A7 nip up

[Greybeard]

The oil in the chain case is there only to lube the chain.

[cznorbert]

I've checked the oil slinger.
 It is old, damaged as you can see in the picture, and very loose in his place.
It spins around easily, it's wavy too, it's definitely easy to get everything through here. I think it should not move.

[Swarfcut]

 Norbert. When the cush drive nut is tightened, the oil slinger is clamped between the drive sleeve and the inner race of the bearing, so rotates with the crank. Without the sleeve it is loose on the crank. Cush nut has to be very tight, 60-65 FT/LBS or thereabouts. Drive sleeve should have a scroll on the outside edge, mine measures 46mm diameter, and is a close fit to the hole in the crankcase. Smooth drive sleeves of 46mm diameter have also been reported. The crank splines are the same on all models, so possible you have the wrong drive sleeve.  Later oilseal type drive sleeve is 43mm diameter where the seal runs, so too small for this engine.

 The oil slinger goes into the crankcase before the bearing, so if it needs to be replaced the whole engine has to be taken apart.

 This is the one for the Longstroke engine.

   https://draganfly.co.uk/shop/74576/drive-side-bearing-shim/#67-1239

 Later models use a different size main bearing and slinger, before all getting the oilseal design in 1953.

 Swarfy.

[Minto]

Hey Swarfy,
That link you just posted is what Draganfly sent me when I ordered the oil slinger for my plunger A10, so that's what is in there. Do you envisage any issues with it? I realised at the time it was different to the usual but assumed DF had sent it as an ok replacement.
Cheers
Jase

[Swarfcut]

 Jase. Drags list two slingers. 67 1239 Longstroke A7  '47/48, and 67-0349 used on the later A7/A10 Bert Hopwood redesign.  The difference is in the outer diameter (maybe) and the inner diameter. The cranks and their bearings are different sizes, so the slinger needs to match the crank.

 Longstroke crank takes a 1 1/8" ID (28.575mm) Imperial Ball Race, later engine has 30mm ID Metric Roller Race. Guessing you had to open the centre up a bit to fit your crank. Outer race is 2 13/16" (71mm) for Longstroke, later engine it's 62mm, so here again a difference. Outer profile of the slinger differs, some appear to be a flat stamping, others have a dished periphery to clear the crankcase. Add to that a fair number of homespun "better than nothing" variants.

 Whether it is effective, who knows. It blocks the hole, so must do the job and was good enough at the time. Close fit of the drive sleeve, smooth or scrolled type, ( whatever you've got ) in the crankcase hole is also important.

  As always it is a bit late to worry, suck it and see and check that primary oil level on a regular basis.



 Swarfy.

Additional. From your later post looks to be the right part number for your bike. Whether it's the right part.....

[Minto]

Cheers Swarfy,
When I ordered it id quoted the part number 67 0349, and what I received was the flat pressed type but it did fit without any modification, just wasn't dished.
With regard to another point you made, the drive sleeve on mine is possibly the wrong one as there is a fair bit of space between it and the edge of the crankcase hole.
If it needs to be changed I can make a visual inspection of the oil slinger then I guess.
What do you reckon?? Wrong sleeve?
Apologies to CZNorbert for the hijack.

[cznorbert]

Dear Swarfy,


Thank you very much for the information, I was able to check the parts and I made a paper washer with sealing paste between the oil slinger and the drive sleeve. Very exactly 46mm all it should be. I tightened the nut firmly, filled the oil as you described and I went for a test drive with confidence. Total success, after about 50mins of riding (and oil cooling) no change in oil levels, big relief.

Thanks again.

I wish you a broad road and rubber tyres 


Minto, it's okay

Cheers
Norbi

[Swarfcut]

 Norbert. I do like a happy ending. I wish all the problems folk have were that simple.

 All the best. Keep checking those levels.

 Swarfy.