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Just getting into my first A65 engine and reviewing the Timing side bush. Read a lot of theories about why it fails and some of the exotic solutions SRM etc.Expensive and not always effective depending on who does it that day
The restriction of end play seems to be a common denominator in all of the solutions.The standard set up, even when built to the factory spec of .002" end float does not take into account that as soon as the engine warms up there will be .010 of side clearance on the crank.
Looked at a drawing of the A70 and BSA seem to have put a really large Thrust washer inboard of the mainshaft timing gear.This effectively controls end play of the shaft very effectively. Has any body tried this fix on an A65?

Hi Rob,
In my opinion problem with restriction of end play is not as common, as a problem with low oil pressure during idle.
Most of the owners of later machines I met complain about it, because they can see it as a blinking oil lamp.
This is why I see some variation of SRM solution necessary in this engine, to improve delivery of oil to the big ends and eliminate end play problem in one stroke.

For a few years I had been using a stock set up and it's holding well during these few thousand miles, but lower than necessary oil pressure is very visible if you observe your oil pressure light closely.
Specially in town, every spirited ride on the freeway cost you longer and longer periods of orange light being on during idling.

Hi Rob,

There's loads of info and opinions about this online and one of the factors is whether the engine has a ball or roller bearing on the drive side with a common view that the earlier engines, which had ball bearings suffer less from crankshaft float than the later roller bearing engines. This means that there is less chance of the oil feed holes from the casing being obscured.

I'm still pretty new to this but have had my early ('62 ball bearing) crank cases fitted with a new drive side bearing and then a new timing side bush which I've had line-bored with the ball bearing.

The idea here is that the important thing with these engines is the limited clearance between the bush and crankshaft journal which maintains oil pressure. If this wears then the pressure drops and you then enter a spiral where wear increases, pressure drops etc.

So I'm hoping that ensuring accurate alignment of the crank bearing and bush along with efficient oil filtering will keep mine running well for a while yet.

Cheers,
Bernie

Hi Adam,I think the end play when hot can start the shaft moving between the bearing faces causing wear and eventually loss of oil pressure.
Hi Bernie, the ball bearing on the drive side is tempting!
This motor is a 1969 Lightning unit pretty much the same as the original Firebird engine without the holes in the crankcase!

I definitely will use ball bearing in my next engine, and needle Timken bearing on the timing side ( already bought ).
No more problems with end play, and with amount of riding I do every year ball bearing will last for a long time.
Only tricky part will be re routing oil and making a quill in the inside timing cover.

I think that the problem on the A series is oil pressure. A well set up roller will work fine and the ball bearing does fine too. You don't have to monkey with setting the endplay with a ball bearing but it is a matter of choice. On oil pressure, I made some changes. I did not have a port (66 model) for a pressure light or a gauge so I removed the OPRV completely and pluggged the return line to the sump. I installed a Tee and one side returns to the tank where I installed a small ball type pressure relief that I bought commercially. On the other end of the Tee I mounted a gauge. This worked as expected except my new OPRV was too small to flow enough oil when cold and the pressure would be 75psi at idle. Once warmee up (about 15 -20 miniutes od riding) the motor registered about 45-50 psi cruising but would drop down to about 5 psi at idle. The culprit here is called hysteresis. To prove this I tested my OPRV with compressed air and while it opens exactly at 60 psi (the set point) but it does not completely close until the pressure is down to about 3-4 psi. The newer BSA OPRV's with a piston might behave a little better but I am not sure as I have no way to measure how it does. Anyway I put the small new OPRV back in the return line and installed a metering needle valve just before it. With the metering valve totally open the pressure was the same as before...45-50 psi cruising at around 3500 but at idle it returned to about 4-5 psi. I closed the needle completely so there was no bypass and I had about 25 psi at idle but it would peg my gauge at anything above idle speed. So I cracked the metering valve open to 1/2 turn and VIOLA I had about 17 psi at idle and the customary 45-50 psi cruising. So a little restriction in the retun line made a big difference. The only problem is I must open the needle valve on cold starts. As soon as the engine oil is warm I close it down to 1/2 turn open. It is good to go for the rest of my ride with excellent oil pressure throughout the range.
On the bush, I too align bored it very accurately and I have always had good oil pressure. I believe this is crucial to longevity on a BSA bottom end.

Mr Mike

Mr Mike, I totally forgot about your exercises with oil system.
Senior moment I think.

Bernie

The end play cutting off the oil flow from the feed holes in the TS bearing are complete BSA myth. If all the pieces used to control the end play are removed, you can not cut off the oil feed holes. You need .125"+ end play to get the oil feed cutoff. To get that much end play, the DS bearing has punched through the case and is in the primary. If that happens, oil feed is the least of your problems!

I agree with Trevor and Rich. I think that if you carefully put a BSA together it will run....and that is not a lot different than assembling other motors...they all need care in assembly. I do think that the quality of the BSA castings had fallen behind the times and I am certain that there engine assembly line left much to be desired. I think if their workers cared as much about these old bikes as we do, the outcome may have been different.

Mr Mike

Thanks for all of the input. Last BSA motor I did was my 63 RGS.
On that one I honed the -.010 main bearing up to standard and had the crank hard chromed and ground to give .0015" clearance.
Also shimmed the outer cup on the drive side to give .001" of end float.
That all seemed to work quite well so May follow the same idea on this one.
I also think some really low compression pistons would be a really good idea to give this motor a chance at a longer life.

I've worked in a few different places and the guys who would retire on the same ground floor grade they joined, always reckoned they knew what was being done wrong by "those idiots upstairs."

Ok- Back to my original question" has anybody tried to install the timing side location system that BSA put on the A70?
Does anybody know anything about?

If anybody could have an opinion it would be Rick Harriet ( Highway ).
I don't know why he is still silent about it.
I remember a conversation with him about this subject, but don't remember it well enough to repeat it.

Over the years I have seen all sorts of mangled, used abused A 65's running quite happily on the original set up.
If you intend it ride it all day every day at or above redline the the existing set up probably needs to be upgraded.
OTOH if you are keeping it to ride once or twice a month in standard trim & tune then the plain bush will serve you well provided that you change the oil very regularly.
With an electronic ignition, Podtronics & spin on oil filter fitted the bike will out last you provided you change the oil very regularly.

The biggest problem I have noticed with the OIF's seems to be bad ring flutter at very high revs which can blow a good portion of the only just sufficient oil strait out. The remaining oil gets way too hot & way too thin.
And by high revs I am talking in the 7000 + rpm range,
This will happen regardless of weather you have an end feed crank or not.

RSG Bob,
Only 202 A70's were made according to Classic Bike. The article does mention a change to the timing side bush and there is(was) a site that showed the parts. It was "Ole's web page" for A65's and A70's. The crank and rods were changed to make it a 750 but most of the rest is identical to the A65. I would think if you take it apart, the same kinds of changes that were made for the A65 could me adapted to the A70. If you need a new bush, they can always be made. I had one made for my A65 and fitted it right into the Vandervell sleeve with a small dowel pin to prevent turning. Worked great.
Mr Mike

Hi Rich, I agree about the myth(cutting off oil supply)! To clarify my comment and concern about excessive end play when hot.
I do believe that there will be about .010" of end play which when that starts rattling back and forward my cause premature wear in the bush and this will reduce oil pressure.
Also have found that the soft crankshaft is sometimes more worn than the bush.
This could be caused by hard particles embedding themselves in the bronze giving the shaft a good sandpapering.
Like everybody says,frequent oil change plus a filter.

Mi Mr Mike, the A70 diagram i looked at showed a large Thrust washer between crank timing gear and the crankcase face-Have not seen that on an A65.

RSGROB,
So is there no thrust washer on the inside between the crank cheek and the bush ala A65?. Is the washer on the outside just spacing out the gear or is it contolling left side movement. I don't understand?

Mr Mike

The thrust washer and shims are on the outside of the timing bush so you do not have to split the case to set the end float. Go to http://bsaocne.org/tech/svc_sheets/a70.html and see the parts list and diagram.

Made my own bush out of, as I recall, aluminum-bronze (a very tough self-lubricating alloy, also used in Vincent valve guides). Then had the crank hard-chromed and ground to size (necessary due to the toughness of the new bush material). Roller on the drive side, shimmed between case and outer race (no shims to wear or fall apart).
Fitted lower comp pistons (8:1 Venolias) and taller gearing.

Been riding her hard and putting 'er away wet for many years with no problems whatsoever.

Yes this is the set up I am talking about.I cannot tell from the diagram if the thrust washer is locked in place by the third oil pump retaining screw and the gear rotates againstit. If this is the case I wonder if the A70 Thrust washer has a bearing material applied to one face?

being a noob to bsa this topic is highly interesting to me as i have a basket case ready for love.i do not want to hijack a thread, but im trying to sort out the details of a lower end build. would it be correct in saying that the design of the a65 is atime tested design and the down-falls are the results of variables such as materials and workman-ship.will the bush-bearing system work fine with the right materials and with a skilled shop such a Rabers here in ca?would fitting a better oil pump help longevity? ive been riding triumphs for decades and never really worried about lower-end issues as these thanks

Hey Trevor, that is superb-just what I was looking for.
Only concern i have left is the fairly small bearing area on the thrust face and thin shims.
I think this solution was BSA's final kick at the can in terms of making the plain bush arrangement work.
Looks a lot less costly and complex compared to the SRM solution and easily transferred to an A65 motor.
Trvor is the end of Plain bush level with the recess or slightly set back?

Hey Trevor, could you provide depth and diameter of the recess?Many thanks
Rob

duster - you need to give the year. Early oil pumps were alloy, the last was iron. Some of the improvements can be applied to early engines.
The outboard thrust washer appears to run against the shims which run against the bare case. This does not look to be as robust as the original arrangement where the bronze faced thrust washer is held in the case and the crank runs against it. These engines were built for flat track racing so longevity was probably not a factor.

hI TREV, looks like it is about .1 deep based on counting the thread pitches in the tapped hole . and i guess we know the diameter by how close it runs to the stud hole.
I think I will leave an extra .005"clearance from the bush end to the thrust washer.
I am going to try this on the firebird engine .
I can machine the thrust washer to eliminate the shims entirely.
If I do end up needing shims I certainly would NOT put them between the Thrust washer and the crankcase.
I will grind enough off the back of the crank gear to give the thrust washer some substance,
Probably make from H13.
Rob

So on the A70, the thrust washer and shims on the outside are sdjustable w/o disassembly and limits the cranks movement to the left instead of using the lip on the primary side roller bearing. Is the internal shim (like on a65's) still in there to limit movement to the right? I did not see it in the bulletin drawing.

Also of interst, Devimeade was being run by a former BSA guy and they were making 750's with bigger pistons where the BSA A70 does it with crank stroke. Was this a philosophical difference that started Devimead? The BSA A70 is now more like the old A10 but with high higher compression and a more torquy rather than revvy engine.

Mr Mike

Hi Alan- I have to go with what I have and what feel I can do.

To my mind, this looks like a half baked attempt by BSA to control the crank end float.

From Trevor's photos and description I believe the system is designed to work as follows:-
- a new recess is counter bored onto the outer side of the TS crankcase to allow for shims and a thrust bearing to be fitted
- a thrust bearing is fitted to the TS side of the crank behind the crank pinion.
- its not clear on the diagram but I assume there is a step in the TS crank to allow the thrust washer to be fitted tight against the crank pinion, otherwise tightening the TS pinion nut would lock the crank up against the cases
- the shims would be fitted between the TS bush and thrust washer to take up any end play

From an engineering principle I would have some concerns with this arrangement which are:-
- its not clear exactly what the shims bear up against on the crankcase. Its apparent that thrust washer secures the shim on one side but on the other side does the shim bear against the slim TS bush and/or the TS crankcase?
- I cant believe the shim would be designed to bear against an alloy crankcase which means it must have been designed to bear against the bush.
- Since the TS bush is so thin I would imagine the shim could easily become damaged and lead to an early source of failure
- I cannot see any evidence of a shim or thrust washer between the crank and crankcase on the inner side of the TS crankcase. It appears that the crank runs directly against the inner side of the TS bush or case, this may be OK though as I think there is a flange on the inner side of the TS bush.

Half baked, that much?
The crank bearing surface is also shorter to match the bush. The shims bear against the end of the main bush and case. If it was to bear only on the bush there would be no reason to make the counterbore larger than the bush O.D. The parts list does not say the thrust washer inside the case is deleted but that may be in the replacement parts list publication. Does anyone have 00-5722?
If the main bearing width was reduced by 0.1" the oil film thickness is reduced by 16% (SAE40, 180F, 50PSI, 0.0015 clearance, 2400lb load, 7000 RPM).
RGSROB - The step in the back of the crank pinion gear is 0.055" so you will not get much substance for the washer there. You might look at making a thin bronze washer held in the recess with split pins half intersecting the perimeter. Shorten the crank bearing surface to slightly more than the depth to the washer and to the diameter of the pinion shoulder. Make the thrust washer I.D. fit the shoulder and the O.D. clear the split pins. Shims can be put between either side of the thrust washer to set the end float.

The shimmed hardened washer was used on Ariel Sq fours from the mid thirties, for oil retention or side play, possibly both. You will loose some surface area as Mad says. You could shorten the pinion gear a little more than the A70 was, and cut into the bushing less.
The early ariels would suffer from low pressure when hot, but so did a lot of bikes back then even with end fed cranks with 2 rods to feed ..A larger version of Triumph plunger fed 2 mains and 4 rods.

You are still up against the small diameter of the actual bearing. To my way of thinking its better to run a heavy series needle roller, the bush probably has a higher load rating, but any comfort in that is taken away by it's practical working, and that's where the roller wins, simple to change, no line boring no crank grinding, end fed, and super long life for the bottom end. BSA should have fixed it properly, the race dept solved it with the combination bearing which Devimead then offered aftermarket. Devimead and others used A10 cranks and big bore kits to make the engines bigger. BSA then did 750 for the A70 only with an extra 1mm of stroke. Having run an A10 crank for a few years I expect an A70 could have been a nice motor.

Or, you can use two half main bushes inserted from each side of the case, add a couple of dowel pins to keep it from rotating and narrow the pinion gear slightly for the thrust washer. I have never seen the pinion gear wear out. It would most likely need to be reamed in place for fit.

Trevor,
I had my SRM roller/ball timing side conversion done 20 years ago. It's still going strong after 50,000 miles only the quill end feed has been replaced, this is the same type of bearing that Devimead used.
With regards to the A70 combination why doesn't any one ask the owner of Burton Bike Bits, he rebuilt an A70 a few years ago and was published in Classic Bike. The A70 was specifically built for racing in America and I'm sure that some of our racing American friends would have had some say as to how they would like the engine to be improved.
I had my conversion done because I didn't want to keep redoing the bottom end and having talked to a number of side car racers, during the 70's, most of them had it done as a matter of course. This allowed them to race for the full season without having to worry about the bottom end or having to dismantle it. The standard bottom end is good enough as long as it's put together properly and the oil is filtered using a car type filter. Ensure the oil pump is in excellent condition and don't thrash the engine too much.
These bikes are getting older by the day, don't expect miracles, but they are meant to be ridden.....

Enjoy them.

Keith.

an earlier poster made mention of the fact that most car engines use plin mains to feed the crank. The big difference is that the mains on the cars are double shouldered solidly locating the crank. The final A70 solution goes along way to emulating the standard auto motive bearing characteristics as far as a guaranteed location and minimal end float.
Yes I would love to put an SRM type combination bearing in and come up with an end feed.However, I want to give the standard set up the best chance of suceeding first. The input from the group is a huge help to achieving this.

The solid flanged main bearings were replaced by plain main with 2 loose thrustwashers with one on each side on the car engines in the UK in the 70's. As 90% of cars in UK are stick shift this worked but the US with 90% automatics stayed with the solid flange main as the auto box pushed the crank more than a stick shift.

Not sure that is the issue with the A65 as the gearbox is not directly on the end of the crank pressing it in and out as the clutch pedal is pressed.

You maybe right, I worked for the company that supplied the bearings for the Zetec engine and it was the UK version they added a series of ramps in the thrustwasher to act as oil collection points which supports what you say. The old brain cells are not what they were.

The biggest problem with BSA's is that the cases are split vertically. This makes controlling thrust in both directions difficult at best not to mention problems with oil leaks. With horizontally split cases (like cars and other motorcyces) installing the thrust washers can be done and measured before final assembly. Some engines have flanged thrust surfaces as part of the main bearing and generally are fitted in one particular main bearing. Others have two half moon thrust washers installed on both sides of the main to control axial thrust. Both styles do the same thing...contol endplay but is not easy to do on a vertically split case. This is particularly important as Kommando says in manual transmission cars as the action of the clutch pushs the crank forward. If the thrust surface is worn out you can see movement of the crank pulley when some depresses the clutch. While our BSA's don't have to deal with the action of the clutch on the crank, controlling endplay is still important and BSA knew this. That's why they originally started with a ball bearing so the crank does not move laterally. When they went to the roller on the primary side they should have installed a ball on the timing side and been done with it. Triumph did it and BSA owned them since the early fifties. BSA has only to blame themselves.
That's why I went back to a ball bearing instead of a roller on my motor.

RSGROB...let us know how you figure out the endplay for that rare A70 you have.
Mr Mike

Yes, many car engines (low rpm, low stress engines) relied on plain bushings for main crank bearings.
Show me one which was stupid enough to rely only on the oil passing through one bush, on one end of the crank for the lubrication of the entire crank.

Theres a bit more info on the A70 differences on the Burton Bike Bits website Here

which sounds like the Moto Guzzi setup. the entire crank lubricated through one front bearing.
my LMII is regularly revved to plus 8000 rpm (track days) and has just done 204.301 km.

the difference is the oil-pump.

regards A

DavidP sez:

"Show me one which was stupid enough to rely only on the oil passing through one bush, on one end of the crank for the lubrication of the entire crank."

Yep..stupid alright, exactly in the pattern Edward Turner set for the Brit industry when he designed the original Speed Twin the same way........

That was different. The bush in the Triumph timing cover wasn't a main bearing and didn't appear to suffer from load or wear.

It would work if the bearings were strong enough and there was enough oil. It's when engineers skimp a bit on everything, there's nothing in reserve. Once the main bush wears a little, the timing side big end appears to get much less oil.

nonesense,most engines are fed thro the mains and many have been in the past includung triumphs, this whole thead is nonesense,theres nowt wrong with the standard set up if done right,iv rebuilt an a70 and really didnt understand why they changed it ,all they did was lose bearing area on an engine that needed more and why after altering all those parts why didnt they just chuck a ball in and end feed it?

I do not see how this can be nonsense . It has added significantly to my body of knowledge on the subject and obviously shared a lot of excellent ideas.
To say the standard set up is fine is definitely head in the sand .Although this does kind of depend how you use and maintain it.
The reason I bought this up was to see if I can do some minor mods to a standard A65 that would minimise some of the issues.
I cannot afford to send my engine to SRM , the shipping from Canada would be more than the conversion.
Somebody in the states was doing the conversion- All I have seen on these was major problems. As a result I believe they no longer offer this.

Rob sez:

"The reason I bought this up was to see if I can do some minor mods to a standard A65 that would minimise some of the issues."

Somehow through all of this thread, not even sure which vintage bottom end you are building....

I agree with wak on the bearing, IMO, the TS bearing is too small, it should be at least 1/4" wider & bigger in diamenter. The oil pump is marginal, especially at sustained high RPM. The OPRV and drain from the OPRV can be an issue (depending on vintage).

And yet with todays oils and a filter, there are lots of A65's that seem to rack up lots of miles. For all the bottom end threads you find on the internet, reality is, very few people actually lunch a bottom end.....

Main bearing, not much you can do for the size. If you use a 2 piece bearing, make [email protected] sure the bearing has a dowel pin to prevent the bearing from rotating or sliding in the housing when running. Both are bad things. IMO, the sliding of the bearing within the housing is where the myth of endplay cutting off the oil flow originated. I have seen early motors with the bearing out of position from sliding and the oil holes cut off. The big ends were trashed.....

Use as late of an oil pump you can find or spend the big dollars for an SRM pump. The SRM is the same capacity of the late BSA pumps. D or DD BSA pumps are pretty decent pumps and not uncommon either. Make sure the currently available crap aftermarket oil pump gasket fits the engine. Most don't and require TLC to make fit.

Run a return line oil filter.

Run a BSA or SRM piston type OPRV. IMO, the SRM OPRV has bettter fit/finish than the BSA OPRV. Use as thin of a gasket possible or chamfer the case and run an o-ring as the seal.

OPRV drain - through at least early 69, the OPRV drain was an angle drilling to the sump. Depending on the casting & machining fixture set up, the angle drilling can range from really good for the engine to really bad. At a minimum, you need 2 full threads between the oil in cavity at the base of the cavity. I apply a thin sealant to the case threads below the drain hole when there are only 2 threads available for a seal. Late cases have a straight OPRV drain that goes to the suction side of the return pump.

Just a little care in these areas does wonders for the reliability of a unit twin. And most of it takes time, not cubic dollars.

Rich B plus fit non whitemetal big end bearings which should never see the inside of an A65, there are plenty of Al/sn and Cu/Pb bearings around including Clevite manufactured bearings commissioned by SRM.

rgsrob, so i take it youve had a bottom end fail due to end float ?

Wak, I don't know if anyone would ever know if end float was the root cause of failure.Especially as thjey sort through the pieces.
I just know that excessive endfloat cannot be good and i am going to try my best to eliminate it.
I am also going to incorporate as many other good ideas that came to light via this string which apparently is of no use to you.

Hi Rich, This is a 1969 lightning bottom end to replace the blown up original firebird unit.
I did NOT blow it up, just bought the pieces and want to build as good a motor as I can to get this on the road again.
Great information from most people, Much appreciated.
Rob

If it was my engine being rebuilt I would definitely try to ensure it didnt go bang after a few years. Looking at the history of the A65 bottom end design, we can see that BSA have made varyious attempts at controling crank end float including using a ball bearing on the drive side, a roller bearing with a shim pack on the drive side and finally an attempt to use shims on the outer timing side case. IM led to believe that the devimead TS roller conversion was based on advise from the BSA race shop.

One can only conclude that something wasnt right with the original design otherwise why would BSA continually tinker with it?

In the end, I suppose what you end up doing depends on how much cash you have and how hard you ride. There certainly seem to be some good options available and the best advise I can give is use an oil filter, decent oil and change frequently.

it wouldnt have taken much for bsa to cast the cases to take a bearing, and rob iv done over a 100 a65 engines mainly standard some end fed some with 3 peice roller bearings and extra bearings on the alternator,if you want advise then unless your going to ride it like you stole it leave it standard,what do you think is wrong with standard ?head in sand again

I can't say whether the main journal is undersized. I looked up the calculations in the machinery handbook and there are too many unknown variables for me. BSA had well schooled engineers and would know how to size a bearing. The design for oiling this TS main bearing in not unlikee most automotive engines except they feed from a main gallery to the main bearings and from there they feed one or two rods...just like BSA. I think and I've said this before that crank bore misalignment greater that a couple tenths will eventually wear out the bush, and oil pressure suffers causing failure. That's the problem in my mind.

RSGROB If you are gonna hot rod this motor I woulds see if I could control endplay using the A70 outside approach with an A65 thrust washer on the inside. if that doesn't work out you can use the lipped roller to limit left side movement as in the roller bearing A65's. If you are gonna just plod along like me, but a ball in the primary side and throw all those thrust washers away.

Mr Mike

How to cure such problems as I am facing same here

The drive side roller was to improve the life. The ball works, just does not last as long on a high specification engine.
The high gear on the five speed gearbox uses the rollers for controlling the high gear end float. There are roller bearings that have a separate thrust collar to make the rollers guide the shaft axially. I am not sure these are available in inch dimension. The closest metric is a HJ306 (30 x 72 x 19mm) 1.1811" x 2.8346" x 0.7480". You could easily modify the case/crank to take this bearing and control the end float that way.
I put the Machinery Handbook journal bearing calculations into a spread sheet. Basically what I found is the pump is too small for high RPM and load. At 7500 RPM, 55HP, 180F, SAE40, 50PSI oil, the main bearing with 0.002" clearance uses 0.6342 in^3/sec of the pump's 1.899 in^3/sec (ideal) output. At 0.0035" clearance the main is using 1.881 in^3/sec and there is still the two rods to feed. So what happens is the oil pressure drops from the assumed 50PSI. The minimum film thickness is 0.000107" which is almost the minimum recommended. This is also why you need a filter. That is not much room for dirt to get through without scoring the bearing.
I need to invert the calculations to solve for oil pressure given the oil pump's output.

BSA HOLY GRAIL: So what we really need is a bigger pump like one that is in the Honda's where there is a 5 lobe outer and a 4 lobe inner that both rotate at the same time - more capacity. There is a name for this kind of pump....

Ah HA here it is. Would somebody throw away the gears in our oil pumps and put in two of these TRICHOID ROTORS (and a 450 watt alternator please!) I bet you could still use the shape and outer dimensions of the original pump!



Then I could run 10W40 year round and the motor would be easier to kick in the dead of winter and I could pressure feed the top end.

Thank you!

Do you mean one like this?

This uses the gearotors from the Suzuki 250 dirt bike and retains the original drive spindle. One problem is the spindle does not quite align with the tachometer drive. The drive axis of a gearotor is closer to the centre of the outer rotor than with gears. There is not much room under the timing cover or between the pump studs for a larger pump or moving it elsewhere. I do not have a set of the 450 gearotors to see if they would fit.
Nothing wrong with gear pumps. Porsche still uses them on the 911 and derivatives. It is just the A65 pump is a little small.
I believe it is possible to mount a three phase generator from one of the Japanese bikes in place of the Lucas. I put one in the triple with just a new mount.

YES YES YES!

I don't see why we couldn't modify the inner timing cover to get some more room. As far as mods go that would be pretty simple. Could you not make a new worm gear on the crankshaft or change the angle of the drive shaft to compensate for the different axis of the new oil pump?

How do we get this built?

Most of us don't have the capability to modify cases and the days when there were shops on evey corner that could do this work are for the most part gone. I have to do what I can do myself. For those that have the capability...go for it. For those that don't, the ball bearing on the PS was used in the early A65's and in the A7/10's and while it has a lot less radial capacity than a roller of equal size it'll do fine if you're not 'riding it like you stole it". What failed most often on these bikes was rod bearings and cylinder siezures and that was a lube issue not the radial capacity of the ball. OTOH if you are running the roads at high speed like Semper, go ahead and beef things up what ever way you can.

Mr Mike

Great idea for improvement of the oil pump. I wonder why SRM, or somebody hasn't used this for their high-capacity pumps. As much as the thing costs, seems like it wouldn't cost much more to use this type of impeller. Maybe one could design a pump along the lines of a rotary engine?
BTW: The gear pumps on Porsche, VW, and triples reside within the case.
I can see where it would be a bit easier to adapt a different alternator to a triple. The alternator doesn't share space in the primary drive on triples. Maybe if I spent a day poking around at the local Jap-bike salvage yard I could dig up something.
All things considered, I'd be satisfied with a new Truxton with the shifter moved to the right side. Seems to be an easier mod.

Hi Mike, I believe all of the the later A10's had a roller main on the drive side, certainly the super rockets and the RGS did.
Not sure when BSA dropped the baal bearoing drive side.

The 1960 A7 Shooting Star I had when I was 18 (49 years ago) certainly had a roller drive side main bearing.
How do I know?--because it threw the drive side con rod and punched a neat hole in the drive side crankcase necessitating a complete rebuild.The crankcase was rewelded by a Lloyds certified welder in a local engineering works for the cost of a packet of 10 Woodbines (cigarettes)---which was the accepted currency in those days for any "foreigner" done in the factory.
Happy Days!

So, that's it, BSA figured we wouldn't complain as long as we could find some, "foreigner," to fix it for a pack of smokes.
No sense cutting into the stock dividends to do real R&D.

i dont know why you lot have bsas there obviously a dissapointment to you, go buy a Honda and put bsa badges on it.

No disappointment,Wak, after rebuilding the motor the bike gave me 9 years and many tens of thousands of miles of great service. It was my only transport for that time.And I was young then with only one throttle position--flat out.
BTW I came to UK a couple of years ago and bought a very similar 1960 A7 Shooting Star (polychromatic green color) and brought it back to US. Interestingly only a couple of hundred numbers different in engine number from the one I had all those years ago.
DavidP--just a slight correction--the Brit factory jargon at that time---a "foreigner" was not a person but a private job carried out in factory time by factory guys (and the management normally looked the other way as they did it too).

many thanks for all the good ideas.
in summary, it appears that a sugnificant number of folks seem to think the standard set up can be reliable if a a late oil pump is fitted and if correct diametral clearances are achieved,
Also if an oil filter is fitted.
All of this if you do not thrash the heck out of it.
I will look into the A70 system of controlling end float as BSA seemed to think it was a good idea
Once again many thanks for a thought provoking string.
Regards
Rob

Most people do not want to irreversibly modify their engines so modifying the timing cover is something to be avoided. There is little room to work with so major changes to the layout is also out. The speed of the pump can be changed by making a new worm but that is expensive. On the triple I was able to change the gear drive to a Virago chain drive to increase the pump speed with only adding a tensioner to an existing bolt.
I am not sure what the SRM pump cost is but these gerotors are about $25 each, retail. I am getting a set of RMZ450 gerotors to see if they fit in the space available. The 250 gerotor is still a little small in volume. I am trying to source off the shelf gerotors, custom pieces drive the cost way up. Parker Hannifin makes gerotors of a suitable diameter but they do not sell individual parts.
A Japanese three phase generator can be adapted to the twins. You have to turn it around and mount the stator to the primary cover.

I found a website with details of a DIY version of the timing side needle roller conversion Here .

I have no idea whether this works well or not but anyway food for thought......

RAGROB,
Sorry on the misinformation. Some one told me the A10's and A7's were ball bearing. Do those motors control float like the A65's. That was one of the reasons I put a ball in mine. So the only DS ball bearing was from 63-66 on the A65 models?

Mr Mike

If I remember correctly the A7/A10 used a two piece timing side bush---a steel outer with a bearing material "cast" onto it.
End float was achieved by shimming between the crank and the inside of the roller bearing inner face.
Been about 40 years since I rebuilt my A7SS but I think the above is correct.
Particularly on the A7 the standard timing side bush was perfectly satisfactory over many thousands of miles.
I believe the problems only started when BSA tried to wring more power out of the A65.
HTH

Tridentman,
I'm pretty certain the two-piece ts bushing was pinned together...

Disappointed? Well, it hasn't blown up yet.
However, if I had perused the vast knowledge and opinion offered by the folks on this fine forum before buying a BSA, I would have held out until I found another Triumph.

I can tell you I have screwed out two triumph,s yet the a65 has survived splendidly. Disappointed.....are you sad that your BSA hasn't blown disproving the theory that all a65 are hand grenades.
I don't think that the general opinion of people on the BSA forum are anti a65's, quite the opposite I would say.
Mark

Trevor,
So on a7/10's the shoulder of the bush was the thrust surface on the right side and the amout of float was controlled by a shim pack on the roller cup? I wouls like that better thatn that thrust washer jingling around in there.

Mr MIke

No, I'm disappointed that BSA learned nothing from the company it owned and re-designed its marginal oiling system to keep up with the performance of its, "All new for '71," engines.
If there were no deficiencies in the design, posts such as this would only exist in the competition section.

Gunner thats an interesting way of doing the roller conversion. I show how I do a roller conversion on this link, though on my own bike I just use a simple external pipe to feed the crank. I also have a bolt on spigot that replaces the wormgear lock nut to run in an end seal. The needle roller I use in the timing side outlasts the Norton roller in the drive side.
http://www.britbike.com/forums/ubbthreads.php?ubb=showflat&Number=212693&page=all

"I will look into the A70 system of controlling end float as BSA seemed to think it was a good idea"

Not sure it was all that good of an idea. They shortened a bearing that is probably marginal in length to start with. From teh parts pages I have seen for the A70, not convinced teh shims were going to survive for a long time in that arrangement.

The standard end play control actually does work, regardless of what all these internet engineers say You just have to set it right the first time and make sure the alternator nut is actually tight. Most of my miles on a bike is on an A65 and have never had a problem due to endplay. A few of them were a bit loose, when the knock at idle got annoying enough, it got fixed.....

"Some one told me the A10's and A7's were ball bearing"

Shouldn't believe everything your "told", do some research. A10's never had a ball bearing. Only the original design A7 had a ball bearing (47 - 49) When teh engine was redesigned to be the A7/A10 engine, the ball bearing was dropped and replaced with a roller bearing.

"So the only DS ball bearing was from 63-66 on the A65 models?"

62 - 65 only had the ball bearing. 66 started the roller

"No, I'm disappointed that BSA learned nothing from the company it owned and re-designed its marginal oiling system to keep up with the performance of its, "All new for '71," engines."

Sounds to me like you may be suffering mental anguish over the company selling a defective product. Better get your self a lawyer and sue them! Maybe even file a complaint with the Consumer Product Safety Commission! Any evil company selling defective product like your 71 BSA that constantly blows up should be punished by the government and a good class action lawsuit. Go for it, let us know how it goes.

"However, if I had perused the vast knowledge and opinion offered by the folks on this fine forum before buying a BSA, I would have held out until I found another Triumph."

There is a classified section on this forum. You can list your lemon there and look for a real motorcycle that will satisfy you :bigt

No Rich - don't send him over there. According to Shel, triumph owners throw handbags at twenty paces. Have some compassion man - some Christmas spirit even. Sometimes a rational person has difficulty admitting to irrational wants and desires. We are, after all, BSA owners and there is no cure.

So, Triumph just wasted its time and money converting their engines to end-fed cranks?
Then why do these discussions even exist on the BSA forum?