Author Topic: 55 Golden Flash Primary Alighnmet Problem  (Read 3696 times)

Offline RAC5558

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55 Golden Flash Primary Alighnmet Problem
« on: 14.07. 2011 18:46 »
I have been working on a 1955 Golden Flash barn find and found a problem.  I decided to remove and clean the clutch plates.   While doing so, I decided to fit a new primary chain.  Before installing the chain, I noticed that the engine sprocket appeared to be further outboard than the clutch chain wheel.  Upon checking the alignment with a straight edge, I found the engine sprocket approximately 3/16 inch out of alignment with the clutch.  I have reviewed many of the threads about this problem, which seems to be not uncommon.  I have researched the cush drive components and engine sprocket and they appear to be correct.  The distance piece is in place on the crankshaft and protrudes about 0.080 in. from the crankcase bearing boss.  The cush drive bearing (splined sleeve) is the one with the thin flange and the sprocket is the correct number of teeth and appears correct when compared to the diagram in the BSA spares manual.  In short, I cannot identify any arrangement of other cush drive parts that would result in the drive sprocket being located closer to the engine.

The clutch is the 6 spring type and shows considerable wear on the plate tabs as well as the outer basket plate tab slots.  Therefore, I doubt that the clutch has been replaced, but can't be sure of what may have been done to the bike over the last 55+ years.  The clutch chain wheel is spaced out from the inner chaincase about 3/8 in. with the chaincase rear tab unbolted from the frame.

I once read that the tranmission mainshaft for an A10 was longer than the mainshaft for a B series.  I am wondering if the tranmission may have been switched out.  Does anyone know what the length difference is?

RAC




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Offline Goldy

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Re: 55 Golden Flash Primary Alighnmet Problem
« Reply #1 on: 14.07. 2011 19:10 »
I don,t know the cause of this but I had the same problem. I made a spacer and fitted it onto the crankshaft.
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Offline MG

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Re: 55 Golden Flash Primary Alighnmet Problem
« Reply #2 on: 14.07. 2011 19:21 »
Err, if the crankshaft sprocket is further out than the clutch chain wheel, an additional spacer won't help much.  ;)

The only way is to machine some material off the splined sleeve and/or spacer (although you can't take much off the spacer, but it might be those few thou that are missing). Use a good carbide tool and take your time, the parts are case hardened (and they did that well)! 3/16 seems much though, I had to take 1.5mm off mine on the A7, that worked okay (off the sleeve that is). A grinding wheel on the lathe is another method, if you are so equipped.
Can't help with the main shaft issue, but there are several members here with Singles, so I'm sure someone will know.
But if your clutch is worn anyway, and you are considering getting a new 4spring, it can be a completely different story with a new clutch adaptor.

Cheers, Markus

P.S.: Welcome to the forum! A little introduction post in "Bikes, Pictures and Members" wouldn't hurt!  *smiley4*
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Re: 55 Golden Flash Primary Alighnmet Problem
« Reply #3 on: 14.07. 2011 21:55 »
G'day RAC, welcome to the forum.
                                              3/16" does sound a lot to be out. the crank/cush drive end sounds good. I too can't help as far as the main shaft difference goes, but if the clutch all goes together right and it works, that may be the answer. Back in the old days we did silly things like that to keep going.
Cheers
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Offline RAC5558

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Re: 55 Golden Flash Primary Alighnmet Problem
« Reply #4 on: 14.07. 2011 22:20 »
I appreciate the thoughts.  I might be able to gain some by thinning the distance piece on the crankshaft, and thinning the hub on the cush drive bearing (splined sleeve), and could even counterbore the back of the sprocket slightly.  All such modifications bastardize all of those factory parts.  It seems unreasonable to me to think that the factory would have allowed so much mis-alignment that such part modifications would be necessary.  Since there doesn't appear to be a problem with the cush drive assembly, there must be something haywire with the clutch, or tranny mainshaft length, or possibly an improper attachment of the transmission to the engine and/or frame.

One other concern, the cush drive spring only compresses between an 1/8 and 3/16 of an inch when the nut is tightened securely against the cush drive bearing.  This seems like not enough preload.  Any thoughts?

Richard
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Re: 55 Golden Flash Primary Alighnmet Problem
« Reply #5 on: 14.07. 2011 23:06 »
The plot thickens. There should be a lot more preload on the spring than that. Say about 1/2". A few pictures might help. Sounds like a bit of a mix of parts.
Cheers
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Offline RAC5558

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Re: 55 Golden Flash Primary Alighnmet Problem
« Reply #6 on: 15.07. 2011 00:09 »
I'll get some photos and include some dimensional information for the various pieces.       BTW, the cush drive spring is 1.5" in length and the OAL of the splined sleeve is     (that includes the 3/16" thick flange).  The spring wire diameter is 0.300".  I would guess the either the spring is too short or the splined sleeve is too long.  Most likely, the spring is too short.  A shorter sleeve would result in the threaded end of the crankshaft protruding past the outer face of the nut. However, whatever is the cause of the lack of spring compression, I can't see that it would have anything to do with the alignment of the sprockets.

A suggestion made earlier about going to a 4 spring clutch is a possibility.  Any suggestions for a reliable source for the necessary 4 spring parts?  After reading many of the posts about junk after-market parts and sordid alignment problems associated with such updates, I'm almost afraid to try it.

I found this bike barn fresh and would like to get it on the road as found.  I have installed new tires for safety reasons, but am hesitant to get too carried away with modifications and improvements.  However, if that is what it takes, so be it.

RAC
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Online Brian

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Re: 55 Golden Flash Primary Alighnmet Problem
« Reply #7 on: 15.07. 2011 00:38 »
I think your misalignment may be due to wear on the clutch. The cush spring is definitely either compressed or the wrong one.

Going by what you describe the clutch is quite worn and I think this may be the problem. There is probably some wear on the splined sleeve and also wear on the back of the first steel plate, the one that goes on before the chainwheel. Add to that wear on the face of this plate and the clutch inserts worn down I think this could all add up to the amount you describe. This particular clutch is not a very good design as it relies on the chainwheel moving sideways to release properly so the chain alignment moves anyway. If the clutch is badly worn and needs replacing I would go for a four spring but you can repair and make the one you have work ok with some work.

Another small point I picked up on with your description, you say the chainwheel is about 3/8" from the inner chaincase with the tab unbolted from the frame, unbolted or bolted this measurement should not change. You need to measure the gap between this tab and the frame and put a spacer or a washer or two to fill this gap so when you do the bolt up it doesnt pull the chaincase over.
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Online chaterlea25

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Re: 55 Golden Flash Primary Alighnmet Problem
« Reply #8 on: 15.07. 2011 01:17 »
Hi RAC,
Another point to note is that the taper on the clutch centre adaptor is different for singles and twins
This is where the different length shaft myth comes from  *conf*
On the single cylinder type the tapered bore is deeper so the clutch sits farther in on the shaft
The sleeve that fits on the crankshaft comes with 2 different thickness shoulders (at least??)

Converting to 4 spring is the best option if the 6 spring clutch is worn (most are !!)
Make sure to get it from a reputable dealer who knows the different models etc
Yesterday I had the chance to compare a UK made chainwheel and a Wassel brand one
The Wassel outer drum is only about half the thickness of the UK made one so the plate tangs are only engaged on their outer tips  *eek*

HTH
John O R
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Offline MG

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Re: 55 Golden Flash Primary Alighnmet Problem
« Reply #9 on: 15.07. 2011 08:02 »
Another thought:
Is the spacer on the crankshaft mounted the right way 'round? The inside is chamfered on one side, and that side has to face inwards, towards the crank web. Otherwise it will sit on the radius of the crank pin there and come further outwards by a mm or two (and it won't clamp the bearing inner race properly!). No explanation for your spring issues, but could be another point to check.

Cheers, Markus
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Offline Stu55Flash

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Re: 55 Golden Flash Primary Alighnmet Problem
« Reply #10 on: 15.07. 2011 08:35 »
Is the bike a swing arm or plunger. The mainshafts are different sizes on these bikes?

Stu
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Offline Topdad

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Re: 55 Golden Flash Primary Alighnmet Problem
« Reply #11 on: 15.07. 2011 12:24 »
Good afternoon RAC and welcome, my A10 has been running quiet happliy  on a B31 Box for 8 yrs to which I fitted a 4 spring clutch (until this year when it was worn out ) so don't think that will have a bearing on the problem ,  I think I'd check the spacer thickness and check it's right way round, regards Bob H.
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Offline RAC5558

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Re: 55 Golden Flash Primary Alighnmet Problem
« Reply #12 on: 15.07. 2011 14:54 »
I appreciate the responses to my questions.  To address some of the suggestions, I'll give this update.

The distance piece on the crankshaft is installed with the chamfer toward the engine centerline.  The spacer protrudes beyond the face of the crankcase bearing boss about 0.080 inches.  I could possibly pick up about 1/16" better alignment by thinning the spacer slightly.  That would still leave 1/8" mis-alignment.  I am inclined to make the switch to a 4-spring clutch before modifying any of the original parts.

If I can find the clutch hub puller I made years ago, I will pull the clutch off the bike and inspect the clutch for damage that might shed some light on the problem.

The bike is a swingarm model.  In what way are the mainshafts different between the two?  When you say "mainshaft" are you referring to the transmission or the engine?  I rummaged around and found another cush drive assembly (minus spring).  It is identical in every way with the one on the bike except that the ID spline on the splined sleeve is smaller (for a smaller diameter cranshaft).  I do have some B34 stuff: so, that might be what it is.

I notice that some of the 4-spring clutches have the cushioning built into the chainwheel whereas some don't.  Is it possible to use the cush in the chainwheel type on an A10 and eliminate the cranshaft cush drive altogether?  If so, who can suppy the necessary crankshaft to sprocket adapter?

I will try to get some photos today showing the parts and the degree of mis-alignment.  On a bit different subject, can anybody tell me the correct speedo and/or tack numbers for this bike (1955 Golden Flash)?

RAC

adm edit:
Quote
On a bit different subject, can anybody tell me the correct speedo
Please keep the thread content relevant to the topic title, see http://www.a7a10.net/forum/index.php/topic,4457.0.html
Thanks.
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Offline MG

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Re: 55 Golden Flash Primary Alighnmet Problem
« Reply #13 on: 15.07. 2011 16:00 »
The speedo no. is S.608/11/L for mph, S.608/15/L for kph.
A tacho wasn't fitted on the Golden Flash originally, the one for the 1954-58 Rocket is RC.83 with gearbox type 70549/4.

HTH, Markus
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Online chaterlea25

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Re: 55 Golden Flash Primary Alighnmet Problem
« Reply #14 on: 15.07. 2011 22:06 »
Hi Rac,
I was reffering to the gearbox mainshafts
The shock absorber clutch centre is intended for alternator equipped models, as on these there is no crank shock absorber!
The cush centre is interchangable with the solid type
I would keep things as standard as possible *ex* and save further agro  *eek* *eek*

HTH
John O R
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