Draganfly used to advertise with steel body oil pumps.
Would they be any better ?
Anyone tried one ?
Something else; i've never even seen my oil pump since I bought the bike in 1973.
It pumps all right, but should i take in out and check ?
(some people say "if its not broke, don't fix it" but I'm starting to worry now...)
No need to take it out if it is working.
The one in my bike works. My spare engine didn't have one so stripping one I got to ensure it is able to work. Before I took it to bits it would not move freely. It wouldn't turn easy even with pliers. So using this opportunity to learn how to service one. Probably never taking my working bike oil pump out.
However, bear in mind the 'tight' condition arises from a deterioration in the material of the Mazac pump body..This is an age related problem and can happen while the pump is in the bike...
It can even happen to a NOS pump whilst on the shelf as well...
I have stripped many engines that were running with an overly tight pump..
Of course, the engine has plenty of power (even the M20 ) to drive the pump in this condition...The result though will be a prematurely worn oil pump drive...
Dropping out the pump is a relatively easy job with the BSA so I would say it's a job worth thinking about during the winter months when the bike isn't in use as much...Ian
Thanks Ian
Have ordered a couple, now received in post. But when trying to screw in the bolt goes a couple of threads then binds. Do not want to force it, could it be a different thread?
I would start by running the tap down the bolt holes...it is quite possible that the threads have been burred by the use of worn/damaged bolts previously...
This will ensure the crankcase thread is good...Then retry the bolts...
If they are still tight use a WHITWORTH die to run down the thread taking the minimum of material from the bolt and then try it again...
If you run a die down the bolt first you may still find it is tight in the hole but you will now have an undersize bolt which may be loose when you tap out the hole...
From the point of view of 'best practice' it's worth noting here that UNC and Whitworth are not interchangeable threads..
Whilst the pitch (TPI) numbers are common up to half inch the thread form is quite different..
Whitworth has a 55 degree included thread angle and UNC has a 60 degree angle...The base and crests of the thread teeth are also different...
So, whilst you can physically mix the two, the fit of the nut to the bolt and vice versa would not correct in that case...
It should not be regarded as good practice to mix the two forms and this should be avoided if possible..Ian
I normally bin the original bolts as they are a pain to undo once fitted especially when engine is fitted into bike.I replace them with allen bolts with a drilled head so I can lockwire them, the advantage of using drilled allen bolts is you can just nip them up then lock wire them, this also helps to prevent distortion of the pump body..Dave
If the thread in the hole is damaged/burred which is possible as it's an original not a new thread, and you reduce the bolt with a die to try and make it fit it may still not go in...
If you then tap the thread out in the crankcase, the bolt, which has already been reduced in diameter in an attempt to make it fit a damaged thread, will then be undersize and thus slack...
It seems more logical to ensure the old thread in the crankcase is functioning properly before thinking of altering a new bolt which may have nothing wrong with it...To check the thread on the bolt a whitworth nut should be used..
Any comments regarding threads are only to point out that mixing threads is not good practice and a die of the correct thread should be used to clean up threads...(or the appropriate thread file)..not a nut of the incorrect thread...
I'm not being either pedantic or critical...I just think it is best to describe the correct methods ...Ian
Yep
Got a die and tap set for the 1/4 inch Whit thread.
Used the taps to clean out the thread in the casting and it worked, the New bolt fits smoothly in now. No movement, no slack.