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Gearbox issues?

Discussion in 'Technical and Troubleshooting Torque' started by CelticKnight, Sep 9, 2010.

  1. Yeah, took the XR250R for a spin this afternoon, FINALLY had a chance (and bravery, I'm new at this remember!) to get the bike into top gear! Woo hoo..

    Anyway, on the way back i found a strait stretch and opened it up, 5th gear (or was it sixth, either way. top gear) at almost full revs the DAMN THING DROPPED INTO NEUTRAL. Lost ALL power to the back wheel, sudden deceleration with me swearing like a trooper. Did what you would immediately expect.. *shit there goes 5th gear! Get on the brakes slow down, revs drop, FOURTH GEAR! Clutch, change down, release clutch, engine screams.. still no power. still in neutral. Why is it suddenly no letting me get ANY GEARS?!

    I pulled the bike to a complete stop, and worked my way back to what i hopped was first, Let the clutch out and gave it some stick, Zip. Nothing, neutral still!

    Moved it to what i think was second, still nothing, back to first.. Up to neutral.

    Moved it back to first gear for the 3rd try, THIRD TIME LUCKY it locked into first gear and i was off, worked my way slowly back up to 5th, it locked fifth in and it didnt say boo for the rest of the trip home (okay was kinda stressed, its an second hand bike, and i thought i might be pushing the bloody thing 5KM to home!!)

    Anyway. What on earth would cause a bike to drop from top gear to aparently neutral with NO warning whatsoever? I didnt hear an almighty crunch, there was no warning, just total loss of power to the back wheel.

    Yes i can hear someone say 'CHECK YA CLUTCH' or 'Ha you had in fourth' or that i had something to do with it.. I didn't.

    The gear box seems to be fine, it WORKS i got home safely, But could this be a recurring issue? should i worry about this guys? I'd hate for the gearbox to give up the ghost some 30 odd kays from town in the middle of the scrub!!


  2. Most gearboxes contain hidden neutrals between other gears. Sloppy gear changes or a slight bump of the lever can find them. So I'd say you found a neutral between 4th and 5th. The lever was either bumped or vibrated there or got nudged there when you come off the power.

    this doesn't explain why you then couldn't get it into another gear.

    the first thing I would be doing is making sure everything is adjusted correctly. Get rid of gear lever slack and make sure the chain is well adjusted. If it happens again I'd say you may internal gearbox problems.
  3. Ahh. That explains alot :) Well ill see if it happens again, it mightve been a one-off gremlin (i hope)
  4. 1} Ensure gearlever is at a comfortable position for you to use when riding, and is fastened tightly enough to ensure it won't work loose under operation.

    2} Adjust clutch cable at both ends, first almost zero the handlebar adjustment and then take up slack from the bottom where it connects to clutch lever. If this isn't the case with your bike then just adjust at top on handlebar. Either way, aim for 10mm of slack at the lever end before you start to disengage the clutch.

    3} Take the bike for a spin. After the bike warms up, do an oil change. Use whatever you like for the oil, but I would highly recommend Valvoline 'Engine Armour' 15W-40 as it has never given me problems. It is also cheap and widely available. Change oil filter after draining old oil and before putting new stuff in - its a $15 part that keeps you engine free of particles that could cause hundreds of dollars worth of damage.

    4} Adjust chain to spec (usually 25mm of slack @ midpoint), then clean (if it needs it) and lube.

    5} Check sparkplugs and replace with good NGK items if neccessary. Check airfilter and replace with good Unifilter item if dirty and paper-type. If foam type, clean in petrol and then work a 50/50 blend of petrol & motor oil through it. Gently remove excess by squeezing filter between hands - not wringing or twisting! Refit and go for a test ride.

    After all that, you should have a sweetly shifting bike that runs better than ever. Note the mileage on the odometer and use that as reference for your next service. I am not familiar with the bike other than knowing its a 250cc aircooled single-cylinder trailie, but would reccommend no more than 5,000km between oil changes...especially if you tend to ride it hard. Check the air filter at the same time, clean if dirty. Replace oil filter every second oil change.

    Cheers mate, hope that helps - boingk
  5. my bike was doing it, id change into 6th gear, but only a weak change then it would pop out and free rev. now i just pull into 6th a little harder and its never happened
  6. and do what boingk said even if it never happens again, thats a good service guide so print it out maybe