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Showing results for tags 'valve'.
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So i adjusted the valves on my dirtbike, it starts good, idles good but when i give it throttle and hold it on neutral its backfiring a lot. Could the valves be a problem or maybe carb ?
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HI, I am new, looked on this forum but did not see a definite answer, I have a zongshen Bull 250 and one day I was riding and suddenly the bike lost all power and now will not rev more than half of max rpm, it acts like it has a rev limiter so low, and it pops and maybe smokes little black, i replaced the carb so it is not an issue there and then noticed after a day that it has low compression on the kickstarter and there is a sound in the air filter/box when i kick it over so i figured maybe a cam chain skipped a tooth and now the timing is off and intake is maybe open slightly so i am trying to adjust the valves but I cannot find the T mark, there are random letters like SM, and then there are 2 lines that match up with the marking on the crank case but no letter T for Top dead center. How are the markings on the cam sprocket supposed to sit relative to the T mark for Top dead center? .. I don"t know anymore where to start and what to do, can someone guide me through valve adjustment and what the clearences should be? I think the engine is CB250, it is air cooled and it is SOHC. THANK YOU! -
hey guys. got a 04 ttr 225 here and alot of ticking in the head. went to adjust valves and intake checked out ok. exhaust on the other had is messed up. the little adjuster bolt thing with a square head wont thread in the rocker arm any more. it threads so far untill it just starts to stick out the bottom of the rocker then stops like it wont go any farther. almost like stripped or wrong bolt or something. very frustrating. it will run but with the most god awful head noise in the world!
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Hey guys - I have a bud with a XR200 that is having some engine noise that he cannot identify. I'm posting the vid for him in hopes that the forum braintrust can help get the right diagnosis. Notes: He has adjusted the valves and the cam chain tensioner. I have asked him to confirm that oil is getting to the top of the valve head. Hopefully he can reply to this thread with more information. @XRepublic Appreciate any and all input :-)
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All, I'm new to the forum but I've been reading quite a bit. I've got a new to me Suzuki DRZ400e with a no start problem. I've never had it running so I have no baseline for what normal is for this particular bike but it looks great. It will turn over but not fire. I do have a good solid spark and I recently rebuilt the carb. I wouldn't be surprised at all if I screwed up during the carb rebuild and that's the source of my issues, however I do have a few questions. For the carb rebuild, I installed all stock jets with all stock settings and I felt pretty good about the rebuilt. Not my first carb rebuild but certainly the most complicated. Through all my attempts to start the bike, the spark plug has remained dry. I tried starting fluid tonight and all it did was pop and backfire out of the carb and start a small blue fire. It did not come close to starting. I also checked my valve clearances and I'm getting some out of spec readings. I was expecting between .10mm-.20mm on the intake and between .20-.30mm on exhaust. What I found was my exhaust valves were in spec but I was getting a max of .457 and .406 on the intake clearances. 1) First question - the pop and backfire out the carb. Is that indicative of bad timing, bad valves, a stuck valve....or what? 2) Regarding the Keihin FCR 39 carb -The airbox and filter are removed and I'm looking down the air intake of the carb. When I rotate the throttle, I don't see any squirt of fuel at all when I attempt to start it. Should I be able to see a mist of fuel spray down the carb throat when I turn the throttle? 3) Regarding valve clearances, could a max of .457 and .406 on the intake clearances cause a no start condition and could it cause the pop and backfire? 4) Even with those valve clearance specs should the bike have started if the carb was ok? 5) Lastly, my cam sprockets are off a bit. I read they were each supposed to be "straight up" but I don't know how specific that should be. On the left sprocket, the number 3 is more at the 11 o'clock than straight up and down. The right sprocket with the number 2 is perfectly centered straight up. In looking at the lobes, I read they should be at 10 and 2. The exhaust is at 10 but the intake seems to be at 3. Seems consistent with the sprocket being slightly counter clockwise. Help please!
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Hey all, just got a DRZ-400 yesterday and absolutely love it. Today I took it out for a ride and when I got back I noticed the tire was leaking from the valve. I looked on the other posts here about leaking valve stems but all of their leaks are coming from the top. The leak on mine is coming from where the stem meets the rim right under the nut. Can I put sealant there to patch the leak? Or what can I do to fix it? Thanks!
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Hi All, Putting together a WR450 with my son as a project. Even after removing one of the shims we get a zero clearance on one of the valves. Any suggestions as to what to do next? Cheers
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I have a project XR100 I've had for a while and never got around to working on, but here I am now. I rode it for about an hour and noticed it was running too rich up top and too lean down low and would also shut off when it got hot. So, I changed the jets from a 38 pilot and 105 main to a 40 pilot and 100 main. Runs great when cold/warm, but still dies when hot. VALVE CLEARANCES duh!!!! In short, after rejetting this bike a few times to get the perfect mixture with my valves out of wack (did not know at the time), will I end up rejetting again once the valves are set to spec or should my new tune still be fine despite the change in valve clearance? Adjusting the valves this afternoon, and just want to be ready to take the carb back off if this ends up being a necessary concern.
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Does anyone know how I can get this cap off of my 2007 KX250F? It’s the bigger one that allows you to access the crank in order to put the engine at TDC and whatnot for setting the timing and stuff. I cannot for the life of me get it to break loose. I’ve tried drilling holes and using a punch and various tools to hammer it loose and it hasn’t worked at all. Not sure what to do at this point.
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Crf100 with a BBR 120 kit, web cam 68/69 cam, Keihin 24mm carb that I’ve been running it successfully for a few years now. It has been amazing. I made some recent upgrades. The main two that might lend some help answering the questions are lightened fly wheel and I port and polished the head. I have built many motors and this one was flawlessly put back together twice since the noise. There is zero valve tap, no bent valves, cam lobes are perfect, springs are perfect, timing is spot on, there’s a ton of compression, no dents in the top of piston from possible valve, and valves are lashed perfectly. Any help would be greatly appreciated.
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I've got a 1972 Honda xl250 with low compression (75 psi, should be 180-220 psi). When it starts after many kicks, it seems to run fairly well. I think the low compression is valve-related, because after a teaspoon of oil in the spark plug hole, compression reading came back the same, 75 psi. I think I'll buy 4 new valves, and once inside the cylinder head, i know I should check the valve guides. How exactly do I do that? Should I replace all valve hardware too, like springs, or check everything first? What else should I look for regarding the compression issue? If i wait until the winter to tear it down and replace the valves, is there any risk of damage from occassionally riding it around now, as is? Thanks for the help.
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First part. I know I screwed up but I need to know how bad. I snapped the intake camshaft journal holder. I applied uneven pressure when tightening the cover. I want to see my options on fixing it. Can I weld it back? If I can't I would have to buy a whole new cylinder head for this one part. Second part. Is this gouge going to be an issue for the c-ring? 2005 Suzuki RMZ250
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Hey guys! Im gonna start out with posting all the information i think is needed for you guys to help me with this problem! Stock engine 2007 crf250r. Valve clearances are good and have JUST been shimmed with a double and triple check. Jetting is 175 main, stock needle position, 45 pilot and 50 leak jet. 1000ft above sea level. Im still having a terrible time starting and it used to be a 1 kick bike. I haven't changed my kick routine at all. 3 slow kicks, 3 throttle twist and then kick. Will sometimes start if i give it some gas when kicking. And then it starts 1-4 kicks after its warm. Im lost and dont know what else to look for. Thanks! -
This has been an ongoing issue, as I am sure some of you are beginning to notice.. sorry for the somewhat repetitive posts in advance. My valves were out of spec, I was only getting 85-90 PSI of compression. I shimmed my valves to the correct clearance, and I got the compression up to 150 psi. Now after riding my bike for 15-20 minutes, it will start doing the same thing it did before - it will idle super low and eventually bog out. I had the idle adjustment turned up very high, when I gave it a little throttle the idle would kick up for a couple seconds, then it would settle back down to extremely low and bog out. To me this sounds like something with the idle air circ, or jetting. Could something with the valves cause this as well? Want to get a second opinion before I send the head in for the $500 rebuild and still have the same issue. Thank you all again!
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Hi All, this is my first time here. I just acquired the above mentioned motorcycle. According to the factory service manual, the valves are way out of adjustment. So, I’m moving ahead to adjust them. Here’s the problem: manual says to remove cam covers, then remove valve lifters and pads. How do you remove the lifters? They look like little pistons down inside a cylinder bore. Any suggestions or methods that have worked for you? Thank you for helping!
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Hi just wondering if anyone could tell me what the valve clearance specs for a 2011 honda crf250r are? I have the service manual but I am still unsure what the clearance spec is. Any help would be great, Cheers
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I have a 2001 rm125 Is my power valve activation rod supposed to have any play in it? I can move it about .5 cm until it’s tight against the power valve spring and actually moves the power valves. It looks like maybe I can just tighten the bolt shown that is on top of the spring.
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Hello, Quick question about valve clearance on my newly purchased '00 XRR. The previous owner uncorked it and put an XR's only competition exhaust on it but kept the stock header. As I was going over the basic maintenance on the bike I noticed the exhaust valves were way out of spec. This is my first bike with auto decompression, so I'm wondering if that has anything to do with it, or if uncorking/changing the exhaust caused the previous owner to alter the exhaust valves but not the intake???? or maybe its indicative of an engine problem that might require looking into. According to the manual I got, the intake should be set at 0.006 ±0.001 inches, and the exhaust should be at 0.008 ±0.001 inches. My intakes were set at a reasonable 0.005, but both exhaust valves were at 0.015, nearly double where they should be! In my limited experience, valves usually tighten up with use, not loosen up. I'm hoping somebody could shed some light on why they might be set so high. I took multiple measurements multiple times to ensure I was TDC on compression stroke, and tried my best not to let the flywheel rotate backwards. I'm planning on setting the valves to within spec, but thought I would ask in case there is some bike specific reason why they are so far out. Thanks guys, Mike
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While trying to find TDC I turned crank backwards heard a pop. Is it likely I caused damage or caused timing chain to skip? (Dumb mistake) -
Just a heads-up alert about all those manually operated petcocks on eBay and the web. Look for the only 1 or 2 out there with the outlet tube or nipple vertical downward and below it. All other 100 models on ebay have the outlet tube pointing right at the choke pull lever. This forces a tight turn which on some fuel hoses will shut the hose and reduce fuel by 80%. Also when removing and installing the tank the hose must first be removed, or its a struggle to get it past the choke pull knob. The knob could be damaged or rod bent. Attaching the hose on the petcock after the tank is in place is tough because of the sharp downward angle needed. Here are a couple of images. I tried 2 different hoses. The light color hose was a high pressure air-compressor hose, it went flat. The black hose is a 1/4" fuel injection hose and it did better. I ended up routing it in a circle forward then back to the carb. Im going to buy a new petcock with the downward tube next.
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I need Valve stem diameter for YZ/WR250F. About to order seat cutter, and I couldn't find it in the book, just the clearance for guide/stem. Thanks
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Hi guys, I got a kx 85 2001 and i have a problem.. since i got it, sometimes its hard to start but since 2 days, i've started it but died when i went for a ride and wouldnt start anymore. So my problem : the bike crank but is really hard to start (if it start).. and if it start, it die.. and again hard to start. -Spark is good, air filter is clean, jetting seems okay (needle look pointed and carb clean), after a lot a cranking the gas get out by the overflow of the carb (so i have gas with good ratio 40:1) and the motor was replaced recently at 135psi of compression. Another thing, a got spooge from the exhaust. Now i am checking for the reed valve, they're not broken but i see a really little gap with my light and if i turn over the plate, its really worse. So do you think they were already turned by someone else ? Does a really little gap can cause a hard start/bogg like this? Should i change them for new ? Another idea on what i should look?? Thx !
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I have a 2006 yz 250f that i bought but it dosn't have all the parts in the valve i need this specific piece on it but there are multiple sizes. Anyone know which size will fit? Everything is oem on it.
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so me and my buddy just bought a 06 rmz450 that supposedly needed a valve shim job. it ran when we got it but the guy had to pull start it with his truck. later after removing the valve cover we discovered that someone had already attempted to shim valves and in doing so broken off 1 of the exhaust cam journal bolts and stripped out 2 intake cam journal bolt. I currently have the intake tolerances at 0.005 in and the exhaust at 0.008. the motor to my knowledge is timed properly. I have the dots facing outwards level with the block and the dots on either cam facing upwards while the motor is at tdc on the flywheel indicator. I reassembled the bike and now it has no compression. the little plastic threads on the decompression cable are stripped and I don’t know where it’s supposed to thread into. could this be the cause of no compression? it’s just hanging on top of the block. i’m planning on selling it after i do the work. thanks
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If it’s Salvageable/reusable, what would the best way be to go about fixing it? None of the gouges affected the valve seat, it was caused failed valve seals I BELIEVE. I have a new top end, full gasket kit already ordered.
