Decided to start a new thread after the woes with engine, and having rebuilt it for a second time, to report on the first experiences running the Square Four in.
Today I went for a longer run to get get the engine up to normal running temperature, set my idle, set the air screw on the carb, check for leaks, and to get a general feel for how everything is running.
She starts now on about the second or third kick with the bi starter in the mid position. Since she would die if I closed the bi starter all the way, I raised the throttle stop a bit and also screwed the air pilot 1/4 of a turn in, and it got better. Still can't shut the bi starter completely, but getting there. Problem is, when she is warm you can't really get in there to adjust the throttle stop without burning your paws. Will have to fiddle with it some more though.
I took it really easy, maybe 80-90 km/h tops, and she shifts fine throughh all the gears. She pulls fine with good acceleration, although the engine seems a bit harsh on top gear, so I'm not sure if it's normal or just the running in phase. I also am getting some vibration on the handlebars coming from the engine. Oil pressure still on over 100 psi when cold, but kept going down as it got warmer, and when I arrived back home and was playing wih the idle the needle actually went down to near 0...???
The only big thing that's bothering me are the oil leaks. A few minor ones from the primary case, but I had the back wheel on the right side slathered in fresh oil! After rolling on the ground like a bug on its back trying to find out where so much oil is coming from, I believe it's fom the timing chest's breather. Now I'm not sure if this was due to the initial high pressure I was seeing, or due to something else. Still, it seems like a lot of oil is beeing pumped into the timing chest.
A major leak is however coming from the gearbox output shaft. That seal is apparently not doing its job, I'm afraid. Other than that I also noticed one tiny spot behing Nr 3 where the otto gasket is not sealing. But after the first run, I will have to check the torque on the head nuts anyway. The only two I can't really get to are the ones below he inlet manifold. Somebody has to show me how you actually get to them and turn them down.
Otherwise the only thing that is not working properly is the speedo. It actually seems to have been serviced by the previous owner and in very good condition, but the needle jumps a lot up 70mph (and I was definitely not doing 70 for sure), sometimes it gets ramdomly stuck and then jumps again, and finally gets stuck between 65 and 70 not going beyond that spot until my speed is much lower, at which point it jumps back down again. Any ideas on what I could check or service on my own, before I send it somewhere for repairs? It might just be something simple from just sitting around for years.
I'll keep you posted on further progress.
PS using a morgo pump and oil is happily and plentifully flowing back into the tank.
Last edited by Gui.dorey
on Sun Jun 23, 2019 7:06 pm, edited 1 time in total.
1951 Ariel Square Four MKI
1954 Ariel NH Red Hunter
1929 BSA Sloper
1946 BSA B31 (project)
1954 BSA C11G
1960 Harley Sportster XLH
1951 Harley WL 45