Hi
I have a problem where on my scooter the head bolts should be torqued to 5nm. I cannot find a torque wrench that allows you to torque to such a low torque value. Can anyone shed some light on this?
Also can anyone give advice on valve adjustments, and whether this should be done as per the guidance in the manual. Many mechanics say no, but only a handful say yes. It has not been completed on my scooter for 24000 km, and being a small engine i.e. only 125cc, I would like to do this task without destroying the engine or valves, and take into account that I have never completed this task myself. The biggest job I have attempted is a coolant change, which is a very easy job if you do not get air locks!!!
Thanks for your advice
Gregory
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Are ALL the head bolts supposed to be 5nm? I suspect that must be a misprint or mistake in the manual, that's about 4 ft-lb which is really not very tight at all, and nowhere near enough for a cylinder head.
I'd expect it to be more like 20-25nm.
After 24000km I would definitely check the valve clearances!
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Are ALL the head bolts supposed to be 5nm? I suspect that must be a misprint or mistake in the manual that's about 4 ft-lb which is really not very tight at all and nowhere near enough for a cylinder head.
The head bolts on my old Yamaha 'Fizzy' were only 6 ft-lb's, and there were only 4 of them. I just used to guess tighten them up. In other words - start by doing them up finger tight, then nip them up with a spanner until they felt about right. Never had any problems.
edit - as for a torque wrench that goes down to small settings, you need one that's specifically made for motorbikes, bicycles, etc.
Edited by Dynamic Dave on 21/07/2009 at 22:21
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>>> The head bolts on my old Yamaha 'Fizzy' were only 6 ft-lb's, and there were only 4 of them. <<<
wow, that's a lot less than I'd have thought.
My Suzi 380 triple's head bolts (4 per cylinder) are 25ft-lb, on Yamaha RD250s it's 18-20ft-lb.
As the OP's scooter is a 125 I would have thought it would need at least double-figure ft-lbs.
I got a reasonable Draper torque wrench off Amazon that does 10 - 80nm for under £20 delivered.
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Inexpensive one here -
www.pvrdirect.co.uk/productinfo.aspx?catref=STW101
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I wouldn't use a torque wrench right at the lower end of its range of adjustment. Make sure that it will go lower than the setting at which you want to use it.
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Why bother with a torque wrench for just occasional use. If I want to torque something outside the range of my torque wrench, I use a spring balance. Measure 12" along the bar of the socket set, and pull with the spring balance until it reads 4lbs, for 4 ft lbs (or 6" and 8 lbs etc.)
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That is hardly more than finger tight!.
I've also used the spring balance method on a ratchet handle.
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I've used the fat-git-stood-on-the-breaker-bar-at-the-right-point method for setting the torque on hub nuts :-)
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I've used the fat-git-stood-on-the-breaker-bar-at-the-right-point method for setting the torque on hub nuts :-)
So do most tyre shops.
Unfortunately few of us carry a fat-git-stood-on-the-breaker-bar-at-the-right-point in the wheel well for use during roadside punctures.
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He said Hub nuts not Wheel nuts. Big difference in torque usually. (certainly on mine, where it is big git standing on scaffold pole on breaker bar).
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A former colleague of mine once asked someone who was involved in the maintenance of Army helicopters what the torque setting was for the bolts that held the rotor blades on.
His answer was "tight as a pink fluffy dice, plus half a turn". :-)
Edited by Dynamic Dave on 25/07/2009 at 00:19
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I've actually got a torque multiplier which we use for our helicopters in the warehouse at the moment for service and recalibration , beautiful bit of kit but a bit big for a scooter..
Sweeny Model 8200 if anybody is interested....
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Yeah, well you don't want the rotor blade spinning of because it wasn't torqued down enough! ;--)
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But Mr Helicopter please tell what torque you use...
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tell what torque you use...
Yes... tight as a bandaid was it? Doesn't sound very tight to me.
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I'll be surprised (quite possible!) if torque settings are used for critical bits of helicopters like the main rotor. I'd expect some sort of strain measurement.
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That particular torque multiplier has a rated output capacity of 3,000 ft lbs......
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