TRX250R.ORG
Workshop => Engine and Bottom End => Topic started by: tylermx71 on February 29, 2016, 05:05:23 PM
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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.
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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.
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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
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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.
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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.
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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.
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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
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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.
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What pipe are u running? An mx pipe will also help.
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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 .
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Mx or esr 7 pipe will help for sure. What carb are you running?
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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?
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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.
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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
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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?
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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.
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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.
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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
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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.
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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?
(http://forums.trx250r.org/vbulletin_imports/1644_7337_2017-04-18_7063.jpg)(http://forums.trx250r.org/vbulletin_imports/1644_7338_2017-04-18_224.jpg)
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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
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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.
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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?
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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
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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.
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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
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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
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Try the PV might be just what you are looking for...
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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.
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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.
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If the engine is running fine, I wouldn't replace the piston. The damage has already been done. As long as it was holding good compression, run it until it needs new rings. Then get the cylinder honed at your cylinder shop just enough to clean up the scuffing, and sand the piston slightly with a fine grit sand paper until smooth.
Also next time you get the cylinder bored, have them set the piston clearance to .003 or a tad over. My 310 cylinder with a forged piston didn't like anything less without getting the old 4 corner seizure marks.
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If the engine is running fine, I wouldn't replace the piston. The damage has already been done. As long as it was holding good compression, run it until it needs new rings. Then get the cylinder honed at your cylinder shop just enough to clean up the scuffing, and sand the piston slightly with a fine grit sand paper until smooth.
Also next time you get the cylinder bored, have them set the piston clearance to .003 or a tad over. My 310 cylinder with a forged piston didn't like anything less without getting the old 4 corner seizure marks.
Thanks ill remember that when I do the top end again. I It runs great, im not sure on the compression but when I kick it over it feels pretty healthy.
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Try a different needle diameter. Like a dgj or dgk. My 310 ran 42-48 pilot.
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I just installed the powervalve and wow what a difference! I havent taken it in the dirt but it feels way more powerful down low. It feels like it has more torque and pulls harder everywhere. Thanks for the help everyone
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And another believer in the power valve.......lol
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And another believer in the power valve.......lol
Man that's good it give you what u wanted and worked out...how did you adjust it/set it up? did Eddie send instructions for set up and dialing in the PV?
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Glad u r happy with it. It's good that ur cylinder can go both ways to really get a good comparison. I always thought my PV wasn't doing much but it must be doing more than I thought.
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Man that's good it give you what u wanted and worked out...how did you adjust it/set it up? did Eddie send instructions for set up and dialing in the PV?
I spoke with Eddie in detail about this in the past. This is what he told me. He typically like to set them where they are just barely compressing the spring. If he wanted a touch more bottom end, he will turn it up to about 5 turns in, but that's it. He said they typically tend to perform the best for all around balance power just compressing the spring a couple turns.
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I spoke with Eddie in detail about this in the past. This is what he told me. He typically like to set them where they are just barely compressing the spring. If he wanted a touch more bottom end, he will turn it up to about 5 turns in, but that's it. He said they typically tend to perform the best for all around balance power just compressing the spring a couple turns.
Thanks guys. Yes this is pretty much what he told me also. I got the powervalve already assembled and everything red locktited ready to go. I turned in the adjuster a couple turns and it works great the way it is, perfect balance of low end grunt and top end.