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Found 7 results

  1. spezza-125

    Low Compression 4-stroke

    So I got an xl185 (4 stroke Honda) which I bought in the summer. Bike had a very poor electrical job and the wrong cdi. It used to start up first to third kick. Now it doesn't. I was playing around on it today for a good hour trying to get it started and once I did, It osunded like there was a rattling/clanking in the engine head. My mechanic said that the bike had low compression and needed the new CDI (As I took it to him when is wasn't running). I read an article by a guy called the motorcycle mechanic saying that it could be one of 3 things and I could test it with oil in the chamber, and seeing if the compression changes. Is the sound caused by low compression? Would it be okay to leave it if I am selling the bike? Also It is harder to kick when gas and choke is on rather than when it is not. UPDATE: Bike sounded fine a few months ago and kicked about the same (Had some resistance)
  2. Hey all! I have a 2011 Gio X31 250cc that is losing compression gradually. It had amazing compression when it was new...but now it's becoming a tiresome task to kick-start when my electric start is down. It's burning a small amount of oil, but I don't even have to top it up between oil changes (~10 hrs. per change). I'm thinking it just needs a valve adjustment to bring the compression back up. I'm surprised how good this engine has been. I ride it hard and it keeps up with bikes 2-3x the hp and refuses to die! I don't know how to adjust the valves on a 4-stroke, let alone a Chinese one. If any of you know how to adjust the valves on a Gio X31 250cc I would appreciate the help! Do I need to pull the engine for this? Thanks
  3. Before I put my 05 CRF250R away for the winter it was running weird. I noticed it was leaking oil out of the engine cover. It was understandable because i had just put a new stator in. The bike had been running oddly for some time before i realized it was leaking. I just took the bike out for the spring and now it doesn't even start. I bought a new engine gasket to try to fix the leak. I am currently installing it. I am wondering if the low compression could've messed up the top end? I rode it with low compression for about three weeks before it started to bog so bag i couldn't ride it anymore. Will replacing the seal fix my issue or have i created a whole new one?
  4. Heres a strange problem for the community, I have a bike thats failing a compression test but passes a leak down with flying colors... 2012 KTM 250 SX-F Valves spot on, clearances spot on New cam chain Dirt Tricks cam chain tensioner HAS fuel HAS spark 4% leakdown on the leakdown test FAILS compression test horribly Thoughts?? I am flat out stumped...
  5. SOLVED*** No timing issue, just had trouble lining up TDC Going to rebuild top end to fix low compression. Thanks for the help TT So I bought my 2003 crf230f a few months ago from a friend. The bike has definitely been ridden, and was blowing a little bit of smoke when I bought it so I knew the rings would be toast sooner or later. After a basic tune-up the bike ran really strong and I continued to ride it a few times a week for a couple months with no problems... Until last week when I was riding and it died on me. At the moment when the bike died, I was coasting down a hill so there was no extra stress on the engine, I just noticed the engine shut off- almost like running out of gas. From that moment on, the bike would not start so I towed it home and checked the essentials... Air, Fuel, Spark, Compression. Air- The new air filter I installed when I bought the bike was already covered in dust, so its possible the piston rings got even more dusted. I cleaned and oiled the filter anyway (the bike wouldn't start with the filter removed). Fuel- I recently changed my jetting to Mike Coe specs, and installed a larger pilot jet to eliminate popping on deceleration. The bike ran great with the new jetting and I know the carb is clean. I went ahead and cleaned out the gas tank and fuel lines and cleaned out the carb yet again. Spark- Spark plug was white due to running lean before I changed the jetting. Plug turned more of a brown color after jetting, indicating better A/F ratio. Replaced spark plug anyway and can see strong blue spark. Also, gas is making it to the plug. Finally did a compression test and had low compression. I adjusted the valves which were a bit out of spec, and saw no improvement. A wet compression test (one tsp oil in plug hole) showed higher compression, but still low, indicating the piston rings are toast. I ordered new rings and top end gaskets and will rebuild the top end next week. I was also wondering if I have a timing issue, since the engine at TDC (pic 1) shows the cam sprocket about 30 degrees (in the retarded position?) off from being horizontal with the head, as it should be according to the FSM and Clymer manuals. Also, when cranking the engine CCW by hand, the flywheel tends to spin past TDC and happens to align the cam sprocket perfectly horizontal with the head. Is my timing way off? Also, the flywheel has a || mark (pic 2) near TDC that I used to adjust the valves. Just today when I took the pictures, I noticed a |F mark (pic 4) that usually spins past quickly so I never saw it before. both marks appear close to TDC but the engine always wants to spin to the natural position (pic 5). Where is my true TDC? Manuals only show a |T mark. Are the cam sprocket lines supposed to be horizontal with the head? Maybe it jumped a tooth? I have read the cam chain tensioners are known to fail also. Edit: Found the T mark, updated photo near bottom of thread tl;dr Bike died on me, has low compression, going to rebuild top end. See pictures. Could this be a timing issue also? Does anyone know if the lines on the camshaft sprocket are supposed to line up with the horizontal lines on the head? Thanks in advance for the help! Pic 1- TDC at || https://imgur.com/QJXXjXH Pic 2- || mark https://imgur.com/v7dBSf8 Pic 3- TDC at |F https://imgur.com/DZCPBaT Pic 4- |F mark https://imgur.com/JbcVYhF Pic 5- Engine wants to spin to this position: Cam sprocket lines horizontal with head- https://imgur.com/S3rPRgd Let me know what you guys think. Has my timing jumped? I appreciate your help! Cheers, Spencer Edit: Finally found the damn "T" mark. Always spins past so I wasn't able to see it before. Updated picture posted near bottom of thread. Timing looks fine so just going to rebuild top end next week to restore compression
  6. Sunflash

    RTW 470

    So I have done lots of searching but can't seem to turn up the info I am looking for. So after a 25,000 mile run from Deadhorse, AK to Yaviza, Panama and back to my home in Alaska on a Rally Raid Level 3 CB500X..... I am now going back to my roots and picked up a 2004 DRZ 400 with about 2900 miles on it. Lots of reasons for it but the cut it short I know I was looking for something different for the rest of the ride around the globe. So my plan is to build a bombproof DRZ that can take me everywhere and back. To that effect I have already ordered an Athena 440 kit, will be going with the Hotrods +4mm crank kit, and the ACT wide ratio gears. Where my plan differs from most of the other power mongers is that I want to keep the compression low enough to run low regular fuel without going nuclear. That type of tuning runs a bit contrary to everything I can find info on. So who out there has done a low comp 470? Since the plan is a mild state of tune rather than the usual fire breather everyone else is trying to build does anyone have a good recipe for the spacer or gaskets to keep the compression low enough? Cams for the milder state of tune? FCR 39 going to be enough carb or should I be looking to the 41? My engine building has been limited to old air-cooled 4 cylinders and for max grunt not longevity on crap fuel. Lots more will be done to the bike but the motor spec is one of the ones leaving me a little out in the cold. Want the grunt of a bigger motor to pull the wide gears but not the short life of a rocket ship. Thanks for the help.
  7. I bought a 2004 DRZ125 for my son last month, it was an upgrade for his Honda XR80R. We live in a rural area and he rides his dirt bike daily. Last week he called me to tell me his bike would not start and it had no compression. He's 11, he said he could push the kickstart with his hand. I have only ridden the bike a couple times, the last time it died on me a few times when I came to a stop (stop sign) after going wide open for a couple minutes. I found it difficult to start but as long as he could start it, it was good enough to make him happy. I stopped at Harbor Freight and picked up a compression guage to try and figure out the problem, it read between 85 and 90 psi (I tried a few times to make sure I was getting a consistent reading). I figured maybe a ring broke but not sure... I have some knowledge of engines but definately no expert! Deciced to take the head and cylinder off to inspect. There was a lot of carbon on the piston and some on the head/valves but nothing I found was way above average. The rings are all good and the cylinder looks very good. I cleaned all that carbon off and put it back together and adjusted the valves. (I was at top dead center but not sure if I was on the compression stroke) I did another compression test and now I barely got 35psi. Called a mechanic friend who told me to take the adjustment screws on the valves all the way out and test compression again. After doing that I got 90psi, same as before I took the top of the motor off. Now... Unsure on where to proceed, I think maybe the rings are worn (It seemed prettry easy to put them back in the cylinder) or the valves are not seating properly? One more thing, as I was taking the head off my son looked in the oil sight glass, there was nothing in there. There is oil in the engine but not enough to show in that little window. When I picked up the bike last month it had a fresh oil change and it read perfect in the little window. The bike did not smoke when it was running. I was told by the seller it sat for over a year in his garage, he cleaned the carb and put it up for sale Any pointers on what to look for and what to replace would be very appreciated