Early GT Clutch springs

Shajota

Shajota

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Location
Whitsundays Qld
Anyone know what is correct length for clutch springs for an early GT and if any replacements of similar size are known / available.
My Eagles clutch has started slipping again. I put new plates in a few years ago and they have only done about 26,000kms and I think new springs would be good. (Clutch started acting up after the river crossing at Bellingen last year:oops:)
If I can't get replacement springs will look at putting a couple of washers in bottom of tubes that hold the springs, hopefully will work good enough...?
 
There’s nothing within the operating mechanism other than the clutch springs to pull the cable back. I found on my GT that I sometimes needed to give the handlebar lever a flick outwards to stop the clutch slipping. This was the case even with a smooth cable!
 
Without checking the literature, I think that spring free length is the same throughout the range. 46mm is it?
I concur, they do tend to slip when cold, leave plenty of free play on the cable. Wear in the bronze bush seems to have an influence as well.
Paul
 
clutch slip is very often the springs, I reckon about 3 or 4 sets of springs to one set of lined plates, I have recently had a very bad experiance with pattern springs from Motalia, dont buy those ones. The very early twins had the springs retained by a cross pin, later and most of them had them retained by 6mm bolts, the spring lengths between these tow types, might be different, that needs checking and I dont have early parts books (Gert?) the 750 SFC had stronger springs and in a bike without a clutch pull mod they would make it unridable, so sorry Paul the spring length may well be the same throughout the range but the SFC is definately a stronger wound spring. If someone knows the source of, and has tried and proved the parts for pattern clutch srings, then I would like to learn who that is, 3 sets needed if the triples use the same types, another check needed ?
CLEM
 
CLEMTOG said:
clutch slip is very often the springs, I reckon about 3 or 4 sets of springs to one set of lined plates, I have recently had a very bad experiance with pattern springs from Motalia, dont buy those ones. The very early twins had the springs retained by a cross pin, later and most of them had them retained by 6mm bolts, the spring lengths between these tow types, might be different, that needs checking and I dont have early parts books (Gert?) the 750 SFC had stronger springs and in a bike without a clutch pull mod they would make it unridable, so sorry Paul the spring length may well be the same throughout the range but the SFC is definately a stronger wound spring. If someone knows the source of, and has tried and proved the parts for pattern clutch srings, then I would like to learn who that is, 3 sets needed if the triples use the same types, another check needed ?
CLEM
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C'mon Clem, we're talking about spring free length, not the strength of them.
Free length new is 48mm, service length is 46.5mm.
750 and triple springs are identical.
SFCs are ridable.

My SF2 has had the same springs and plates since 1992 and over 150 000 km.

Paul
 
Ummm, well, I understand I know jack shit, but I am surprised to hear that my engine isn't warm enough to avoid clutch slipping. I just wish I knew that before stripping the clutch out.....
(edit)
I thought I had a reasonable handle on what is happening and I believe for better or worse the clutch springs the most likely culprit (as noted by Clem).
Anyway, not to worry I will get it sorted.
**Just for info - it should be noted that the early bikes had fewer clutch plates than the later 750's and I am sure the springs are not the same length, I just haven't been able to find the spec - hence the question.
I see springs advertised for 750's as being 47.5mm long (including the heavier duty ones , just different number of coils - supposedly for SFC spec) however these would clearly be too long.
(Wolfgang advises me that the GT springs are no longer available and I am sure he has more cred than me.)
No offence meant to anyone, I was just finishing a long Saturday night with a couple of Kirin Ichibans when I thought I'd see if I had some suggestions.
I now realise a couple of black beers will be in order and hopefully I will remember my old mans words - don't take offense, it's what keeps the dogs in and the cows out ......................... 😊
 
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The early steel-bodied clutch did indeed have different springs than the later alloy clutch. Wire guage is a tad thinner than the later items but with the same winding count, therefore the spring rate will be slightly lower. But, as I've never had the opportunity to get hold of new originals, I have no idea of the free length of these. The later springs can be used in the early clutches without issues.

In my experience, clutch slip is often caused by warped plain plates, sometimes by worn out springs, sometimes by worn hub and basket splines and rarely by contaminated lined plates. Sometimes by all at once, to save time and expense, just swap out the whole caboodle (or as much as possible)... at least the steel hubs are the least prone to wear.

piet
 
sfcpiet said:
The early steel-bodied clutch did indeed have different springs than the later alloy clutch. Wire guage is a tad thinner than the later items but with the same winding count, therefore the spring rate will be slightly lower. But, as I've never had the opportunity to get hold of new originals, I have no idea of the free length of these. The later springs can be used in the early clutches without issues.

In my experience, clutch slip is often caused by warped plain plates, sometimes by worn out springs, sometimes by worn hub and basket splines and rarely by contaminated lined plates. Sometimes by all at once, to save time and expense, just swap out the whole caboodle (or as much as possible)... at least the steel hubs are the least prone to wear.

piet
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Thanks Piet. As I mentioned to Paul I was concerned about trying to compress the springs which I presume are a fair bit longer than originals. (I will send you a pm later today).
 
Shajota said:
Thanks Piet. As I mentioned to Paul I was concerned about trying to compress the springs which I presume are a fair bit longer than originals. (I will send you a pm later today).
Click to expand...
Have everything in stock Peter
Leaving Darwin this afternoon, home Thursday
 
The first time my 3c went on a Dyno the operator made an interesting comment about clutch slip. He mentioned making sure all the springs were the same length, having one shorter could produce a flutter and sudden slippage at high revs. He did another thing I found interesting at the time, he drained each float bowl into a measuring beaker to confirm equal float heights.
 
Shajota said:
Thanks Paul, did you have any issues compressing the springs to get the pins in?
I know I had enough trouble compressing the shorter springs when I changed the plates.
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It was 25 years ago and I don't remember having a problem.
I made a tool from copper plumbing tube in the form of a T. T handle a split at the bottom of the tube to get the pins in.
I'm not certain now that I changed the springs!
They had a washer under each and the clutch was ridiculously heavy. I may well have rebuilt it simply taking out the washers and reusing the springs, and it works fine, though it does get hot and fussy in traffic, no doubt due to the steel basket.
Paul
 
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