Britbike forum Forums British Motorcycle specific Brands Bsa bulletin board A65 timing side mods

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?

Doesn't matter, it was STILL an improvement which BSA declined to implement.

David is pretty much on the strong side of this arguement. When BSA went to unit construction (huge modifications with new castings), they could have put the roller on the primary side and an equally sized ball bearing on the timing side and end fed the crank. For what ever their reasons they did not follow the Triumph design and a lot of other motorcycles of the period. In the ensuing years they changed bearings, rods, oil pumps, OPRV's, points system in an effort to limit failures. TRheir warranty repairs were killing them financially. These forums are for "monday morning quarterbacking". That's why a lot of us have A65/50's today that are more reliabale than the bikes that came outof the factory. It is hard for me to staunchly defend BSA (and BSA is all I own) which went from the worlds largest motorcycle manufacturer to bankruptcy in about 10 years. OTOH, their demise is our gain. BSA's are nice classic bikes and are very reasonably priced. I can make one run reliably but wouldn't necessarily design one the the way BSA did it....and I enjoy hearing what others have done to their bikes.
Mr Mike

Another deficiency of the timing side bush is it is almost impossible to get a good fit. If it was a split shell it would clamp around the crank, as a plain bush it has to be fitted over the end of the crank, this requires a greater clearance

Yes, was I supposed to see something bad?

Face it: Unit BSA twins explode.

Personally I would invest in a SRM needle roller conversion if I had my engine in bits. OK it costs a bit more than a re grind and bush but then that's it. The weakest point of the engine is eliminated, The oil has an easier path to the big ends via the end feed, The big ends get more oil pressure due to less plain bearings and the end float problem is eradicated. My last A65 had a home made needle roller timing side bearing/end feed, Devimead big bore barrels and an A10 crank. I guess it was around 830cc. It was a racing sidecar outfit and was regularly revved to 8500RPM (and more accidently)

From time to time this thread has touched on the topic of engine improvements in general, so...

I'm surprised that the subject of crank balancing has not come up. Maybe this is a "given", but a well-balanced crank, side-to-side balance being as important as, if not more important than a specific balance factor, cures a myriad of ills, one of which being bearing and thrust surface wear.

I seem to be agreeing with most of what you write, if you improve the balance on a reciprocating mass then it's wear characteristics will improve.

The TS bush isn't any different than the shelled cranks ALL vehicles have now, the only difference is horizontally split crank cases, a set of shells wouldn't be too clever in a vertically split crank case. The real improvement he factory aught to have done IMO is had a centrally mounted bearing surface. My race motor when it goes back together will have a TS bush, fitted by a company whom I know do good work ( and who's machining I'd trust over SRM) my mates A65 was done by them over 15,000 miles ago and it still goes strong, he doesn't hang about on it either, only person that has given it any harder riding is my self, and it's still a sweet quiet motor. I also know a successful racer who still has a TS bush on his race bike.

I'm not saying the needle roller isn't good ( my road going A65 has it, and it's a doddle to change the bearing. But it isn't necessary.




If and when mine does you can ram this back at me, but mine gets "red lined" often, it also was machines properly, checked regularly and serviced frequently with an external filter setup. Unit twins don't explode, they just give up and throw up when they haven't been looked after properly and ridden like a Harley.

Your correct the gerotor oil pump has as yet not been built. If your using a needle roller Brg on the T/S the pump only has to feed the big ends and even the alloy pump in good condition can supply enough pressure and volume for that job. the T/S and D/S Brg only then need a splash feed to keep them going.

As was pointed out earlier, getting the gerotor pump to fit into the original space and maintain the drive centre are issue which need to be over come. Then you need to build a test jig in which you can prove both the pressure and volume and longevity at various RPM. To much pressure and volume can be as much a problem as not enough.

John

If there was an issue with oil pressure the bikes wouldn't be fitted with a pressure release valve. A good gear pump and ball type oprv ( I've found the piston types from a well known maker to stick!) has no problems supplying pressure.

SRM used to list all these specs on their website, they rated their own pump at a higher output at different revs. I still know of no hard evidence where the pump is an issue. Only poor engineering.

I thought the use of junk metal to manufacture the oil pump was poor engineering.

I'm not so sure, mine did around 20 k miles in the last 7 years and still going strong.
Nothing fancy about bottom end but iron pump and HD oil filter, bush is all bronze type.

Went through the design exercise already for a gearotor pump, just have not had the time to machine it. It fits in the existing space but due to the differences in centres between a gearotor and gear pump design the tach drive does not align with the inner case hole.

I have the theoretical gear pump volume around someplace (difference in volume between teeth).

I don't think 40 years of numptys fitting them incorrectly helped either. I'm using the SRM pump, it has an anodised Alu body and never brings the oil warning light on ( might have something to do with the fact one isn't fitted) te oprv though is a different matter. I always urge anyone who complains about the light staying on, low pressure etc to check the oprv before stripping the motor, or reverting to the ball type if nothing else but for test purposes. As these units ( aftermarket) have been known to stick. The ball type is also better serviceable.

Please design and put the gearotor pump into market, but there has been no evidence on the original design being a failure. Other than poor machining or distortion. Many of us have ridden A65's and A10's thousands and thousands of miles without an issue, certainly never from oil problems anyway. Blown engines were also not a problem caused by oil starvation.

All I'm asking for is clear representation on why a gearotor is better and why you feel the gear pump is inadequate or at least some evidence to support it.

The only pump I know of which has resulted in a shagged crank was a gearotor pump. This was on a Honda with 20,000 miles on it. There is even an after market mod to fit the bigger/deeper gear mechanism from the 750 as they don't supply enough pressure. The feed side on the 400'4 pump is bigger than you can fit in an A65, and any slight pressure loss ( I have a cylinder base gasket which weeps occasionally on mine) the light will come on below 3000 rpm. It also has restricters in the rocker feed which are there to maintain pressure at the pump.

Now from memory, British bikes have a reputation for leaking oil.

The reason I use an SRM pump is because of the points I mentioned, ( poor original machining and distortions from mal-use). The SRM pump was also easier to obtain despite me having to re-import one from the USA ( because back in 2007 SRM, couldn't keep up with demand)


The gear pump was used on pre units and units alike, singles and Twins. The SRM pump is quite possibly a back step from the later iron pump that bsa used, however the failure of the earlier pumps was resolved by fitting dowl pins to aid in keeping the pumps aligned during assembly.

Yes my points are repetitive, but 60 years of use on various bikes show that the information I'm giving on the gear pump isn't unfounded.

I really do hope I'm boring you into leaving as you seem to have come into the board with another fantasist who dreams up modifications for non problems.

Dave Madigan has published on here for a very long time that he intends to make a gearotor pump, his work has to be respected and I can do no other. But at no point has he tried to claim that the original design was poor. If anyone can make this work then it would be DM.

I also see no reason for you to keep battling on with insults ( as I told someone recently, I've been called much worse than you could imagine and I've taken them all as compliments - so maybe your not making insults ) nor do I see the reason for the childish spitting of the dummy and attacking another board member who is well respected and tried to aid you with your forum manners.

I also don't have any shares in SRM or AMAL (although I do sell AMAL) but I do appreciate a good product when I have used one, I also listen and appreciate a constructive discussion. Something that this is not.

Can I just add that your handle seems to sum you up, the BSA Barracuda was also under developed and self destructive

Norton Commandos have a rotary gear pump that is very similar in design to a BSA pump. I haven't checked the gear sizes, but eyeball calibration says they are about the same and I would guess the through put volume is similar. Other than wet-sumping, which occurs with wear, there are hardly any complaints on the Norton forums about oil pumps. The Norton pumps are all cast iron though.

All the gearotor pumps that I have seen in Japanese motors have aluminum (usually cast) housings and seem to stand up well.
Obviously an iron housing is better for distortion that the zinc alloy used previously but first off, these motors were not intended to be race engines, rather plunking along back and forth to work type motors. Second, how many people have had one of these unmolested from new and the oil pump was the first thing that needed replacement? How many people have inch-pound torque wrenches and measured the assembly bolt torques when assembling or use a torque wrench when bolting it to the motor? It sits on a gasket which compresses and can cause uneven seat pressure.
The A75 motor was designed with larger 13 tooth gears rather than the 14 tooth A65 gears. The volume between the teeth on the A75 with 5 plain bearings is 0.25858 in^3 and the A65 with 3 plain bearings is 0.04559 in^3. The A75 pump scaled up from the A65 would have been 0.07598 in^3 (1.667 times) but it is 5.67 times more volume. I do no know how the A65 pump compares with the A10.
There is no more room for larger gears. Using a gearotor is for convenience. It will fit in the space available with more displacement and the only drawback is the tach drive not aligning with the inner case.
It could also be a 6 piston rotary plunger pump, 3 feed and 3 return in a rotating drum. A swashplate moves the pistons back and forth as it rotates. Higher cost though.
Putting in a modified XS650 crank solves even more problems: a centre bearing on the crank, all needle/roller ball bearings (spray lubrication), steel rods, shorter cylinder and readily available 80mm pistons to make it a 750cc.

Fair enough point, NickL.
DM, Matchless vertical twins had a centre main bearing for the crank, and two oil pumps! Yes, yes, I know, but these machines should be judged in the context of their era, not by misinformed legend! But I think your Eton type pump is brilliant.I think the Japanese oil pumps owe their long service lives to proper oil filtration.
I honestly believe there was nothing intrinsically wrong with the initial design and theory of the BSA twin oil pump. I think the issue was cost cutting with the pump body material, lack of efficient oil filtration, and " knowledgeable" owners!
A bit off topic, and a totally different type of pump, but during the '50's, Triumph tried different materials for their pump bodies ( in the interests of cost cutting, I reckon ) .Initially, the bodies were brass, then as mentioned, they tried both cast iron and alloy. But they soon reverted back to brass!
What a pity that BSA didn't use cast iron until the very end!
Incidentally, I do own an inch/ pound tension wrench. Aren't I lucky!