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Phil Pearson clutch fitting problem #607481
07/06/15 3:21 pm
07/06/15 3:21 pm
Joined: Jul 2015
Posts: 20
Dereham, Norfolk
G
Graham Sullivan Offline OP
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Graham Sullivan  Offline OP
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Joined: Jul 2015
Posts: 20
Dereham, Norfolk
Greetings all.
Some years ago I purchased a Phil Pearson clutch and inner primary chaincase sliding plate.
After the Gold's storage for 27 years I am attempting to put it back on the road but I have tried without success to get the clutch to fit.
On initial assembly I found that the clutch basket was running out by 1/8th of an inch. 2x.064 thou thrust washers were needed to line the assembly up with the primary sprocket.
Then I found I could not get the crank nut started on the crank while having the shock absorber spring in the line.
Screwing the nut on without the spring, it would only go no more than approx. seven of the ten threads. To make it fit full-thread it was necessary to remove one of the 64 thou thrust washers.
This leaves me with the clutch basket running out by 1/16th. inch, which I feel will put wear on the alloy teeth.
The only way I have found to get round the problem is to refit my Triumph 4 screw clutch which will put up with the 1/16th. run-out as it has steel clutch-basket teeth.
This means I cannot use the Pearson inner primary chaincase sliding plate and use the standard BSA version, which I have re-fitted also.

The only way I can see round the prob. is to have a new nearside crank with an extra 1/8th. length made (but my motor is unused since a Pearson engine overhaul).

So, is any board member using a Pearson clutch successfully? I feel I'm missing something vital, ('can't see the woods for the trees' syndrome).

Many thanks in advance for any replies.

Graham Sullivan.

BSA Gold Star eBay items

BSA Gold Star forum This board is dedicated to BSA Gold Star motorcycles.

Re: Phil Pearson clutch fitting problem [Re: Graham Sullivan] #607483
07/06/15 3:27 pm
07/06/15 3:27 pm
Joined: Mar 2007
Posts: 1,153
Winona, MN
Swan Offline

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Swan  Offline

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Joined: Mar 2007
Posts: 1,153
Winona, MN
Graham,

It can be done, I am work at the moment and cannot get in to it too deeply, but take a look at this for reference: http://archives.jampot.dk/Technical/Transmission/Suzuki_Clutch_conversion.pdf


1966 Triton
1962 BSA DBD34 Gold Star
1966 Triumph Bonneville
Re: Phil Pearson clutch fitting problem [Re: Swan] #607485
07/06/15 3:59 pm
07/06/15 3:59 pm
Joined: Feb 2014
Posts: 382
Cork Ireland
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chaterlea25 Online content
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chaterlea25  Online Content
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Joined: Feb 2014
Posts: 382
Cork Ireland
Hi Graham,
From your description it sounds likely that the clutch shaft adaptor does not have a deepe enough taper?
The tapers are different depths between singles and twin BSA models

I would contact Phil and discuss the issue ?

The adaptors can be machined if you have the facilities to hand

With the alloy clutch sprocket the alignment needs to be perfect !!
I have photos of two worn Pearson sprockets caused by misalignment
I usually set this up with the rear primary removed for access

HTH
John

Re: Phil Pearson clutch fitting problem [Re: Graham Sullivan] #607494
07/06/15 4:35 pm
07/06/15 4:35 pm
Joined: Jul 2015
Posts: 20
Dereham, Norfolk
G
Graham Sullivan Offline OP
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Graham Sullivan  Offline OP
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Joined: Jul 2015
Posts: 20
Dereham, Norfolk
Thank you gentlemen for your speedy replies.

Swan; That is the write-up which made me decide on Phil's clutch.


chaterlea25; I have heard there are two adaptors for the Triumph clutch but have never seen one for a 'single' for sale, or even seen one for sale labelled as such.

I also believe Phil's clutch centre adaptor is the same as the Triumph one but I cannot remove it to find out, but as they both run out the same amount they must be identical.

It's a shame Phil didn't make his adaptor to fit 'straight out the box' for a single. A lot of grief would have been avoided by this action.

I did ring Phil and he stated it would be O.K. to pack the crank out but doing so has made me run out of crank to re-fit the crank nut fully.

Are you sure taking 1/8th. of an inch from the rear of the 'twin' adaptor, as it seems I have, will not mess up the corrolation of it regarding the mainshaft taper and keyway?

Many thanks again, chaps, for your replies but the only quick fix is one shim and the Triumph clutch or I'll miss the summer, which is quite rich for me to say given I've abandoned the bike for 27 years!

Regards, Graham.

Re: Phil Pearson clutch fitting problem [Re: Graham Sullivan] #607542
07/07/15 7:38 am
07/07/15 7:38 am
Joined: May 2011
Posts: 432
england
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GS DAVE Offline
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GS DAVE  Offline
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Joined: May 2011
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england
All main shaft tapers vairy and new off the shelf mainshaft adaptors vairy massively,I believe Phills have the scroll machined off to accommodate his alloy sliding plate.
In the past Phill has machined the adapter to suit my mainshafts so I could get good alignment.

Re: Phil Pearson clutch fitting problem [Re: GS DAVE] #607596
07/07/15 1:08 pm
07/07/15 1:08 pm
Joined: Feb 2014
Posts: 382
Cork Ireland
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chaterlea25 Online content
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chaterlea25  Online Content
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Joined: Feb 2014
Posts: 382
Cork Ireland
Hi Graham,
As GS Dave says its the taper bore thats different, sorry if this came across incorrectly.
Another thought is that some engine sprockets have different amounts of protrusion on the rear face, I have not measured them to compare the overall thickness,or offset (to see if this would effect a cure for your problem)

Most recently, I fitted an engine sprocket to an A10 which has a significant shoulder on its rear face (Wassell)
I used this in conjunction with an SRM clutch shaft adaptor and was delighted to find that it all lined up 100% !!
The chain line was now 1/8th plus further from the rear primary case
but had plenty clearance

HTH
John



Last edited by chaterlea25; 07/07/15 1:09 pm.
Re: Phil Pearson clutch fitting problem [Re: Graham Sullivan] #607652
07/07/15 7:15 pm
07/07/15 7:15 pm
Joined: Jan 2013
Posts: 185
Blue Mountains, Sydney Austral...
G
geordie Offline
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geordie  Offline
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Joined: Jan 2013
Posts: 185
Blue Mountains, Sydney Austral...
Just looking into my gearbox at the moment and got wondering if there is a measurement we should be looking for regarding how far the mainshaft protrudes from the gearbox, just a gasket missing from betweew the main case and inner cover would extend the mainshaft protrusion by the thickness of the gasket, also if the Mainshaft 1st gear is not pressed all the way onto the shaft it could have the same effect maybe not 1/8" but it all adds up


58 goldstar
74 commando
70 Thunderbolt
81 Darmah
Re: Phil Pearson clutch fitting problem [Re: Graham Sullivan] #607871
07/09/15 11:51 am
07/09/15 11:51 am
Joined: Jul 2015
Posts: 20
Dereham, Norfolk
G
Graham Sullivan Offline OP
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Graham Sullivan  Offline OP
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Joined: Jul 2015
Posts: 20
Dereham, Norfolk
Fellows,
you are right about the clutch hub tapers. I was speaking to the chap at Lyford Classic Spares and he has a stock of hubs, all of which are slightly different to each other in the taper bore department. He kindly offered to check mine against his if I sent mine to him, as he might be lucky and find one which may be closer to my needs. He also said he hadn't heard of 'single' and 'twin' versions.

GS Dave; You're correct there. Phil's adaptors don't need an oil thrower scroll as he made them to fit with his oil seal mod.

Chaterlea25; I had thought initially of getting a thrust washer to fit behind the sprocket but that move would add tension to the shock absorber assy., just as the two crank thrust washers have done.

Geordie; I think all the bikes should have the same distance from the gear sprocket to the end of the taper as all the shafts were made the same length. Could I be wrong?

However, chaps, this thread has, with the best intentions, turned into a discussion of the varied merits or not of the four spring clutch.

I would love to know how you blokes out there got the Pearson clutch to fit, (apart from GS DAVE's obvious and best solution - allowing you have the gearbox out and live in Great Britain).

Any offers from around the globe? Otherwise the four spring clutch stays and Phil's version with the plate become a discussion item hanging on my garage wall!!

Many thanks to all again, watch out for my next thread, should make you smile.

Regards all, Graham.

Re: Phil Pearson clutch fitting problem [Re: Graham Sullivan] #607889
07/09/15 2:26 pm
07/09/15 2:26 pm
Joined: Feb 2012
Posts: 1,212
Middle East,
Kerry W Offline
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Kerry W  Offline
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Joined: Feb 2012
Posts: 1,212
Middle East,
I had one of Phil's clutches on my DBD, though it was fitted by his mate, who rebuilt the rest of my bike, and lives about 1/2 mile from Phil in Norfolk. John Edwards is his name. let me know if you think talking to him might be useful (he's fitted a lot of Phil's clutches) and I'll PM you his contact details.

Kerry


No generalisation is wholly true, not even this one.
Oliver Wendell Holmes
Re: Phil Pearson clutch fitting problem [Re: Kerry W] #607896
07/09/15 3:32 pm
07/09/15 3:32 pm
Joined: May 2011
Posts: 432
england
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GS DAVE Offline
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england
Give Phil a call he will be able to sort it for you.
You don't live far away from him compared to most of us..

Re: Phil Pearson clutch fitting problem [Re: Graham Sullivan] #607902
07/09/15 4:44 pm
07/09/15 4:44 pm
Joined: Feb 2014
Posts: 382
Cork Ireland
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chaterlea25 Online content
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Posts: 382
Cork Ireland
Hi Graham,
I have sent you a PM re photos of setup

I found a measurement on one photo which shows 15.5mm of threaded mainshaft protruding through the adaptor, (original 4 spring) and the same dimension with a 6 spring adaptor
A pattern adaptor sat 1mm further out

(I dont have a setup to post pics here)

John

Re: Phil Pearson clutch fitting problem [Re: chaterlea25] #607956
07/10/15 6:11 am
07/10/15 6:11 am
Joined: Jan 2013
Posts: 185
Blue Mountains, Sydney Austral...
G
geordie Offline
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geordie  Offline
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Blue Mountains, Sydney Austral...
I have my clutch apart now I will get some pics so you can make comparison
Baz


58 goldstar
74 commando
70 Thunderbolt
81 Darmah
Re: Phil Pearson clutch fitting problem [Re: Graham Sullivan] #607968
07/10/15 8:42 am
07/10/15 8:42 am
Joined: Jan 2013
Posts: 185
Blue Mountains, Sydney Austral...
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geordie Offline
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geordie  Offline
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Joined: Jan 2013
Posts: 185
Blue Mountains, Sydney Austral...
I took the engine sprocket off and I had 0.050" of shim in there, the bottom pic is an attempt to measure the large end diameter of the taper





58 goldstar
74 commando
70 Thunderbolt
81 Darmah
Re: Phil Pearson clutch fitting problem [Re: geordie] #608006
07/10/15 3:45 pm
07/10/15 3:45 pm
Joined: Feb 2014
Posts: 382
Cork Ireland
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chaterlea25 Online content
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Joined: Feb 2014
Posts: 382
Cork Ireland
Hi All,
The previous measurements I gave were to suit a twin cylinder BSA,
I'm very limited at the moment due to injuries sustained in a fall so banned from the workshop !!
However I had a quick look at a Pearson clutch this evening and it measured the same as Geordie's

HTH
John

Re: Phil Pearson clutch fitting problem [Re: chaterlea25] #608024
07/10/15 10:00 pm
07/10/15 10:00 pm
Joined: Jan 2013
Posts: 185
Blue Mountains, Sydney Austral...
G
geordie Offline
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geordie  Offline
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Joined: Jan 2013
Posts: 185
Blue Mountains, Sydney Austral...
Originally Posted By chaterlea25
Hi All,
The previous measurements I gave were to suit a twin cylinder BSA,
I'm very limited at the moment due to injuries sustained in a fall so banned from the workshop !!
However I had a quick look at a Pearson clutch this evening and it measured the same as Geordie's

HTH
John

It will be apart till monday so any more pics or measurements you need just ask


58 goldstar
74 commando
70 Thunderbolt
81 Darmah
Re: Phil Pearson clutch fitting problem [Re: Graham Sullivan] #608360
07/13/15 12:23 pm
07/13/15 12:23 pm
Joined: Jul 2015
Posts: 20
Dereham, Norfolk
G
Graham Sullivan Offline OP
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Graham Sullivan  Offline OP
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Joined: Jul 2015
Posts: 20
Dereham, Norfolk
Greetings fellows, many thanks for your replies and the effort you put in to posting them, I appreciate it very much.

geordie; Ace pics, my setup looked exactly the same with the Phil Pearson hub but it was a no-no as I posted previously. I have the 4 spring clutch put back on now and all 'buttoned up'. As it will run with just 1 1/16th inch out I cannot bring myself to waiting for me to get the Pearson hub machined to fit and bolted on. Unfortunately I didn't measure it when originally offered up but it looked just like yours, certainly.

Kerry W; will keep that in mind if I ever decide to fit Phil's clutch. You said you HAD his clutch on your bike, any reason why you changed it? (Just nosey!).

I'm not sure if I explained my prob. properly fellows, but I ran out of crankshaft thread for the crank nut trying to fit the 2x .064 thou thrust washers to move the crank gear cog into line. The crank nut would only go on about 7 threads out of ten. One washer allowed it fit on full thread. Good enough for me and the 4 spring clutch (and Bobbie McGee).....

Once I have;
sort out the seat no-fit problem;
find a small drum for the handlebar end of the valve lifter cable;
get the 'new' kit start quadrant stub turned down so I can fit the kick-start lever;
got my speedo back from repair;
get the electrics working (though, in all honesty, I haven't tried them)and numerous other things I should be on the road!

Just trying to out-run the Grim Reaper!!

As an aside, my mate Johnny Kemp owned the Gold - 283HJH - in the early sixties and I bought it off of him when he decided to get married. (It was always quicker than mine - 1732 MK).

He worked at Smith's Industries in Cricklewood and often came home with odd bits (Police speedos were the best, large things complete with certs.) which the BSA reps. gave him. The best part is the 190mm 2LS front brake which is on the bike.

It is very distinctive and shows where it had been modified a number of times whilst in BSA ownership. The alloy welding craftmanship is worth a good look. I sent a pic of it to the Gold Star Owners Club some 25-30 years ago but am still waiting a reply. I watch the letterbox daily..

I feel the only way round the problem is to take the gearbox out and have the Pearson hub machined to fit.

Maybe sometime but not in my lifetime, I feel.

Many thanks all for your replies in attempting to get round the mis-alignment. They are appreciated very much.

Graham Sullivan.

Re: Phil Pearson clutch fitting problem [Re: Graham Sullivan] #608485
07/13/15 11:35 pm
07/13/15 11:35 pm
Joined: Feb 2012
Posts: 1,212
Middle East,
Kerry W Offline
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Kerry W  Offline
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Joined: Feb 2012
Posts: 1,212
Middle East,
Graham - bike was sold with Phil's clutch fitted...clutch was fully functional and all you'd expect.

Took it to the Gold Star summer event at Brooklands in June 2012, where I ran it up the test hill a few times. I was interested to see how the clutch coped with the hill and an RRT2 first gear, with a 21 tooth engine sprocket - no problems - could easily get it into second gear before the top, accelerating.

The Brooklands event was on the same day as Wal Handley won a 'Gold Star' on a hot 500 Empire Star, 75 years before. the plan was to have more Gold Stars in one place than every previously recorded. I think there were 275 in the end..

Having trouble uploading the relevant photos at present, but will post those if I can figure it out..

KW


No generalisation is wholly true, not even this one.
Oliver Wendell Holmes

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