I think the spec for the CD's on XU-1's was none in Summer and ATF in the winter...

welll all good, up and running, the L`8 sus if anything are running a little lean, got it running as good as i can, little bit back firing throughcarbs at times. Have booked in for tune monday :)

Got eh atf dextron 4, a little thinner than most apparently.

I didn't notice much difference with the lighter oils. I have gradually worked my way up to 70W90 gear oil.

I just recently sucked out the oil/gas mixture that was in the carbs and filled them with fresh 70w90. The carbs seem more stable. Nice long, rich accelerator pump effect but the throtle response also seemed a tad slow. Not bad but noticable.
I need to try something a little thinner.

Quote:The thing is, ... it worked perfectly.
Once warmed up, the engine accelerated with the best of them, but carby piston bounce, & the resultant unstable mixture, was much reduced when on rough road surfaces with the heavier oil, so the damping effect was increased with unexpected but welcome benefits.
Besides, there's always some oil left over in the container after an oil change, so why waste it.

ATF fluid is an excellent starting point for SU's and similar type carbies. The weight of the spring above the piston in the carby also needs to be considered when selecting the correct weight of oil,as they both work together to determine the mixture delivered to the engine. Generally speaking, the heavier the oil & the spring, the greater enrichment under acceleration. This can be helpfull, but you aslo need to check that the piston open fully at the point of max HP. At one time I was using 2 by 1.75 inch SU's on a 1400, and needed to use the lightest springs available to ensure full openeing. Hope this helps.

For old british SUs, I guess you could use anything. It runs out soon anyways?

For twin Hitachis, it's best to use the light Nissan Elephant Oil. Dman, it's not like you to take shortcuts in your Datsun craftsmanship.

I was just bone lazy & used engine oil in my Hitachi's. The opening rate wasn't too fast in mid winter when it was sub zero cold, but then I didn't push it untill it was fully warmed up anyway & the oil in the carbs thinned out nicely.
Never had flat spots from lifting too quick & the carbs were more stable on rough roads, so these things were just side benefits from being too miserable to buy the right stuff.

I use ATF (automatic transmission fluid).
The sewing machine oil and 3 in 1 oil I had to top up regularly.Since using the ATF it takes a bit longer before I need to top up again. I did'nt notice any performance difference between the two.

I used to run motorbike fork oil in the dome top SUs in my Zed. I think it was 10w.

Hahahaha

Yeh ive learnt to hate the bloody things. My boss had 7 of the things laying around the workshop at 1 point. Non of them ever ran right. Even after re-coning the engine, heads, carbys, gaskets, manifolds, carbys, dizzys...

I spose i hate em coz i got all the pricks of jobs. Like clutches and subframe re-conning! I can pull a head off and have it running again in under 30mins

Now im just straying way off topic... But im just trying to spam my way upto dattomaster! only 20 odd posts left!!!