then get the power valve and/or bump up the compression and run race fuel
If your goal is to take the top end power that you have and move it to bottom end or midrange, then you need to have the cylinder re-ported to reflect that intention. Hope this helps. The pipe that you are running should also reflect the intention of your cylinder and where you are wanting the power to be.

tylermx71 · « **Reply #17 on:** March 01, 2016, 11:42:37 PM »

Thanks that does help. I'm not sure what dome is in there the previous owner couldn't remember but he was running half pump half race gas. I'll have to borrow a compression tester and see where I'm at. I'm also going to check my boyesen reeds out and make sure there still intact. Worn reeds explain why there is so much oil in my intake, small jets and such little bottom end. I'm going to check them out in the AM and let you guys know

Michael88R · « **Reply #18 on:** March 02, 2016, 09:46:33 AM »

Worn reeds have always made mine hard to start. If the PV is $140, I'd say it's worth a shot to try it out. The new PVs are adjustable too.

tylermx71 · « **Reply #19 on:** March 02, 2016, 10:17:30 AM »

Heres a picture of the reeds. they are slightly bend up and I can fit a .015 feeler gauge under the tips. Can I flip the reeds over to make them seal or should I order new ones?
Also look at my piston. Looks like four corner wear, ive always warmed up the bike before riding. Do I need to replace this piston?

tylermx71 · « **Reply #20 on:** March 02, 2016, 10:40:12 AM »

Quote from: Michael88R;65106

Worn reeds have always made mine hard to start. If the PV is $140, I'd say it's worth a shot to try it out. The new PVs are adjustable too.

Its never been too hard to start, just alot of oil in the intake that gets messy when it makes its way to the filter. I think im going to give ESR a call and order one

Jerry Hall · « **Reply #21 on:** March 02, 2016, 10:47:32 AM »

The reed petals may have some slight fatigue but is more likely they need the grit removed from the fulcrum point. The reeds are just a one way air valve and petals like yours will completely close the instant the crankcase mixture tries to flow backward. There is reversion in any intake tract and some wetness in the air box hose is normal.

The marks on your piston skirt is the result of an old "4 corner seizure". It is not normal ware. I see a lot of 4 corner seizures on the 310 big bores because the recommended piston clearance is too tight.

Carburetor theory says the needle jet is not suppose to flow fuel at closed throttle, but it will and can affect the pilot jet size and air screw setting especially on closed throttle deceleration.

If your pilot jet needs to be excessively small it may be the result of a worn needle jet or needle. This diameter may be too small and just needs the straight portion of the needle to have a larger diameter. Ware in these two areas is very common because the aftermarket Keihin carbs use bronze rubbing bronze and causes accelerated wear to the needle and needle jet. The OEMs that use Keihin carbs use dissimilar metals for the needle and needle jet. The OEMs use a bronze needle jet with a hard anodized aluminum needle and they last forever.

tylermx71 · « **Reply #22 on:** March 02, 2016, 11:03:11 AM »

Quote from: Jerry Hall;65110

The reed petals may have some slight fatigue but is more likely they need the grit removed from the fulcrum point. The reeds are just a one way air valve and petals like yours will completely close the instant the crankcase mixture tries to flow backward. There is reversion in any intake tract and some wetness in the air box hose is normal.

The marks on your piston skirt is the result of an old "4 corner seizure". It is not normal ware. I see a lot of 4 corner seizures on the 310 big bores because the recommended piston clearance is too tight.

Carburetor theory says the needle jet is not suppose to flow fuel at closed throttle, but it will and can affect the pilot jet size and air screw setting especially on closed throttle deceleration.

If your pilot jet needs to be excessively small it may be the result of a worn needle jet or needle. This diameter may be too small and just needs the straight portion of the needle to have a larger diameter. Ware in these two areas is very common because the aftermarket Keihin carbs use bronze rubbing bronze and causes accelerated wear to the needle and needle jet. The OEMs that use Keihin carbs use dissimilar metals for the needle and needle jet. The OEMs use a bronze needle jet with a hard anodized aluminum needle and they last forever.

Im using a DGH needle that I just bought new. On the Keihin Air Striker is there a way to replace the needle jet? I dont have the carb in front of me so i cant look.
Also would you recommend I replace that piston?

dem3500 · « **Reply #23 on:** March 02, 2016, 11:09:00 AM »

Quote from: tylermx71;65112

Im using a DGH needle that I just bought new. On the Keihin Air Striker is there a way to replace the needle jet? I dont have the carb in front of me so i cant look.
Also would you recommend I replace that piston?

hold the slide in one hand, crab the cap in the plam of your other hand and use those fingers to pull up on the spring. push the cable down in the slide and move it back. the cable will come out of its catch. once thats out of the way unscrew that catch and the needle will come out. it will be easy to understand once you have it in front of you

tylermx71 · « **Reply #24 on:** March 02, 2016, 11:31:00 AM »

Quote from: dem3500;65114

hold the slide in one hand, crab the cap in the plam of your other hand and use those fingers to pull up on the spring. push the cable down in the slide and move it back. the cable will come out of its catch. once thats out of the way unscrew that catch and the needle will come out. it will be easy to understand once you have it in front of you

I know how to replace the needle itself, I changed to the DGH needle when I bought the carb. I was asking about the needle jet in the carb body. The peice the needle slides into when the slide closes, is that integrated into the carb or is it able to unscrew and be replaced? Like Jerry was saying if that is peice is worn down it could cause me to run richer than normal.

dem3500 · « **Reply #25 on:** March 02, 2016, 11:32:35 AM »

Quote from: tylermx71;65115

I know how to replace the needle itself, I changed to the DGH needle when I bought the carb. I was asking about the needle jet in the carb body. The peice the needle slides into when the slide closes, is that integrated into the carb or is it able to unscrew and be replaced? Like Jerry was saying if that is peice is worn down it could cause me to run richer than normal.

ahhh! ok my bad. i misunderstood. sorry i dont know lol

tylermx71 · « **Reply #26 on:** March 02, 2016, 11:37:41 AM »

Quote from: dem3500;65116

ahhh! ok my bad. i misunderstood. sorry i dont know lol

No problem man! I appreicate the help, I wish I had the carb in front of me so I could look for myself

kb250r · « **Reply #27 on:** March 02, 2016, 01:51:27 PM »

Try the PV might be just what you are looking for...

tylermx71 · « **Reply #28 on:** March 02, 2016, 02:02:53 PM »

Quote from: kb250r;65119

Try the PV might be just what you are looking for...

I just placed my order with ESR, hopefully it will get here better next weekend so I can give it a shot.

Jerry Hall · « **Reply #29 on:** March 02, 2016, 04:29:08 PM »

Quote from: tylermx71;65112

Im using a DGH needle that I just bought new. On the Keihin Air Striker is there a way to replace the needle jet? I dont have the carb in front of me so i cant look.
Also would you recommend I replace that piston?

The needle jets in the PE, PJ and PWK carbs are not replaceable. When the needle jet becomes worn you have to replace the carb or find a different number needle to get the mixture back to where it is correct. Worn needle jets in Keihin carbs is one of the main reasons it takes a different needle to make engines of the same build run the same.