Author Topic: Replacing Clutch plates on early GT  (Read 747 times)

Offline Shajota

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Replacing Clutch plates on early GT
« on: October 29, 2019, 07:00 »
Don’t post on the forum much anymore (not sure, perhaps in our age of easily offended it is not quite the freewheeling media it once was (dunno)) but one thing for sure it is a great mine of information and I always search here when I need to undertake something unfamiliar.
Last year couldn’t find a lot of info on replacing the clutch plates on the early 750’s with peg retainers so thought I’d try and add something. Obviously will be nothing new to many on here however hopefully this may help someone new to these older models (as long as it makes sense!!) At the very least I’ll post it for my own amusement :-[
So, after getting the American Eagle up and running it’s clutch started slipping. Couple of oil changes had little impact so decided best to bite the bullet and replace the clutch plates.
A bit of research prior suggested this may not be as straight forward as imagined however onward we must.
I took some notes and pictures at the time and thought I would eventually post some details up from my know nothing perspective – so here goes!!
Ok, so off with primary cover, undo crank nut and hit first snag.

Couldn’t get the oil pump gear off for love or money. Ask some more questions and just gently keep trying (noting advice not to lever the gear!!) Eventually I felt some movement and confident the key was in the right spot applied a bit more force and out she came. One of the problems was that the shaft was tight and did not turn freely in its bore – more on that later. My key way was at 3 o’clock.
So off with the sprocket, primary chain and clutch drum. 
Had a good look at the pegs securing the clutch and decided they shouldn’t be too hard to get out but obviously needed a slotted tool to push while removing the pegs.

So whipped around to my tool bench and manufactured an appropriate tool!!

Actually that is a bit of hard plastic tube I found on my garage floor from an unknown source which had the perfect inside and outside diameter. I just cut a slot and shoved a screw driver down the other end as a push handle ;)
Removing the pegs turned out to be quite easy. As you compress the buckets just turn the rods so pegs are vertical and once buckets pressed far enough in they just drop out, so pretty much a one handed job while holding the bike stable.
With clutch apart also thought it best to replace the clutch cush rubbers so this obviously necessitated removing the rivets (subject has been well covered before). Rivet rivet...:-

Read on here that it best to drill the rivets to avoid damage, however as I did not have a drill press decided to cut them off using (Pros, look away now :o) – the dreaded Dremel. Actually this worked brilliantly as I could cut close to the surface and with a very gentle tap the rivets just fell out. (obviously using the proper reinforced Dremel cutting wheels available and not the standard ones which shatter at the mention of any hard work.)
With all apart, took the clutch drum to my local engineering works (who I know are particular) and had them drill and tap for replacement screws. Put in new clutch rubbers and assembled using hex heads as recommended.
All done, new clutch plates to hand and time to reassemble. Clutch drum looked fine:-

Ahhh, first question, how to hold everything while you compress the "buckets" against the clutch springs to enable placement of pegs with motor in situ?
Enlisted one of my adult sons for help, however this resulted in much arguments about who was not doing their bit right, bike nearly toppling over a couple of times, no pegs inserted and as it was Friday night, tools down and tinnies up (drink)
Next morning decided to tackle by myself with a clear head and new thought process.
Process was – Sat on a low stool with chest directly in front of the clutch (bike was on a lowered bike ramp)
Held top frame rail with left hand, positioned push tool slotted end in each "bucket" with other end pressed against chest (suitably padded with rags) Pushed on tool with chest to compress the clutch springs and used right hand to place pegs in hole with needle nose pliers, often just starting them off then easy to tap them home. After a couple of goes, Eureka, in they went and smooth sailing using this process for the remainder of the pegs. Easy as!!
(Obviously another solution would have been to very securely tie bike down, but c’mon no easy options here and I think it felt more secure holding against own weight!)
Reassembled the primary drive and tried inserting the oil pump gear however the shaft was definitely binding.
Had previously cleaned up the bore in the pump with a bit of wet and dry and ensured it turned freely however something was definitely amiss as when inserted it was not free to turn. Took apart and loosened pump. Inserted and all good. The pump was definitely going out of alignment when tightened. Decided a shaft needed to be inserted prior to tightening so used a 12mm (I think it was) axle I had to insert giving me room while starting to tighten. I also replace the slotted screws with some cap heads so I could then take out axle shaft insert the gear shaft most of the way and still able to tighten further. I know the manual says to partly install gear to ensure alignment but this really needed to be in until nearly fully tight or the pump would somehow misalign. This worked well and gear could now be inserted freely and rotate easily. Amazing, another win!
Reassembled primary cover, installed the advance mechanism and points, put in fresh oil and took for a test spin. Glad to say, no slippage and effort well worth it…………….. 
(Hope that helps someone & the write up doesn’t contain too much dribble or bad advice :-\)
PETER

Offline Cosi

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Re: Replacing Clutch plates on early GT
« Reply #1 on: October 29, 2019, 07:40 »
So the Friday night was a bit of a letdown by the sounds of it...
Hastings Point 2489 Australia

Offline Shajota

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Re: Replacing Clutch plates on early GT
« Reply #2 on: October 29, 2019, 08:00 »
So the Friday night was a bit of a letdown by the sounds of it...
Probably should have said - we nearly got there a few times but just couldn't seem to compress the springs far enough to expose enough hole for the peg. I was nearly convinced new plates were too thick! Plus not enough space for 2 of us and if you saw my garage you'd understand (Full of crap  :o )
Actually it always amazes me that after you sleep on a problem a fresh approach often solves the issue - oh well.............
PETER

Offline Vince

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Re: Replacing Clutch plates on early GT
« Reply #3 on: October 29, 2019, 08:08 »
Just that and a cup of coffee were the basic tenants of Zen and The The art of Motorcycle Maintenance. It just took him 1000 every long pages to get down to it.

Offline bazzee

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Re: Replacing Clutch plates on early GT
« Reply #4 on: October 29, 2019, 08:21 »
Laverdapedia has some extra tips on cleaning up the clutch drum while it's out of the engine, plus drilling oil drainage holes.

Cheers,

bazzee
« Last Edit: October 29, 2019, 09:10 by bazzee »

Offline Paul Marx

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Re: Replacing Clutch plates on early GT
« Reply #5 on: October 29, 2019, 08:24 »
Nice illustrated story.
Note the large teeth on the oil pump/ignition drive gears.

Paul

Offline Dellortoman

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Re: Replacing Clutch plates on early GT
« Reply #6 on: October 30, 2019, 02:59 »
Good write-up Peter.

Never seen those spring retaining pegs before. Were they used on all 750 twins?
My Jota has bolts to hold the springs. Much easier to assemble.

Cam
Location: Tasmania, Approx 42°53’S 147°23’E

Offline Paul Marx

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Re: Replacing Clutch plates on early GT
« Reply #7 on: October 30, 2019, 06:58 »
Good write-up Peter.

Never seen those spring retaining pegs before. Were they used on all 750 twins?
My Jota has bolts to hold the springs. Much easier to assemble.

Cam

Nope, those pegs were only used until sometime during 1970.
Along with a steel clutch basket and tensioner wheel rather than slipper.

Paul

Offline Tippie

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Re: Replacing Clutch plates on early GT
« Reply #8 on: October 30, 2019, 13:11 »
Great little write up mate. It's not a hard job is it. Did you use a rattle gun for the crank nut?
From the comment about oil drain holes, I have not modified the outer drum on either my race or road SFs and never had a problem.
SF2 17483 (race)
SF2 17424 (road)
An Australian living near Oslo in Norway

Offline Shajota

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Re: Replacing Clutch plates on early GT
« Reply #9 on: October 30, 2019, 20:34 »
Thanks for the comments gents (tbh wasn't sure how it would be recd...)
Tippie - Yep, used a rattle gun on the crank nut. Agree, process is not hard, just hadn't seen much comment on these clutch set ups (to be fair it is pretty obvious how the pegs go in and out :-[) Probably more about what you might come across..............
I normally use things such as the green book for a base when undertaking something new, but I always trawl this site as it will often unearth many variances on process but will eventually get to some important nugget of information, so just thought I'd add this for the hell of it. (Also not averse to asking the experts)
Actually I am often surprised these days reading about the pitfalls of doing things I've done previously.
Used to think like that old advertising slogan "Just Do It" but getting a bit paranoid these days :o ;D
PETER

Offline Vince

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Re: Replacing Clutch plates on early GT
« Reply #10 on: October 30, 2019, 23:34 »
When you have a component virtually explode while doing a very simple job then I become paranoid about doing anything. I while back I replaced a tyre on my Pantah and while nipping up the rear axel at what I thought was a reasonable toque something suddenly went bang and flew across the shed with great force. It was one of the alloy curved plates that had the wheel adjuster slot in it. There 5mm thick alloy and one had shattered. It still shocks me how hard it went at not much pressure. I now second guess everything I do on the bike. Got some spark plugs to change and it worries me now.

Offline Dellortoman

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Re: Replacing Clutch plates on early GT
« Reply #11 on: October 31, 2019, 01:34 »
Blimey Vince. I've never heard of one of those aluminium axle plates busting before. It's difficult to understand why it would happen. They're basically just a gap filler between the curved swingarm tube and the flat washer under the axle nut.
Location: Tasmania, Approx 42°53’S 147°23’E

Offline Vince

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Re: Replacing Clutch plates on early GT
« Reply #12 on: October 31, 2019, 02:18 »
The only thing I could think of was an unsupported cavity or gap somehow suddenly compressed. The bang was like a gunshot. I had fun finding a set, an odd bit of trivia, 3 are the same and one is a bit thicker. Got a set off that Melbourne Euro Wreaker at eye-watering cost, happy they at least had them.

Offline Dellortoman

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Re: Replacing Clutch plates on early GT
« Reply #13 on: November 01, 2019, 00:22 »
… an odd bit of trivia, 3 are the same and one is a bit thicker.

Well, you learn something every day! I've never noticed that. I've probably reassembled them in the wrong position on my MHR then. Whenever I've had the back wheel out, I've not taken any notice of which plate goes where.
Do you know the reason for the thicker one, and where it's supposed to go?
Location: Tasmania, Approx 42°53’S 147°23’E