I have a 125cc 4 stroke scooter.
I have done 18,000 kms in two years (used daily) and it is soon due for the major service which includes valve clearance check.
My question is, it has been ridden really gently and oil changes have been done every 1000 miles as per the schedule. Spark plug and air filter changed/ cleaned regularly!
What else can I do to prolong the life of the motor?
Thanks for any advise.
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What else can I do to prolong the life of the motor?
Bubble wrap it and never start it again. ;o)
Seriously, I don't think there is - you're doing everything right. As you don't have control over the gears, you don't have to worry about being gentle with it.
1000 miles is what I've heard to be a good interval for singles.
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And how long should it take to check the valve clearances. Is it a big job? Is it better to check them at a higher mileage?
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Chances are they wont need adjusting though best to have them checked because if they have closed up you can burn out a valve, if they have opened up you will probably hear a ticking.
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So what would be the tell tale signs if the valves are too closed? Would there be a specific noise or smoke or anything?
Thanks
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What else can I do to prolong the life of the motor?
If the valve clearances are required to be checked at the next service interval, then questioning how long it will take, what if they're too closed, or too open is pointless.
To prolong the life of your motor, stick to the service interval requirements and get the valve clearances checked (and adjusted where necessary) when they require checking.
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Funny thing is that in the 'old' days when we had heavily leaded petrol, valve clearances got bigger due to wear of the rocker arms etc, but now with unleaded, the opposite is the case. Engines are built from better materials, so the valve seat erosion from lack of lead in petrol causes clearances to gradually close-up instead. Having large valve clearances is annoying and noisy but doesn't damage the engine exept in extreme cases, whilst having small clearances gradually contibutes to burning out the valve seatings over time.
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Valve clearances should be done on a cold engine.
Preferably on an engine that has cooled overnight.
If you ride your bike to the dealer and get it back later that same day then when did it get cold enough to check valves ?
I'm convinced that most dealers just listen to the engine - the clever ones will introduce a small oil leak on the cam covers.
Most bike engines will not need adjustment till at least 40k miles, assuming the oil has been changed within the schedule
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Valve clearances should be done on a cold engine.
Entirley down to each engine some engine manufactures do not quote a preference some quoted hot and cold clearences
One engine i worked on quoted tappets to be checked whilst hot
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Most bike engines will not need adjustment till at least 40k miles, assuming the oil has been changed within the schedule
The manufacturers recommend checks between 6000 and 27000 depending on the bike, that does not mean that they need adjusting rather that they should be checked. My ZRX is supposed to be checked every 7500 though Kawasaki have upped this to 15000 on later models I think simply based on feedback from dealers that no adjustement is needed until at least 15000.
Many Yamahas are 27000, quite amazing for 15000 rpm engines producing IRO 200 bhp/litre.
40000 is way to long between checks for any bike.
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I've got 75,000 miles on my bike now with checks every 27,000.
Luckily they're still in spec as lifting cams, followers and changing shims on 20 valves is a nightmare with the engine tucked up into the frame and would probably warrant doing it on the bench with the engine out.
There again, my old single cylinder 4 valve 650 needs them adjusting every 5000 miles, but is a piece of cake with old-style rockers.
Martin
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>>40000 is way to long between checks for any bike.<<
I agree - but I did say 'adjustment' not check. Adjustment is much more complex than check.
Also, I believe most bike engines are checked cold. It's often not possible to check them hot (ie at normal working temperature) becuase some form of dismantling is required - eg the radiator may need to come off. On some bikes - Honda's VFR VTEC is one - the engine may need to come out !
Cars can be quite different: on my Mazda - which has similar valve operation - the mnnual just says to listen to an engine after about 60k miles.
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Well, I expect I will get the valve clearances checked then.
But very interesting reading, and thanks for all your responses.
Greg
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And are valve stem seals anything to do with the valves and adjustment?
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They're nothing to do with the adjustment.
They sit on the stem of the valve and are intended to help stop oil running down past the valve guides and into the cylinder. Common symptoms of needing them replacing is blue smoke when you open the throttle after you have coasted for a while - maybe downhill with the throttle closed. Although there are other reasons for blue smoke.
Martin
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On a scooter, because of access I expect that to check the valves some of the plastics might need to come off.
I am hoping it shouldn't take longer than 2 hours. On my CG125 it probably takes an hour as access is really easy. I will let you know once I get it done
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I went down my local garage, and they listened to the engine and said it sounds fine. No reason to check the valves.
Obviously, the book says to check them every so often. The garage says if they needed looking at, then I would hear it being loud or the performance would be lacking.
I think I will just get them checked as per the service book. But it is amazing how much contradicting advice I have recieved!
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It all depends on the engine, some have screw and locknut which is easy, others have shims over the buckets, yet others have shims under the buckets (time consuming if you need adjustment, my old FZ750 took me 10 hours first time as the cams have to come out). Too tight and the engine will be quiet anyway, then it'll get hard to start. As previously mentioned, just go by the recommended service intervals
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I wouldn't say you've had a lot of contradicting advice.
Go by the book and you can't go far wrong.
Bloke listens and says "they're fine" - will he give you a letter saying that if you burn a valve he'll rebuild it as a freebie?
The gaps may well be fine in which case you think you may waste money checking them properly - but what if he's wrong?
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