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About jeffcoseo

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  1. jeffcoseo

    Spark plug o-ring?

    I have a 2004 RMZ250 that stopped running, and now has no compression. I took the spark plug out, and there is a small rubber "seat" where the spark plug seals against the head. But, i don't see that part on the OEM fiche. Is anyone familiar with this rubber seat? Thank you.
  2. So, one of my best customers came in with a problem. His son sank his YZ250F in 3 feet of mud, and it took 20 minutes to pull the bike out. After the bike was pulled from the mud, the kid (great kid, didn't know better) started the motor and rode off. Obviously, it died in 10 seconds and won't restart. The motor is FULL of mud. Bottom end has 2 pounds of mud in it, valves, head, carb is full of mud. Oil lines are full of mud. BUT, the cooling system drained perfect Engine Ice! Wooohoo! Would YOU rebuild this 2004? Or buy a $1400 ebay motor?
  3. jeffcoseo

    XT350 - No compression

    Well, I pulled the head on this motor. It turns out both intake valves were bent, and one of them had a chunk missing. Valves are expensive... $70/ea... I hope these seal the compression leaks and we can move on. Bore and rings look good.
  4. jeffcoseo

    XT350 - No compression

    Yes, i had the throttle wide open. I did not disconnect the de-comp cable, but kicked from halfway-down where it is not activated. Even if it was activated... compression should be more than 30psi, right?
  5. jeffcoseo

    XT350 - No compression

    Hello, I am working on an XT350. Cleaned the carbs, spark looks good, but wouldn't start. So, i pulled a compression test and got ~30psi. So, i pulled the top end off, expecting to see a mess. But everything looks good...? Cylinder is clean. Rings give me a 0.1mm ring gap in the top/middle of the cylinder...? Where do i go from here? What should the piston/cylinder gap be? Thank you.
  6. jeffcoseo

    Thinking about switching to a 2 stroke....

    WOW - i understand. As soon as all my bikes and quads are running perfect, i purchase a new headache. It's totally crazy. Then i have to buy new tires, rejet the new bike, oil change, the chain is stretched, sprockets are worn, it doesn't start right, etc, etc, etc. It's a fever. Stop the cycle. Spend more money riding, and less money fixing up used bikes that have been neglected. Trust me, i know the addiction... 200x, arctic cat 300, arctic cat 250, xr250r, trx450r, trx450er... ride your XR250r.
  7. jeffcoseo

    New XR250R owner her, a couple of ??'s

    I'm in Dallas with similar weather, elevation, humidity (lack of). I run the 48/135 jets, and they are great. Pull the snorkel, clean the air filter, and find out what jets you have in there. New tires are important. Make sure you're kicking from Top Dead Center. If you're not familiar... quickly but lightly stroke the kick lever, it will STOP at a point, release the kick lever from the top, and give it one big HUHHHHH! Adjust your valves, it's pretty easy to do, and extemely helpful. Replace your spark plug - just do it. send me an email if you have any specific questions, i bought a great 2003, bone stock, last year. Tinkered with it for 6 months, and now it's my dream bike. It took plenty of headaches in the meantime.
  8. jeffcoseo

    XR250 Hot Start - solved

    Yes, i changed pilot jet as well, from 45 to 48. Plug looks identical, i don't think the mixture changed. It feels less restricted, and the bike wants to start. I wish i could explain it???
  9. jeffcoseo

    XR250 Hot Start - solved

    I've owned my 2003 XR250R for 9 months. I almost gave up on the bike because of the hot start issue - once dropped, i could not get that bike to restart. I am mechanically inclined, so maintenance was not an issue. i had the valves adjusted perfect, clean air filter, jetting was right, etc, etc. If i stopped the XR in the woods, i couldn't get it fired up for 100-150 kicks. I know the "sequence", i kicked through with decomp lever, then gave it a few good kicks from TDC. Nothing. I started shopping for a used crf250x when i lost my job in January and decided I would have to put up with the XR for another year. I don't really need a e-start, i just need a bike that STARTS. This week i pulled the exhaust baffle - magic. Obviously, i stepped up to 135 jet because it breathes a bit better. I rode for 90 minutes today. i killed my bike purposefully 10 times. I killed it from 1st gear, 3rd gear, high revs, low revs, you name it. It started without the "sequence" on the 1st or second kick. I couldn't believe it. Blistering hot (it's 70 in dallas today) motor, and one kick to start. Heaven on two wheels. If your riding area allows it - i would strongly suggest you pull the stock baffle. It's absolutely louder, but doesn't bother me. I left the tip in place, and the spark arrestor in place. Also, i live in Texas and we're not too worried about noise down here. I'm sorry if you live in a more restricted area, i know that can be tough. I ride on mostly private land in far off rural areas. I'll keep the baffle in the truck if someone complains - but they I WILL complain! Good luck...
  10. jeffcoseo

    Singletrack Photos

    Awesome! Thanks for posting. I've never been able to self-portrait while riding on single-track. But i'll try this weekend.
  11. jeffcoseo

    XR250 cuts out at Full Throttle

    It doesn't seem like Rev Limiter. The bike not only cuts out, but almost dies, chokes bad, and won't take throttle for another 3 full seconds. I'll try a larger Main Jet. Thanks for the ideas! Keep 'em coming.
  12. I have a 2003 XR250R, purchased a few months ago. As i get better at riding this bike, i'm starting to see a problem develop at WOT. Bike runs like a champ, starts easy, good power. But, after 5 seconds at WOT, it will cut-out, and ALMOST dies. I lift off the throttle, and it sputters a bit, and eventually revs back to life. Everything is perfect up to 90% throttle. I assumed the floats were too low. So I lifted the level until gas was coming out of the overflow, then just backed it off until that stopped happening. That didn't fix it. Same thing happens, no change. Pilot is #48, Main is #130, no snorkel, aftermarket airfilter, 70F and sunny, no humidity, 400ft elevation. Many thanks for any ideas.
  13. jeffcoseo

    Decompression cable adjustment

    You won't SEE any place to measure. You kindof have to shove a little feeler gauge in there. Once you try it, it will be super easy from that point on. I think the exhaust valves are WAY easier than intake if you've never done this before. Start on the front left and work clockwise for increasingly challenging valves.