Square Four MkI - first rides after restoration

[Gui.dorey]

This weekend I did a few more rides.

I am now happy with my idle settings and can now close the bi starter all the way.

Cold start procedure is to open the bi starter all the way, kick 2-3 times with ign off and throttle closed, bi starter in the mid position, ign on and she starts on the 1st or 2nd kick while twisting the throttle a little bit.

Oil pressure cold is over 100psi, and goes down after warming up. However, after a ride the pressure gauge shows 0psi while idling. Any thoughts on this?

I am getting the oil leaks under control, although I'll have to open the coupling gears cover to reseal it, as I have a leak on the underside of the cover.... bother! For the timing breather, I did the suggested mod with a copper pipe taking the opening to the area around the camshaft sprocket. This cured the major spewing of oil onto the back wheel. On the drive side, there is still a major leak, although I am not sure if it is coming from the gearbox output shaft or from the primary chain case. Probably will try Cam Steven's suggestion and see if that cures it.

My attempt at fixing the speedo wasn't very successful. It was very greasy inside but otherwise in good condition. Everything was cleaned, but the needle still springs back and forth and many times just stays at 0 and doesn't move. I believe the springs are not holding the sprockets or something is not quite working with the escapement. Any experts here with some suggestions?

As far as the engine goes, it has a smooth idle and runs very smoothly up to moderate speeds, with good acceleration and all that. However, at higher rpms (in top gear above maybe 70-80km/h or so) it seems a bit rough to me and as if it is not getting its full power. Still not sure what is going on, but feels like ignition timing. Either not set properly or the advance arms are not opening up as the should. I have a Thorspark ignition kit. Anybody using one on a Square Four? If so what is the best way to check the timing with a strobe light? What does one use to put some marks and check? I was thinking of using the front crankshaft, by unscrewing the inspection cap and putting some marks on the nut.

That's it for now. All in all feeling happy.

Cheers,

Gui

[paul.jameson]

If your oil pressure is say 25psi when going along at 45mph in top gear then a lack of oil pressure at tick over would suggest to me worn rocker gear. Provided that if you blip the throttle at tickover and then see something on the oil pressure gauge, I wouldn't worry too much.

[chris.shearwood]

I have a Thorspark ignition kit. Anybody using one on a Square Four? If so what is the best way to check the timing with a strobe light? What does one use to put some marks and check? I was thinking of using the front crankshaft, by unscrewing the inspection cap and putting some marks on the nut.

Hello Gui,
I use electronic ignition on my Sq4 (not Thorspark) and to strobe time it I do as you have been thinking: a couple of marks centre-punched onto the front crankshaft nut, one for TDC at 12 o'clock and one for full advance. Some oil sprays out so a large-surfaced pan comes in handy.
Regards, Chris

[Simon.Gardiner]

Gui:
Dunno if this article on overhauling chronometrics is any help on the speedo issue
http://www.wdbsa.nl/Jaeger-Chronometric-Overhaul.pdf

SG

[simon.holyfield]

Gui,

Did you check your rocker oil lines? Which one is the gauge connected to, big one or small one?

[Gui.dorey]

Thanks for the article on the speedo Simes. I had it already and that is what I used. I'll have to open it up again and see if I can find out what is wrong. Maybe I missed something.

Regarding the oil lines, I still have them backwards, with the larger going into the rockers. I haven't changed it yet because the larger oil flow hasn't been giving me any trouble until now, and the job has been put on the list for winter. But I thought the purpose of swapping the lines was just to restrict the oil flow to the rockers. Does it also have an effect on the system pressure? if so, how?

[simon.holyfield]

Remember where the gauge takes its pressure reading.

Pressure loss in a pipe is affected not only by the size of the hole but also by the length of the pipe, so that long, small pipe to the rocker creates a restriction in oil flow to the rockers which has the effect of increasing oil pressure at the banjo, and hence increases the pressure the gauge sees.

With the lines the wrong way around, the effect is similar to having an oil leak near the gauge line. I wrote a blog post on swapping them round, I'll find it for you.

[simon.holyfield]

Here it is:

https://ariel-square-four.blogspot.com/ ... d.html?m=1

[Gui.dorey]

This weekend had some progress. I timed the ignition with a strobe light and indeed it was a few degrees retarded. However, I noticed the advance didn't seem to be working properly, and this was confirmed by a trial run. So back to the distributor and the advance mechanism. The weights seemed to have been stuck and after some head scratching and disassembling it and some trial and error, I had botched up the assembly and done it wrong. So, got everything back in the right holes, changed the springs to the proper holes and everything was working properly again. After retiming the ignition, went for a short trial run under a hot 33 deg blazing sun, and now I can say she is running well. Still get a vibration coming through the handlebars at higher rpms, but otherwise she is running much better of course.

Now, I'll have to tackle the oil leaks which still are way too much, especially from the drive side.

She now starts consistently on the first kick and I have the pilot screw out 1 3/4 turns with a steady idle. Oil pressure is just below 50, engine warm, while running on top gear at somewhere around 40-50 mph.

[chris.shearwood]

Now, I'll have to tackle the oil leaks which still are way too much, especially from the drive side.

What is the oil level in your primary case?