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Messages - K2-K6
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5026
« on: July 01, 2011, 08:39:15 PM »
My broad band (ha ha ha) connection is very poor early in the evening so any other stuff kind-of slows it all down too much.
Into the Stone Roses though as preferred choice.
5027
« on: July 01, 2011, 08:29:50 PM »
I know this is somewhere adrift of the original post but has some very interesting points that are relevant.
The HGV stuff certainly puts us into perspective as regards longevity. As I understand it when you change the oil frequently what you are really doing is throwing away the contamination as opposed to the oil breaking down from it's normal operating function. This is why you should limit on choke running to as small as possible time to prevent just throwing petrol/combustion waste into the oil on these old bikes.
For years we've had oil spec for example rear axle of a car that has no polutants from combustion and no requirement to change them for the life of the vehicle.
I understand for new engines now one of the issues of running in is to get the bores and rings to seal properly and modern synthetics can prevent some of this process happening. If you accept that the rings when squeezed into the bores are not perfectly matched to the bore shape then, it's the action of the bore hone sharp edges that effectively "file" the rings into a best possible match and hence most effective sealing. Once the minute sharp edges are smoothed from the honing process then very little further improvement will happen, this is the reason for some very specific oil requirements for initial running and you also need to use the engine throughout a wider range than past convention would suggest. I believe some car turbo desiels suffer from high oil use later in their mileage if this is not effectively completed. In effect you initially at least have a conflict of promoting some ideal wear characteristics while still protecting the other bearings etc from any wear. This is also why you need an oil change so soon to throw out the tiny particals you've worn off the bores/rings.
5028
« on: June 29, 2011, 10:51:07 PM »
I think that if I were in that position certainly it would be worth trying.
Couple of things give me a benchmark to go on.
1, car use. We owned an audi 5cyl petrol bought second hand direct from owner at 48000 miles which had been run from new on shell synthetic. We changed it to Mobil1 and ran it to 150000 miles (then sold) but you could look into the cam cover and still see the clean aluminium of the head plus the original grind pattern on the base circle of the cam lobes. the oil was always changed at 6000 miles intervals and came out a pale fairly clear golden brown i.e. similar to when it went in. It had no work other than service items during this time and ran fualtlessly, also revved to 7200rpm so not far off some of these old SOHC but longer stroke so could even have a higher linear piston speed than these.
2, Friend worked on military aviation jets and explained to me that as the oil used was not subjected to fuel contamination then there was much more detailed examination of oil performance as it virtually looked new although it would be at the end of it's performance life. This really showed me how dirty four-stroke motors make their oil from combustion by-products and degrade the oil.
From these I formed some opinions of my own about oil use. First is that combustion polutants get into the oil by going past the piston rings (specifically the top compression ring) and can be general blow by from poor sealing in normal use and much more blatant with extended use of the choke during warm-up.
The audi showed me that a well designed and good materials used engine, when run on synthetics had easliy almost nil wear over it's 150000 miles so a testemant to synthetics I think and certainly agrees with your use ST1100.
If you can get low wear from the start of your engine's life you will simply have less oil contamination anyway as you have not worn the piston rings/bores in the first place and so long term oil performance would always be less compromised. You'd probably have less need to change the oil any way.
IF there was an issue with the clutch, some sensible investigation (maybe use a stronger clutch spring to raise the clamping pressure) could deal with it.
5029
« on: June 29, 2011, 07:08:50 PM »
I'd have a look at the carbs generally first to find out what is actually in them as it will at least not waste time in chasing through other routes.
Has it got two fuel feed pipes to carbs one to each pair? if so check they are both clear.
5030
« on: June 29, 2011, 07:04:10 PM »
A lot of the internet comment seems to ASSUME that synthetic and derivatives is mythically more slippery and I don't know if that statement is true.
My understanding of synthetic is that the long chain molecules (these are apparently the bits that keep your pristine metal bits from touching each other and hence prevent wear) are more stable, stay intact longer and under wider conditions i.e. heat contaminant etc still manage to perform the job over and above the ability of non-synth type oils, all the stuff by the oil companies seem not to claim it's more slippery.
The clutch is specifically designed to expel oil from between the plates (that's what all the little detail gaps in friction plates are for, to break the oil film when they come into contact with the metal plates)when you let go of the lever and, the materials are matched to that environment to operate effectively. I guess if you had any specific effect it would be in the time the clutch took to bite fully as the oil cleared.
If you take the demand of an air cooled four stoke engine into account I would say that the benefits for using synthetic are definitely there i.e. localised hot spots that are better managed with water cooling are potentially offered improved operation with a synthetic. Also things like the F2 cam area, and any of the later SOHC engines that run wth lean carbs and probably higher temps.
5031
« on: June 28, 2011, 09:09:54 PM »
The F2 carbs step to a different strategy for running the motor at varying speed and load.
They are set to run as lean as possible in a steady state constant speed (probably this era saw the first real steps on bikes to clean up emissions) and are supplemented by an accelerator pump that operates as you move the throttle open more. It just pumps more fuel in to accept the load you are trying to put out so instead of going lean as the slides come up a spray gets it temporarily rich to facilitate the acceleration phase.
They also have a cable operated choke that gives rich run to start but pushed in half way will run the motor at about 2000rpm with mixture backed off to avoid making the bores too wet (you can see the change in intent from the old set-up and overlaps what we were saying about contaminating the engine oil) and also helps to get the engine hotter faster, Has benefits to the exhaust too as it runs dryer like this and gives less chance to help rot the pipes from the inside.
The F2 motor has bigger valves, wilder cam and higher redline so the spec jetting for the F2 carbs may not be entirely accurate for previous engines, guess you'd have to run a set-up to correct if not ideal.
Probably not much different from a rider point of view, maybe marginally snappier if you wack it open quickly.
5032
« on: June 27, 2011, 07:55:48 PM »
Den, that's a really useful collection of information and helpful to quite a lot of the people on here.
Greame, that could be arguably the best way to set them (using a gauge) intially as it is physically correct and will not take into account of any other irregularaties so assuming the carbs are near enough correct it then allows a good platform to work through any other stuff.
The slight increase in idle can have another benefit whch is often overlooked with these bikes which you'll feel when you ride it more. When you close the throttles completely i.e. slowing into a corner, with the carb slides right down at the bottom and engine revs up then the vacuum in the carbs makes it quite difficult to smoothly roll the throttle back on. The effect you get is it feels unduly resistant then, as you put more effort into it suddenly you snap to more opening, it's not dangerous but a bit difficult to get it smooth. If the idle is slightly higher it minimises this feel and allows a smoother operation just not enough to feel it's pushing you when closed, at a guess 1100/1200 for low speeds maybe 1300 if you used it faster for a longer period. It has a much cruder action than some modern CV carbs which natuarally damp this feeling for you.
5033
« on: June 26, 2011, 10:58:40 PM »
Ha, no wonder it was chuntering it's chains with carb set-up like that. Seems you're getting it to how it should be though now.
Mostly it's hard to get a really even tickover below about 1100rpm, perhaps when brand new maybe a little lower but I percieve it to be kinder to the generla health of the chains to be smooth at that rather than chase a lowered figure without any good reason.
As you've found you can get the sync pretty close by eye when on the bench but you can also do them with an improvised "feeler gauge" under the slide to get a really good physical match and I'd be willing to bet they'd be very close when checked with vac gauges.
5034
« on: June 26, 2011, 10:13:48 PM »
The carbs should be able to run that motor, some are even using bike CV carbs on car engines for example so they should be able to be configured to get it going. and I'd guess at the original demands being not that far off what you need to at least get some half sensible response from it.
Assume they are all in good order i.e. clean clear and minty with good diaphram sealing?
Fuel pipe, can you use anythng from a car spares shop as they sometimes have copper of varying sizes available.
5035
« on: June 25, 2011, 08:28:38 PM »
It seems that the argument against car and synthetic oils in these is primarily the clutch slip potential, and if that is all there is then I'd consider it worth a test to judge it for yourself.
All the other properties of the oil you've put in are surely what you'd want to achieve so plain logic would go for it rather than against. Again it's not going to cost much if you decide against it, if a clutch problem is evident then stop and think again.
5036
« on: June 25, 2011, 07:54:35 PM »
On the oil issue. I've no experience of any synthetic in these motors so have no means of commenting on that one.
To me though any oil diluted with petrol is almost certain to be out performed by most new oils so whatever you put in now should help protect it better. If you change your mind then just switch it it's not going to be a disaster.
5037
« on: June 25, 2011, 07:48:55 PM »
Looking at the tensioner "strategy" I feel that the spring rate applied can only really try to keep the chain reasonably quiet and stop undue stress from any uncontrolled flapping about, it's not very sophisticated else it would probably be damped as well.
If you think of the drive chain under load then with the tension run pulling the clutch basket all the slack will be roughly held in-check by the tensioner but nothing more.
If you then look at the chain under reverse load i.e. rolling along the road with the rear wheel turning the crank then all the slack will probably be on the opposite run with the tensioner pushed as far out as possible (200-300kg of bike and rider is easily going to push that spring rate) so it then has little or no effect anyway.
I don't see how we can argue with the original Honda design on this one unless you are particulary well informed on drive train analysis, so would choose to leave it as stock if no defects are present.
5038
« on: June 24, 2011, 06:52:10 PM »
Steff750, the example I had was a chemical process that was basic but flow was critical for 6 seperate solutions and controlled by wopping great ball valves that everyone was scared to move in case we couldn't return it to original. We put in flow measuring impellers and sure enough the readout just jumped about all over the place (like a bunch of monkeys in a coffe house) making that report unuseable but then a clever computer guy at the company wrote a little program to collate and clean the data on a real time basis and it really worked. certainly opened my eyes as to the potential of mixing different mechanical, computer and pure maths logic systems.
It's engineers that have manufactured the modern world remember.
5039
« on: June 24, 2011, 06:39:31 PM »
I've always run these 750 motors on the original Castrol GTX 20/50 car oil, this is from and in the 80s and never had any problems at all. None. This experience pre-dates any current discussion (pre-dates any of these forum!!) so I've not taken into account any current discussion.
I looked after a K6 in that era for a friend and this took an unimaginable thrashing that would truly make you wince but it never ever suffered any lubrication problems running on that oil never smoked, broke or stopped.
It's slightly odd after oil change as when you've put all the plugs/filter back on ten filled the tank with oil, as you start it the tank level will usually go down very quickly as the system refills via the oil pump so makes sure you have enough in the tank to avoid sucking air.
You can take the plugs out and spin it over with no compression at first if you want to be kind to it.
It's my opinion that mainly oil contamination by petrol has caused many petrol motors to wear prematurely over the years and have use of choke is a disaster to the general health. It's only to make it rich enough to fire and should be backed off ASAP and use higher tick-over to keep it running as this has no detrimental effect. I always smell the oil over any engines I'm asked to check as to me any smell of petrol means it's defective for it's principle purpose of lubrication.
5040
« on: June 22, 2011, 11:32:15 PM »
Primary chain tensioner is not that strong it just keeps the slack at bay and slows down a bit of backlash nothing more. Sounds reasonably ok from your inspection.
The primary seems easily strong enough to take the strain from a standard motor and shouldn't give many problems. I believe it has a harder time if you were to thump it down through the gears as when the torque is driving the crank from the clutch then the tensioner is pushed out of the way so the chain can flap around (I guess if it was really too worn it runs the risk of trying to wrap round the crank in the above scenario) it's very rare to hear of a road bike have a problem with this though.
Petrol will get into the oil if you keep running it on choke, in my opinion it will also kill the engine (loss of protection for plain bearings and cam) if left like that so worth changing it asap.
I've always run 20/50 oil in these with no detergent addatives.
Oil system is a two stage dry sump. Scavenge lifts oil from sump to tank and there will always be oil in the sump pan or the pump would suck air. second stage of pump is fed a stable supply from tank and feeds direct to bearing system so should be maintained above minimum to avoid air intake there as well. levels sound about right I usually check this with the bike level and engine running.
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