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Trouble hill starting

Discussion in 'Maintenance and Servicing' started by MeltingDOg, Apr 16, 2012.

  1. Hi all,

    Well another day another issue with the T500 Titan.

    Well actually, this might not be an issue exactly. The problem is the bike wont accelerate from stop in first gear until it reaches power band. It feels completely gutless. Which means hill starts? Forget it!

    When rolling through, say, a tight corner and dropping back to first everything's fine. But it really struggles if theres a bit of an uphill gradient.

    All other gears feel fine to me.

    Would anyone know why this would be occurring? Thanks!

    (PS the T500 is a 500CC 2 Cylinder inline 2 stroke).
  2. The answer may be to learn to love slipping the clutch from a standing start in order to keep the revs where the torque lives.
  3. Thanks Pat, can you extrapolate on that a bit more (sorry - newb here!)
  4. OK. I'm making the assumption that there is nothing wrong with the bike. I may be incorrect in this, but we'll use it as a starting point.

    From what you say, there's not much torque at low revs, which makes starting off from rest difficult. That vaguely surprises me because I don't recall the 500 Suzuki to be particularly weak at low revs but my memory isn't what it was.

    So if there's no go at low revs, we need to keep the revs higher, where there is some. At low speeds this is difficult because, obviously, engine speed is proportional to road speed, isn't it? Well, not quite. It's certainly the case with a gear engaged and the clutch fully home, because, all being well, you then have a solid driveline between tyre contact patch and crankshaft. But if you partially disengage the clutch, you can, with some practice, obtain a variable speed drive, by holding the clutch just at the biting point and making small adjustments to keep the engine at a constantish speed where it's producing power, whilst bringing the road speed up to match.

    We actually all do this on any bike when starting from stationary, because we need to obtain drive from a rotating engine to an initially stationary wheel and it is physically impossible to match the speed of a rotating object with that of a stationary one. There has to be some slip somewhere and that somewhere is the clutch.

    This isn't generally referred to as "slipping the clutch". However, as the length of time before the clutch is allowed fully home increases, there is a somewhat fuzzy line where a normal start becomes "slipping the clutch". Back in the days of four speed gearboxes, part of the mythology of the road registered race bike was the need to be moving at 30 odd mph before the clutch could be fully release due to an inevitably very high first gear and an engine which wouldn't pull below 5000 rpm.

    Another example was when I first stuck a sidecar on my Suzuki GSX550 but didn't initially lower the gearing to suit. Setting off from rest in a hurry involved holding the engine at ~5500 rpm and feeding the clutch in slowly, balancing throttle and clutch to keep the revs more or less steady until I was moving fast enough to let go of the clutch entirely.

    It does require some coordination on the part of the rider and it is quite hard on clutches. The former isn't too hard to learn and the lattter aren't too hard to change though :D.

    It would, however, be worth ensuring that your carbs are properly set up and appropriately jetted though. That is a task that really requires someone on hand with more two stroke tuning experience than I have.
  5. Got it! Thanks Pat - Will give it a try!
  6. I started this thread last year which might help.

  7. + 1 to PatB. Excellent post.

    I can't recall that I ever rode a Titan, but a 500 Smoker without chambers and pretty conservative porting, should pull OK from fairly low down.

    I'm going to work on the opposite assumption, that the bike isn't right, and suggest a full tune-up and carb sync be done by a mechanic, and get him to do a compression test and a pressure test of the end seals. Smokers get tired after a while. They'll still run, but they lose compression and the crank end seals go, and it's only at higher revs that all the goodness doesn't have time to leak out before the spark arrives. They get fat and lazy and sluggish across the entire rev range, but sometimes it's at lower revs where it's most noticeable.

    A Titan is no spring chicken. If that motor hasn't been rebuilt in the last ten years or so, then maybe it's time it was. On the bright side, it's a very simple motor and an experienced bike mechanic could do it in his sleep. Test the compression and the end seals to see if needs doing.

    And in the mean time, give it plenty of revs to get going.
  8. Thanks Pat - worked a charm. Instead of releasing the clutch more casually I have begun doing it more slowly whilst keeping the revs level.

    Yep - as I thought just something I need to get used too!

  9. Revs, mate - There's some porting in those barrels, plus the spannies, so most of the power is higher in the rev range. Used to move all 100kg's of me just fine!
  10. Decades ago I rode one a bit. It wasn't mine but i had access rights, even rode it around Tas.

    Like Pat my memory of it isn't all that clear but i don't recall having to do anything special to get it off the line.

    In fact I test rode it for the guy who bought it and recall taking off slowly with him on the back and then turning up the throttle and nearly thowing him off the back of the bike (I think this is why he bought it).

    Sounds to me more like a specific issue with your bike. So I guess check the basics. I am no expert on 2 strokes but are carbies working correctly? Timing correct?