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Found 12 results

  1. Okay. I'm stumped. I have a 2017 ktm 250 xc-w. Bought it a year ago, second hand, and the jetting with the Mikuni has never been spot on. I finally decided to figure it out, and came across many posts claiming that the old Keihin model is much less finicky than the new Mikuni. Lo and behold, a kid near me was parting out his 2010 ktm, with a 36mm Keihin, so I snatched it up. I cleaned the carb the other day, and today I installed it. Full disclosure, it came with a 160 main, and I drilled it equivalent to a 172. I know, I know, drilling jets is considered a felony, but it's the only way I could test it then and there. The bike seemed to idle very rich at first (White smoke though. I have other reasons to believe I'm burning coolant, but that's a story for another time. Ran like that for a while.) It smoked a ton, and had a large burble if the throttle was snapped from idle. I took it for a little ride around the yard, through two or three gears, and when I parked the idle seemed MUCH better. Still a tiny lag, but nothing real unusual. Seemed to run better than the Mikuni already. I played with the airscrew for a bit, and found a nice responsive spot, maybe 2 turns out, but then all of a sudden the idle started to get faster and faster (kind of like a lean hanging idle). I killed the bike, started it again, and it did the same thing. Now it won't start at all. Just turns over and never fires. Figured maybe clogged pilot jet. I pulled the carb back off, and the pilot and main jets both look free of debris. I have fairly fresh gas in the tank, and my plug has never given me issues. Bike always ran rich, so it was a bit fouled, but I cleaned it up during the carb swap. I can't think of any other important details, but does anyone have any clue what the heck could be going on? Thanks! Jetting @ 2,000ft: Keihin pwk 36mm 40 pilot 172 main n1ei needle, 3rd clip 7.0mm float height Airscrew ~2 turns out
  2. The purpose of this post is to review the STIC Metering Block for Keihin PWK carburetors, particularly in the application of my 2017 Husqvarna TX300. BLUF: If you don't want to read the long of it, all you need to know is the STIC metering block is 100% legit. It does exactly what it claims to do. I can tell you with 100% certainly that there is not a single pipe, head, reed cage, or any other type of engine mod out there that can increase power like the STIC does, especially at the price of $295. For the record, nobody gave me one of these to test for free. I paid out of pocket for it. I am not affiliated with the inventor, George Boswell, or any of the dealers of this product. Background: In general, the TX300 is one of, if not THE best bike I have ever owned (and I have owned many). Even with the Mikuni woes, this is a very good bike out of the box for a multitude of applications. I use mine primarily in the high-desert of New Mexico, but also use it in the mountains from time to time, and it handles both with ease. I have an insatiable urge to tinker and make things better, even when they are already very good. To that end, I have thrown the book at this bike in terms of modifications. Every single modification I have made to this bike has made the bike a bit better, with the exception of the Lectron carburetor. For the purposes of this thread, we'll just discuss the carburetor mods. The JD jetting kit for the Mikuni worked well, but, given my nature, I decided to try the Lectron. In the words of my friend, it "makes old man power". He was right. I hated the characteristics the Lectron brought, so I sold it after two rides on it and bought a Keihin 38mm PWK short body from JD, with his jetting kit. Night and day better. It was crisper everywhere and just ran better in general. I landed on a 38 pilot, JD Red Clip 3, 170 main, 1.5 AS for my conditions (5200', 75 degrees at the time). Again, being that I can't leave well enough alone, I decided to give the STIC a try. I purchased it from Derek at HP Race Development originally. It came with a .115 needle jet. I gave it a shot and couldn't get the bike to run right. It would load up really bad off the bottom, then clean out and hit really hard in the midrange, then flatten out up top. I ended up contacting the inventor, George Boswell, directly about the issues I was having and that I needed a smaller needle jet. Mr. Boswell contacted me within an hour of my email and explained to me the interworkings of the STIC system. He sent me, on good faith, an entire new STIC with the correct .114 needle jet, a 50 pilot and a 182 main jet installed, and only asked that I return the one I originally bought from Derek to him when I received the new one. Unbelievable customer service, and my hat is off to him. I installed the STIC into my Keihin with the supplied jets and went out for a test run after work. Atmospherics and initial settings were as follows: 5200'/90 degrees F 50 Pilot JD 2 Scribe Red Needle, Clip 3 182 main 3.5 AS Right off the bat, it was abundantly clear that the bike was making more power everywhere. It ran MUCH cleaner with the .114 needle jet installed. The best way I can describe the power the TX is putting down with the STIC installed is that it has the bottom and midrange of a 300 on crack, and a top end that pulls like a 250 on crack, and it revs out much further where before, it would flatten out on the top end. It seems to just keep pulling and pulling. The only spot that felt like it might be running a bit rich was on the main, and I figured I might as well try one step smaller on the pilot as well. To be clear, even with overly rich settings, it still ran really well. I installed a 48 pilot and a 180 main, and left the other settings the same. The bike ran cleaner on the main, but didn't seem to want to pull as hard (however, slightly) as it did before. I reinstalled the 50 pilot and kept the 180 main and everything felt perfect. The spot I rode today is full of deep, power robbing sand, big whoops and very steep sandhills. I found the steepest, sandiest hill out there and made a go at it with little to no running start at it. Not only did the bike make it, but it accelerated the whole way up and I was actually able to upshift and continue accelerating. I wouldn't have made it previously, without the STIC installed. I couldn't believe it, honestly. I will be doing more testing with this system, but again, I am more than impressed and I can say with full confidence that its legit. I need to start saving money for rear tires 🙂 More to follow.
  3. Hey Guys, I hope somebody can help. I have a 2003 DRZ 400E with a Keihin FCR39 carb. The bike starts easy, idles well and pulls nicely. It really runs well, but it dies instantly at WOT. Doesn't matter when or how fast I am going. If I open the throttle all the way the engine dies. If I am riding and close the throttle a bit, then she fires up again and i can keep going. I'd say she has full power and pull all the way up to 95% just that last bit is missing.
  4. So I had an overflow issue on my 03 CR250R. I only had the bike for a few months. I haven't been on a dirt bike for years (I primarily rode street). So I'm no where near to know jetting just by the feel and sound of the bike. I had some grit in the bowl, so I cleaned everything including the jets. This is the first I had them out. The pilot is 55 and the main is 170 From what I've been reading the pilot seems rich and the main lean. The bike seems to load up at lower rpms, but clears out almost instantly when hitting the powerband. Any help with what I should run would be greatly appreciated I mostly ride woods. It's a little technical, but has some open spots I usually ride in 2nd close or in the powerband. There's only a few spots where I can really wind it out in 5th I recently had the top end plated and honed and I have about 5 hours on it The bike has : Vforce3 reeds Platinum 2 and r304 shorty I've been running REC 90 and adding VP octane boost to get 94octane. klotz R50 32:1 My elevation is between 1000-2250ft
  5. My girlfriend and I have been rebuilding this one bit by bit. Backstory: We got the bike last summer as a project. It belonged to a motocrosser who didn't have time for it any more and let it sit for a while. We took the carb completely apart and soaked all the metal parts in cleaning solution. Pretty much everything metal in there was gooped up and everything rubber was brittle and flaking. All the parts that could be scrubbed out were- no metal was used to scrape the inside of metal, so that's not going to be an issue. We put a Motion Pro rebuild kit in to replace all the nasty bits, and that part is going okay. I had to order a new accelerator pump diaphragm, because that was completely toast. Two questions- 1.) The flat slide no longer slides cleanly through the carb body. The vacuum plate doesn't sit flush any more. The rubber o-ring on the roller plate looks okay, but the vacuum plate also has an o-ring on it. I didn't know about that when I put the plate in the cleaning solution. Is there a way to get a new o-ring for the plate, or do I need to order a new one? I'm hoping not to spend $100 on a new part if I don't have to. https://www.ebay.com/itm/Vacuum-release-plate-seal-Keihin-FCR-MX-flatslide-carburetor-37-39-40-41-NEW/191533918039?epid=16002473425&hash=item2c984fa757:g:gUgAAOSwq~tZQ8L1 This looks like it should work. 2.) I had to remove the throttle position sensor. Apparently, that's not something you should do because it's synced. https://www.dirtrider.com/features/protips/141_0707_keihin_fcr_carb_rebuild#page-45 There wasn't much I could do to avoid that- I didn't want to dunk the TPS in the cleaner, and the whole carb was gummed up with so much nasty stuff that a toothbrush and Simple Green weren't going to cut it. Is this something I'm going to have to take to a shop to have them redo? Is there anything else I should know, or any other useful rebuild tips? Thanks!
  6. I have a Keihin Pwk carb on my 03 Cr250. I want to get some new jets for it but want to make sure I get the right ones. And I looked up the model number on the side of the carb but can't find anything. S66A2 HGJ. I saw somebody with S66A2 PWH. So I wasn't sure if that would be the same or not. Anybody have any info on this?
  7. I have an 06 KX250 with a Keihin. When working on cleaning the carb this last time, it occurred to me that I have no idea what the TPS and Solenoid must do and when. I don't think the TPS effects timing, but I'm not sure. I've always had fouling problems without warning up the bike. If I do a long warm-up, it still needs "cleaned out" with WOT under load for a bit. I think deleting the solenoid circuit might help, but I want to understand the Why behind it all. ?
  8. Hey everyone, I have a slightly modded CRF230F with a Pro Circuit T4 exhaust, uncorked airbox with 45p, 03-05 needle @4th clip, and a 120main, a ProCom CDI box, and a Twin Air filter. I am looking to bore out the stock 26mm carburetor to 28mm so I can get more top end while keeping most of the low end I have. Would this be a good idea?
  9. I've been looking all over the web for information on the midbody of my keihin FCR MX39 carburetor, but I can't find much information. I've seen rebuild kits, but I cannot find a diagram. I'm not sure that I need to rebuild the midbody but my carb is roughly 20 years old, and I think I my have damaged it when I cleaned it. I recently cleaned it bye following instructions I found online and in my Yamaha survice manual (the carb is in an 03 YZ450F). I took apart the carb, the jets, the float, the slide, the excelerator pump, everything rubber that could be damaged bye carb cleaner, and I soaked it over night. I had no Idea that the midbody had gaskets that could be damaged bye this process though. Has anyone rebuilt the midbody on keihin fcr or have a diagram that they could post. I don't want to tare into it without knowing what I'm doing first.
  10. So my 09 KX250F had started to bog when I open the throttle really quickly so I thought I needed to clean the carb so I did. Put it back together and it still does it. So now I replaced every jet in it inspected the AP diaphragm and adjusted AP and it's still doing it. Everything seems to be fine. I'm in NE Ohio elevation is 0-1500 ft about 60 degrees right now. My jetting specs are Main - 180 Pilot - 42 Needle - NHJT Clip Position - 4th from top Fuel screw - 2 turns out If anyone could PLEASE help me this is mind boggling to me. Thank you Enclosed is a video to what it does. https://youtu.be/dxkedcr2iMg
  11. Carb question for y'all. Have an '06 Husaberg 450fe with a Keihin MX FCR 39 TPS. Got it back from the shop after an engine rebuild, and it won't run reliably and is near impossible to start. I pulled the carb and the spring on the needle was hammered, bent and completely smashed. Could it be the reason the bike won't run? I tried to straighten it and stretch it but don't want to put it back together if it needs replaced. See pics. It still has spring but I have no idea how long it should be. It has a Taffmeisters carb kit. FYI, it's not going back to that shop. Any info would help. Thx.
  12. I have been chasing a stumble off idle for a while , and it’s beating me at the moment . I have owned my DRZ400e with the stock fcr39 slant body for about 7 years . I have 160 main jet , 40 pilot and a red JD needle middle clip position . A flex jet fuel screw 1 turn out at present . It used to run fine without any problems with richer settings .Over the past couple of years fuel consumption has got worse ( was always around 20kms per litre now can be 15/16 kms per litre ) The bike runs great on the open road and returns reasonable fuel consumption and performance . The problems arise when I’m riding single track and riding slowly ( yes I’m old and fairly slow )less than a quarter throttle , closing it fully often and then back on the throttle it stumbles like it has a very rich mixture or it’s flooded . In fact if it stalls it requires an open throttle like it’s flooded to get it going again . ( I have fitted a new float needle and seat and checked the float height ) . In these conditions this is when the fuel consumption gets dramatically worse . And the bike becomes very hard to ride as it stumbles and misses . I’m convinced it’s a fuel thing as my fuel consumption changes so dramatically. Once upon a time the bike ran great on a 45 pj 2 3/4 turns out on the fuel screw , I am now running a 40 and it still seems rich with only one turn out on the fuel screw . So my question is can a worn coast enrichener cause an overly rich mixture off idle after the throttle has been closed ?
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