TRX250R.ORG
Workshop => Carburetor, Intake, and Exhaust => Topic started by: nick20555 on May 27, 2016, 08:52:53 PM
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New to the forum here. I will put a thread up on my 86 250R soon but in the mean time, I am looking for some info. So while working on my R that I bought last week, I found that the carb bowl was cracked and the corner actually broke off when I disassembled it. I figure it will be just a much to get a new carb as it is to replace this broken bowl and a few other parts that are in bad shape on it. It already has a Curtis sparks exhaust, uni air filter, outerwears cover to replace the lid (in the mail), and unknown engine work (was told its been worked on but I don't know for sure. I will find out soon enough). I'll probably get it ported and rechamber the head soon and maybe add some more stuff and potential big bore in the long run. So my question is, what is a good carb for these future mods I'm looking to do? I'd rather only have to buy a carb once, not one now and another later. I do a lot of woods riding. I'll also need some jetting suggestions with whatever carb I go with as well if you guys can help.
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38 air striker is a great all around carb. I have run it on 290cc motors up to my 363. i think its probably one of the most favorite out there.
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When looking, it seemed like the 38 air striker was pretty common but my concern with going that much bigger on a carb is power down low. I do woods riding so low to mid power would be nice but I don't mind some of that power up top as well. Really my goal eventually is to be able to get a stock or piped 450 in a drag but be able to use that power on the trails as well.
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the 38 A/S is the a very versatile carb and will adapt to engine changes easily. for example, adding a big bore, port work or pipe change.
john
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What are you doing with the bike? If you are doing MX or dunes, 38AS is a good choice. If you are doing hare scrambles, tight trails, then look at a 35AS. The 35 will work better in the lower rpm range, plus it can be bored if you need a bit more. Should be able to find either used, for around $100-120.
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Like said a 38 a/s will be a great carb an will work well goin up in motor size for a future build
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The Air Stryker series of Keihin's are PWK's which are more of a mid to top end carb. The smaller PWK's will give better throttle response in the mid but sacrifice some top end power. If you want more grunt you could go with a bigger PJ but they have a combined choke & idle circuit which can give you problems plus they don't pull up top like a PWK. Another option is the Mikuni TMX. I never tried one but hear there as good or better than a PJ down low & a PWK up top. The 38TMX is the carb I'm going to get for my wife's R since it get's riden in the woods mostly.
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I have a tmx carb if interested maybe 2 of them. Pm me
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I do some woods riding and ride around on back roads as well so I'd like a good well rounded carb. Having a good mid range would be best. I'd like some down low for the woods but I'd still like to hit the highs for the back roads or when the trails open up.
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I ride woods, fields, and seasonal roads and really like my 38 A/S on my 310
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I used to have a 36 pj on my 310, it worked great in the woods. I switched it out for a 38mm pwk air stryker when I switched to mostly all dune riding.
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I've used Keihin 38 A/S in the past, but on my most recent build I tried the Mikuni 38 TMX and love it. Being a flat slide it is supposed to have better throttle response and top end. I've found it to be a great performer all around. It doesn't have all the hoses the A/S does either, which I find annoying. Does a small carburetor really need 5 vent hoses? The TMX is also much narrower than the A/S, around 70mm, so you might have to use a reed spacer. Before I bought it I read comments that Mikunis are harder to adjust and more temperamental than Keihins. Not true. The jets are actually easier to change. The drain plug at the bottom of the float bowl actually holds the bowl in place, whereas with the Keihin has 4 phillips screws. I got mine at Niche Cycle Supply. Good prices and fast shipping.
http://www.nichecycle.com/ncs/mikuni/carburetors/tm38-27-mikuni-tmx38-flatslide-carburetor-44mm-by-mikuni.html
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Not sure which to choose. Good info on both the tmx and A/S
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On the zillas we ran tm38 bored to 41 or 42.5 and they were easy to jet if you put a pwk you couldn't jet them.
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I've run the 38AS on an OEM cyl with nothing but bolt-on mods and I was very pleased with it. It ran very strong, including down low, and responded predictably to jetting changes. I ran that same carb on my trike when I did a 350 big bore and it worked well on that too. I have since swapped to a 41.2mm PWK on the 350 as it is a better fit to the build theme and so far have been pleased with that choice. Not to say the 38AS didn't perform well on the big bore, it did. I just feel that the 41.2 is a better fit in that situation.
The 38AS carb works very well on alot of different applications. Hard to go wrong if you choose one.
Another alternative you might consider is the 39mm PWK. Not being an AS type carb, it will be easier to bore out should you end up with a big bore cylinder and decide you want more carb down the line. Carb boring is cheaper than a whole new carb. I initially asked Eddie Sanders if he could bore my old 38AS and he said while it can be done, it can be a real pain due to the vanes in the venturi. He recommended I trade in my 38AS for the ESR bored 41.2 standard PWK so that's what I did.
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I prefer the TMX off of a Cr250. I have ran a 38 and 39 pwk. Absolutely amazing throttle response. No loss on the bottom and plenty up top. Once I figured out the jetting, I have not had any problems. I doubt that I will ever go back to a Keihin.
I have not tried the other TM carbs because I have got these carbs so cheap and they just flat out work for me.
I just put on a taper bored tmx and that is a badass carb!
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Dammit, every time I think I've decided which one I want, you guys make me rethink the other lol. Great info. Sounds like I really can't lose either way. I may but end up replacing the bowl on the stock carb (for now) just because I didn't realize you could pick one up so cheap. The stock carb really just needs a new needle and clip (one that was in it was bent somehow), bowl, a rebuild kit, and a couple different main jets (maybe a pilot too). I'll probably pick up one of those 2 carbs down the road though. Gotta try to ride it for a while on what it's got and went it needs it's rebuild then I'll build up the motor. I'll just focus on the cosmetic issues until then.
I need to start my build thread so you guys can see what I'm dealing with. This R was a rescue lol
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I prefer the TMX off of a Cr250. I have ran a 38 and 39 pwk. Absolutely amazing throttle response. No loss on the bottom and plenty up top. Once I figured out the jetting, I have not had any problems. I doubt that I will ever go back to a Keihin.
I have not tried the other TM carbs because I have got these carbs so cheap and they just flat out work for me.
I just put on a taper bored tmx and that is a badass carb!
I keep hearing this. What motor are you running the tmx on? I have one I pulled off my cr250. can you pm me some baseline jetting?
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Welcome to the site. Pickup the A/S and call it a day. Best carb you can run.
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The 01 has an s-9 nozzle and needs to be changed to an s-8. The 02 has an s-8 in it. On my mildly ported cylinder, I was at 32.5 pilot, clip in the middle, and a 390 main. On a more aggressive ported cylinder, i ran 430 main.
I have a Bubba Ramsey ported cylinder with a +4 crank and it loves fuel. 35 pilot, s-9 nozzle, clip in the middle and a 440 main.
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I have ran this carb on 3 different cylinders without a problem. I'm not saying they are better than a Keihin, but I personally prefer them over a Keihin. I have not used it a big bore, but I wouldn't think that you couldn't get it jetted.
Also make sure that if you buying one that it is a cr carb. I bought one and it was actually off of a yz. They put them on 97 and 98 and look the same but the size is a little smaller. I'm sure it will work though.
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I have ran this carb on 3 different cylinders without a problem. I'm not saying they are better than a Keihin, but I personally prefer them over a Keihin. I have not used it a big bore, but I wouldn't think that you couldn't get it jetted.
Also make sure that if you buying one that it is a cr carb. I bought one and it was actually off of a yz. They put them on 97 and 98 and look the same but the size is a little smaller. I'm sure it will work though.
There's also the TM38 off the quadzilla as well and there's some differences in it vs the tmx for the life of me I don't remember the difference between them though. Both you should be able to bore out to 41mm as well.
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I am really surprised that there is interest in the tmx carbs. Just a year ago the only help I could get was to throw it away and get a airstriker. But I don't give up and I will help anyone.
Sent from my MotoG3 using Tapatalk
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Every time I think I've decided you guys make me think about the other. I don't think I can lose either way though. I think that (for now) I will just replace the bowl on the stock one. I didn't realize you could get them pretty cheap. I'll probably pick up the bowl, a rebuild kit, new needle and clip (old one was bent somehow, not even sure which position he was aiming for), and a few new mains and possibly a size bigger pilot. I'll have to start a build thread soon so you guys can see what I'm dealing with. This R was a rescue lol. For now though I think I'll work on it cosmetically to get it looking decent and just get it running the way it should. Once it's due for a rebuild then I'll start building the motor and pick up one of these carbs. I appreciate all the info that was given to me and I will use it in my decision down the road.
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I am really surprised that there is interest in the tmx carbs. Just a year ago the only help I could get was to throw it away and get a airstriker. But I don't give up and I will help anyone.
Sent from my MotoG3 using Tapatalk
I currently only have Keihin's but will be trying a TMX soon. I think these two carbs bring up a debate much like a Holley vs a Carter/Edelbrock in the car world. I was always told to stay away from Holley in my car days & only ran Carter/Edelbrock but I ended up getting a Holley & now I have a bunch of them & wouldn't run anything else except for maybe a quadrajet.
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I currently only have Keihin's but will be trying a TMX soon. I think these two carbs bring up a debate much like a Holley vs a Carter/Edelbrock in the car world. I was always told to stay away from Holley in my car days & only ran Carter/Edelbrock but I ended up getting a Holley & now I have a bunch of them & wouldn't run anything else except for maybe a quadrajet.
If you do Kevin let me know I'm pretty sure I still have some smaller main jets in my toolbox you're welcome to try.
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I currently only have Keihin's but will be trying a TMX soon. I think these two carbs bring up a debate much like a Holley vs a Carter/Edelbrock in the car world. I was always told to stay away from Holley in my car days & only ran Carter/Edelbrock but I ended up getting a Holley & now I have a bunch of them & wouldn't run anything else except for maybe a quadrajet.
I think this is spot on.
I had Ski-Doo sleds that ran TMX's if I'm not mistaken and they never gave me any trouble. Granted, I never got into modding them the way I have with my R, so jetting changes were rarely needed. Mikuni has been around a long time, and for good reason. No hate for Mikunis here... :) I just have had very good results with my Keihins on my Hondas and never had a need to look elsewhere
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I have ran a 38 Keihin A/S on both my sons 250R and also on my 330R for quite a few years and have always been satisfied with that carb. Over the past couple of years a friend of mine suggested I try his Mikuni 38 TMX carb. Finally I decided to give it a try. It did take a little bit to get it dialed in but I found the TMX Mikuni did help with a better low end power with my particular setup. I ended up recently switching to the 2001 CR 250 Mikuni TMX and just love it. I have always taken notes on the jetting of both our quads with the Keihin for all 4 seasons of the year that we have here in Wisconsin. If you do decide on the Mikuni carb, the one to get according to Eddie Sanders is the 2001 CR 250 one directly from Honda. The part number for that carb is... 16100-KZ3-L12. It comes with a 420 main and a 35 pilot both of what were rich in my ESR 330. The needle 676BBH173 was spot on in the center clip position. Regardless of whether you choose the Keihin or the Mikuni take the time to keep notes on your jetting until it becomes second nature.
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38 mm Air stryker very good carb for top end dune riding but only issue with them is installing it so don't know if you want to tackle that small problem. 38MM is not a bolt on it will cause a bit of a headache at first, but you would have to mill intake bell don't have to but recommended leave intake boot out in sun to make plyable maybe buy a reed spacer + gaskets to get proper angle to fit carb.
Stock style Honda CR 500 PJ carb also good but not as good as air stryker but you may have same issues all apps differ. So it all depends what you want to do what issues you want to tackle and what you don't want too. Stock PJ carb very good but will not give you top performance of big HP as others but they are reliable and parts readily available.
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I have ran a 38 Keihin A/S on both my sons 250R and also on my 330R for quite a few years and have always been satisfied with that carb. Over the past couple of years a friend of mine suggested I try his Mikuni 38 TMX carb. Finally I decided to give it a try. It did take a little bit to get it dialed in but I found the TMX Mikuni did help with a better low end power with my particular setup. I ended up recently switching to the 2001 CR 250 Mikuni TMX and just love it. I have always taken notes on the jetting of both our quads with the Keihin for all 4 seasons of the year that we have here in Wisconsin. If you do decide on the Mikuni carb, the one to get according to Eddie Sanders is the 2001 CR 250 one directly from Honda. The part number for that carb is... 16100-KZ3-L12. It comes with a 420 main and a 35 pilot both of what were rich in my ESR 330. The needle 676BBH173 was spot on in the center clip position. Regardless of whether you choose the Keihin or the Mikuni take the time to keep notes on your jetting until it becomes second nature.
I remember seeing this version of the TMX on Eddie's website but I never could find it until now. It's different than the one you'll get from Niche Cycle Supply. Eddie doesn't have them listed on his website anymore. I wonder why? It looks like you can still get them from Honda for around $250.
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I have ran a 38 Keihin A/S on both my sons 250R and also on my 330R for quite a few years and have always been satisfied with that carb. Over the past couple of years a friend of mine suggested I try his Mikuni 38 TMX carb. Finally I decided to give it a try. It did take a little bit to get it dialed in but I found the TMX Mikuni did help with a better low end power with my particular setup. I ended up recently switching to the 2001 CR 250 Mikuni TMX and just love it. I have always taken notes on the jetting of both our quads with the Keihin for all 4 seasons of the year that we have here in Wisconsin. If you do decide on the Mikuni carb, the one to get according to Eddie Sanders is the 2001 CR 250 one directly from Honda. The part number for that carb is... 16100-KZ3-L12. It comes with a 420 main and a 35 pilot both of what were rich in my ESR 330. The needle 676BBH173 was spot on in the center clip position. Regardless of whether you choose the Keihin or the Mikuni take the time to keep notes on your jetting until it becomes second nature.
I remember seeing this version of the TMX on Eddie's website but I never could find it until now. It's different than the one you'll get from Niche Cycle Supply. Eddie doesn't have them listed on his website anymore. I wonder why? It looks like you can still get them from Honda for around $250.