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I think my mechanic used the wrong sprocket (GPX250)

Discussion in 'Maintenance and Servicing' started by Tiger_grrrrl, Aug 4, 2012.

  1. Hi!
    I was hoping some fellow GPX250 riders could let me know which gear they ride in and what their RPMs are when they're going at 100km/hr? I got my bike serviced last week with a new chain and sprockets put on but now my bike has gone from being comfortable in 5th gear on the freeway to revving at 8000RPM in 6th at 100km/hr. I just want to make sure that's abnormal before I ring up the mechanic and accuse them of stuffing up.

  2. It should have the number of teeth stamped on the sprocket. You can compare that to stock with a web search.
  3. Standard sprocket are 14 front and 45 rear
  4. As a matter of interest does it seem to accelerate harder now? Maybe if you bought it secondhand someone had geared it for top end speed although 8000 rpm at 100k in 6th sounds high. I'm going up the freeway tomorrow I will check it out and let you know.
  5. Why not just ring and have a nice friendly civil conversation?
  6. 7500 in 6th on mine.
  7. Thanks guys. It was second hand, that's why I thought I should check first. I'm not sure what they put on the front but it looks like they put a 42 on the rear. I can't say I've noticed accelerating any harder since the change either. I only noticed something was different when I was on the freeway the other day and went to change gears and found I had no more to change up to.
  8. Of course that's what I'll be doing. I just wanted to make sure that it was RPMing too high before I called them in they tried to blow me off and try telling me that's what it should be doing when it isn't.
  9. 42 might just suit the chain they used, standard sprocket diameters are 61 and 217
  10. 100 km/HR sees me around just ove 7,000rpm in 6th gear.
  11. Ditto maybe a tad higher