TRX250R.ORG
Workshop => Carburetor, Intake, and Exhaust => Topic started by: hub97119 on May 31, 2014, 08:53:40 PM
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I envy the people that say they start first or second kick. I have never been able to do that. On a cold bike I can kick forever and not get anything. I have been pulling the plug and putting a little mix right in the cyl. and she starts right up. Plug is always dry on a cold start, choke or no choke. I have tried adjusting the pilot from a 50 - 58 with no help. Once I get it warmed up I can start it all day. Right now i am 55 pilot, 180 main, 38mm a/s, br8es with 18 gap. 112 race fuel at 50: 1 amsoil, open air filter on a 300 sphinx bored to a 310, dune port all built by LED. I recently bought this motor and the guy was running 100:1 amsoil but i decided to come down to 50:1 running Dominator. Like I say I can start this all day once it's been warmed up. I did up the pilot from a 52 when i changed the mix and one size up on the main. Any ideas why I'm not getting any fuel to the plug on a cold start ? Forgot to mention - Vforce reeds
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I envy the people that say they start first or second kick. I have never been able to do that. On a cold bike I can kick forever and not get anything. I have been pulling the plug and putting a little mix right in the cyl. and she starts right up. Plug is always dry on a cold start, choke or no choke. I have tried adjusting the pilot from a 50 - 58 with no help. Once I get it warmed up I can start it all day. Right now i am 55 pilot, 180 main, 38mm a/s, br8es with 18 gap. 112 race fuel at 50: 1 amsoil, open air filter on a 300 sphinx bored to a 310, dune port all built by LED. I recently bought this motor and the guy was running 100:1 amsoil but i decided to come down to 50:1 running Dominator. Like I say I can start this all day once it's been warmed up. I did up the pilot from a 52 when i changed the mix and one size up on the main. Any ideas why I'm not getting any fuel to the plug on a cold start ? Forgot to mention - Vforce reeds
How far is the bottom of the slide from the bottom of the carburetor when the throttle is closed on the engine side of the throttle slide? You will probably have to pull the carb out of the rubber reed manifold to measure it. You can use a set of drill bits to slip under the slide to measure the distance.
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Could it be weak spark? Maybe try a non resistor plug (B8ES) instead of the BR8ES & see what that does? Have you checked the ignition components with an ohm meter to make sure there within spec?
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putting a little mix in the cylinder not only puts fuel in but it all so puts oil there for a better ring seal;low compression will cause hard start but not so sure it explains no fuel on plug.I do understand jerrys line of thought the more open the slide the less effect the choke or slow circuit would have and with not much draw across the nozzle,it would not pull fuel thru
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It is not uncommon for Keihin carbs to have cold starting problems when you have a pilot jet that is too large. If the pilot jet is real rich the slide will have to be open much more than it should be to make it idle.
Like Fred said, If the slide is open too far the choke circuit and the pilot jet transition holes do not experience enough vacuum to draw enough fuel.
Due to a what I feel is a poor design of the PJ, Pwk, Air Striker and PWM series of carburetors, it is not uncommon for the slide to be open around 1/8" or more to make the engine idle and have good throttle response when you get the jetting combination ( pilot, needle, slide, air screw) that performs well on the track. It has been my experience that when you have the right pilot jet in the carburetor and the air screw about 1 1/2 turns plus or minus 1/4 turns and a needle that has the correct taper and initial diameter for good track side performance, there will be a lean bog when you suddenly open the throttle after the engine has been idling for more than about 10 seconds. With the correct pilot jet we need to be able to have different needle jets and or multi-angle needles to properly fuel the engine as the throttle is opened. Keihin made a large selection of needles that have different initial diameters with different single taper needles, but this still does not replace having needle jets of different diameters and very small initial tapers on the needle.
Setting the carb not to idle will often cure the hard starting problem but now the engine may get loaded up every time you close the throttle for more than a couple of seconds.
I think that Keihin did the dirt bike industry a disservice when they dumbed down their series of dirt bike carburetors. I think that they felt everyone in the industry had the tuning skills of Forest Gump so they removed the features of no air correction jets, no replaceable needle jets and not offering dual or triple angle needles like most engines need.
The PJ carburetors had a terrible design for a choke/idle circuit.
I think that the fins in the air striker inlet are snake oil and most consumers do not have the tuning skills to test the feature objectively, if they did I think they would be disappointed in their purchace. I think that the marketing department at Keihin thought they needed something that was visibly different from the other carburetors competing for the same market. Adding the fins to direct the air over the needle jet suppose to increased the air velocity over the needle jet for improved throttle response. The fins also hinder airflow as compared to other carburetors of the same size. I think that this marketing gimmick sold a lot of carburetors to entry level consumers and tuners that did not have the tuning skills to allow them to accurately test one design against another. Unfortunately our market is filled with companies that and are controlled by the marketing divisions and not the divisions that try to design better products.
I have seen it time and time again when sales are dropping, the marketing departments instructs engineering to create a new mousetrap that looks different from the old ones but still catches mice just like the old ones that everyone already has. The manufactures want to keep the production lines busy making stuff. It is unfortunate that the average consumer does not have the engineering education or experience to look at or test some of the stuff on the market and determine if the products COULD functions as advertised or is just another disguise of the same old stuff.
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so are you saying that mind as well just stick with a 38pj or 38 pwk. the a/s carb isnt any better?? well that just blows!!
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so are you saying that mind as well just stick with a 38pj or 38 pwk. the a/s carb isnt any better?? well that just blows!!
PJ choke curcuit and idle adjustment sucks, I would upgrade to Pwk or AS for that alone. As to whether or not the AS is better than PWK for throttle response, IDK. I can see the fins in the AS being a restriction on bigger motors.
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Jerry, your knowledge is mind boggling.... I like it a lot!
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Im with you Colin, I love having jerry on here,he doesn't pull any punch's. we are all lucky to be rid of that other jackoff and to have jerry, Dave Neil and Arlan on here as well as a lot of others on here.
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recently bought this motor and the guy was running 100:1 amsoil but i decided to come down to 50:1
I don't like the sound of that at all....I would never run any ratio less than 40:1 no matter what the oil manufacturer claims you can run it at.
have you measured your compression?
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so are you saying that mind as well just stick with a 38pj or 38 pwk. the a/s carb isnt any better?? well that just blows!!
I do not think the Air-Striker properly tuned performs any better at the initial throttle openings than a properly tuned PWK. I do prefer the PWK series over the PJ series of Keihin carburetors only because the PWK got rid of the terrible choke circuit that the PJ had.
This stuff is not rocket science. I sounds like you may be another victim of Marketing.
Shops or stores that do not have the test equipment or the knowledge of how to properly test products will not have first hand knowledge about the products they sell. Businesses that only sell parts DO NOT HAVE FIRST HAND KNOWLEDGE ABOUT THE PRODUCTS THEY SELL. Without first hand product knowledge, the shops, mail order houses, Ebay and the big wholesale to the public parts warehouses are going to push products that have the BEST MARKETING PROGRAM and the HIGHEST PROFIT MARGINS.
The Keihin dirt bike carbs suggested retail prices are about 25% higher than comparable sizes of Mikuni. Shops have to mark up the products they sell in order to make a profit and stay in business. Shops with integrity are going to try to sell what is best for their customers and not try to sell what will generate the most profit. Did you buy a particular carburetor based on research you obtained from asking questions to 10 people face to face about how they liked their carburetor. The second best way to do research is to use your smart phone to talk other people that are using or have used the product you are considering purchasing rather than using it to visit numerous web sites for looking for the lowest price.
Places that have the lowest prices cannot afford to have someone on staff that is qualified to answer technical questions!!!!!!!!!!!!. It cost a lot of money to hire employees that have the knowledge that can answer any of your technical questions. The guys that can effectively answer tech questions usually work in the shop and is not a SALESMAN that only mans the phone. A business that has enough knowledge about the products they use and sell, can ask the consumer the right questions, supply the customer with the product that is gong to fit the customer’s needs, but they cannot do it at the prices the discount parts stores sell for. Again…..this stuff is not rocket science.
Find a shop that works on the type of toys you have. Find a shop that has someone that has a lot of experience with the types of problems you are experiencing. Find a shop that has been in business at least 10 years or more and support them by using their services and BUY YOUR PRODUCTS FROM THEM. Businesses in our industry that have not been in business for at least 10 years or the mechanic has not been working on big boys toys for more than ten years will not usually have the experience necessary to give you the quality work that you are expecting. You are probably going to pay more, but now they can afford to support you by giving you future technical assistance. In the long run you will spend less. If you cannot afford to take this route with your hobby you are doing something that you really cannot afford. You probably need to take up another hobby. DO NOT go to these small shops and get answers to your tech questions and then buy your carburetors or what ever from the discount parts warehouses. They can only afford to support those that support them!!
Remember there are no free lunches. There are cheap lunches. And in the long run, you usually get what you pay for……….
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the only reason i actually bought the air stryker carb was because of the reviews and feed back for it. you read it everywhere from ppl recommending the 38 a/s for just about any setup. i am gona run the 38 a/s with a 350 big bore from esr with all around porting. would that setup work good you think? will have a trx5 pipe to go along with it
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so are you saying that mind as well just stick with a 38pj or 38 pwk. the a/s carb isnt any better?? well that just blows!!
This is also what Arlan told me, so I just went with the 38MM PWK
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....................................the only reason i actually bought the air stryker carb was because of the reviews and feed back for it. you read it everywhere from ppl recommending the 38 a/s for just about any setup. i am gona run the 38 a/s with a 350 big bore from esr with all around porting. would that setup work good you think? will have a trx5 pipe to go along with it
This is one of the points I have trying to make. YOU CANNOT DO HONEST ACCURATE RESEARCH READING THE MAJORITY OF THE PROMOTIONAL GARBAGE ON BUSINESS WEB SITES.
The Air-Striker is as tune able as any of the other Keihin two stroke carbs, but I do not feel it is any better. I think that the Air-striker is one newest Keihin dirt bike carburetors. Being one of the newest Keihin carbs on the market, it is going to be the carb that the marketing teams of the manufactures and retailers are really trying to push just like the new Smart Cabs.
Who are the people recommending it everywhere for just about any setup? This is the same comment I hear on a daily basis from guys suffering buyers remorse. We are constantly bombarded with advertising. With enough advertising and hired cheerleaders over a long enough time, it eventually changes our subconscious perception about products, services, politics and just about everything around us. The people you are referring to are not usually real people they are the effects advertising has upon our brain and convinces us that a lot of people have saying a lot of good things for a long time about a particular product or service. The reviews on many of the forums are often written by hired cheerleaders.
You have to be a skeptic and do your home work or you will always have stuff that does not work as advertised. You will also be out of money because the people with good marketing skill will keep your pockets drained until you learn how to really think for yourself and make wise purchasing decisions.
Marketing people are trained in techniques on how to get inside peoples head and make them make purchasing decisions they do not realize they are making. A person that has a marketing degree has to take a lot of Psychology classes in college. The marketing classes are not called psychology classes but that is what they are.
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jerry i dont think your understanding that im not getting this info from promotional websites. im getting it from actual forum members over on .net about 3 years ago. at the time i got my cylinder ported and then moved up from a 36 to a 38 a/s. ppl posted thier actual experiences with the carb and what they thought of it. ive honestly hardly read any bad reviews on this carb. not any more than any other carb. this is the first from you. i think my carb works awesomely. now i have never used any other carbs but keihin so i wouldnt know what the difference is
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I wonder how the hell I ever kept my r running with a/s on it,nevermind all the years I ran a pj 38. really though,thats not what I got out of what jerry said.
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i sure did. he put the info in big bold letters. i was never scammed by somebody saying buy this now!! just did a lil research on the forums and saw good results so i bought one. what other carbs are you guys running? only other i know if is mikuni. are they better?
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i sure did. he put the info in big bold letters. i was never scammed by somebody saying buy this now!! just did a lil research on the forums and saw good results so i bought one. what other carbs are you guys running? only other i know if is mikuni. are they better?
I have two a/s and Im not selling them to buy anything else I don't ride at an idle and you probably don't either .what I got out of what jerry said is that most of use get sold a bill of goods and we are not armed with enough info to make best use of our money.If I were you I would not be disappointed in owning a a/s
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dude i dont own a pwk i own a 38mm air striker
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dude i dont own a pwk i own a 38mm air striker
He's saying we were all fooled by thinking a newer Keihin carb with a fancy "air stryker" name would be a huge improvement.
Lots of people switched to the A/S when it really didn't have any proven benefit. Just a very good marketing scheme. Don't take it personal
Now back to the original topic.......have you by chance checked the compression on the engine?
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dude i dont own a pwk i own a 38mm air striker
yea me too.they are basically the same thing .I will edit that
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its cool bro i am not tryna argue one bit. i think its hard to understand the tone in reading words. i understand they are pretty much the same thing now. so yes back to the op!!
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He's saying we were all fooled by thinking a newer Keihin carb with a fancy "air stryker" name would be a huge improvement.
Lots of people switched to the A/S when it really didn't have any proven benefit. Just a very good marketing scheme. Don't take it personal
Now back to the original topic.......have you by chance checked the compression on the engine?
sorry mr T ,Im old and I get side tracked really easy
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I have two a/s and Im not selling them to buy anything else I don't ride at an idle and you probably don't either .what I got out of what jerry said is that most of use get sold a bill of goods and we are not armed with enough info to make best use of our money.If I were you I would not be disappointed in owning a a/s
I am not trying to promote Mikunis or telling you guys to throw away your air-strikers. If you have an air striker or an old Bing or remote flow bowl Amal that is well tuned and works to your satisfaction, why consider the next new carb design that may be released. In some of the earlier post I was just trying to alert those of you that may be new to the sport and want to jump on every new thing that comes along when what you have is probably as good as the new stuff especially if you are still try to develope your carburetor tuning skills.
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Remember me ? I'm the guy who started this thread. Nice dialog,; it seems sometimes my questions elicit this type of exchange, good for all. Jerry I haven't had time to take the measurement you asked about. If the slide is sitting to high is there an adjustment which would correct it. Also someone asked about comp. and electrical. I'm at 210 and all electrical is within spec. That is one of the first things I checked. I have this intake set up because it was what was with the motor when i bought it and he had no problems with it so I wanted to keep things intact. I have carbs from 34 - 40.5 MM I could try, PE, PWK, PJ etc. but no Mikuni. When this bike is warm it runs like a bat out of hell. Anyway like I said it is just hard starting but maybe it is my 60 yr. old leg, but I doubt it as I'm still able to get up and around trees all day long. I have tried a b8es but still the same. I suppose i will continue to pour a teaspoon of mix in the cyl. for the time being. I should post a picture of the pipe I have on it and let you guys try to guess what it is. ( I don't know, but it pulls hard in every gear ). That should be fuel for some more lively exchange. Thanks all Ron ( Gaston, OR. )
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Remember me ? I'm the guy who started this thread. Nice dialog,; it seems sometimes my questions elicit this type of exchange, good for all. Jerry I haven't had time to take the measurement you asked about. If the slide is sitting to high is there an adjustment which would correct it. Also someone asked about comp. and electrical. I'm at 210 and all electrical is within spec. That is one of the first things I checked. I have this intake set up because it was what was with the motor when i bought it and he had no problems with it so I wanted to keep things intact. I have carbs from 34 - 40.5 MM I could try, PE, PWK, PJ etc. but no Mikuni. When this bike is warm it runs like a bat out of hell. Anyway like I said it is just hard starting but maybe it is my 60 yr. old leg, but I doubt it as I'm still able to get up and around trees all day long. I have tried a b8es but still the same. I suppose i will continue to pour a teaspoon of mix in the cyl. for the time being. I should post a picture of the pipe I have on it and let you guys try to guess what it is. ( I don't know, but it pulls hard in every gear ). That should be fuel for some more lively exchange. Thanks all Ron ( Gaston, OR. )
The throttle opening can be reduced by turning the throttle stop screw counter clockwise.
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Thank you sir