uberf1end
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| posted on 10/3/03 at 09:12 AM |
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B*stard Blade Clutch
I've got issues with my clutch and, being mechanically challenged, I am having trouble actually working out what the problem is.
Basically, the clutch does not disengage properly after downshifts. You have to give it a couple of thousand revs then back off the throttle and it
disengages.
The pedal itself stays depressed until the clutch comes out.
As I said, I am very much a beginner when it comes to mechanics and, looking in the F'blade Haynes manual, clutches look all wrong to me!!
Do the uprated TTS springs have any bearing on releasing the clutch?
(I assume these are the multiple small ones not the larger ones with the cicumference of the plates)
Could it be the return spring on the little arm on the clutch cover? If so, can you get beefier ones?
I have checked and the oil level is just right.
Any help much appreciated..
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Rorty
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| posted on 11/3/03 at 03:28 AM |
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Are you absolutely sure the oil level is correct? A slipping clutch in that scenario is a classis result of overfilling.
BTW, someone's bound to pop up and say don't use fully synthetic oil for this reason. BOLL@X! Either the clutch works or it doesn't.
The problem could be due to several other anomalies:
1/ If you have a very long (soft) pedal, the clutch will often slip.
2/ The friction plates may simply be worn out.
3/ The steel plates may be warped due to overheating (lots of slipping = vicious circle)
You're correct in your analysis of the clutch springs. I feel the main problem though, could be your technique. You can't drive a BEC like a
conventional car, as the gearbox/clutch designs are totally different. With a dog box (bikes have dog engagement boxes), the clutch shouldn't be used
when changing gear, especially when down changing. Regular cars have synchromesh boxes, and won't normally engage without using the clutch.
If you fit new clutch plates, or otherwise fix the current problem, you'll end up destroying the clutch and more importantly (read: expensive),
you'll destroy the selector forks and drum, and could also end up damaging the dog teeth on the sides of the gears.
Only use the clutch for pulling away and stopping.
I race a BEC off-road, and thrash the suitcase out of my ZZR1100 engine. I even move off in 1st without the clutch sometimes, though admittedly, only
on grass.
The best advice I can give you, is to learn a new style of driving. Also, even though it may sound fantastic, don't change down as you brake, using
the engine compression. It works in a car, but you're asking for trouble in a BEC. Brake with the brakes, and quick-shift when engine and wheel
speeds are almost equal, then you can jump back on the power to exit the corner or whatever. You'll never have clutch/box problems again, and it will
make you a better driver. Cars nurture bad habits!
Cheers, Rorty.
"Faster than a speeding Pullet".
PLEASE DON'T U2U ME IF YOU WANT A QUICK RESPONSE. TRY EMAILING ME INSTEAD!
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StuartA
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| posted on 11/3/03 at 11:21 AM |
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Don't you mean especially when up-changing? I always thought it was OK to go up through the gears without the clutch, but you had to be a bit careful
doing the same thing coming back down? 
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Jim
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| posted on 11/3/03 at 11:35 AM |
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I heard the same as Stuart. I have just asked a biker at work and he says the same thing. Clutchless up shifts and clutched downshifts
Cheers
Jim
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MK9R
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| posted on 11/3/03 at 12:04 PM |
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I used to ride bikes and thats how i did it; clutchless up, clutch down
Cheers Austen
RGB car number 9
www.austengreenway.co.uk
www.automatedtechnologygroup.co.uk
www.trackace.co.uk
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uberf1end
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| posted on 11/3/03 at 08:28 PM |
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Cheers Rorty, I will experiment.
You're right about normal cars - at present I drive an Escort (gotta have something sensible to go with your BEC)
and my only real experience of a decent car is a Lancer Evo 6 which will forgive you anything - just point it where you want to go, put your foot down
and the magical little Japanese brains sort it all out....
The rest of you....just stop confusing me . I was happily reading Rorty's message, feeling pretty confident and pleased with his response...then you
lot go and throw a spanner of doubt in....cheers
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Rorty
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| posted on 12/3/03 at 04:18 AM |
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StuartA:
quote:
I always thought it was OK to go up through the gears without the clutch, but you had to be a bit careful doing the same thing coming back down?
Up or down.Yes you do have to be careful when changing.
It's like telling a L driver they have to be careful with the throttle pedal....you develop a technique.
Trust me (as all good Gynaecologists say), it's definitely clutchless up and down. I've raced these things off-road for years, and I've had
street bikes, trials bikes, motocrossers, and it's always been the same. Dog boxes don't require clutching when moving, they do require a
technique, which is quickly learnt.
If you still don't believe me, ask William Hewland, Hewland makes dog boxes (and others) for just about everything with an internal combustion
engine.
Any of those mentioned above who use the clutch for down shifting....well, OK, whatever you like. A bike has less mass than a car, so the effects
won't be so detrimental.
I really abuse my car, and I don't have any clutch or gearbox problems, simply because I leave the clutch alone.
Cheers, Rorty.
"Faster than a speeding Pullet".
PLEASE DON'T U2U ME IF YOU WANT A QUICK RESPONSE. TRY EMAILING ME INSTEAD!
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ProjectLMP
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| posted on 12/3/03 at 04:53 AM |
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You can pretty much use either technique for downshifts. The following hewland FAQ describes the options for up and down shifting
http://www.hewland.com/svga/help.htm
Home of the Astronomicalcost Mid engined LMP project
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StuartA
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| posted on 12/3/03 at 09:22 AM |
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Sorry wasn't trying to confuse anyone 
I have ridden bikes for a few years too, and read many magazines which promote the use of clutchless changing. However all those magazines seem to say
it is OK for up changing but not highly recommended for down changing. I agree that if the engine revs are correct then it isn't going to do any
damage on the down change, but the method for up changing is very easy to master (pressure on the lever, blip the throttle, in she goes ). Still not
convinced about the down change and I've never done it on the bike (and I'm not about to start), but it seems as if it is OK so long as you are
careful so go for it.
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loafersmate
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| posted on 15/3/03 at 09:17 PM |
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Talk to anyone who has raced gearbox karts, they only use the clutch to bump start the engine!!! the technique is to apply a small amount of pressure
to the gear lever before you actually want to change, then as the revs/wheel speed meet the gears will schnick together nicely!!....this is all theory
to me though as the sva test is still a month away!!
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loafersmate
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| posted on 15/3/03 at 09:18 PM |
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Talk to anyone who has raced gearbox karts, they only use the clutch to bump start the engine!!! the technique is to apply a small amount of pressure
to the gear lever before you actually want to change, then as the revs/wheel speed meet the gears will schnick together nicely!!....this is all theory
to me though as the sva test is still a month away!!
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Alez
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| posted on 21/6/05 at 10:55 AM |
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Bringing up this old thread..
I've been reading this interesting thread, and I was wondering something: if you wanted to down-shift say 3 gears (let's say you are
approaching a slow bend) as quickly as possible (while braking hard), is there a reason why you would use the clutch 3 times?? This question is
assuming you want to use the clutch for downshifts. Could you not push the pedal, do the 3 down shifts, then release?
Cheers,
Alex
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mad-butcher
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| posted on 21/6/05 at 07:58 PM |
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if memory serves me right from when i used to have a k series 750 4 outfit each down shift was worth 2000 revs so changing down 3 at once you would
have to scrub off some speed as your rear wheels would be driving the engine.four strokes are brilliant for engine braking 2 strokes on the other hand
are crap change down 3 let the clutch out the F~~~ing thing just goes faster
tony
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ReMan
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| posted on 21/6/05 at 10:56 PM |
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Could it be the b*stard clutch cable stiff and dragging causing these problems.
Does it have a loop/ tight turn in it?
www.plusnine.co.uk
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