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250 Shift Speeds (or am I rooting my bike?)

Discussion in 'New Riders and Riding Tips' at netrider.net.au started by NothingExpert, Sep 21, 2012.

  1. Ok so I'm not sure if this should be here or in tech but this seemed the more likely post. Firstly thanks in advance and I apologise for what might seem like a stupid question, but I'm new to bikes and I don't really know what they can handle (I know cars fine but feel like this is a slightly different animal). I don't have a tach on the Virago and it drives me nuts as I don't know if I'm damaging the engine by riding it too hard. I'd like to think that I will keep the bike in as best as possible condition until I'm ready to move up to a real bike and I really can't afford engine related repairs right now. It's a 2012 model and I've put nearly 4000ks on it since the end of July. People on Virago Tech Forum were discussing shift speeds and most shift very early, ending up in fifth while travelling at 40mph (they are yanks in the main). Now this was the way I rode before the first service to ride the bike in. Now it is ridden in, I've been pushing it harder, particularly as I've been commuting and want to keep out in front of traffic to avoid becoming jam. The bike seems to handle the way I am riding it (it's not screaming its guts out like it has on the two occasions when I have shifted down too far at high speed) and I don't know if I am capable of shifting to second at 15km!!! (Maybe I should I be looking at trading it in for a Ninja? lol) I weigh about 100kg and I'm not carrying more than my work uniform and maybe a text book or two.

    My shift speeds are as follows and the variations depend on how hard I am riding:

    1->2 35-40kmh
    2->3 55-60kmh
    3->4 75-80kmh
    4->5 95-100kmh



    As I said the bike is not screaming at me when I'm shifting and by no means do I have the throttle the whole way open - more like 3/4 I think. I feel like there could be a little more in the engine than what I'm getting out of it but I really don't want an arse full of my top end and no way of getting to work.

    tl;dr: Are the above shift speeds too high for the XV250?

    Thanks in advance guys. I need experienced opinions!!
     
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  2. Dont do it Bill
     
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  3. Higher is generally better for the engine.
     
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  4. So, I'm also a bit of a noob, but that sounds similar to where I'd be shifting gears on my VTR250 for brisk but not hoon-level acceleration. On my bike, that'd be upshifting at ~ 7000 rpm, a fair way back from the redline at 11.5k, but enough to leave most cars in the dust.

    If I'm e.g. stuck behind a grandpa in a Yaris, I'll be shifting much earlier - probably 1->2 almost as soon as I'm rolling, 2->3 at 30-40, 3->4 at 50 and 4->5 at 70. Obviously using a lot less throttle here too - as Lilley alludes to, low revs with full throttle isn't the best thing for an engine.
     
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  5. Bikes rev more than cars.

    Peak power is just before the redline and maximum torque is well into the rev-range. Just shift before the redline. Or before the rev-limiter. Don't think too much.
     
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  6. sell it
     
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    • Like Like x 1
  7. I used almost exactly those gear-change ratios on my CB250. No dramas.
     
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  8. I saw a reference recently that proposed the 'normal' rev range for most operation is between 30 and 60% of peak HP. If you assume this is close to redline, then for a high revving 4cyl 250 like the Across with a redline at 17.5K this translates roughly to 5.5K to about 11K for most running.

    This matches welll with what other people are saying here, too, and what I'm finding after a bit of experimentation. 5th gear, 60K at 6K seems to be a good compromise, there's still plenty of pick-up for normal situations without havimng to drop down a gear, and there's plenty left up top. If I'm on a 50K street I'll drop back to 4th and keep it around the 6K mark, and I don't tend to drop up to 6th until I'm settled into a nice cruise at 80(ish) on the highway (L's don't forget...) and it's reasonably flat, otherwise I'll just let it rev a bit in 5th. This doesn't apply to fanging it, just 'normal' riding. Use the whole rev range if you want/ need to get going quick smart.

    How does this match with other peoples perceptions.

    Cheers
    JM
     
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  9. Not true at all - especially not true for a Twin

    Agreed
     
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  10. theres a dyno chart here > http://www.alternativecruisers.com/images/dyno_comp2.gif
    looks like 6000 rpm is exactly perfect.
    gives you a bit of roll on acceleration after that.
    not a whole lot going on after 8,000, just getting louder. (whilst in the background a 2fiddy ninja blows you away.)
    kinda mentioned by Lilley allready > you won't break it by letting it spin up a bit.
    it's much worse to let the engine lug or get bogged down because the revs are too low in the gear you're in.
     
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  11. I'd say that's a little low as far as 250s are concerned, their ideal operation would be more like 50-80% of peak hp.

    An Across will struggle to accelerate from 5.5k and when you consider that it'll sit on around 9-10k when just cruising at 100-110kph you're obviously going to want a lot more revs if you expect it to accelerate anything like it was designed to do.

    So to the OP - don't be afraid to use the revs. The redline/rev limiter on a Virago is most likely set a lot lower than what the engine is actually capable of so don't be afraid of hurting it (it's lack of revs that does the most damage).
     
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  12. omg wow wtf omg
    your 2 fiddy virago is kicking some serious butt under 8000 rpm.
    game is over by then anyway i can believe it .
    virago with more hp than a ninja until you hit 8000 rpm ...
    ur gotta be happy with that.

    i have heard you cany break those viragos - dam ugly things though ...
    upgrade to vstar when you can and go the 1100. )
     
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  13. that nighthawk looks pretty lame - i got a rebel in the garage that is a pain to ride,
    gear changes constantly ....
     
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  14. Context missing. If it were in regards to cars then I'd agree. Cars at largely expected to reach 250-300k with general disregard for maintenance. Holding them at 6 or 7k rpm for their lifetime isn't how to do that.

    this is a joke right? Please tell me this is a joke...

    On a 250, at 60 ks, 3rd at most.
     
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  15. Looking at this dyno chart, the virago has a very similar curve to the Nighthawk (otherwise known as the CB250). I ran my CB250 just like the OP runs their Virago. You want to be doing most of your acceleration in the 6k-8k band, so changing up at around 8k seems good.

    OP, I think you have it right for that bike.
     
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  16. Context was obviously multi cylinder high-revving small capacity motorbikes, given that's what the discussion is about. Why would I be 'joking'? The Across accelerates happily from around 4K without stumbling and 'lugging', from above 5K it's brisk, and 6 and above and there's plenty of go. I don't see the point in screaming its tits off for no good reason.

    My car has bags more straight line acceleration than the Across but in cruise mode at 60K the Across would out accelerate it - Across 6K in 5th, car 2K in 5th- it's a 6 speed with an 8K redline/ max hp.

    Cheers
    JM

    Cheers
    JM
     
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  17. You have a very warped understanding of what is meant by lugging then.

    You're talking about an engine designed to cruise happily at 10,000rpm for hours, with peak acceleration at 14,500. Chugging around at 4k is only going to foul the plugs and cause serious long-term damage to the engine.

    It would only seem fast compared with your car because trying to accelerate from 2K in 5th on anything other than a large displacement V8 (with considerable low end torque) is just as bad. From the figures you've given what you're suggesting is trying to accelerate from 60kph in a gear designed for 240kph :shock:.
     
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  18. Because I had trouble believing someone would be that daft to say such a thing.
    Have you ridden anything other than your across?
     
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  19. As far as I can see, no it wasn't. It was about a Virago which is not high revving, unless you compare it with a car, which you shouldn't.

    +1
     
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  20. Surely it depends a lot on the engine and the gearing. On the VTR250 (a V-twin like the original poster's Virago), 60 ks in 4th gear is 5000 rpm, which "feels" right to me: not making too much noise, and there's still easily enough power to climb hills or accelerate without feeling like the engine is lugging. FWIW the instruction book claims that 5th gear is suitable for "40 km/h and above" which I think is incredibly optimistic.

    Actually it's pretty normal and even recommended by many car manufacturers of to shift at that kind of rev range, even in a 2L hatchback. Modern fuel-injected, VVT car engines are designed to operate under moderate load at low revs to meet emissions standards. Then you get outliers like my 1.4L turbo Golf which would happily sit at 2000rpm at 100 km/h in top gear, and easily accelerate from there up to speeds that are only legal on the Autobahn. (Torque on that engine is basically flat from 1500-4000rpm.)
     
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