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The previous owner has installed an oiltemperature thermometer. You use it instead of the oil cap and it has a short sensor stick which is a few centimeters in the engine body and in the oil. On the top is a little temperature idicator.
You can buy it at the typical motorbike shops.

For an air/oil cooled engine it's a nice gadget to keep the oiltemperature in view. Especially on really warm days and in stop and go traffic in the city.

Hello.
I am a quite fresh Freewind owner and I try to do as much maintenance as I can on my own.

Regarding the idle mixture setting, I have read many instructions for DR650 and similar bikes online which generally say:
1. turn in pilot screw completely
2. start turning it out slowly to find the highest revs/most stable engine running position
3. if you find the sweet spot between 1.5 and 3 turns from the start position, you are good

But, how to apply this method to two parallel carburetors?
Should I turn in both screws and start with tuning one of them, or should i turn the screws out on both of the (1/2 a turn at a time) in parallel?

I think you have to put both on 3 turns out. Then you adjust the first. Then you adjust the second.

They say you shouldn't turn the screw more than half turn from the 3 turns, but I did so I get a higher RPM.

Thank you very much for the suggestion. I will try that.

Right now I guess I have set it too lean during my first experiment. Engine runs just fine on idle, but it dies sometimes on the traffic light, it's slow to come back down to idle rpm and it feels like it lacks a bit of power on the full throttle.

Than again, when I push full throttle from 3k rpm, it responds much smoother then before. It seems I have been running a little bit too rich before the adjustment I've made.

Following the advise, I have screwed out both of them 3 turns.
Afterwards I have tried to find the best position (stable running, highest RPM) and ended at 5 turns for left and 4 turns for right carburetor.
At that position, I could reduce throttle stop screw a lot and engine would still run on ~1500rpm completely stable.

Unfortunately, I have felt some loud trumping during the heavy acceleration from 3k rpm.
For me that sounded like engine choking for a moment because of too reach mix, so I have reduced both carbs by 1 whole turn ending on 4 turn on left one and 3 turns on the right carb.
In order to keep idle ~1500rpm, I had to screw in throttle stop screw a bit, but now it seems that trumping during low revs acceleration is gone and idle is stable.

Any suggestions how I could double-check if now I'm running too lean or too reach?

Still on topic of running too rich or too lean...

Is this spark OK or does it show too lean mixture?


symbol for aluminium

Looks good to me. By the way, mine runs great when I turned the screws like I told you. Maybe try to clean carbs and air filter.