The BSA A7-A10 Forum

Technical => Lucas, Electrical, Ignition => Topic started by: Mosin on 13.05. 2010 10:30

Title: Touchy Feely
Post by: Mosin on 13.05. 2010 10:30
I realise that I am probably out on a limb here asking a load of grizzled old bikers, mechanics, engineers and the like to discuss feelings, but here goes....

I am pretty new to the whole classic bike scene but have recently done a lot of work on my A7ss and it now starts and runs pretty well. Or so I thought. Because I have been running it in after an rebuild I have not really been using much throttle or taking the bike over about 40mph. This has been fine. However, now that I have covered nearly 1000 miles, I am thinking about gradually opening it up a little and this is where my question lies.

The bike seems to be running sluggishly, particularly at the lower end of the rev range, and does not seem very willing to accelerate much past about 55mph (although I must admit I have not pushed it very hard). It also seems to be running quite hot - although it has never shown any sign of siezing on me. During the rebuild, I converted to Pazon electronic ignition and I am very pleased with that, but I am concerned that I may not have got it set quite right.

I have read dozens of threads where people talk about their bikes runing "slightly advanced" or running "excessively retarded" or whatever. My question is, how can you tell this by riding them? What does advanced or retarded ignition actually FEEL like when you are riding the bike? There is a certain amount of advance/retard adjustment on the pazon unit (I think about 20 degrees) and I have currently got it set in the middle of this, but I could do with knowing which way to rotate it in order to fix things, but I will only know this if I can establish whether I am (or more specifically, the bike is) excessively advanced or excessively retarded at the moment.
Title: Re: Touchy Feely
Post by: MG on 13.05. 2010 11:44
Don't worry, we all have an emotional side when it comes to our bikes.  *smile*

IMHO the best way of telling whether ignition is set up properly is getting a cheapo timing strobe gun (25-30 Euros here). Mark one teeth on the crankshaft sprocket and make some marks on the inner primary cover with the degrees from TDC to maybe 40 deg BTDC accordingly and you can really see what the igntion system is doing at different revs and whether your setup is correct.

This is what I'm using:
http://cgi.ebay.co.uk/NEW-DRAPER-PISTOL-GRIP-XENON-STROBE-TIMING-LIGHT-52616-/290416446574?cmd=ViewItem&pt=UK_Diagnostic_Tools_Equipment&hash=item439e2b4c6e

Cheap and no means of adjusting the strobe timing, so nothing to go wrong *smile*

Ref feeling: Retarded ignition feels very much like you described it. Lack of power and an increase in exhaust temperature (ex pipes turning blue rather quickly).
Over-advanced ignition on the other hand causes premature detonation (pinging), which imposes extremely high stresses on all the engine components (rods, crank, pistons, bearings), finally leading to serious damage (worn bearings, holed pistons, broken rods/crank etc.). The pinging noise sounds like someone hitting a bell with a small hammer and occurs when accelerating and/or at high revs. At lower/middle revs the engine goes very well, but when you demand higher power at high revs (going flat out or accelerating uphill) it will start pinging.

HTH, Markus
Title: Re: Touchy Feely
Post by: Mosin on 13.05. 2010 12:42
Thanks for the tips Markus. I have got a timing disk, but no strobe so it looks as though one of those is going to have to be my next purchase. However in the mean time I think I will try just advancing the ignition by rotating the Pazon unit a little... say 5 degrees or so, to see if there is a marked improvement in performance. It's a relatively easy job to do this and I can always shift it back again if necessary.

Simon
Title: Re: Touchy Feely
Post by: groily on 13.05. 2010 13:58
Think that's a v good idea Mosin. Because frankly, where it's possible easily to fine tune by ear and experiment - which it is with an adjustable backplate like on  most electronic units - it's often the only way to get it just how you want, regardless of what the degree disc says. It's certainly how I played with the Boyer system on my Enfield twin (it just remains for me to strobe it to see what I actually ended up at next time I have the primary outer off). There are so many variables, but if it starts right, sounds right, pulls right, doesn't detonate or ping and doesn't overheat etc etc, it probably darn well IS right or pretty close.
Is also why I think Orabanda's slotted mag mod is one of the best ideas out there!
Title: Re: Touchy Feely
Post by: Mosin on 13.05. 2010 16:54
I was so excited by all of this that I decided to finish work early to give it a go! I initially advanced the timing by five degrees according to the increments on the slotted backplate. I then took it up the road, but there was little recogniseable difference. I advanced it a further five degrees and though slightly harder to start, it the gave me a small improvement when taken out up the road. Finally I advanced it yet another five degrees (total 15). It kicked back more than usual on starting but once running seemed to be running much better. I am not sure if it is any cooler, but there was a perceivable improvement in performance and as far as I am aware no "pinking" even when I ran it up the local hill in top gear. I have now reached the limit of adjustment on the slots and any further adjustment is going to have to be obtained by re-setting the whole timing.

I'm going to have to get a strobe aren't I?
Title: Re: Touchy Feely
Post by: muskrat on 13.05. 2010 20:41
G'day Mosin,
                 5 degrees are very large incriments when it comes to timing, and 15 from where you started is heaps. Yes, get a strobe. You should be looking at about 34 degrees full advance at about 4000 rpm.
Cheers
Title: Re: Touchy Feely
Post by: mike667 on 14.05. 2010 18:12
I was so excited by all of this that I decided to finish work early to give it a go! I initially advanced the timing by five degrees according to the increments on the slotted backplate. I then took it up the road, but there was little recogniseable difference. I advanced it a further five degrees and though slightly harder to start, it the gave me a small improvement when taken out up the road. Finally I advanced it yet another five degrees (total 15). It kicked back more than usual on starting but once running seemed to be running much better. I am not sure if it is any cooler, but there was a perceivable improvement in performance and as far as I am aware no "pinking" even when I ran it up the local hill in top gear. I have now reached the limit of adjustment on the slots and any further adjustment is going to have to be obtained by re-setting the whole timing.

I'm going to have to get a strobe aren't I?
yes - kickback is almost always a sign that your to advanced - as muskrat says 15 degrees from the start is a huge change - i bet you'll find that you won't need to pull out the unit and readjust the magnetic rotor - it will be somewhere between where you started and have ended up...

i have a pazon unit on my commando -  and find that a very small amount of movement on the plate makes a dramatic change in the timing by strobe....

also remember no matter how "on the mark" your timing is -  if the valves are not set correct and the plug gap too its all for squat!
Title: Re: Touchy Feely
Post by: wilko on 14.05. 2010 21:58
You'd better pull off timing cover and check cam timing if nothing else works!
Title: Re: Touchy Feely
Post by: Mosin on 15.05. 2010 21:32
A development... although not a good one....

This evening I bit the bullet and ordered myself a strobe off ebay as suggested. In readiness for its arrival, I figured I'd pull off the primary cover and fasten my timing disk to the crank using my SRM cush drive nut.

When I took the primary case off, I was surprised to see a couple of small bits of metal drop out. It turns out that they were formerly one of the rollers of a link of the primary drive chain. On close inspection, I also discovered that one of the other rollers was badly cracked and about to drop off too. I have never known this to happen to a chain before.

I removed the cush drive nut and spring and with the bike in neutral span the clutch. To my surprise the crank shaft sprocket immediately slid about 1/2" out along the crankshaft and sat there spinning perfectly. This suggests to me that the two sprockets are not in alignment and the excess pressure caused by this has caused the damage to the primary chain. It also might go some way to explaining the relatively poor performance of the bike....

To cap it all, I can't for the life of me find my parts book. Can anyone enlighten me as to whether there should be any shims behind this sprocket to keep the chain running true or something else that I am missing? 
Title: Re: Touchy Feely
Post by: muskrat on 16.05. 2010 08:59
G'day Mosin,
                 yes there are shims to adjust the engine sprocker 67-2056/7/8 but these will not take up that much. I think you will find the g/box is scew-if (out of line with the motor). This often happens if the bolts have not been loosened enough when adjusting the primary chain. Back off the adjuster and loosen the bolts now push the box forward and back a couple of times then tighten them. Now spin it again and see where it ends up. Use a new chain.
Cheers
Title: Re: Touchy Feely
Post by: bsa-bill on 16.05. 2010 10:24
I think there is also a spacer on the crank with a internal chamfer prt no 67-1138, is this in there ?

apologies if this is a bit obvious

All the best - Bill
Title: Re: Touchy Feely
Post by: chaterlea25 on 16.05. 2010 20:44
Hi Mosin,
I remember back to when you were dismantling the bike after the blow up and you had trouble with
removing the clutch centre!! so presmably you had to go and buy a new one???
There are a lot of absolute "shite" ones about *ex* *ex* *ex* *ex*
Some of them have even the scroll on the back for the sliding plate running in the wrong direction *ex* *ex*
Also the depth of the tapered hole for the shaft varies quite a bit
I know that BSA made different centres for different models to accomodate chain alignment
It can be a tricky problem to solve sometimes,

I normally trial assemble the primary drive without the inner casing fitted to ensure the sprockets are aligned using a straight edge, also check the fit of the clutch centre on the gearbox shaft, It has to be a 90% contact over the taper
If the centre is a poor fit and relying on the key for drive it will soon wreck the gearbox shaft
They are not that hard and can be turned or ground internally to move the clutch inwards a bit.

Next you have to check that the chain will not  rub off the back of the inner case, there is not normally room for a heavy duty chain there,and beware of industrial chain will self destruct in short order *sad2* *sad2*

If there is not enough clearance for the chain, the plate sandwiched between the crankcase and primary case can be thinned down or a new one made, or even use thinner or no gaskets just sealer!
Next, you MUST make a spacer or suitable washers to bolt the rear of the case to the frame without stressing it.

Let us know what you find as the work goes on
Regards
John O R





Title: Re: Touchy Feely
Post by: Mosin on 16.05. 2010 22:40
I think I've got this one sorted. Firstly, the spacer which sits behind the cush drive and the shims which are used to adjust it were missing. (I've ordered replacement parts from Draganfly). To make matters worse, I then removed the clutch (after my problems with my past clutch I splashed out and bought a brand new four spring one from JB restorations which seems to fit and work very well. When I removed the clutch, I discovered quite a lot of scoring towards the back of the primary inner where the chain had obvioulsy been catching. I removed the primary inner and noticed that there is a sizeable gap between the rear mounting on the primary inner and the lug on the frame which it bolts to. When I assembled the inner I remember this and figured that since there had been no spacer there to begin with I would just use the bolt to tug everything into line. I have now looked at the parts book and realised that there should be a spacer (as mentioned by John O R) to fill this gap without twisting the primary inner whichis what had happened.

I originally bought the bike as a 'complete non-runner' and am now starting to realise that the P.O. had obviously cobbled it together as much as possible to make it look like it had been done, without paying too much attention to putting things back as they were supposed to be. Frankly I wish he hadn't bothered. Never again will I assume that just because something is set up as it was when I bought the bike that that is how it should be. Luckily I discovered the error before too much damage was done.

And to think that this started off as a thread about ignition timing... It's funny how one thing leads to another... Nothing is ever simple is it?
Title: Re: Touchy Feely
Post by: chaterlea25 on 17.05. 2010 18:34
Hi Mosin,
if the crank spacer was missing, I think I would be right in saying that the cush drive inner sleeve would have been rubbing up against the crankcase??
This obviously is not a good situation and could have ground ally away and into the main bearing??
The shims involved here are only for minor adjustments, I dont like the shims and make new spacers to the correct size
You cannot assume that parts supplied will fit and make everything work!

Assumptions are the mother of all f**k ups!!!! *eek*

Going back to my previous reply the only way to ensure correct alignmant is with a straight edge, I do this along the rear of the sprockets with no cases fitted, today out of curiosity I tried out 3 centre adaptors I bought at Stafford
last month, an original BSA 6 spring and 4 spring and one of the shite pattern ones that I bought for less than £20 to experiment on!! They all sat on the taper in different positions, about 3/16 difference in total, one fitting roughly halfway between the other 2 *ex* *ex*

HTH
John o R
Title: Re: Touchy Feely
Post by: Mosin on 17.05. 2010 21:28
Hi John

Thanks for the suggestions. I've just checked the back of the main bearing and amazingly it does not even appear to be marked! That's obviously a massive relief. I will certainly take your advice about lining up the sprockets with a straight edge. As regards where the clutch centre sits on the gearbox shaft, I suppose that it doesn't really matter wheter the two sprockets are a couple of thou one way or the other just so long as they line up and don't cause the chain to foul the chain case?

Cheers,

Simon
Title: Re: Touchy Feely
Post by: Mosin on 20.05. 2010 20:43
Well, I got all my bits and pieces today including my brand new strobe, the illusive crankshaft spacer etc etc and took the afternoon off work with a view to getting everything back together and working. First I lined up the sprockets without the primary inner on using a straight edge accross the back of them. With the spacer in place it was very easy to get them perfectly lined up. I then refitted the primary inner, and the clutch, fitted my brand new primary drive chain adjusted the tension perfectly using the gearbox adjusters. everything seemed to be spinning just fine, so I fired her up and used my new strobe firing at my new SRM timing disk which was fastened to my new SRM cush drive nut to set the timing which I got spot on to 35 degrees BTDC fully advanced. I then took the bike up the road and she was running better than ever before and I was grinning like a cheshire cat by the time I got home. All that remained was to stick the primary case on and tidy up... a job well done...

Or so I thought.

Now the bloody primary outer case won't fit on. The new spacer means that the cush drive is now sitting further out towards the end of the crankshaft and it is fouling the inside of the dome on the primary case. So much so that there there is a half inch gap between the two halves of the primary case at the engine end.

I've spent about eight hours on the thing today and It's still not right. Bah. Can anyone suggest anything? At all? Please?

Cheers,

Simon



Title: Re: Touchy Feely
Post by: chaterlea25 on 20.05. 2010 21:18
Hi Simon,
A photo would be worth a thousand words??
The cush drive nut should be tightened fully and torqued 65ft lbs(??)
The nut should go on until the end of the crank shows through
The "missing" crank spacer should be the first piece fitted, this goes through the seal and buts up against the main bearing, then any shims then the cush inner splined sleeve, the nut should wind up clamping the splined sleeve in place solidly
I cant see how the case is half an inch away???? presumably you removed the timing disc????
HTH
John O R
Title: Re: Touchy Feely
Post by: Mosin on 20.05. 2010 21:29
Hi John,

I'll try and get a photo, but basically all that I have on the main shaft are the spacer which is up against the main bearing. Next to this is the splined sleeve. Over these are the sprocket, the cush drive cam, the spring and then the nut which I did torque up to 65 ft/lbs. I have removed the timing disk, and even tried going back to the original cush drive nut, but all to no avail.

Simon
Title: Re: Touchy Feely
Post by: Mosin on 20.05. 2010 21:53
Some pics.

Simon
Title: Re: Touchy Feely
Post by: trevinoz on 20.05. 2010 22:19
Have you got the spacer between the inner chaincase and crankcase?
It is only about 1/8" thick.
As John says, the end of the crankshaft should be proud of the original nut, there is a hole for a split pin which must be exposed.
Trev.
Title: Re: Touchy Feely
Post by: bsa-bill on 20.05. 2010 22:31
Looks like the cushdrive nut needs to go further on, you should not see any of the nuts thread within the end of the nut.
On mine there is about a quarter of an inch of the nut left before the end of the crank and my outercase fits on flush.
a small point that sometimes gets misunderstood is that the cushdrive is not a rattle clutch - it is not designed to fully slip if your gearbox locks up, it's role in life is to give a little when you drop the clutch thereby allowing a little feathering of the drive, to do this all that happens is the ramps move against each other a tad.
Try putting it together with the original cushdrive nut, if it goes on allright then check that the threads on the end of the crank are not damaged, I had to run a die up mine to get the SRM nut to screw on even though the original nut went on without any problem, maybe they use a tighter tap at SRM ( I think this might have been covered here once before)

All the best - Bill
Title: Re: Touchy Feely
Post by: Mosin on 20.05. 2010 22:32
Have you got the spacer between the inner chaincase and crankcase?
It is only about 1/8" thick.
As John says, the end of the crankshaft should be proud of the original nut, there is a hole for a split pin which must be exposed.
Trev.

I don't have the spacer between the crankcase and the primary inner, but if it's only 1/8" then surely it wouldn't account for the measured half inch gap that I currently have. Would it?
Title: Re: Touchy Feely
Post by: bsa-bill on 20.05. 2010 22:37
Spacer is more than 1/8, 1/4 at least IIRC.
Also the SRM nut covers the split pin hole (not needed they say) and due to the nut bit on the end the crank does not project through
Title: Re: Touchy Feely
Post by: Mosin on 20.05. 2010 22:39
Looks like the cushdrive nut needs to go further on, you should not see any of the nuts thread within the end of the nut.
On mine there is about a quarter of an inch of the nut left before the end of the crank and my outercase fits on flush.
a small point that sometimes gets misunderstood is that the cushdrive is not a rattle clutch - it is not designed to fully slip if your gearbox locks up, it's role in life is to give a little when you drop the clutch thereby allowing a little feathering of the drive, to do this all that happens is the ramps move against each other a tad.
Try putting it together with the original cushdrive nut, if it goes on allright then check that the threads on the end of the crank are not damaged, I had to run a die up mine to get the SRM nut to screw on even though the original nut went on without any problem, maybe they use a tighter tap at SRM ( I think this might have been covered here once before)

All the best - Bill


Thanks for the thoughts Bill. I tried it with the original cush drive nut, but it made no difference at all. My SRM nut is tightened hard up against the end of the cush drive bearing sleeve (beneath the spring) and is torqued up correctly. The spring is pretty well compressed, although it does move as required, but there's no danger at all of it fully slipping under any eventuality.
Title: Re: Touchy Feely
Post by: bsa-bill on 20.05. 2010 22:56
Hi trevinoz I misread your reply, my apologies  I thought you were talking about the other spacer, you have a good point there.
Mosin do you have the spacer that goes between the crankcase and the inner primary case, can't see it in your pics, it is a large spacer the same size as the hole in the inner case.
Also the spring is not compressed as much as mine is, somehow the nut needs to go on further, wonder if you've got wrong sprocket and cushdrive parts, I think there are different versions
Will take some pictures of mine tomorrow
Title: Re: Touchy Feely
Post by: chaterlea25 on 20.05. 2010 23:25
Simon,
It looks to me as if the nut is not fully home, ??
What thickness is the spacer you were sent?
The spacer should have a large internal radius cutaway this goes on the inside towards the radius on the crank and against the main bearing, if its inside out it will not go up against the bearing!!!!!
so the sleeve will not go far enough in, or the nut?????
If this is the case you will have to align the sprockets again???
HTH
John O R
Title: Re: Touchy Feely
Post by: Mosin on 21.05. 2010 11:50
I am at work at the minute so am not in a position to be able to measure the spacer. However, I remember that it does have a cutaway as described on one side. I remember that this confused me a little because neither the bearing or the back of the sleeve has any sort of a raise on it for this to marry up with! This is weird.

Unfortunately I am now away for the weekend and won't be able to have a proper look at it until Sunday night when I think I will take off the primary chan and strip down the cush drive so I can measure the spacer. I will obviously take photos of everything so that I can feed back here for inspiration and advice!



Incidentally, This thread has now done a complete U-turn from being about ignition to mechanics and as such should probably be moved from the "Lucas & Electrical" board into the "Tech Topis" one if any moderators have the ability and feel the urge! Thanks!

Simon
Title: Re: Touchy Feely
Post by: RichardL on 21.05. 2010 15:38
Simon,

First, let me say that I am not expert regarding plunger parts versus swingarm parts, particularly in the primary and, even less so, with regard to 4-spring clutches. Nevertheless, never one to resist sticking my neck out, I did a bit of research and came up with the pictures shown below (borrowed from www.basmotor.se, much thanks to them). It appears to me that the plunger splined sleeve is longer than that for the swingarm by about the exact dimension of your problem. Having said that, more experienced folks than I can jump in. It does not seem to me that thread at the bottom of the thread run would be so damaged as to resist 65 ft. lb. It would just give up and get more damaged. 

Anyway, whether this possibility is right or wrong. you are going to need that spacer between the crankcase and primary cover. With due respect to Bill, I recall (not near the bike right now) that it is much closer to 1/8 than 1/4. Nevertherss, you will need that 1/8-ish (and I'll enjoy eating that crow if I am wrong about the thickness.

Richard L.
Title: Re: Touchy Feely
Post by: bsa-bill on 21.05. 2010 16:18
Hi Richard - I think you might of cracked it, it would explain mosins problem.
I did explain also in my last post that I had misunderstood trevinoz  post ( I was talking about the spacer that goes on the crankshaft  *doh*)

Tried to photo my parts this morning as the cover is not on yet but ran into the file to large thing and then ran out of time as I had to go out, but they would not have shown the difference in splined shafts.

Look forward to Mosins next mail
Title: Re: Touchy Feely
Post by: chaterlea25 on 22.05. 2010 22:53
Hi Simon,
I took some photos of the assembly from an engine I have on the bench,
As far as I'm concerned the spacer between the crankcase and inner primary varies from bike to bike and the thickness is governed by having to position the inner case happily between the gearbox sprocket and the primary chain, not forgetting the sliding plate/scroll on the back of the clutch centre!!!
more photos to follow
HTH
John O R
Title: Re: Touchy Feely
Post by: chaterlea25 on 22.05. 2010 23:00
Cush drive assembly, one piece added at the time
The photos show that there is almost the full depth of thread for the nut
I omitted the lockwasher that fits between the nut and sleeve, I dont fit this preffering a couple of drops of threadlock instead

Awaiting the next installment *ex* *ex*
John O R
Title: Re: Touchy Feely
Post by: trevinoz on 23.05. 2010 06:13
I measured three spacer plates I have and they are all the same. Steel 0.095" thick, probably the old 12 gauge.
Closest modern equivalent here is 2.5mm.
                                                           Trev.
Title: Re: Touchy Feely
Post by: Mosin on 23.05. 2010 19:45
I read this with some excitement as it all sounded perfectly plausable. Well, I've finally got the kids bathed and into bed and whipped off the primary chain and cush drive to see what I could see. The findings are in my photos.

The only thing that I did notice was that my main bearing does not look even remotely the same as John's, but other than that everything seems to be pretty much as it should be.

Grrr.
Title: Re: Touchy Feely
Post by: Mosin on 23.05. 2010 19:45
a few more pics...
Title: Re: Touchy Feely
Post by: RichardL on 23.05. 2010 21:05
Simon,

OK, so my guess was wrong about having the wrong Cush Drive Bearing (I don't know why they call it this, to me it would be more like "cush sprocket carrier sleeve"). I'm going to make new some new comments here. I suppose and hope John or others will confirm or correct what this looks like to me.

First, refresh my memory, have you had the entire bottom end appart since acquiring the bike?  It looks to me that your Cush Drive Distance Piece, that fits inside the seal, is in place and rusted to the crankshaft. It also looks like it is not as long as John's, which protrudes past the seal. In John's case, he apparently did not need any additional shims to align the sprokets. In your case, it appears you are adding a whole second Cush Drive Distance Piece to align the sprockets. It makes me wonder if there is not something going on with the clutch that is requiring you space out the Cush Drive Bearing so far. The shims meant for this purpose are 0.030" and less.

Anxious to know what you and others think about this.

Richard L.
Title: Re: Touchy Feely
Post by: Mosin on 23.05. 2010 21:11
Richard,

I was just starting to draw the same conclusions myself. The engine has recently been completely rebuilt with a needle roller bearing conversion, so it is unlikely that anything is siezed or rusted. I think that the next task has to be taking off the clutch... again... and trying to work out if I should be doing anything to make it sit a bit further back on the gearbox mainshaft.

Cheers,

Simon

Title: Re: Touchy Feely
Post by: RichardL on 23.05. 2010 22:41
Well, maybe wait for additional oppinions. Remember, I'm more student than teacher.

Richard L.
Title: Re: Touchy Feely
Post by: bsa-bill on 23.05. 2010 22:52
This might be helpful if you have a large variation in distance from the clutch sprocket to the inner primary chain case.
Remembering that there will be some variation between bikes.

Pictures could be sharper but you can read the distance in CM
Title: Re: Touchy Feely
Post by: bsa-bill on 23.05. 2010 23:00
And at the front sprocket
Title: Re: Touchy Feely
Post by: chaterlea25 on 24.05. 2010 00:09
Hi Simon,
In my photos the crankcase oil seal is not yet fitted, when this is done it will look very like your first pic!!
The seal runs on the outer of the crank spacer!
I now believe that your crank spacer has been in place all along???? (we did not have photos before?)
And the source of your problems is (was ) that you added a second one, all be it a bit thinner??
If you look at my pics again you will see that the spacer comes just proud of the crankcase face, this is correct!
I think you will have to go back and look at the clutch which is the item that has been changed from before the "blow up"
Check how far the centre adaptor fits onto the gearbox mainshaft
some more photos will help!!

Regards
John O R
Title: Re: Touchy Feely
Post by: Mosin on 24.05. 2010 20:16
Here are some more pics taken tonight. As you can see my gearbox sprocket is sitting a good 5mm further out than Bill's which would explain a lot. I then removed the clutch and even the primary inner but the clutch centre does not seem to go any further on than it is doing. I even tried putting a bit of copper grease on the shaft and gently trying to drift it on using an appropriately sized socket and a rubber mallet, but it does not want to go any further at all.

Avid fans of my tales of woe will remember that I had to cut off the previous clutch centre with a dremel because it was so tightly siezed to the gearbox shaft (if you missed that thrilling installment, you can read all about it here: http://www.a7a10.net/forum/index.php/topic,2263.msg15555.html#msg15555 )

Having done a bit of measuring, there does not seem to be very much preventing the new centre from slipping on and I am tempted to just hear it up and try it, but I thought I'd post my pictures first and see if anyone could point out anything glaringly obvious before I get out the heat gun.

Cheers,

Simon
Title: Re: Touchy Feely
Post by: Mosin on 24.05. 2010 20:17
A few more
Title: Re: Touchy Feely
Post by: chaterlea25 on 24.05. 2010 23:49
Hi Simon,
In your photos (4&5) it is quite apparent that the scroll oon the clutch centre is not engaging with the sliding plate!!
The clutch centre looks very like one of the (CRAP) Faulty ones made by MCA(??)
Can you pull it off and send in a photo of the scrolled section, These have the scroll cut in the wrong direction!!!!
I am pointing the blame for your troubles on the centre!!!
Get onto whoever supplied the clutch and tell them the centre will not engage with the sliding plate and the chain is way way off line!!!
Heating and tightening up more will not fix your problems!!
The centre MUST be assembled dry and clean on the taper, use solvent to clean the parts, if the shaft is scored it can sometimes be lapped to the centre, this also checks the taper fit
HTH
John O R
Title: Re: Touchy Feely
Post by: Mosin on 25.05. 2010 00:02
But surely the sliding plate is attached to the primary inner case? I have tried sliding the centre onto the gearbox mainshaft even witht he inner case removed and it still doesn't go any further on...

Also, with the primary inner case removed, the clutch centre fits through the hole in the sliding plate perfectly.

Sorry if I am not understanding you.
Title: Re: Touchy Feely
Post by: trevinoz on 25.05. 2010 01:08
Simon,
               I agree with John.
When assembled the scroll should be inside the sliding plate.
I had the same problem with a new 6 spring centre and it was found that the taper was wrong and not letting the centre fit to the correct position on the gearbox mainshaft.
Trev.
Title: Re: Touchy Feely
Post by: Mosin on 25.05. 2010 10:23
Here are some pictures of the clutch centre as requested. As you can see, it slots perfectly well through the hole in the sliding plate when the primary inner case is off the bike. But there does seem to be some problem with its ability to slide home on the gearbox centre shaft.

Your ideas and suggestions are most welcome fellas, keep them coming!
Title: Re: Touchy Feely
Post by: bsa-bill on 25.05. 2010 19:37
Looks to me like your centre is of the original type and probably OK, I base this on the internal thread for the puller as the repro ones I've seen have very little thread for this (one turn) and the scroll on yours looks like it is right ( kind of hard to get my old brain around what's clock or anti clock in a photo these days), if this is the case then the taper is probably ok.
This leaves the position of the engine,geabox,main-shaft or the primary case in question.
Don't think you want to delving into the gearbox without good reason Mosin so I would suggest removing the primary inner case and assemble the clutch and cushdrive then check chain alignment, then lets see what is good and not so good.
Is this possibly going to be something strange like bent engine plates ?

all the best - Bill
Title: Re: Touchy Feely
Post by: chaterlea25 on 25.05. 2010 23:50
HI Again Simon,
The point of my observations were that when assembled the scrolled part ofthe clutch centre
should be sitting well into the sliding plate, not fully hard up into it but almost,
I dont think its possible to assemble the engine / gearbox plates wrongly so the gearbox would be out of line
but at this stage I'm running out of ideas!!
By any chance do you still have the remains of the original clutch centre?
If you have sit that on the gearbox shaft and see where the back of the scrolled bit sits relative to the sprocket nut and compare with the new one!
By any chance was the inner primary case loose when you took the earlier photos which show the gap???
I'm presuming the spacer and gaskets are fitted between the crankcase and inner primary?
The total thickness of these should be around 0.130 in, in a previous reply its said the spacers should be 0.090 and say 0.040 for the  gaskets??
Fit a 5/16 bolt into the centre front hole to pull that side in as well as the two rear bolts before you check the position of the scrolled bit to the plate,

If you assemble the drive without the cases as Bill says lets see how much misalignment is there??

Its possible to turn out the tapered hole a bit to let the centre go onto the shaft a bit further,
It takes careful setting up and I have found using a spare shaft helpful for setting the taper on the lathe
Also as you know already a certain amount of shim/spacer can be fitted between the crank spacer and splined sleeve.

If you get the sprockets lined up, then its possible to reposition the inner primary case to a degree by adding or removing gaskets or fitting a thicker /thinner spacer between crankcase and primary

Awaiting the next episode ????
John O R
Title: Re: Touchy Feely
Post by: Mosin on 26.05. 2010 11:04
I think we might be making some progress.

For the record, I removed the primary inner casing a couple of days ago, figuring that the most important task was to get the two sprockets to line up. Once I have done that I will sort out fitting the casings around them!

I am attaching a photo of the remains of the old six spring clutch centre alongside the new four spring centre. It can clearly be seen that the collar on the old centre is shallower than the scrolling on the new one by almost exactly the same distance as my sprockets are out of alignment (5mm). It stands to reason then that with the old centre, the clutch would be able to sit further back along the gearbox mainshaft, thus bringing the sprockets into alignment.

Yesterday I spoke to the chap I bought the clutch off and as it happens I am working in the vicinity of his workshop this afternoon, so I have arranged to take the clutch centre along and try it on an A7 which he has got there. This bike is also running a four spring clutch so we will be able to compare the two centres side by side and this should reveal a great deal I hope.

I will keep you informed.

Incidentally, the second photo is purely to show the damage I had to do to the old clutch centre just to get it off the shaft back in February. Even now I'm amazed that it came off without even marking the shaft at all!
Title: Re: Touchy Feely
Post by: Mosin on 26.05. 2010 22:42
It's fixed!

And it turns out that the clutch was fine all along. This afternoon I went to see Paul from JB Restorations who I bought the clutch from. He is a top bloke and It turns out he knows quite a bit about BSAs! He informed me that unbeknown to a lot of people, BSA actually made two different types of cush drive sleeve, both the same length, but with different thickness flanges on them. He supplied me with one with a thicker flange and tonight I fitted it and guess what? With a few shims added for final adjustment, both sprockets finally line up perfectly and the primary case goes on as well!

I am amazed that no-one else has experienced a similar problem on here, but hopefully by documenting my experiences here I can save a huge amount of time and sleepless nights for the next poor sod who has a similar problem!

Anyway, a picture tells a thousand words, so here you go:
Title: Re: Touchy Feely
Post by: chaterlea25 on 26.05. 2010 23:09
Hi Simon
Every day's a school day *smile* *smile*

Cheers
John O R
Title: Re: Touchy Feely
Post by: wilko on 27.05. 2010 02:01
I knew all along,  i just wanted you to suffer!  *smile*
Title: Re: Touchy Feely
Post by: muskrat on 27.05. 2010 04:59
Great work. Now the ? is which one is for which model, and their part #'s. I knew the plunger/rigid differed from the S/Arm.
Cheers
Title: Re: Touchy Feely
Post by: bsa-bill on 27.05. 2010 17:42
Nice one Simon - it's been a bit of a journey but you got the answer that benefits us all

All the best - Bill