Royal Enfield Interceptor - Knowledge Base
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| Unless stated otherwise, the information in this Knowledge Base is for Royal Enfield Interceptor only. Some information could of course be applicable to other models. |
A
fundamental problem in the S II 's Lubrication System (Ole)
Oil
Pressure Problem (Bill) (see Bill's Interceptor)
TECH
NOTICE. (Quaser)
More
on the search for better oil pressure (Bill)
Thoughts
on Pulsation Dampener (Bill)
Oil
Pressure No Better (Bill)
Important
notes from manual (Kickan)
Notes
on the Windkettle (Bill. Ole)
A
little more windkettle news (Bill, Ole)
Rolling
Lab - Oil Pressure Improvement (Bill, Ole)
Pump
cavitation has to be the culprit (Ole)
Thoughts
on Oil Pressure, cavitation, etc (gREgg)
Alarmingly
little oil drips off the exhaust rocker arm (R. Fisher)
There
are 3 leak passages in the pump : (Ole, Bill)
I
used a chamber capacity around 20cc (Peter - is Back)
A
picture that shows how the trick is done
Trochoidal
- Pump (gREgg)
Driving
the pump by means of a spade connection(gREgg)
A better Norton Oil Seal for Timing Cover/MainShaft Seal(Ole)
Tips for better oil flow and thoughts on Oil Pump (gREgg)
Quick two start driven oil pump(Bill, gREgg)
External oil pump off the tachometer drive (Tom)
Modified Pump Ports (Ole)
Electric Oil Pump! an Interceptor Pacemaker(Paulus)
Actual specs of the Tacho driven pump(Tom)
Electrical Oil pump for a test(Tom)
Search for better oil pressure - Oil Pressure Update(Bill)
Thicker Oil Helps too!(Bill)
Using a Honda Oil pump (with drawings)(Ole)
Oil Pressure Problem
Bill,
(Mechanical Engineer, Houston)
For years I have notice the problem of low oil pressure when the bike is above 65 mph. I have finally isolated the cause of this problem.
The 3/16" diameter oil passages in the engine block and timing cover are too small for the volume of the oil pump. To prove this theory, I drilled the suction port in the timing cover through to the outside and threaded a 1/4" fitting into the cover. Then I tapped a hole in the drain plug and connected a hose from the drain plug to the 1/4" fitting. Before makeing this modification, the oil pressure would start to rise with engine rpm until about 3500 rpm when it would fall off to about 5 psi. After the modification, I ran the engine at over 5,000 rpm and still had over 30 psi pressure.
Now the problem is how to put a bigger fitting in the timing cover. The suction port is so close to one of the bolt holes that a 1/4" diameter fitting is the largest thread that can be installed and the 1/8" hole that can be drilled in the 1/4" diameter is still a little too small to provide sufficient oil flow.
The only two options I can think of are to weld a boss on the timing cover so that a 3/8" diameter (1/4" NPT) fitting can be installed or to put in a smaller pump. Which brings me to the following question. Does anyone have an pressure pump from a Series I engine that they can install in a Series II engine to see if it will provide better pressure?
The Series I engine had the old dry sump system that used the large pump to scavenage the sump and a smaller pump to supply pressure.
My 1956 Indian Woodsman had this system and I think the pumps have the same outside dimensions.
(fr. Quaser)
TECH NOTICE.On My Rickman Enfield (1969 Ser 2 )I have made two significant modifications, both to do with the oil system. The first was to graft in a decent filtration system, the second was to install a circlip to stop the timing side crankshaft seal from blowing out.
I have been unsucessfull in stopping the inherant oil pump cavitation which all these engines have. You would never know unless you have an oil pressure guage fitted.
There is not a problem if the machines are ridden quietly but any sustained high speed work will shorten engine life drasticly because of a severe drop in oil pressure. The higher the RPM the lower the pressure. That oil guage has saved me a lot of grief especially before I installed the circlip. It's the small oil-feed Seal in the Timing Cover, I'm referring to. I've seen ( in my own engine - which I've had from new and always handled with care) the original seal pressed into the Pump worm gear and made into minced-metal & rubber !
Not a pretty sight !! So I've re-machined the Cover to house the Commando Seal ( slightly bigger OD) and made a Circlip groove to lock it. I have a drawing describing the operation if you are interested.
The big (external) Crank Seal in the drive side ( mounted in the Inner Drive Casing) has been ok - as far as I know. Being in the process of changing the primary drive to Belt + Dry Coupling, however, I'll know for sure next season if this seal works as we think it does.
11 September 2002 10:58 PM
Ole,To begin with, I have not found a solution to the oil pressure problem yet. I tried drilling the suction oil passage in the timing cover through to the outside, tapping it to 1/4-28, brazing a grease fitting to a hydraulic fitting and connecting it to a hole tapped in the oil drain plug to increase the suction flow. This did not help.
Then I saw the message from Peter about the pulsation dampener so I disconnected the hose to the drain plug and capped the hydraulic fitting to make an air chamber. This did not make any improvement either. So then I thought the chamber was too far from the pump so I drilled another hole in the outside of the timing cover, about 1/4" from the pump and installed the hydraulic fitting air chamber, plugged the first hole, and started it up. Same result, no improvement. I am to the point of giving up on the air chamber and I am now trying to find the right size ball to make check valve in the suction line.
I will keep you posted on the results. (Bill)
1 October 2002 10:36 PM
Hi Royal,
I wish I did have some better results but all I have managed to do lately is break some parts. I got the idea that the spring that holds the oil pump disk down might be weak after only 30 years hard service. So I tried to put a washer behind the spring to tighten it up and guess what...I cracked the oil pump cover because there was not enough free clearance for the washer and the spring.So now I just received a new spring and cover and I hope to try them out this weekend. This weekend I hope to go to the North Texas Norton Owners Association rally that is being held about 200 miles North of Houston.
If the pulsation dampener is ever going to show any results, this will be the time. The weather will be in the 80s instead of 95 to 100 like it has been here all summer. Anyway, after this next test I will post on the web site.
REgards,
Bill
10 October 2002 11:07 PM
Well Interceptor Friends, I can now report that my experiments with puting a pulsation dampener on the suction side of the oil pump have not improved the oil pressure when the engine gets hot. Of course I have seen 80 psi on the gauge at startup but after a few miles on the highway, it's back down in the 5-10 psi range. And this was with fresh 50 weight oil and 75 degree air temperatures.For anyone who is interested, I started this experiment by drilling the 3/16" oil passage in the timing cover straight through to the outside and then tapping the hole for a 1/4"-28 thread. I made a fitting by welding a 1/4-28 grease fitting to a sawed off hydraulic fitting elbow and then capping the elbow. Installing this fitting seemed to have no effect. Then I plugged this hole with a bolt and drilled a 5/32" hole from the outside of the cover to intersect with the oil passage just before it enters the oil pump cavity. I installed the elbow and cap and tried again. Still no improvement. I also tried putting a small rod in the elbow, to reduce the internal volume but this didn't help either.
I am beginning to wonder if I have some other problem. On the other hand, this bike has worn out 3 speedometers and it's still running strong so I am not really worried. I am also wondering about the reference to a "two start pump drive". This is certainly possible with the right-angle worm gear that drives the pump. Does anyone know if this is a commonly available part? In any case, I have not given up and I will keep everyone updated as things progress
Regards (Bill)
Thanks for sharing your findings with us ! When reading your account on "plumbing" activities, I can't find any reference to the size of your vacuum chamber or "windkettle" !?
I actually got the impression that you don't have one ? - except for the volume in the drilling and fitting ?
From what I've heard - and from what I've seen in other applications - that volume should be quite substantial !? Is there something I have misunderstood ?Best regards
Ole
25 October 2002 8:05 PM
Hi guysTravelling to work on the train, reading the work shop manual to pass the time, I found this interesting piece of information - see §49 in the Series II manual. /Kickan
49.Oil Feed Relief Valves
There are two pressure relief valves in the oiling system, both are located at the top of the crankcase, behind the right hand cylinder barrel. (See Fig. 11).
The right hand screw holds a 5/16 dia. ball and spring in position, forming the main relief valve holding a pressure of 60 lbs./sq.in. in the oil supply line to the big-ends. It is important
that the correct washer is used under the head of the screw, a thinner washer or no washer at all will give a higher pressure than intended.Too high a pressure in this part of the system could cause damage to the crankshaft seal in the timing cover and leakage at this point will reduce the amount of oil passing the main release valve. This could cause oil starvation at the rockers and lead to excessive wear of cams and tappets and poor lubrication of camshaft bearings.
If the pressure in the main system is too low, the amount of oil reaching the big-ends will be reduced. The second screw forms a pressure relief valve for the oil supply to the overhead rockers. The unit is pre-set at the Works to release at 10-15 lbs./sq.in. and cannot be adjusted.
25 October 2002 11:41 PM
Ole,Sorry to take so long to get back to you on the size of the pulsation dampener but my last post seems to have gotten lost in the ozone. Anyway, I measured the fitting and calculated the volume. The hole in the fitting is 3/16" diameter and 1 5/8" long with a 90 degree bend in the middle.
The volume is 0.045 cubic inches (0.74 cubic centemeters). Adding a short length of rubber hose to increase the volume didn't make any noticible difference. I also tried putting a 3/4" long dowel in the fitting to reduce the volume but this didn't make any change either. If you have any ideas for some other experiments, let me know.
Regards Madmax (Bill)
Madmax,
My gut feeling is that 3/4 cm3 is far from enough volume !?
Could you find a bigger (thickwalled) hose that goes on the outside of your existing hose ?
If you did this, you could easily ( !?) - with a suitable length - create a volume of 5 - 10 cm3, which I think is appropriate.The oil system might "starve" for a couple of seconds after start-up, but since it's the "old" oilfilm, anyhow, that needs to take care of lubrication at this phase, I'm sure no harm will be done - as long as one doesn't immediately flick it into 1st and roll the throttle.
Looking forward to hearing from you again !
Thanks !!
Ole
21 November 2002 12:14 AM
As Ole suggested, I recently modified the suction side pulsation dampenener (windkettle) to increase the volume from 0.75 cubic centimeterers (cc) to 3.35cc. Unfortunately, this did not improve the oil pressure and in fact the pressure was a few psi lower with this greater volume.For comparison, I measured the volume (displacement) of the oil pump and it calculates to 0.85cc. Based on these results,I now believe that the windkettle idea does not work. Once the oil gets really hot, the viscosity gets so low that there is simply too much leakage in the system to keep the pressure up.
I measured the flow rate with a very crude orifice and two pressures gauges and the flow at 4,000 rpm is down around 4 gallons per hour (gph). The theortical flow based on pump displacement is about 14
gph so this might indicate that there is simply too much leakage around the pump piston. The next thing I want to do is to check for wear on the pump. More later as things develop.Does anyone with a factory oil cooler also have an oil pressure gauge? If so, I would like to know what kind of pressure you are seeing. I am beginning to think that more cooling for the oil might be a better solution.
Regards to all,
Madmax in HoustonMadmax,
You've certainly been busy over there in Houston !
Thanks again, so much, for sharing this most interesting knowledge with us !!About 2 years ago, when I started mailing with Royal about this oil-pressure problem, I had never thought about cavitation.
My theory back then was the same as you are suggesting now : Oil gets hot and thin , leakage rate around pump-piston and -rocker body increases , consumption ( = "leak rate") at big-ends increases. ( Lower viscosity + bigger gap - on account of aluminium rods and steel cranks ; high revs increasing the effect of the "centrifugal crank-pump"! - all supporting a large big-end through-flow that naturally drops the pressure in the system.)Then I learnt through Royal about the widespread theory of cavitation ( wich is also known from other bikes ? ), and having read the account from Peter in Holland ( whom we can't get in touch with any longer !?), I became a full believer of the cavitation theory.
One of the reasons I converted so willingly is that I tried the Enfield oilcooler - with no effect ! Well, it's probably not fair to say no effect because I didn't go around the business very scientifically back then in the early seventies. I just noted that under long, hot trips I would still - with the oilcooler - suddenly loose all pressure to the heads. It might have helped a little ? - but it certainly didn't cure the problem.
As it didn't really help - and since it started leaking because of porosities in the casting - I took off the oil-cooler and have ridden without it ever since.
The sudden pressure drop is equally well explained by the cavitation theory as it is by the theory of gradual pressure drop - as long as we are talking head-pressure - because the presence of any pressure here is controlled by the first, "big end" relief valve, set to 45 psi.Once this valve closes, the "crack-pressure" to get it opened again will be substantially higher ! Thus the characteristic "on-off" picture ( an inherent feature of all relief-valves) !
Now that original oilcooler is a very crude and inefficient job compared to modern (and also contempory -) types. It cools the oil after it has left the pump. The oil that enters the pump is still hot oil from the sump. So it's probably not correct to say that bringing down oil temperature doesn't help !?If you are thinking of mounting an oil-cooler, I suggest you use a better one than the original Enfield. Be sure to find one that is designed for the pressure (45 psi). Many of the nice small oilcoolers are designed to work in return-systems, where there is very little pressure. I still have the original parts necesary for cooler mounting ( modified filter cap and centre-tie-bolt + hoses and fittings) - if you are interested.
Please Royal, if you read this, give it another go - finding Peter from the Netherlands !
Best regards
Ole(PS to Madmax : You have never told us precisely where you measure your oil-pressure !? - or can't I read ?)
Rolling Lab - Oil Pressure Improvement
23 November 2002 12:18 AM
Ole,I certainly appreciate your relating your experience with the oil pressure and the factory oil cooler. I have been running a modern Lockhart oil and using the factory oil cooler connections. I have tried mounting the cooler in several locations and I currently have it mounted down low on the front of the engine in the same location as the factory oil cooler. I am sure this cooler helps some but it certainly does not make any siginificant difference.
Regarding connection of the oil pressure gauge, on the original setup (before adding the oil cooler) I simply tapped a hole into the round, finned cover on the oil filter. With the oil cooler plumbing, I have
a tee in the line where the return from the cooler connects to the cover. At one time I made a fitting to connect the gauge to the circuit that goes to the rockers to see if the rockers were being starved for oil. This test indicated that the was always some pressure to the rockers. I never saw the rocker pressure fall to zero.Thinking some more about the results of the oil flow test, I think the fact that the actual flow from the pump is so much lower than the theoretical flow indicates that the problem lies with the pump and not excessive leakage in the engine. I expected to find a big change in the oil flow as the pressure went down which would indicate that the pump was bypassing. Alternatively, I thought the flow might stay high but the pressure would get low which would indicate leakage in the engine. The fact that the flow was not significantly different at 40 psi then it was at 20 psi leads me to believe the pump is bypassing unless the oil is very thick. By the way, I have seen 80 psi during warm up from cold with 50 wt. oil . I'm sure this would be enough pressure to blow the crankshaft oil seal out of the timing cover if I had not already had this happen and had locked the new seal in place with several heavy centerpunch swages around the OD.
Anyway, I have not given up yet and I'll let you know as things progress.
Madmax - On the Road Again
Madmax,
Great hearing more from you !
You have certainly been going about this detective work much more competently than I ever did.
Your pressure-monitoring in the high pressure system ( ie - before the Rocker Relief Valve ) is very valuable as opposed to my monitoring that only covered the Rocker-pressure.
It seems obvious - as you are also implying - that the only explanation that fits your observations - lies in the pump itself - and cannot be explained by gradually increasing consumption from the big-ends !
If the culprit is the pump, however, and and your monitoring confirms a sudden (not gradual !) pressure-drop, then the only explanation - according to my feeble brain - is cavitation !!? And the only medicine for cavitation is either to improve the feed route (as you already tried) - or to add a windkettle ( which you have also tried ) !?So, what next ? Are we missing something ? Are there any sharp brains out there that can help ? Is the only practical solution to add a low pressure (electrical, temperature controlled ?) pump that feeds the original pump ? - Or to replace the "Rocking-body" valving system with ceramic balled non-return valves ?
Just for the record : In my last mail I referred to the Rocker Relief valve pressure as being 45 psi. This is not the original setting - which is 60 psi - but a lowered value, that I obtained by replacing the original 1,5 mm thick fibre washer under the (primary) relief-valve with an O-ring sealed, 4,8 mm thick distance ring.
The pressure drop I experienced - in the Rocker circuit - was always from approx 15 psi ( secondary relief-valve setting ) to approx zero ! ( The 0,5 mm diam. "emergency-passage" in the primary relief valve is not sufficient to maintain any measurable pressure in my Rocker circuit !)Best regards, Ole
PS : Keep that rolling lab running !
Pump Cavitation has to be the culprit !
Madmax,
Some more thoughts after having discussed ( yet again !) this bad business with good friends :Maybe we can all agree - based on your measurements - that pump cavitation has to be the culprit !
Why then doesn't your pulsation damper help ?
Well, cavitation is pretty complex - but can be equalled to boiling : When the piston withdraws from the oil-surface, it becomes "easier" for the oil to release gasses from its surface than to follow the movement of the piston. So, which factors promote this process ? :1) Temperature. The higher the oil temperature - the more willingly the "boiling" phenomenen occurs. On the other hand - the thinner the oil , the less resistance will the oil column excert in following the piston.( becuase of less viscosity driven friction - not, of course, because of slightly less specific mass !)
2) Speed ( revs ). This factor pretty much only works one way. The higher the speed, the higher the vacuum - and thus the easier the "boiling"! ( Like water boiling at a lower temperature when you're at high altitudes - your eggs needing 8 minutes instead of the usual 5. )
3) Obstacles / discontinuities. Sharp edges or "corners" promote the initiation of cavitation - probably because you get small local areas with very high oil-speed and thus low pressure - i.e. easier "boiling".
4) Poor oil quality. Good engine oils are formulated to have as high a boiling point as possible. ( I've heard, however, that some of the real good anti-wear additives lower the boiling point - so its not all that straight forward !?)The guys at Enfield thought they might fix the problem ( there's no doubt in my mind that they knew about it !) by adding the oil-cooler - i.e. manipulating factor 1). We know, that it's not a good fix - allthough it might help a little !
There's not much to be done about factor 2) !?Factor 3) : Those ports in the Rocker-body are real bad stuff ! There's no doubt that it is actually here - if not at the piston-end-surface that the cavitation initiates. I'm pretty convinced that it would be helpful investing a lot of hours with small, high-speed grinding tools to expand these drillings into "chease-profiles" - and to round-off all the sharp edges where permissible. Big question, though, is : Would it be enough ??
Final question : Would using a windkettle in combination with the above help ?? ( the effect of the windkettle being to lessen the necessary inertia-change of the oil-column in the suction line.
I'm beginning to think that the odds of finding a way through this labyrinth are pretty bad ! I need to feel certain that the engine is always getting a lot of oil - especially when it's running hard. I don't think I'll ever get that feeling from the present system (- that actually gives up when the going gets tough !).
So I've decided that I will start looking at converting to a gear-pump ! The company "Morgo" sells a gearpump that replaces the Triumph piston-pump and it's said that it works great ! There's plenty of room ( in rear-wards direction ) to apply an adapter-plate to the present cover-face and then build on a gear-pump. How to fix the porting, I don't know yet, but there's bound to be a way.
In order to find the right gear-pump, I looked at my old calculations on pump capacity and I was happy to see, Madmax, that they matched your figures pretty well ( 14 g/h - 4000 rpm ). Please do me the favour of checking out the calc. below to reassure me that it's not a coincidence !? : I'll probably be happy with a gear-pump that puts out 25 - 50 % above this figure. ( I want lots of oil to the rockers !)
Piston dia : 9,525 mm (3/8")
Piston stroke : 12,7 mm ( 1/2")
Geometric displacement (approx) : 0,9 cc per stroke.
Efficient displacement (approx) : 80 % of 0,9 = 0,72 cc per stroke ( approx 20 % "valve-overlap" loss !)
Pump Spindle / Crankshaft gear ratio : 1 / 6
Pump strokes pr Pump Spindle rev. : 2 ( double acting pump function !)
Displacement pr engine rev. : 0,72 : 3 = 0,26 cc
Pump rate at 4000 rpm : 0,26 cc x 4000 = (approx) 1 litre / min = 60 l / h = (approx) 15 - 16 gph (US !)
As soon as I've found a suitable gear-pump and thought some more about how to build it on nicely, I'll let you know.Best regards
Ole
26 November 2002 12:11 AM
Ole!
Well Ole, I can see you have been thinking about this problem guite a bit. I'm not sure I know where to start. First, I agree with your flow rate calculation except for the following two details.I mistakenly used 3/8" stroke instead of the correct 1/2" stoke and I did not include an efficiency factor. I don't think we should include efficiency in the displacement equation. I think efficiency is calculated from the actual flow divided by the "displacement" flow.
You make a good point about cavitation and I can not argue with anything you say. It's just that I have not be able to change the conditions enough to make any real difference.
I think the gear pump is a great idea! I have been thinking about it also but I don't have the machine tools to make the parts. An adapter to put a gear pump on seems relatively straight forward but I have not, as yet, put pencil to paper to work out the details.
I really like the idea of adding an external oil pump, perhaps incorporated into the oil cooler, that would draw from the sump and add to the existing flow. This way, if anything went wrong, the existing pump would still be working.
Here's one more little piece of information from an experiment I did over the weekend. I rigged up my 1/16" orifice and two pressure gauges to a water faucet and pumped water through the pressure port in the timing case. With the existing oil pump blocking the pressure port I saw full flow from the suction port at about 30 psi. With the pump removed and the oil pump cover replaced, I saw similar leakage at the shaft drive shaft. I have yet to varify the difference in viscosity between water and hot engine oil but I suspect they are similar.
Maybe some of the problem is simply leakage between the rotating pump disk and the case and between the drive shaft and the case. I don't know what to make of this information but I will continue to think about it. Let me know if you find a small oil pump or a suitable gear pump.
And thanks very much for discussing this with me. It helps so much to have two brains working on a problem.
Madmax (Bill)
Thoughts on Oil Pressure, cavitation, etc (gREgg)
25 November 2002 4:22 PM
Just a few things to add to the conversation:1. Norton had severe cavitation problems with the early 1970's Commando when they re-designed the return system. At higher speeds the return became ineffective, and wet-sumping resulted. There is a well-documented fix for this, involving significant welding in the crankcases and re-machining to correct the problem.
2. As one may know, the Commando uses a gear pump, and this on its own does not prevent cavitation ... in fact it introduces a problem of its own: oil leaking past the pump gears will cause wet sumping during idle periods ... another curse that Norton owners live with.
3. The pre-Series II machines also had oil coolers available as an option, though I can't say that I've seen anything other than illustrations of them. They were identical to the Series II cooler, but were plumbed into ports in the crankcases, exposed by removing plugs in the oil ways. I should check, but I can't recall whether it was on the feed or the return side ... I agree
that it would be best fitted on the return .. but of course that would not be possible on the Series II.4. I wonder whether some of the ineffectiveness of the oil cooler is due to the lack of an oil thermostat. For a cooler to be effective, the oil has to spend some time in it for the heat exchange to occur, rather than shooting straight through it. Of course, this cannot be done on a cooler on the feed side, unless the thermostat is a diverter type that closes the regular path
at the same time that it opens the path to the cooler.5. The thought of matching the porting of the oil pumps with the timing cover to improve flow has some appeal, and I think I'll do that. When I built up my Series 1a engine, I spent a lot of time opening up the oil ways, matching the transitions, and smoothing the corners wherever I could.
6. The dual relief valves in the Series II engine are really a bad thing, because as mentioned before, if the pressure to the big ends decreases below the main relief valve setting, the top end will be starved. The earlier engines had positive feed to both the big ends and the rockers via the double acting feed pump, which was a much better system.
7. I've often wondered how much of the oiling problems some people have are caused by assembly errors in the oil pumps:
a) interchanging the feed and return pumps on the earlier enginesb) using an early style feed pump on the Series IIc) failing to carefully lap the pump disk into the timing coverd) failing to address grooves and notches in the pump disk or the timing
cover, either of which will cause loss of pressuree) and the easiest of all to avoid: ensuring the oil pump spring is
adequate to keep the disk on its seating ... otherwise it will blow off,
instead of the relief valve.8. I'll offer one last thing: I wonder how many people ensure they have the correct timing cover gasket, *and* that the holes are of the correct size *and* they register with the oil ways. Yes, there are several different gaskets, and they do not interchange. It's clear that the factory experimented lot in this area, since I've had numerous engines with variations on the oil routing, and one even had a timing cover that had been welded up and machined to alter the flow ... obviously a running change in production.
Hope this has been of interest,
... gREgg
Alarming how little oil actually drips off the exhaust rocker arm
26 November 2002 4:55 PM
Good day all.
I'm very interested in the poor oiling system as I ride my Series II for thousands of miles a season and by the end of a day on the Interstates and the odor emanating from the overly hot engine re-enforces every suspicion you have on the unsatisfactory oiling system on RE Twins and drives home that fact that this is a tough, tough engine ( I have other Brit bikes that
would literally explode if subjected to the oil starved conditions that these Interceptors live with every day).My experience is with Series II's and I would like to add my two cents worth on this very worth while discussion on oil pressure (or the lack of it on our beloved). As for using twin pumps from a Series I, remember that Series I's were dry sump systems and one pump is for pressure and one for return or scavenge-ing. Second, Series II owners won't have to worry about leakage past the gears if you fitted a gear type pump because they have a wet sump (hence the single, "pressure only" pump on Series II ).
This year I purchased a so called rebuilt Series II engine that turned out to be a bodged up amateurish mess and during the break in period I lifted the rocker cover to check for oil flow to the rockers and it is alarming how little oil actually drips off the exhaust rocker arm (the intakes get much more as they are closer to the feed line from the crankcase and hence "rob" the majority of the pressure / volume). I even spoke to Allan Hitchcock about this issue and he said this is just the nature of the beast.
So on that note I encourage all your efforts on addressing this Achilles tendon of a poorly designed (read cost cutting) feature on this otherwise great bike. I will read all submissions with great interest. As an aside the Dutch members of the AJS / Matchless group commissioned 50
redesigned high volume oil pumps for AMC twins (that sold out quickly) if someone is about to make an improved pump for RE Twins please put my name on the list to purchase one of the first batch.Cash waiting!
kboil.htm