The BSA A7-A10 Forum

Technical => Clutch, Primary, Gearbox => Topic started by: unclerob on 01.12. 2013 13:30

Title: New acquisition! Gear + Clutch questions
Post by: unclerob on 01.12. 2013 13:30
Thought I'd post some thoughts now I've had the bike for a couple of weeks....
The first ride was a fairly apprehensive one as the last on an A10 was at least 25 years ago, main concern was the brakes but happily far better than I expected, the rear is excellent (especially when used to change gear!) and the front adequate. I wasn't expecting the forks to be great but surprised by how just how harsh they feel, wondering if harder than standard ones were fitted during the rebuild so planning on trying a pair of the multi rate springs that I see Paul Goff sells, will also take the opportunity to fit long shrouds at the same time....
The only other disappointment was the gearchange, it has a very notchy feel to it, something I don't ever recall, guessing its clutch related because there seems to be a momentary hesitation in it releasing...almost as if theres glue in there instead of oil...if you see what I mean!! No problem in finding neutral though....any thoughts?
Otherwise, very very pleased, it was rebuilt about 4 years ago, very few miles since and whoever rebuild the engine did an excellent job, mechanically quiet (the exhaust isn't though!), no oil leaks at all, no wet sumping and starts second or third kick....which is fortunate since the compression is so high I think about 5 would be my limit before exhaustion sets in...

edit: split from http://www.a7a10.net/forum/index.php?topic=7718.0
 
Title: New acquisition! Gear + Clutch questions
Post by: fido on 01.12. 2013 16:00
They don't like fast gearchanges but if you do it in a slow, methodical manner it should be fine. If you have been exclusively riding modern bikes you need to get used to the much greater flywheel inertia of the A10.
Title: New acquisition! Gear + Clutch questions
Post by: unclerob on 01.12. 2013 17:05
True....I am used to more modern bikes but I think its more than that, for instance if you engage gear straight after pulling in the clutch it will clonk and almost lurch forwards...wait 2 or 3 seconds and its fine. I expect all will be revealed when I have a look inside, am planning several jobs on it but not til Xmas and in the meantime was just wondering....
Title: New acquisition! Gear + Clutch questions
Post by: duTch on 02.12. 2013 11:30

G'day Rob, I hope the neutrals you find is the one you need, there can be others where you don't expect...!!

  What Fido said about the changes, but mine is fairly quick compared to my Gutzzi...
 I reckon just use it for a while and get the feel...if it hasn't been used much, might just need a settling in period- take it out and play with it..!!

 lookin' good though, cheers , duTch
   
 PS, I think my G changes are quite slow, as it requires a lot of thought- L?/R?.....Up?/Down?......???-hit or miss!!
Title: New acquisition! Gear + Clutch questions
Post by: unclerob on 02.12. 2013 15:59
Know just what you mean Dutch...I've got a Honda with a reversed gearchange and a normal one on a Ducati and my feet have got totally confused! But it is more than just that, today I went to use it and the clutch wouldn't disengage at all, took all the slack out of the cable...then a bit more and it finally freed, re adjusted the cable but now it slips all the time....can't even kick it over....will investigate further when I have time. If something is really past it in there I might be tempted to buy it a Pearson clutch for Xmas!
Title: New acquisition! Gear + Clutch questions
Post by: duTch on 05.12. 2013 16:03


   *eek*
Quote
... and a normal one ....
*conf* *???* *dunno*
Title: New acquisition! Gear + Clutch questions
Post by: Stephen Foster on 05.12. 2013 16:32
Wonder if Anyone could please give Me some information on the "Pearson Clutch" please ?
Have a six spring nightmare on the "Shooting Star" & am looking for something better .

Thanks in advance ,
Steve ...
Title: New acquisition! Gear + Clutch questions
Post by: Triton Thrasher on 05.12. 2013 16:40
True....I am used to more modern bikes but I think its more than that, for instance if you engage gear straight after pulling in the clutch it will clonk and almost lurch forwards...wait 2 or 3 seconds and its fine.

That sounds like the spinning parts taking time to slow down. Thicker oil in the gearbox might help.
Title: New acquisition! Gear + Clutch questions
Post by: chaterlea25 on 05.12. 2013 21:49
HI Steve,
The Pearson Clutch is similar to the one in this post by Orabanda
http://www.a7a10.net/forum/index.php?topic=708.0
Attached are a selection of photos of the Pearson set up
Not a cheap option !! A 4 spring from a reputable supplier will be cheaper, Beware!! of the ones sold with crappy plates and nasty Wassel chain wheels !!!!
HTH
John
Title: Re: New acquisition! Gear + Clutch questions
Post by: unclerob on 06.12. 2013 17:31
Thank you for moving this..it sort of changed mid way through....sorry!
Anyway, I'm now fairly certain something is very wrong with the clutch, or worse....maybe the gearbox? The other day I managed to stop it dragging whilst I was playing with the cable adjustment but it was slipping when I tried it (with free play at the lever), today without touching anything it won't disengage at all!
My theory (for what its worth!) is the whole clutch is moving in and out somehow and making the pushrod length/adjustment constantly alter?
As far as I can recall that either means the bit attached to the mainshaft is loose but wouldn't it just come off and there'd be no drive at
all? Or worse, the gearbox mainshaft itself is somehow moving in and out but then it still selects all gears ok? Its a 4 spring type clutch by the way....
Will investigate properly as soon as I have time to spare but in the meantime I'm just about to order a Pearson clutch, I don't have any clutch parts at all for the other bike I'm putting together so from that point of view its not so much of an outlay (just under £500 inc the oil seal mod)
I've scanned an old magazine article that might be of interest....
oh, and btw there was a time when a right hand gear change was normal to me as well! I stopped riding British bikes in the early80's when I became a courier, after 10 years and more than 400 thousand miles on a variety of Honda 250's left hand ones were definitely even more normal!!
Title: Re: New acquisition! Gear + Clutch questions
Post by: morris on 07.12. 2013 09:19
Sounds exactly like mine when I got it. Slipping clutch, and when trying to adjust it wouldn't disengage anymore. Cause was the clutch loose on the shaft. The PO managed to dislocate the washer behind the nut when tightening it, so it worked itself loose. Worth a check.
Cheers.
Title: Re: New acquisition! Gear + Clutch questions
Post by: bikerbob on 07.12. 2013 14:39
Your problem could be the oil that is in the primary case if the oil is engine oil then the oil tends to make the clutch plates stick together thus making for a clonk when you put it into gear. I would recommend using straight 20 fork oil in the primary case much better for the modern clutch materials.
Title: Re: New acquisition! Gear + Clutch questions
Post by: Rocket Racer on 02.01. 2014 19:31
Any problem with the clutch will manifest as a difficult gearbox. You mention it almost lurches forward, ie is dragging. If its doing that throughout the box will feel sticky.
I'm guessing you haven't identified what clutch you have:
The 6 spring clutches are notorious and while its possible to get them to work adequately (I put up with one from 1985 until last year!) they would be an embarrasment in a washing machine. The primary issue being the bearings are patheticly budget balls rather than rollers so the baskets typically wobble and flop about.
The latter triumph type (4 spring) is a better bet and still standard and should be able to be made to function well although superior modern replacements including belt drive types are now available too if finances or engineering capabilities permit.

In my race A10 I run a Bob newby racing 6 spring belt drive (loverly  *respect*)
and in my super rocket I have a modified suzuki clutch.
my ZB33 now has a four spring triumph type and its a huge improvement, I was starting to think my plunger box was a bit sad, but a decent clutch really improved it.

However a BSA pre unit box will will always be a fairly slow changer (compared to anything modern) unless you upgrade to a TT industries replica box which is filly modern and your pockets are way deeper than mine.

Lovely bike!
Title: Re: New acquisition! Gear + Clutch questions
Post by: unclerob on 02.01. 2014 20:37
I haven't taken it apart yet as I'm waiting for a new clutch to arrive first so still don't know quite where the problem lies....it has a 4 spring clutch at present though.
I did think about a Newby one but decided on the Pearson partly because I'm a bit wary of belt drives, and also because I like the oil seal conversion that he does....
I'd be happy with the box if it was like other A10's, on this you veered across the road every time you changed gear because you had to put so much effort into it!
Though I wouldn't exactly describe it as dragging, I did find that if you held the lever in for maybe 2 seconds then changed gear, then it changed ok...ish, now though, its given up with that and slips continually...I haven't done anything at all except play around with cable free play.
I'm sure I'll find the problem when it comes apart but what I can't understand is if the clutch centre is loose on the mainshaft then surely I'd have no drive at all, end of story?
Its been so long that I can't remember how things are arranged but is it possible that the mainshaft is somehow moving back and forward a bit inside the box and causing this, rather than an actual clutch problem?
Title: Re: New acquisition! Gear + Clutch questions
Post by: morris on 02.01. 2014 21:05
I'm sure I'll find the problem when it comes apart but what I can't understand is if the clutch centre is loose on the mainshaft then surely I'd have no drive at all, end of story?

If it's a taper shaft (should be) then there's a woodruff key, so even with the clutch loose on the shaft you will still have drive.
Title: Re: New acquisition! Gear + Clutch questions
Post by: Rocket Racer on 03.01. 2014 00:50
There are many variables in clutch issues around wear or loose parts.
The 4 spring is not a bad clutch, I would suggest investigating before you spend.

Drag comes in various increments, could be wear in the basket or uneven lift making the clutch less free than it could be. but if the bike tried to creep briefly or doesnt find neutral while stationery its dragging.
Title: Re: New acquisition! Gear + Clutch questions
Post by: unclerob on 04.01. 2014 16:37
Well, problem found I think! I last rode it a couple of weeks ago, dragging quite badly but the after a couple of miles it started slipping....so much so that when I tried to start it the next day you couldn't kick it over...Today, I tried it again and clutch wouldn't release at all, so although I haven't got any new parts yet I just had to look and see...
First took out the case level bolt and a good bit of oil came out (have checked a few times and doesn't seem to be wet sumping btw), then drained it....over a pint of thick oil....gear oil I think. Way too much I believe? (Still haven't got round to buying a manual!!)
The clutch seemed to be lifting evenly so I took the springs and pressure plate off, still solid though, you could turn the engine over using the clutch nut (9:1 comp and plugs in), began hooking the plates out and they all seemed almost bonded together, some I had to force apart with a knife blade... you could still turn the engine with one of each left! Also the insides of the basket coated in a red rusty coloured thick grease and lots of pitting on the plain plates....
Should mention here that I bought the bike recently from someone who had had it rebuilt and then not used at all for about 4 years, all of the clutch parts seem to have been replaced.
So, I'm thinking that the general lack of use was causing the dragging and then as it got soaked in oil as I rode it, it began to slip, leave it for a while...the plates stick themselves back together again and so on....?
I was fully expecting to see the clutch hanging off and maybe some damage to the mainshaft so fairly pleased really, my plan was to fit a Pearson clutch to this bike and use the existing one on a bike I'm building from parts....is it worth attempting to clean the friction plates in some kind of solvent? I've tried cleaning up the plain ones and they are going to be OK I think...
Title: Re: New acquisition! Gear + Clutch questions
Post by: Triton Thrasher on 04.01. 2014 17:03
They'll clean in petrol, or any sort of kerosene.

Or boiling water and detergent.


The primary case may have filled with engine oil while the bike was idle for a long time. Some people use monograde 40 or 50 oil, which is very thick when cold.

A whole pint shouldn't leak through from the gearbox.
Title: Re: New acquisition! Gear + Clutch questions
Post by: muskrat on 04.01. 2014 19:50
G'day Rob. Sounds like the PO used the wrong oil and too much of it *ex*. Clean plates (and rest of primary) in solvent/petrol. Use ATF in there and try again, the older grade ATF type D is best. Set the lift square and all should be good.
Cheers
Title: Re: New acquisition! Gear + Clutch questions
Post by: WozzA on 04.01. 2014 22:32
When leaving the bike unridden for any length of time
we used to pull the clutch leaver in, & slip a 2" strip of bicycle tube over it & the grip.
to keep the plates separated...   *idea*
Title: Re: New acquisition! Gear + Clutch questions
Post by: muskrat on 05.01. 2014 00:49
Did you use new springs when re-commisioning it?
Cheers
Title: Re: New acquisition! Gear + Clutch questions
Post by: WozzA on 05.01. 2014 05:44
naaaa....  Harley springs never loose their tension...     *whistle*
Title: Re: New acquisition! Gear + Clutch questions
Post by: muskrat on 05.01. 2014 08:42
That's right WozzA, the gear changes are that slow you have time to use both hands on the lever. *fight*
Cheers
Title: Re: New acquisition! Gear + Clutch questions
Post by: unclerob on 06.01. 2014 20:23
Cleaned the friction plates in Jizer and got the worst of the corrosion off the plain plates, put it back together....and tried it....lovely!!!
Gearchanging is so much better and no sign of it slipping either....
I still have a Pearson clutch coming but no problem as the other bike I'm putting together has no clutch at all....just need to decide which one deserves it the most!
Title: Re: New acquisition! Gear + Clutch questions
Post by: muskrat on 07.01. 2014 08:42
Great to hear Rob. By the looks of the weather over there it'll be a while till it gets a good test.
Cheers
Title: Re: New acquisition! Gear + Clutch questions
Post by: Topdad on 07.01. 2014 12:36
Unless Rob fits floats !! BobH
Title: Re: New acquisition! Gear + Clutch questions
Post by: unclerob on 09.01. 2014 17:03
Or maybe try riding on water as Guy Martin did the other evening on tv! But really just pleased that I can now change gear easily....several other jobs I can think of to keep me busy though so new question in the fuel section now....
Title: Re: New acquisition! Gear + Clutch questions
Post by: unclerob on 18.01. 2014 11:21
Fitted the Pearson clutch this morning, lovely piece of engineering and very light. It came complete with a modified sealing plate with an oil seal in it since the clutch is designed to run wet, no problems at all fitting it and the only mod is to shorten the original pushrod. I hadn't realised before that the pressure plate bolts are just done up tight so there aren't any concerns about getting an even release...or how having to adjust the amount of pressure they apply, I don't think that's the case with the Bob Newby clutch so glad I chose this one.
Its wet and cold again today so only a brief try out....first impression is how light it feels, gearchange even better, finding neutral easy and from the feel of it so far, no question of it even thinking about slipping!
Now, I might have my rose tinted specs on at the moment but I think the whole transmission seems quieter as well...so, overall very pleased!!
Title: Re: New acquisition! Gear + Clutch questions
Post by: muskrat on 18.01. 2014 12:32
Isn't it marvelous what a difference a good clutch makes. Gear changes twice as quick and neutral is where it should be.
BSA made a great step forward with the plunger 6 spring, then 4 steps back with the s/a 6 spring. *problem*
Cheers
Title: Re: New acquisition! Gear + Clutch questions
Post by: unclerob on 19.01. 2014 12:13
It is....had another ride this morning...(the suns shining for a change!)....and it feels like a different bike....
Since I'd already sorted the problem with the original clutch I was wondering if it was going to be sensible buy but it is, no doubt in my mind at all.
Oh, and btw, found a probable reason for the high oil level before, the level bolt hole was blocked with sealant...thinking whoever assembled it before kept on putting oil in until he ran out of the stuff!
Title: Re: New acquisition! Gear + Clutch questions
Post by: BSA_54A10 on 28.02. 2014 03:41
Have you checked & changed the gear box oil ?
It is not uncommon for owners to "fix" a leaking gearbox by shoving grease in there.
This will make the changes really slow