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Synthetic oil

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Synthetic oil

Post  seipgam on Fri Mar 30, 2018 10:02 pm

Stupid question time,
With everything else being as it was, can a change of oil (to synthetic) cause poor running/missing in the upper rev range?
Kestrel 66, 13D, type 3/4 carb.

Cheers, Geoff.
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seipgam

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Oil

Post  kerabo on Sat Mar 31, 2018 6:58 am

It may affect the fuel settings of the bike as the Syntetic oil is thinner and so your mix is thinner. This means more fuel will pass through your jet and by the needle making it rich.
Turn off your fuel and see if the problem goes just before it cuts out.

You can easily turn the needle down a touch but if it's in full throttle you may need to go down a size on your main jet.

Ken
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kerabo

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Oil

Post  seipgam on Sat Mar 31, 2018 9:20 am

Thanks Ken,

No main jet in the type 3/4 carby, just the needle valve.

Your theory seems feasible though, so sounds like it might be worth going back to the original Castrol oil and seeing what I get.


Cheers, Geoff.
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seipgam

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Carb

Post  kerabo on Sat Mar 31, 2018 9:29 am

Is that he type you adjust the needle on a cable? Very strange idea.

If that's the case it's still easy to adjust.

Still just try turning off the fuel and see what happens just before it runs out

Ken
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kerabo

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Oil

Post  seipgam on Sat Mar 31, 2018 11:44 am

Simple screw adjustment above the needle.
Had it set up well, but playing up in the upper rev range since the change of oil (25/1 mix on both)
Can't get a satisfactory setup either way since, so will go back to the Castrol and the previous needle setting before I chase my tail too much.

Will report how I go in a few days.

Thanks again, Geoff.
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seipgam

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Oil

Post  seipgam on Mon Apr 02, 2018 6:24 am

So, Changed back to the Castrol 2T I was using before and the needle setting I was running with that, no better.

Checked all setting again, all good, removed the carby to clean and check its settings.
Found that the float has taken in a small amount of fuel, so time to get a new one and see if that sorts my issues.

Have started another post "Type 3/4 Float"

Cheers, Geoff.
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Re: Synthetic oil

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