850 Timing Cover

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JTBS1

JTBS1

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Can a 850 MK3 timing cover be fitted to an earlier MK1 850 without modification to either the cover or crankcase please? I am rebuilding a MK1A and have both cover types available and would like to incorporate the anti wet sump feature.

Regards,

John
 
Yes it fits straight on but you absolutely must use the mk 3 oil pump seal,this is flat instead of conical
 
baz said:
Yes it fits straight on but you absolutely must use the mk 3 oil pump seal,this is flat instead of conical
Click to expand...
Also, the wider Mk3 oil pump seal 'bush' or 'spigot'.
 
However, if you are doing this an as anti wet sump measure, you may be disappointed. After very little time it is common for the valve to jam open.

Much better to be doing this particular mod to have the cam chain tension hole!
 
Thought of doing this. MK111 oil pump seal and bush/sleeve are required. Then someone told me I should use MK111 timing gears as these are a tad thinner than previous. That's as far as I got with that project. That said , I have never had an integral MK111 anti-sumping plunger stick open. Better just to send your pump to AMR for anti-sumping work methinks.
 
I have a MK3 that has never been apart beyond taking the cylinder head off.
The antisump feature still works very well, at least 2 months to drain down.
As long as I remember to start it once during winter storage, it is good to go in the spring.
So the original setup can work and continue to do so for a very long time.

Glen
 
worntorn said:
I have a MK3 that has never been apart beyond taking the cylinder head off.
The antisump feature still works very well, at least 2 months to drain down.
As long as I remember to start it once during winter storage, it is good to go in the spring.
So the original setup can work and continue to do so for a very long time.

Glen
Click to expand...

Great that yours works but unfortunately my experience is the opposite, a pre Mk III bike but has had a Mk III timing cover since before i bought it (1984). I now have a tap (with electrical cut out) in the oil line. Despite the timing cover being worked on a few times wet sumping was never cured for long for me.
 
Torontonian said:
Thought of doing this. MK111 oil pump seal and bush/sleeve are required. Then someone told me I should use MK111 timing gears as these are a tad thinner than previous. That's as far as I got with that project. That said , I have never had an integral MK111 anti-sumping plunger stick open. Better just to send your pump to AMR for anti-sumping work methinks.
Click to expand...

I don't think you need to use the thinner MK3 gears. They are thinner because the MK3 cases are a bit wider in some areas to accommodate the wider crankshaft, not because of changes in the timing cover.

Ken
 
Just found this thread searching for an answer to the opposite dilemma. So can a pre Mk3 timing cover be fitted to a Mk3 engine with just the change of oil pump seal? Is the spigot/bush referred to, what the seal sits on?

Al.
 
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