Okay to use thicker oil in a Honda 125cc?

[alexmarjanovic98]

Hey guys, I have a Honda XL125V Varadero V Twin with 35k miles runs excellent after recent carb rejetting to factory settings. I used 10w40 synthetic and semi from several brands, mostly motul and it doesn't burn a drop of oil between changes. On my last OCI I tried a cheaper Bardahl fully synthetic 10w40 oil and it seems to be very thin, like it isn't even a 40 weight. Engine is more free revving but on very hot days (like 95 F) after taking off from low rpms and high load ( So I assume the problem is in the oil.
I shall switch back to what worked, namely the Motul 10w40 or should I go a grade thicker (10w50)?
I just hope that the engine isn't worn, it shouldn't be because it doesn't burn any oil and I did a compression test and both of the cylinders read 95% of a new engine with almost no difference between them.
Manual calls for 10w40 (10w30 in colder weather) for the widest temp range but single grades are also acceptable which I don't intend to use.
I change the oil at 1.75k miles interval (manual says 7.5k!!) because it has a 1.5 quart dry fill sump capacity and the oil gets pitch black within 1.5k miles so no problems there.
Also, why is the oil getting black so fast? Could be that the previous owner followed the manual for oil change intervals and the engine sludges up some so the oil is cleaning it now? I am the owner since 19k miles and since then on every OC I get black oil really fast (in the beginning it was black in 300 miles (!!) but after following oil drains the oil stayed clean for longer and longer).
Thanks in advance.

 

[Ducked]

Yes.

 

[Ducked]

I've used CPC SAE 40, Mobil Delvac 15W40, and Castrol 20W50 in Honda Clone 125 and 150 cc singles here, and the CPC SAE 40 in a 133cc Yamaha RZR 2-stroke gearbox.

All seemed fine, but I prefer the CPC SAE 40, for the usual reasons. A straight 40 perhaps wouldn't suit year-round in Belgrade (if you use the machine in winter) but might do as a summer fill.

Cleaning-wise, what you're doing with the Motul) seems to be getting the job done for you.

I've had good cleaning results with a 50:50 mix of SAE 40 with Delvac 15W40 in a car, but havn't tried it in a motorcycle.

 

[alexmarjanovic98]

Originally Posted by Ducked
I've used CPC SAE 40, Mobil Delvac 15W40, and Castrol 20W50 in Honda Clone 125 and 150 cc singles here, and the CPC SAE 40 in a 133cc Yamaha RZR 2-stroke gearbox.

All seemed fine, but I prefer the CPC SAE 40, for the usual reasons. A straight 40 perhaps wouldn't suit year-round in Belgrade (if you use the machine in winter) but might do as a summer fill.

Cleaning-wise, what you're doing with the Motul) seems to be getting the job done for you.

I've had good cleaning results with a 50:50 mix of SAE 40 with Delvac 15W40 in a car, but havn't tried it in a motorcycle.

Thanks for the reply. I use the machine down to freezing temps. If the roads are dry then I do drive in sub-freeying temperatures.
I plan on continuing to use multigrades (10W-x) at most since I don't like to idle to warmup since it takes forever so I just start and let it idle for a minute (or the time it takes to put on my riding gear) and take off under 1/2 of the rpm range and very low load (prefering lower gears and higher rpms) so quick flow is important for me, but I don't tend to choose 5W-x because of shear stability and tendency of lower HTHS and because I don't drive a lot in winter, but every trip isn't considered short tripping (>40km).

 

[Panos]

I think you worry too much. Every motor oil gets black in the first 300 miles, that is normal.I also think that 1500rpm is way too low engine speed to request a high load. My twin ninja does not like to rev lower than 2000rpm and have that throttle twisted hard.I think you ll be perfectly fine with every 10w40 there is available

 

[Kamele0N]

 

[alexmarjanovic98]

Originally Posted by Panos
I think you worry too much. Every motor oil gets black in the first 300 miles, that is normal.I also think that 1500rpm is way too low engine speed to request a high load. My twin ninja does not like to rev lower than 2000rpm and have that throttle twisted hard.I think you ll be perfectly fine with every 10w40 there is available

Thanks for the reply. The thing is, it didn't use to knock on any other oil that's why I got a slight concern. Also, it should be designed to handle 100% at any point in the rev range on a stock engine, even with some safety margin in case oil shears and/or weather gets exceptionally hot. My clutch is almost worn (not slipping but when releasing the clutch suddenly it doesn't grab immediately but slower) so I don't want to burn it any more than necessary.
PS. I was with the bike in Greece on vacation at the beach in Pefkohori

beautiful there
The only thing that's sucked was driving 90kmh for 850 kms one way.

Anyway,
For the oil getting black fast, in my Celica after 10000kms it's still golden, not the way when in poured it in but a darker golden color, nowhere near as dark or brown, I use it at highway only though at slow speeds (85-95 km/h).

Originally Posted by Kamele0N

Hahahaha
ÄŒovek bez stomaka kao mercedes bez znaka