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Just got carbs and valves done....

Discussion in 'Technical and Troubleshooting Torque' at netrider.net.au started by duff_boy, Oct 30, 2008.

  1. Hey guys, i normally do all the work on my bike myself. The bikes a GSF250v, It has VVT on the inlet cam and the valve clearances are a pain to set. I finally tracked down the workshop manual and there's actually 24 spots you need to measure the clearances and use shims just to set the intake cam. So i thought bugger it ill let the suzuki service dept. do it for me.

    Anyway. I was complaining of hard starting when cold even though the carbies are clean, adjusted, choke working fine etc.(hard starting can usually be attributed to inlet valve clearances being wrong, from what ive read) And the valve train is also very loud/rattley.

    So what they did today:
    Adjust valve clearances(apparently inlet were "spot on" and didn't need adjusting and the exhaust were too tight so they have been reset.)
    Balance carbies(usually should be done when you do the valves)
    They also did a compression test which had good results. They replaced the spark plugs while out as they were a little worn looking.
    Also chucked some "cleaning additive" in the fuel.

    So i picked it up. First thing i notice when i start it(its already hot as they just finished work) - valve train is waaaaay louder than it was before it came in! Not quite what i was expecting, i was expecting it to hopefully be quieter. Apparently the valve train is always loud on these because of the VVT(or so they tell me anyhow) but it seems quite excessive to me. Like if you step back from the bike when its idling the engine noise almost overpowers the exhaust(and its got quite a loud pipe on it)

    They had set my idle speed down to 1000rpm, so i put it back up to 1500rpm and rode home to see how it goes. No noticeable differences in engine performance, but the engine is definitely alot louder and more rattley than ever. So i get home and jump off.

    Second problem: I notice if i give the throttle a quick sharp rev up to say, 5000rpm - the revs take a while to come back down to idle speed, just drop back to around 2500rpm and then slowly fall back to 1500rpm idle. However if you just slowly bring the revs up with a small amount of throttle and then let it go, the revs drop back straight away like they should. Its as if when i quickly open the throttle a large amount like that, something sort of even jams a little bit. Does anyone know what could cause this?

    What do you guys reckon i should do? The above costed me $369 and i cant say that im exactly happy, as if anything in my mind the bike is now in a worst state than when i dropped it off.
  2. Sounds to me like a shit job.When i take my zx9 in for that it comes out smooth,quiet and with a marked improvement in performance.This is also coming from a bike that has done 126,000 ks :grin:
  3. It stands to reason that if the exhaust valve clearance was tight and is now correct that there will be a corresponding increase in mechanical noise. Clearance equals rattles.

    Your engine shouldn't be outrageously noisy but hey, I can't hear it from where I'm sitting.

    Your idle speed is hanging because the idle air/fuel ratio is lean. The idle mixture is determined by static engine compression so again, if this has been altered (via a valve adjustment), the fuel demand will change. it probably only needs the mixture screws backed out half a turn.
  4. For all i know, he might have messed with my pilot jets, he did screw with my idle speed after all, ill check those on the weekend.

    Yep I realise excessive clearance causes rattles, but the right amount of valve clearance as per manufacturers specs, should be pretty quiet you would think?

    In my opinion the engine is pretty damn noisy - i cant say i can recall another engine as loud. But then again, the valve cover on this engine is made out of very light magnesium and is probably around 5mm thick at best, perhaps not the greatest for noise insulation, a partial cause perhaps. What i might do is have a look at another bandit the same as mine for a bit of a comparison. But i still do think mine is excessively loud, but you never know, i may be wrong.

    Is there any other bandit 250 owners on this forum that can comment on their own, or even any in brisbane that might even want to meet up?