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91
Technical Discussion Forum / Re: Crank Case Breather
« Last post by Rick Parkington on July 07, 2019, 04:43:45 PM »
Wet sumping is certainly a likely cause with a circulating system - in theory the Sunbeam telltale should cut the oil feed supply until the engine is started but I was told that the since the telltale is o the outlet of the pump, the pump itself is still subject to the full head of pressure from the oil tank and that can cause oil to migrate from the feed side of the pump, via wear in the spindle housing, to the scavenge side where it trickles down the scavenge line back into the crankcase.
On my '32 9A I attempted to cure this by making a ball valve in the scavenge line. The ball operates under its own weight with no spring so that oil pressure can easily lift it but in theory gravity seals it when the engine is at rest. It didn't seem completely successful though so I did what everybody else suggested and soldered up the Number 1 position on the tap and turned it off.
But if it's a Best and Lloyd/Pilgrim type setup presumably that's total loss and I guess there is a tap anyway? In that case maybe check that the breather valve is operating. Although not all engines have a timed/valve breather, it seems those that do can build up excess pressure when the valve doesn't close properly.
Breathers are not so much there to cope with the descending piston because there should be an equilibrium between piton up and piston down, the breather is primarily there to get rid of excess pressure caused by blowby at the piston rings and if it doesn't close, this blowby added to the fact that it i inhaling as much as it exhales seems to create a build in pressure that leads to leakage.
So if wet sumping isn't the cause I would suspect a problem with the valve not operating correctly or maybe excess pressurisation from worn rings or bore.
Cheers Rick 
92
Technical Discussion Forum / Vibrating fork spring
« Last post by Thomas on July 04, 2019, 06:51:24 PM »
Hi all!

At 45mph in fourth gear my single fork spring vibrates at high frequency. When pulling the clutch and going to idle the vibration entirely disappears. Hence, the motor is it and the spring is in resonance. I wonder if this is okay and fear that this can destroy the material in the long run. Or is that normal?

Cheers, Thomas
93
Technical Discussion Forum / Re: Crank Case Breather
« Last post by Rennmaschine1930 on July 03, 2019, 11:41:48 PM »
Did you drain the sump before riding? A lot of oil can get into the case by gravity over a short period of time. Despite numerous adjustments, good mechanicals, my 1930 ohv will sump within a week of inoperation. IMHO, You have to drain it first or you'll end up wearing it.
94
Technical Discussion Forum / Re: Dismantling the steering friction discs
« Last post by Rennmaschine1930 on July 03, 2019, 11:29:27 PM »
The rear fork spindle should essentially slide out - you can tap the end with a drift to get it moving. Remember to remove both links - one end is threaded onto the spindle. Bronze bushes are pretty resilient. This is a great opportunity to look for any wear along the spindle shafts and bushes. Did you recently grease the spindles and the excess is coming thought the steering damper onto the friction discs?
95
Technical Discussion Forum / Re: Dismantling the steering friction discs
« Last post by AndyB on July 01, 2019, 09:23:54 PM »
My forks have just been reconditioned, and I didn't personally dismantle them - I don't think that as standard there would have been any bushes, but who knows what has been done in the last 80 plus years?!
Best regards
AndyB
96
Technical Discussion Forum / Re: Dismantling the steering friction discs
« Last post by Thomas on July 01, 2019, 09:03:46 PM »
Thanks a lot, Andy! That was the information I was looking for. Tricky business but easy if you know what's going on. Did you have any problems when pulling out the pin? I ask because I presume that there are bronce bushes which can easily be damaged.
Cheers, Thomas
97
Technical Discussion Forum / Re: Dismantling the steering friction discs
« Last post by AndyB on July 01, 2019, 08:50:11 PM »

But what is the "bottom back fork bearing pin"?

Cheers, Thomas

Hi Thomas,
As it happens I have my forks apart and was able to take the picture attached.
As you will see the lower rear fork pivot shaft passes through the steering damper, so this is the 'pin' which you will need to pull out far enough to release the damper, once you have completely unscrewed the damper shaft from it.
Hope this makes sense!
AndyB
98
Technical Discussion Forum / Dismantling the steering friction discs
« Last post by Thomas on July 01, 2019, 05:57:16 PM »
Hi all!

The friction discs of my steering damper are full of grease and I have no idea where this grease is coming from. I want to clean them but dismantling is a mystery (see the two respective pictures). After dismantling the adjuster at the top with its long axis the locker at the discs does not go loose (see arrow). Strange! Slightly tapping with the damper wheel from the top doesn’t help. How do I get the lower counter part off?

In "The Book of the Sunbeam" I find "If the damper needs to be dismantled at any time for the renewal of the friction disks, bear in mind that the bottom back fork bearing pin must be removed, as this passes through the steering damper body".
But what is the "bottom back fork bearing pin"?

Cheers, Thomas
99
Technical Discussion Forum / Crank Case Breather
« Last post by rakehill on July 01, 2019, 01:20:53 PM »
I enjoyed a great ride on Saturday at the Annual Rally. My bike a 1929 Model 2 350cc side valve went really well, without any problems on route. At the end however I noticed that one side of the rear tyre was coated in oil as was the adjacent frame and other items. It seems to me that I'm getting too much oil onto the rear chain from the crank case breather. The surplus oil is the being flung off the chain all over the place. Does anyone know how I can control the oil flow or does it mean that there is something wrong with the oiling into the crank case. The bike has the Best and Lloyd oil feed pump which is a sight feed similar to a pilgrim pump. I have it set on a fairly slow drip feed.
100
Technical Discussion Forum / Re: Lubrication of Gearbox
« Last post by VicYouel on June 26, 2019, 09:41:57 PM »
Two tap is available from our club shop...... not cheap though!
Vic
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