Setting idle speed dynamic timing on a 500.

[McCabe-Thiele (Ted)]

Quite a lot of mentions about checking  the dynamic timing F mark  at 2500 rpm for the full advance check - what is an acceptable idle speed for the lower timing mark ?

Not mentioned specifically in my manual.

[Johnwebley]

I think somewhere I read 1,200rpm,



Sent from my SM-A546E using Tapatalk

[K2-K6]

Original 750 manual asks for 850~950 rpm to check  the lower end timing. I don't have the 500 copy, but should be viewable here via Ash's stash.

Also above 2,500 rpm for the maximum advance check.

The lower one shouldn't matter, that's if the mech is retracted reliably, as the full advance is the more critical for running to give torque without overstepping the total advance and risk complications from that effect. If the lower check is a problem, then it's mechanical not setting as you can't move this without altering the max figure.

Really just checking the maximum advance should be fine for reliable running at factory settings.

[deltarider]

A CB500/550's advance begins at ~ 1150 and ends at 2300~2500 rpm.

[McCabe-Thiele (Ted)]

Thanks guys my engine idle is currently set at 1200,  I can lower it to  below 1000 but 1150-1200 sounds sweeter.

I've been tasked by SWMBO with other duties today so hope to check it tomorrow.

[McCabe-Thiele (Ted)]

Checked the Dynamic timing this morning it was spot on for 1/4 & 2/3 so I must have done a good job of setting the points & static timing.

More worryingly there was some oil in the bottom of the inside of the points housing - not a huge amount but enough to think the worst about the crank seal.

I am kidding myself I might have been a tad enthusiastic on oiling the points pad or the advance/retard unit. I have used a cloth to remove the oil that was just in the bottom - no sign of it having flung out from the crank rotation.

After removing all traces I have had the engine running again bit no sign as yet of more oil - I'm going to keep my eye on that as you can well imagine. 

[Bryanj]

Ted, in all honesty i have never seen an oil leak from that seal unless the seal was damaged fitting, and then it would pour out

[McCabe-Thiele (Ted)]

Ted, in all honesty i have never seen an oil leak from that seal unless the seal was damaged fitting, and then it would pour out

I took great care fitting both the crank seals & the gearbox ones.
I've just run the engine for another 5 minutes with the fan on - twice with a 15 minute standing gap  - it is still dry.
I have experienced a car rear main oil seal on my Mums Micra that would drip slightly after every oil change for a couple of days.

As I am so far into the rebuild I will continue so I can run it and monitor the situation.
I'm pleased to say its running really well on all four cylinders so I will start assembling the petrol tank fittings this week when Wendy is at work.

[Bryanj]

You have the correct ideas Ted