Oil settings

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nickst4
Posts: 37
Joined: Wed Feb 19, 2020 7:31 pm

Oil settings

Post by nickst4 »

Forgive me: I bet this isn't a new topic but....

I've been putting some enjoyable miles on my fresh-engined '75 GT550, and am up to 350 miles with no problems at all, and lovely smooth engine performance up to my current peak of just short of 5k revs. However, the bike does produce quite a bit of black liquor after a ride, and I'm wondering if vehicles behind me are staying back because of the pong! There's no visible (to me) haze of smoke once the motor has warmed up though. I have new scavenge valves in the crankcase too.

I'm running it on Motorex fully-synthetic 2T oil, with the pump set exactly as per the handbook, which was obviously appropriate for old-fashioned oil in 1975. Considering how much leaner things like modern chain-saws run, I wonder if I can safely back off the oil delivery? A new engine does well to have a comfortable sufficiency, of course, but what do other riders think?

Thanks for any advice,

Nick
barney01
Posts: 3118
Joined: Wed Sep 26, 2012 7:33 pm
Location: Prestatyn.Wales

Re: Oil settings

Post by barney01 »

You are correct in saying oils have vastly improved since these bikes were designed and made. You will find quite a few owners on here do in fact turn down the oil pump. However IMHO i would rather have my pump set correctly and not have to worry. I know 2T oil is not cheap especially fully synthetic but for me its worth it :D
NO SMOKE .......NO POKE
asco58
Posts: 122
Joined: Sat Nov 21, 2020 2:24 am
Location: London

Re: Oil settings

Post by asco58 »

Usually, when manufacturers are reducing oil ratios in two stroke engines it's to do with particulate emissions rather than any advancements in oil technology or engine longevity. Even Suzuki were trying to cut down visible smoke emissions for the GT's with the SRIS (check valve) system. The oil helps with cooling as well so it would probably be a good idea to use the correct settings so that the correct quantity of oil is delivered to each cylinder.
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