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Showing results for tags 'jetting'.
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INTRO: Long time listener, first time caller. For the umpteen millionth time, here are questions about the "standard mods" for the DRZ400SM. I realize much of this has been covered over the years so thank you for indulging me, but it's hard to find quantifiable differences in fuel economy and air intake noise bw stock/post mod rather than just decreased mpg/increased air intake noise. I know, I know ... Smiles per gallon. I guess I'm trying to figure out if it's worth the extra stops to the pump in doing these mods (esp since I believe California tank capacity is 2.5 gal?). INFO: Most of my riding is in the canyons plus freeway to/from. As it's getting warmer, I'll probably start taking bike more recreationally as well, but not touring or any crazy distances. Since I have an exhaust on there, I plan to jet after 600mi break in service. Only other performance mods thus far are 39T in rear to help with freeway cruisin'. THE DEBATE/OPTIONS: (a) jet only (b) jet and pull snorkel (c) jet and full 3x3 mod. QUESTIONS: How much less fuel economy could I expect? How much louder is air intake? Is pulling snorkel going to make any difference without 3x3 mod? If 3x3 is done, is it also good to bypass/remove CA emissions stuff? -
Hello, I have a 1981 Honda XR250R. It hasn’t been running in a while and I am at much higher elevation now. I was wondering if anyone has a chart or something knowing what size jets to use. I live in utah at 5k feet. And will ride up to about 8k feet with this bike. Carb is fully stock (to my knowledge) Any help will be appreciated. Thanks
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Hey fellas, I recently picked up a 2010 klx110l that has seen a rougher life to say the least. Other than looking like it has been on its side 1000 times it starts and runs pretty well. I'm an old two stroke guy so these four stroke pitters are pretty new to me. I noticed right after I picked it up that it just doesn't like to be goosed from an idle. When you crank the throttle from an idle it bogs and almost dies. Upon further inspection I found that the gas in the tank was bad and after tearing the carb apart found a little bit of gunk in the bowl. I cleaned all of the jets and the carb body as good as I could and it still does the same thing. I am aware these bikes don't have an accelerator pump, but this much bog just doesn't seem normal. The bike is 100% stock and has fresh fluids and a fresh air filter. Any leads to the problem would be greatly appreciated.
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Okay im not sure if this is a problem or not but it kinda bothers me. I have a 2004 yz250. I had jetting problems with it but I believe I have fixed it (in a way) the stock main jet was 178 and pilot was a 50. Stock needle at 2 clip position. That jetting ran fine for 2 years at 500ft elevation. Earlier this month it seems to sputter and bog at high rpms ans not hit the powerband and it would bog just riding bumpy trails too and hitting hills it would bog BAD! I checked reeds ans they are fine. I repacked the silencer and I checked power valves for carbon build up ans they seemed fine and it all moved good ans smooth. So I bought a JD jetting kit and the pilot jet i have in now is a 45 and it called for the main jet to be 172 and red needle at 3rd position for my elevation. I took it to the trails and it still was bogging at high rpms and riding bumpy trails. So I changed the main jet to a 168 it had in the kit and the top end power was fine after that it hit the powerband and stuff but low end it wasn't great so I moved the clip position from the 3rd to the first at the top to lean it out and it seemed to help. It doesn't bog low end or anything but it seems the first 1/4 throttle it tends to bog just a tad. So my question is how can I fix that little bog and is my jetting okay for what elevation im at? Is it too lean?? It seems to me some other people run their main jet at 172 for 500 ft elevation. Thank you for reading and your responses! I'll be sure to check here every now and then to get the problem fixed.
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Hi there, I have a 2002 Cr250 with a brand new top end. Running 91, 44:1 golden Spectro, 400 main, 30 pilot with a aftermarket pipe and silencer (Buds Hgs racing. The bike has perfect throttle response and runs strong. Brand new spark plug aswell. When I try to rev 1st and 2nd gear out it sputters really bad and has 0 to little power in 1st and 2nd. When I shift up into 3rd and above the thing takes off like a rocket ship. The air fuel mixture screw is 2 turns out. I’m not sure what to do. Any help/suggestions would be highly appreciated. Thanks in advance.
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Hey everyone, sorry if someone has answered these questions already I just couldn’t find them I have a 2014 125sx and ever since I replaced my main jet and pilot jet with a new pair of the same size I have encountered 3 issues since doing this. 1) My bike has started started bogging at full revs which it hasn’t done before changing jets. 2) Fuel usage has risen a lot more than normal. 3) There isn’t as much spooge as before, if at all. I am riding same location with same conditions and I don’t know why it would be behaving like this. Any help would be great.
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Crf450X Backfiring, unknown modifications and mild starting issues
Liam Lefevre posted a topic in CRF450X
I just bought a 2005 CRF450X because I heard they never die. It had been sitting in an old police chiefs garage and it was his sons. It runs alright for the most part and has plenty of power but as I was riding it today I noticed some backfiring on deceleration. It has a full pro circuit titanium exhaust and in the box of spare parts I got I found an empty JD jetting kit for a 40mm FCR whatever that means and the airbox has been cut out as well. Just wondering if any of that is normal for a bike with those kind of mods. Thanks to anyone who responds! on a side note I want to put a K&N air filter in it as well. Any advice on that would be appreciated too. -
I need to do a tune-up/re-jet my carb for the elevation here in Rio Rancho. it runs ok but runs better with the choke on and higher rpms. has slight backfire when decel and a bogg when burping the gas. Id rather have someone knowledgeable to assist rather than try on my own.
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Okay... so I have replaced my top end before on my 04 yz250 just to make things clear. I changed it last year around july, and I rode it a crap ton during that summer on trails and in some open fields and some every now and then during the winter. 40:1 with P97 using amsoil dominator 2 stroke oil is what I used everytime. Well one day this year back in March I got on it and it it just wasn't right. Itd sputter before the powerband kicked it, i had a lot of spooge coming from under the pipe on the motor and going up hills seemed impossible because it wouldn't have any power because it was too busy sputtering. So I checked the reeds and they're good and I changed the air filter and it was good but it still wasn't right. Then I figured it was jetting. So I had the stock jetting that was in it that had been in there for 2 years and ran great, MJ 178, PJ50, need position 2nd from the top. So I experimented and got the jd jetting kit and it said to use a 175 jet but it was too rich with that and would sputter top end so I have the jets at MJ 168, PJ 45, and red needle at the 1st position but is still choppy on the low end about 1/8 - 1/2 then it'll kick in good. So I have read that worn rings on the piston can cause for rich jetting and having jetted it pretty lean to run better and still not perfect I went ahead and bought new gaskets and a wiseco piston for it so see if it'll run better. But my question is, when I change it should I change all the jets and needle position back to stock? Or should I use the JD jetting chart and go by from what that says? Thank you guys so much. If you have any tips let me know please
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So, bought a stripped down bike (07 YZ250F) and the carby was already apart. (They lost interest apparently) can anyone tell me the part that is circled and what it’s for as it looks blocked off intentionally to me. it does not have a thread and pushes in and out. The parts breakdown I can find online don’t have this section apart so I’m thinking it’s been disassembled a bit too far? i bought a rebuild kit online for the specific bike I have and this part isn’t contained in the kit.
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Hey guys i recently acquired a 2012 Yahama yz250f and i will need to be re-jetting the carburetor. I'm not really sure where to start on what size jets i will need. I ride between 7,000 and 10,000 feet in elevation. -
To those of you who ride both during summer and winter, how often and which jets do you have to adjust? Let's say you get the jetting bang on during the summer at 30 degrees. How much of a temperature difference is enough to make you re-jet? And if there's a big change in temperature (let's say you want to ride at 0 degrees during the winter, same altitude), which jets do you change? Is it enough to just change the main jet and adjust the air screw, or do you change the main jet, pilot jet and the needle (or the position)? I want to hear from those who have personal experience, concrete examples with jet sizes would be nice. I've read many tutorials on jetting, but most of them just tell you how to adjust the jetting right now, not the things I mentioned.
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So I have an 07 cr 125 fouling plugs before the bike even has a chance to warm up, plugs come out wet and oily on the tip. had both crank seals replaced last season because my main drive side seal blew. While it was split I had a new crank put in, we noticed my cylinder plating was pooched so I sent my cylinder off to be re-plated, put a new piston in the shiny new looking cylinder put the old warped head back on and called it a day. then rode it all season having absolutely no idea about the warped head because I overlooked it when I was excited to put my bike back together and ride. Its now winter, snows on the ground. I recently went to go for a put and fouled a plug before I could get to the end of the street and back. I was also smelling coolant so checked the rad while running the bike, lots of movement and tiny bubbes. Pulled the head off and sure enough it was warped to the point where I could rock it back amd fourth on the mirror and see a small gap... so NOW after I replaced the head my problems persisted and I can still see little bubbles swirling around vigorously in the rad if I rev it with the cap off, I've had boiled it down to my cylinder probably being warped then I found a leaky hose by the exhaust that was dripping coolant onto the outside of the exhaust port. Which brings me to what I think may be an incredibly stupid question, could it just be the loose hose sucking in air that is causing my rad fluid to have small bubbles in it? And maybe im just experiencing increadibly rich jetting now that my head is actually sealed properly? over and out. -
I'm tearing down my '06 CRF250X for winter prep. I checked the spark plug (see pics). I've rode with this plug for most of the summer. I'm thinking it's a bit rich, so for the other 250X owners out there, what jetting are you running/what do you think I should run? The only mods I've done is install the JD Jet Kit (165 main, 42 pilot, Red needle 4th clip, and thick o-ring), FMF Q4, and 4" x 4" hole in air box (with No Toil Super Flo Kit). The bike seems to run alright, but should I drop a few on the main jet?
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I have a 2004 Yamaha WR250F that the previous owner modified and the bike doesn’t run the way it should. It has an FMF muffler with an aftermarket pipe coming from the engine. There’s no other silencers or restrictions in the exhaust. When I got the bike, it was backfiring every time I let off the throttle no matter what speed I was doing. When the previous owner first started the bike, part of the exhaust pipe was cherry red while he was warming it up by giving it more throttle. I took the carburetor apart and found out that I have a 178 main jet, 40 pilot jet, and 72 leak jet. The needle clip was in the middle in the 4th position. I adjusted the fuel screw back to the 1.5 turns out position from the 3.5 turns out position the previous owner had it set at. I changed out the pilot jet to a 45 and the bike no longer backfires while I ride it but it does die when I leave it to idle. Sometimes it dies immediately after letting off the throttle and other times it will idle for a minute or two before dying. Now before this gets too confusing, I ran the bike with the fuel screw at 1.5 turns out and 3.5 turns out after changing the pilot jet. At 1.5 turns out, the bike would only run when choked and would die when idling. At 3.5 turns out, the bike will run with the choke off but will still die when idling. If anyone has any suggestions to try, please let me know.
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Have a johnny cash bike (stole it one piece at time...didnt cost me a dime...) apparently. Main frame and motor are 06, subframe was an 05, replaced it with an 06 so my exh midpipe would have something to bolt to. My idle has been really funky lately with the heat (100+ days) so I built a heat shield to keep the carb cooler. On tight trails it hunts for an idle and that gets kinda nerve racking with bike constantly lurching, sure wears my clutch hand out quick. Pulled my air filter out to clean it and it had separated at the seam...whoopsies. So bought a new air filter and its still running funky at idle. Pulled the carb last night, figured the idle air jet may have garbage in it since its right there by the intake boot. Nope, its clean. So pulled the bowl since I didn't have a clue what pilot jet and MJ was in it. I know it has the factory needle and in the 4th slot. Was in the 3rd but I dropped it(the clip, not needle) one position to fatten it up and have it run a little richer (cooler). Well the main jet and the PJ are way too big based on the 06 manual. So for grins I got out my dial caliper and measured the bore on the head side and bam...its 41mm FCR carb. Supposed to have a 40mm on it. So downloaded the 08 manual and realized that the MJ is right on point for the 41mm carb. 178 but the idle jet is a 68! the manual says 42 is right, and from what Ive read everyone goes to a 45. So since this is a 41mm should I go with the 45 or maybe a 48? Not sure if the bore will matter since the slide will be closed most of the way anyways at idle.
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I recently purchased a brand new 2015 CRF250X. Since purchasing I installed the JD jet kit, and completed the air box mod. I live and ride in Kentucky, between 800 - 1200 feet above sea level, with the temperatures ranging from upper 70's to high 90's. I followed the JD jetting instructions and replaced the stock main jet with a 158 main, the pilot jet was changed with the 42 that came in the kit, and I replaced the stock needle with the red needle, with the clip in the fifth position from the top. I also removed the stock air mixture screw and replaced it with a R & D racing flex jet fuel screw backed out 1 3/4 to 2 turns. The bike has completely stock exhaust, with the OEM air filter. The bike seems to run alright, but there are a few things that I have some questions on. Before doing the mods to the bike you could pull the hot start lever all the way in and the bike would die. But now since doing the mods the bike will idle faster once the hot start lever is pulled in all the way. The same thing happens with the choke lever. Once the bike is good and warm if you pull the choke out the bike at first doesn't really do anything, but once you give it some throttle it will idle faster. The bike now has a backfire problem, which I never noticed before I did the mods. The backfire isn't necessarily a high pitched loud popping sound, but more of a low sound, almost like a large amount of air is being forced out. I've noticed the backfiring mainly happens when decelerating, or when dropping gears too quickly. My 250X does have the smog equipment attached. If I stall the bike while out riding it seems to be very hard to start, and most times I have to pull in the hot start lever to get the bike started. Before the mods I never used the hot start after I stalled the bike. As I try to restart the bike back it makes the same backfire noise like it does when I am out riding. The idle speed seems to not stay consistent. I'll warm the bike up and check the Works Connection hour meter and it will be reading around 1800-1900 RPM. Once I've been riding for some time, and come to a stop, the RPM meter will be reading more in the 1700 range. The RPMs at idle don't stay constant, I find myself adjusting the idle screw a few times while out riding. I am also having the problem of the bike randomly stalling. For example, I could come to a stop with the clutch engaged, sit still for a few seconds, and when I give the bike a little rev it will stall and die. The throttle doesn't even come open when it stalls, I just barely give it a turn and it will die. Like stated before, when this happens the bike is hard to start back, and backfires when trying to be started. I have tried playing around with the fuel mixture screw, but nothing seems to correct the problems I am experiencing. The bike seems to run fine other than the stalling and backfiring. I am not sure if changing jet sizes or clip position would correct the problems I am having. I have tried researching these topics, but nothing seems to be like what I am experiencing. Any advice would be greatly appreciated.
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I rode around a bit reving it out then made a final hard pass before i removed it.
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Ok, so I have had my DRZ for over 16 years now but for the last 2 years its been hell keeping it alive. I think its the carb.. but not totally for sure. I have rebuilt it three times in the last 2 years and keep finding junk in my bowl and jets. I have cleaned the tank, put in fuel filters and fuel lines.. I dont know if its coincidental but after getting my new tank from IMS its been down.. I asked them if the tank needed to be cleaned out prior but never got an answer. Its weird tho, each time I rebuild it I have to replace the pilot jet and the float valve and seat. It seems like it runs like new for one day.. but then its back to crap and not idling again. Just pops and dies.. then my pipe is glowing red hot.. I am about to give up on this thing. I purchased it in 2001 right from the dealer it had Calif License Plates and street legal. Love the bike when its running. So I have people telling me its my carb still.. I just took it out the other day blew it out with carb cleaner removed the jets and made sure all looks good. The carb is not leaking fuel so the float valve and seat are still good. I am thinking about buying a refurbished/rebuilt carb for 525$ is the best deal I have found.. But dang.. if that is not it I am really beating myself up good. Then someone from Kiehn said it was my Mid gaskets.. I am just really frustrated. If the replacement carb works I am going to tear this one down and replace the mid gaskets and go from there and test it.. if its good. then it will go on ebay and try to recoup my money back.. What do you all think? 2 years now if pulling that thing off and on and 3 full rebuilds.. Also I found this link on "How to DRZ400.." it shows a flat side like mine going on an SM model to swap out the mikuni carb.. I noticed one of the pics (see attached) shows to remove the Pilot air jet on the intake side of the carb.. why is that? Why do I still have mine(which I replaced every jet on the carb just back in November again). Also included is a link to it running and what it does, even with choke on its not as smooth as it used to be, DRZ Running Thanks in advance for any input.
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Just bought a 2 stroke, 1982 IT175, and it runs good but sprays out spooge from the silencer, and dribbles it out at the header where it bolts to cylinder. Bike runs good but may be a bit sluggish at low rpms. Not the the point where it bogs. just a little sluggish. From research it seems like it may be running rich. Wondering what I should try. Raise the clip of try a smaller jet? Running 32:1 right now. Any help is appreciated!
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Whats the jetting for 2000ft elevation on a stock 2008 yz450f main and pilot to start with ? On my sidecar it has a custom pipe and exhaust
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Hello all! New to TT and the dirtbiking world. Just recently purchased a 2014 klx250s at altitude (5000 feet). I almost immediately moved down to 2200 feet in the desert. I don't know what pilot and main jets are currently installed but I can assume it needs to change as the bike is probably running really lean. If anyone has recommendations for what jets to use and other settings to change before I start taking things apart would be gladly appreciated! I don't have a very permanent garage situation so every tune up/part replacement I do I try to make a one day job. I brought the bike with a FMF Q4 Muffler and Power Bomb Header Pipe. Thanks!
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Trying to get some opinions on the 2017 Husqvarna tc250 jetting. I have 2.5hrs on the bike and 2 fouled plugs. Since switching from a yz250 and various 4t's, I have realized that my carburetor knowledge and setup is not what I thought it was. I'm currently at stock jetting and needle settings. If you have suggestions for jetting, air screw positions, idle screw from factory, etc. Please let me know!
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Hey guys I've got a 2009 CRF450X with a RS-2 Yoshimura full system on it. I've had it for 2 and a half years now and its great, but since I put the Yoshimura on 8 months ago, it has not stopped backfiring on deceleration. I've played with the fuel screw both ways, and when I finally pulled my plug the last time I had my bike apart I saw white, so I turned the fuel screw out to give it more fuel. Didn't work. Actually seemed to make it worse. I'm beginning to suspect that I'm barking up the wrong tree, that there might be something else going on besides just jetting. The guy who owned it before me put a JD Jetting kit in there with a 165 Main jet with the red needle in the 4th position from the top. Maybe I'm overlooking something or maybe it something deeper. Help me Thumper Talk! -Kennedy p.s. I just had my valves adjusted about a month and a half ago
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Hey All, I have a question about needle taper and how it affects fueling? 2003 DRZ400S (E model FCR39, 3x3, E Header with fiber wrap, Stock S muffler with endcap mod, and stock S cams). JD JEtting stage 2 Kit for DRZ E model, not for the S model with FCR Current Carb Settings: -155 main -Blue needle 2nd clip from top (DRZ E taper profile) -Coast enrichener removed -everything else stock E Carb settings (including slow jets, and air jets) -idle screw = 2 1/8 turns out (and idles perfect) I ordered the EMN needle as per suggestions from other TTers My Question: I was just wondering what the EMN needle would do to my AFR graph? The taper chart doesn't make sense to me. If you see the attached image, my AFR seems to be rich at 1/4 and 4/4. I believe the EMN needle will flatten/richen out my mid range. So, to compensate I also bought a 150 main. Is this a correct assumption? PS. Is the first rich state the AP effects? I know it's too rich because it's not a punchy as a pumper should be. I'm saving up for a leak jet kit/power bowl/AP cover, but was just wonder what effects to look for when I start tuning more in the next few months as funds become available? Thanks! Note: Blue is first run with needle clip in 4th from top. Red is 5th run with needle 2nd from top to lean it out. Note:
