Thank you Peter,that may be the way that I will have to go .. I can't have my son on hand ever time I remove the shock absorber to check timing !!. Do you know how much the machinist removed from the taper?, Thank you again. James.
The other solution is to buy the correct clutch adapter, there are several versions out there and one batch made some 10-15 years back seems to be terrible wrong, I have one of those in my bin for samples of badly made parts. The one I am running now on the Clubmans is from Tony Hayward and has the large thrust bearing support as used on late A65, this one is a perfect fit.
Per Goldi Clubmans Goldi Scrambler Rob North R3 OIF A65
I was gonna say something in that regard as I ran a Triumph type clutch in my vintage racer for 10 years and never had to make any adaptions to get it to line up. The late pre-unit BSA's used that clutch from the factory.
Boomer ... It's always confused me why my GS required extra crank shims for correct chain alignment and others as yourself don't have the problem. hmmm. Fitting the crank nut always caused problems even tho I would use the special socket with an air impact.
I've heard of a couple possible reasons... There may be a difference in tranny mainshafts? I have several I could compare. But the most likely reason is the repop clutches are all flat across the back side vs the 'dished back' as was often (always?) seen OEM with the sprocket teeth offset toward the tranny ~ 1/8"' I dunno ... any ideas?
For several years I had used the Tony Hayward clutch adapter as Per has mentioned. Hayward has these adapters made to fit the later model Tri/BSA type design 3 spring clutch belt drives to pre unit BSAs. This is a precision piece with the larger diameter thrust face and floating 'shim' that prevents the thrust face from cutting into the backside of the clutch, moving the bearing race and causing the clutch to wobble even more. I figured this out looking over the pieces of our GSR modified Hayward belt drive clutch on the Goldie dirt tracker.
Short of pulling the clutch all apart on the "ole 62" all I can go by is what I remember when I assembled the racer in the early '80's. I basically took a late pre-unit Triumph/BSA four spring clutch with the adaptor and mounted it to my stock scrambles ratio gearbox. I believe all the parts were OEM good used as I was just building a local club level fun vintage race bike. Over the years of racing at least once a year that clutch came apart to service the engine/gearbox or in one case to weld the frame below the center mount oil tank, which I was told by frame guy Vern Fueston that that tube was made to thin and cracked often. It always went back together fairly easy. I found a tool, shock tool???, that made short work of tightening down and loctited.
James .. I guess I wasn't clear enough on fitting the the Hayward adapter.. Tony Hayward sells a belt drive for our pre unit BSAs. As I've mentioned we have one on our GS tracker. The belt drive clutch is based on the unit BSA/Tri 3 spring clutch and uses the same cush hub. To make this clutch fit on a pre unit BSA he supplies a unique 'clutch adapter'. This is the adapter I've mentioned that works so well with a early 4 spring clutch.
I would also like to mention some important info for fitting a 4 spring. We all agree the OEM 6 spring mainshaft nut was a soft POS that was difficult to tighten properly. This crap nut not being tightened properly or coming loose is the cause of so many mainshaft tapers and keyways being messed up. Here's the deal .. When fitting the 4 spring use the BSA OEM nut, washer, and lock tab as listed in the late A10 parts list.
This is also the correct/best fasteners to fit a belt drive clutch. ------------------------------------------------------------------------ I feel your pain dealing with fitting the crank nut after adding shims to the cush assembly. aargh It seems to me the proper correction for the problem would be to modify the clutch adapter as the guys have mentioned. hmmm
To use a timing light on a running Goldie I consider it important to remove the spring and lock up the cush cams. The cush drive is designed to allow a small amount of movement due to the non linear rotation of the crank and this would screw up your timing light indications with a 'fluttery' reading.
Hi James Re removing the shock absorber nut to fit a degree disc. This is the adaptor I made to fit on the crank nut on the timing side. With this method there is no need to remove any nuts from the crank. As can be seen I drilled a hole and brazed on a 1/4" nut, and flange on a socket. This can be locked on the crank nut with the grub screw, and a disc attached to the flange.(I have various discs) As Dave said the bump stop system is a very accurate way to establish TDC, After timing the engine, I then adjust and lock the stop to contact with the piston at 39 degrees or whatever your desired setting. This can then be re-installed at any time to check the timing, without the need to to fit a disc. (But obviously you require multiple stops for individual engines) I put a radius on the stop to avoid any sharp edge contact with the piston. and a flat on the thread to release the air. Brian.
Hi Brian .. what a great idea!.. it never occurred to me to use the timing side!!, duh!!. Nice looking tool too. Good 'ol Brit. inventiveness . The socket that M/man shows .. I have made that one .. lots of filing !..no milling machine. I have the necessary piston stop to accurately set TDC. With regard to the clutch adapter .. the one I have is smaller than Haywards,I cannot re-machine the taper .. not enough length left on the shaft taper before the adapter will hit the shaft shoulder.I guess it will have to stay the way it is .. not enough $$$ just now to buy a Hayward adapter. I made some bronze thrust washers,only needed one,to fit behind the clutch hub,it takes up the space twixt the back face of the hub and the inner face of the basket ,the diameter matches the hub OD and the washer ID matches the boss on the hub,the washer is .072" thick .. the whole assembly runs true and does NOT wobble at all. Thanks to all for advice and ideas. James.
Last edited by limeyrider; 03/13/1310:49 pm.
Re: Magdyno mounting questions
#481209 03/14/132:36 am03/14/132:36 am
A timing disc on the timing side should work fine for those doing 'static timing' as some of you would be happy with. But then a proerly done 'stick down the hole' would also be OK. I sure wouldn't want to run my engine with the timing side cover off with no oil supply to the engine trying to use a timing light. Whatever ..
for those doing 'static timing' as some of you would be happy with. But then a proerly done 'stick down the hole' would also be OK.
I don't have my G.S. data handy, but a table I computed for my A10 makes Dave's point. Although the numbers will be a little different with the stroke and con rod length of a G.S., for an A10 the piston moves 0.022" in going between 38-deg. and 39-deg. That is, if your stick can determine the position to ~1/2 mm, you can set the position of the engine to at least a degree.
However, setting the position of the engine is one thing, but making sure the points actually open at precisely that position is another. Also, most people use protractors smaller than the nice one DBDBrian shows, making it problematic to claim accuracy any better than a degree anyway. So, back to Dave's point, if you're going to set your timing statically, you might as well do it only with a stick. Um, actually I think Dave's point isn't this -- I think that it's that you shouldn't rely only on static timing.
Just look at the gears they are well out of mesh! (its a very good quality photo !) Its not easy to get it spot on but the mag must be shimmed on its base and maybe a shim behind the engine to get the mag centred to the mag seal in the crankcase plus getting a bit of rattle in the gears ! They are superb wonderful bike but the Goldie but must have been a nightmare for the BSAs production team, no different than a Manx I suppose ! For shimming no cork ! use steel shims cut from say oil cans! Plus watch the sideways position of the mag, the rotating pinion, as it could touch the crankcase seal when clamped up, I araldite a washer on the back of the crankcase inbetween the mag to ensure clearance !! Even if the mag moves !
Thanks all for chiming in with comments and suggestions. I chased the threads on the armature with a new die and screwed on a new nut and it works beautifully. Spent several hours yesterday timing the ignition. I used a degree wheel on the primary side, held with rare earth magnets and it worked beautifully. I used a dial indicator gauge to find absolute Top Dead Center (TDC) and then set the points to just about open at 37 degrees Before TDC. Triple checked my settings and they are good.
I put fuel in the carb for the first time so I could start my bike only to discover the threads on my jet block are stripped and fuel pours out the bottom of the carb. So close...
1966 Triton 1962 BSA DBD34 Gold Star 1966 Triumph Bonneville
Hi Swan .. typical luck eh? .. just when you think you have it .. BAM!!. When you performed the timing adjustment was the mag. strapped down... it looks from the photo. that it is just sitting in place. Is it ok to leave the mag.loose?. When I practiced timing I fitted the dynamo and strap to be sure that everything was tight ... as when the motor would be running. Just curious. Thanks. James.
OK, hopefully I did this right.. LOOK at the picture with the mag shaft way off of center.. You guys need to listen to what Dave said... SHIM the FRONT of the mag to the cases at the top case stud boss.. that moves the mag towards the rear and thus will get the mag shaft centered properly.. no need to fix or modify anything to try and fix the worn case slots... Yes, shim the mag UP if the cases are totally worn.. Use good mag straps an move on... the geometry of the mag straps pulls the mag forward, and the round pegs in the mag, well.. it just digs in to the aluminum... so the shim trick is the best solution...
Originally Posted By: Swan
Thank you all for chiming in with your thoughts, experiences and theories. We are making this so much easier for the next person to sort this out.
Nothing is easy.... I removed the timing cover, dynamo and magneto to check everything again.
Yes, I am using the correct service tool to remove the magdyno pinion.
Note the eccentric ovalling of the magdyno hole in my crankcase, this was throwing me off when I was first positioning the unit. It looks like it was damaged when the mag strap loosened in its past life. The top portion of the hole aligns well with mag spindle but the bottom left is way out. Here is the magdyno spindle through the hole, without tension from the straps. Thoughts?
My magdyno driving pinion nut's (long type, 24-0195) threads stripped out after tightening it to the spindle. I pulled the magdyno and inspected the spindle, it was not damaged and I confirmed it is 20 TPI. I e-mailed Joe V's Cycle to ask what thread standard he used when he turned or chased the threads on my spindle. I'll order another pinion nut but I may also need to order a 3/8" 20 TPI BSF die to chase the threads of the spindle. Of course, this means all work on the magdyno mounting stops until I get parts and tools to sort this out.
I did add a small bit of metal between the mag and the mounting strap and added a bit of cork between the strap and dynamo, but not between mag and dynamo. I also made a thin gasket of cork to fit between the mag body and the timing side of the crankcase. Sorry, no images or dimensions at the moment. I can also confirm the pegs on my mag body and slots on the crank shaft are not damaged.
Originally Posted By: limeyrider
Peter .. thank you for your informative reply. My next question .. how to mount a timing disc on the crank with the shock absorber in place?.I will need to remove the mag. to put a gasket in place,tend to the mounting slot / pin issues. All of this will mean the ignition timing will need to be re-set. I had so much trouble getting the shock absorber nut on to the crank, I really want to avoid .. if I can .. taking it off again. Thanks for any and all help. James. PS ... I have no way of drilling the shock absorber nut to attach the disc.
Limeyrider, I had the same problem last night. I am going to try using double stick adhesive pads and a very strong rare earth magnetic disc to affix my timing wheel to shock absorber nut. I will add some witness marks with a Shapie on the back of the timing disc which correspond to lines on the shock absorber nut to insure the disc has not moved out of position while I rotate the crank.
This a very busy week for me at work, but I am going to try to make some time to get in the shop late at night to keep moving forward on this bike. Please be patient for updates.
A question about the gasket ... is it simply a circular piece with a hole to fit over the mag. shaft,or does it cover the whole mag. face behind the timing case... or does it even matter ?. Thanks. James.
OK fella's .. I'm having one of those days.I got the cork gasket sorted,shimmed the mag. for good backlash on the mag. pinion,shimmed the front space to stop the mag. moving for'ard.Timing !!.. I followed Daves guide to the letter ... not even close .. no reflection on Dave ..I'm obviously doing something wrong.Start out with a good TDC position on comp., lower the piston 1/4" or so, bump stop just touching the piston, a reading of 15deg on the disc noted,turn the back wheel backwards until piston contacts the stop, 17deg noted,this is a spacing of 177deg .. mark to mark.Take out the stop,turn the motor forward to 1/2 the 177deg.,nowhere close to TDC... what am I doing wrong??. Any and all help much appreciated. Thanks, James.
If you turn the rearwheel backwards, the backlash between crankshaft/camwheel/idler/ mag pinion/ will move to the oposite direction and causing a huge amount of inaccuracy. Could this cause the problem that you see here ?
Not sure if this is what went wrong, just a thought. All engine rotation should take place in the normal forward direction for static adjustmentof the mag.
Last edited by Peter R; 03/25/136:25 pm. Reason: typo
Peter. 1974 Commando 850 1972 Trident T150T 1961 Goldie DBD34 1969 Benelli 250 sport special
Hi James To set TDC using a bump stop. Set the engine at TDC on the compression stroke by eyeball down the plug hole. Fit the disc on the crank with the indicator at TDC. Turn the engine backwards approx 40 degrees and then use a probe to assess the distance at which to set the bump stop . Turn the engine backwards to approx mid stroke.Screw in the bump stop.Turn the engine forward gently until the piston contact the stop.Take a reading on the disc.Remove the bump stop.Turn the engine forwards over TDC to approx mid stroke.Refit the stop.Turn the engine backwards gently until the piston contact the stop.Take a reading on the disc.Now split the difference between the two readings.Reset the disc at X holding the piston against the stop.Remove the bump stop turn the engine backwards over TDC to approx mid stroke. Refit the stop.Turn the engine forward till piston contact stop. This reading should be the same as X the other side of Zero. Zero on the disc is now TDC exactly. Time the engine to your desired figure.Adjust the bump stop to contact the piston at your timing figure. The stop can now be used at any point in the future to check the timing without the need to fit a disc. Hope this helps. Brian
Thanks to Peter and Brian, there are some days when I should keep my toolbox locked. I was dividing the wrong values!!,as soon as I went back to my bike after posting my message it hit me like a hammer. Thanks again. James.