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VikingTrad3r

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VikingTrad3r last won the day on November 16 2022

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About VikingTrad3r

  • Birthday 01/01/1982

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  1. chain is tight, didnt see any strange behavior on the way the rockers were moving while doing compression tests with rocker covers off leakdown test showed minor leakdown past rings. minor. valves tight id say the rings are slightworn yes but down on a bit of compression/power is really different than it coughing and sputtering at high rpm this quad starts instantly, purrs like a seeing machine, and blows zero smoke. im doubting compression now. i have a second “parts” moto4 and decided to test the ignition coil of it vs the current patient. to my surprise on the patients sparkplug wire/coil, i was reading open from the coil orange wire to the spark plug connector. meanwhile the parts read 10.75 kiloohms. so i swapped them. installed a new petcock in the fuel tank and just sat it on the frame. After some minor carb tuning it ran like a sewing machine. So.....i will take it out for a rip tomorrow but im thinking....compression is a bit down yes. But thats red herring. i am thinking the sparking was jumping inside the wire from the ignition coil to the plug. somewhere there mist be an open because i could not get a resistance reading out of it. that may explain the high rpm sputtering. faster spark and the jumping of hypothesized gap crossing made the timing off. thats my theory and ill know more when i get a chance to drive it tomorrow. also i cant rule out the weirdness of the compression incremental rise. yes if i keep going with the starter it maxes at 75-80 psi. if i then bump the starter several more times it randomly adds compression up to 120. strange!
  2. I tried the oil down the spark plug hole trick and got no change. tried a different test with same result. im trying a leakdown test to see where the air escapes. absolutely zero smoke. none. AND it starts easy as pie. will also run a borescope in but i wont be able to get it to turn around and face up at the valves.
  3. I have an 86 yfm250 (moto4 250) i picked up. It bogs and pops a bit out the tailpipe if you can even get it higher up in the rpm. It is pretty gutless. I have other 250’s (timberwolves) and its ultra gutless compared to them. It has an aftermarket carb on it that has a “W” on it Its not a mikuni but it looks close i figured jetting was off at the high end. i had a mimuni that was very crusty, swapped the main jet into the W carb, and the needle, which was set on low slot 4 so left it there. it actually ran much better, and cured what i thought was a problem caused by a lean condition from the W carbs main jet being too restricted when i compared to the factory mikuni I had it out and was enjoying the upper rpms that i couldnt reach before without bog. at wot it would fall on its face low top speed. after getting it hot, it would actually refuse to start after dying. back to the drawing board. when i first got it i adjusted the valves. So i retraced my work and thought maybe id overtightened. double checked, nope all good. .005 exh , .003 intake, check. So i checked the compression. here is the trickyness. help me understand this. I am at 3500ft asl in calgary canada - initiate test, it goes to 75psi right away. this is low. Even at my elevation im thinking 110psi minimum but....this thing starts no problem. even -20c it starts. makes no sense to me. so i press the starter again and it goes to 85. Then i press it again and no change. Then i turn over again and it jumps to 95. Then again...no change. Then again and it goes to 115. finally finishes at 120 and i cannot get it to go any higher than this. ive repeated this multiple times. i press and hold the starter...it will max at 75. Then a series of maybe 10 more quick turnovers from the starter and compression inches up to 120psi. So, i think the low compression explains the low top end, and even the backfiring out the exhaust when hot. The exhaust is rich enough (incomplete combustion in chamber) and to ignite in the muffler. it gets worse when hotter. makes me think i have a crack, or something that is low down on the cylinder wall. When the piston stops just above it on the upstroke, and i then turn it over again, it adds pressure to my tester reading. thoughts?
  4. anyone have experience with this? ive got a few 250 timberwolves, 2 moto4 250’s, one moto4 350. planning on picking up a late 80’s or early 90’s big bear. ive found they are cheap, and bombproof. but im looking for rear shocks for my 86 yfm250 moto4 and want to keep my input cost as low as possible. there is zero damping effect left from the originals and when i searched “yfm250 yamaha rear shock” i found a few generic “universal” shocks and wanted to ask here if others have had success. cheers. vt
  5. Just replying here again. The reverse light is all good fixed. The main issue of only starting in gear is not solved. im not super skilled at reading wiring diragrams nor troubleshooting wiring. i thought i had it narrowed down to a relay. ordered the relay but still not fixed. quad will still ONLY start if the neutral light is off. It is starting in gear, but wont start in neutral. is it possible that a wire is reversed somewhere? seeing as it is doing the opposite of what is supposed to be doing.
  6. i tested the reverse position indicator light socket/receptacle and its showing 12.4 volts. the little bulbs i put in were rated for 2.4 volts. so i think that explains why they glowed very bright for a second then burnt out. so does anyone know where i can get a real reverse indicator light? it would be the same as the neutral light id imagine
  7. switches are functioning properly. ive discovered something else. the reverse indicator light bulb is mia. so was the reverse switch. installed rev switch. had s bulb laying around, blew rev i dicator bulb immediately. bulb mau be too wussy though anybody know where i get a replacement bulb? this is for the little red bulb the actual bulb
  8. thnx. yeah i looked in my manual got the wiring diagram and it looks like its got to be in the relay. something is reversed in the relay. will inspect. wont be surprised if a bubba messed with it
  9. im back with more info. first, the reason it felt like i could shift below neutral is because the shifter leaver was loose. thats fixed. but the main issue remains: here is an update, 1. the reverse indicator switch is broken down on the left side of trans. i dont think that affects the starting circut though. ive ordered the switch. 2. it WILL START if its in neutral, but only i have the neutral switch unplugged. IE, the neutal light is OFF. so something about the neutral light being ON when im in neutral, stops the quad from starting. its like there something reversed somewhere. the quad is ONLY. supposed to start when the neutral light is on but instead it will only start when its off.
  10. picked up my third timberwolf 250 for my daughters. these are great light weight little quads. have a strange one for you. the quad will NOT start in neutral. it will start in first. if i lift up on the gear selector just enough to hear the little click (its not loud, sounds like a contact clicking, perhaps the neutral safety switch?) the light will go out, but it won't yet be in first either. that is how i have shown my daughter to start it and she can. id like to carry out whatever repair is needed. i have the pdf of the shop manual but it doesn't really have a flow through diagram. any help appreciated! thank you. i need to add something. it feels like i can switch into another gear BELOW neutral. so if i switch to neutral, i can keep pushing the gear selector, and it has another click below the neutral. the light stays on, and when i pull up into first it kind of feels like it has two positions it moves through to arrive at first.
  11. can i ruin anything by lightly driving it and does the engine have to come out for this ill get the pdf
  12. 250 rwd timberwolf 1993 i checked the bolts and they are tight. anyone have this issue and did they install new gasket with engine in-frame?
  13. thnc dtb. I had another person suggest the 1 way bearing clutch? does that sound right?
  14. just bought a 91 big bear 4x4. if i go too fast it locks up and the rear wheels will not turn. if i put it in reverse and back up a bit it "resets it" and i can keep going. does this sound like a tranny issue? diff issue? or transfer case issue? i will tear it down but if you guys have an inkling of what could cause this issue it would give me a place to start regards, VikingTrad3r.
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