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How should my bike ride?

Discussion in 'Technical and Troubleshooting Torque' started by Glennb, Sep 8, 2005.

  1. Just got 2000 model GPX250 and just had a few questions?

    1st Q. Im finding that sitting on 110 kph(which I think is 100ks cos cars are still passing me) that I get a bit of a vibration(small) through the bike and can feel it up through the handle bars. 100ks seems ok.Is this normal for a 250 cos it revs so high??

    2ndQ. Did they make my model bike with the speedo out? buy around 10% under. Just finding that my speedo must be out cos traffic is traveling at least 10-13ks faster than me at 100kph.

    3rd Q. How much slack should i have in my chain? It has about 2" of slack is this ok?

  2. 1. There will be some vibration associated with twin cylinder engines, nothing to worry about unless your feet become so numb that you fall over at the first stop light...

    2. Speedo may be out due to different gearing or tyre size (if the speedo is gearbox driven). Find out what 100k's equals on the tacho and work from there.

    3. Make sure to check the chain tension whilst on the bike, get someone else to sit on it if you have to. If in doubt check a manual or ask a shop.
  3. if you are able get into a coffee night or on one of the learner rides and see one of the blokes ( just ask one of the people to point some one out to you ) and ask them to take it for a ride , they will be able to tell you if its a normal run of the mill issue.
  4. Cheers Cammo, I would of thought twin cam would of made it a bit smoother.
    So the chain tightns when weight is on the bike?
  5. Most twins will have some vibration, regardless of balance shafts etc, it is an inherent characteristic of their design, I wouldnt worry too much, they have better punch down low than a 4 cylinder for their capacity.

    Being a recent model and with low km's i don't expect that there would be any issues.

    The chain slack should only be measured when the rider is sitting on the bike, as when the rear suspension compresses, the bottom chain run becomes tighter. You can (sort of) see the difference by jumping on and using your foot (old shoe!), or get someone of a similar weight to sit on the bike to get a closer look yourself.
  6. Sure does.
    Have a look at other people when they hop on their bikes.
    You'll see what we mean by saying the chain stretches, its more the chain tensioning as you weight down the supsnsion and the swingarm.
  7. The GPX250 does vibrate, it isn't completely smooth and at certain revs the vibration isn't well cancelled.

    This is the case with most bikes from a few years back (the GPX250 is an older design), and some recently designed bikes as well.
  8. they couldnt possibly have made GPXs up to 2000... I thought they were
    replaced by the ZZR in like 1990

    1. vibration is fairly normal as people have mentioned, but it might need
    a service (in particular a carb sync)

    2. everyone speeds, dont worry about it :p
  9. You can still buy them new!
  10. 05 GPX $5990 at PS
  11. sorry may have been 04
  12. Ill get the GPS out and check my speedo using that(Im into 4wding/camping as well)was going to do it tonight then I rememberd I have to be 00 alco.

    Does the twin cam give better economy and more power??
  13. Lots of roads have Speedo Check sections where you can travel for 5 kms and check and see if your speedo reads the same. You shouldn't have 10 kph error unless the bike has non-stock sized tyres. My Hornet is .1kph out (low) after 5 kays.
    You can fix the error with a device called the speedo healer, not quite sure where to get it, but ask the guys at coffee, they'll know. Either that, or put the right sized tyres on it!
  14. 1. GPX will vibe a little at 110km/h, but it's not so much that it'd really bother you, IMO, and probably isn't much different to most 250s.

    2. Speedo is driven by the front wheel, so it would only be out if you had a different size wheel (standard is 16") or some odd profile tyres. I find people overtake me a bit - but it's just because they like to prove something to themselves by overtaking a bike... :p Try a speedo check though, if you're concerned.

    3. Chain slack on a GPX should be 35-40mm. 2 inches is probably a bit much, and you might want to tighten it. It'll start getting noisy at around 2 inches, and your chain will wear quickly if you don't keep it properly adjusted.

    Good luck with the bike - they're a very reliable little machine! Enjoy. :)
  15. Grab a push bike speedo and install that...you'll get a more accurate speed reading and a number of other functions you wouldn't normally have.
  16. Speedo healer===> http://www.motofx.com.au/mfparts.php?idmanuf=97&mfcat=70

    You could probably get any bike shop to order you in one as well :wink:
  17. Could be 40mm I didnt check precisly. Is it easy to tighten the chain?

    at $160 dollars for speedo healer I think ill give it a miss. Its under not over so Im not to concerned.Ill just find out how much it is out and just adjust when riding.

    Cheers all