RS34 Tuning Assistance Please

Groovy Daveo!! Has your oil consumption dropped? 400miles per quart is Waaay excessive, is it falling out? Baffle doesn't resemble an oil burner.

17.5 pilot jets and fuel screw adjustments have improved the spark plug color uniformity considerably:

 

...and non-ethanol 90 ⛽️ 

😊

To address oil consumption, I let the T4 engine oil drip out of the motor for the past two days.
I'll return the new jug of T4 bought Saturday, and carefully pour a gallon of T6 in the motor instead.

Could someone advise me which T6 Rotella will be better for my motor, given the choice of 5W-40 or 15W-40?

Tough decision to make this change, but the results of changing fuel is making it a good bit easier.

😉
 
200    200+   190+   200+

Personally I would go with the 15w-40. These old motors weren't designed to run on thin oils and it may improve your consumption.

Wookie58 wrote:

Personally I would go with the 15w-40. These old motors weren't designed to run on thin oils and it may improve your consumption.

+1

Plugs look better  🌝

The motor is very happy with the T6 15W-40 Rotella..  Consumption is less, and leaks are minimal...limited to the cam cover gasket at a couple end plugs.

Switched to .9 air jets and dropped the needles (clips in 2nd slot)...and she likes this setup a lot!
 

Those plugs look good. 

Since I've retired a couple of months ago, I've been spending way too much time on Bob Is The Oil Guy.  Regarding oil, I'd switch to 15w-50 Mobil One.  This stuff has more ZDDP than Rotella T6, and even though it doesn't have a MA/MA2 rating, it has a great reputation with the motorcycle crowd, so you can rest assured, your clutch won't be affected. The Bob guys call Rotella, Brotella, due to its popularity with the motorcycle crowd.  Shell did themselves a solid by going through the MA testing.  Regardless, though, the M1 is "the stuff" for an air cooled bike like our KZ's.

At the end of the day (just my opinion) these thin oils were developed for modern motors running much tighter tolerances due to modern manufacturing processes and the demand for greater fuel efficiency and lower emissions (my diesel Jaguar ran 20k mls between services on 0w30 and only needed a couple of liters top up in that time but it was built for it)
 I will be running my build on Motul 20w50 which is specifically intended for bikes of our era