Runs well but smokey at times

[Arrow]

There is a 12% tolerance from the factory on pumped oil amount. This is for everything though, bigger bores, pump cam wear, and I guess bigger jets.

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[rd400canuck]

Im going to do 40:1.... its more than I do now and should provide more protection against wear.

I deleted the pump because I happened to drive it one day with it disconnected from the throttle during testing and I was so surprised with how light the throttle pull became. It felt so good I decided to run premix. It's psychological...  when the throttle is resisting so much it makes me feel like the bike is struggling to do anything... a light pull makes it feel like the bike is freer revving under load and lighter in general. Try it sometime and see if you are as crazy as me.

[Arrow]

The pulley on your pump has two possible holes for the pulley spring. It may have been on the 'tighter' one.
Interesting what you say though. Yamaha made those springs softer and softer overtime. On pumps that are still available new, the spring only just about returns the pulley, even with the plunger in the out position!

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[Clem710]

Ive taken a wind out of flatslides before to lighten the throttle so I see where you are coming from, but I love the pump on a street bike:)

25-30:1 guy here with jaso or tc oil in the aircooled gear.  Theres an article around somewhere with a test for maximum power from back in the day and IIRC it may have been 20 or 16 to 1.  Also, iirc, i think they still ran even down to 6 or 8 to 1.  Oil is easy to buy, cylinders, cranks and pistons, not always.

MX bikes run in tight woods tend to load up a bit as well, totally normal, clean em out on the hill climbs or in the fields.  Seeminglu less of a problem on bikes meant for trail riding.

I've done a fair amount of experimentation on an old weedeater and a 50cc razz with injection and it seems that any oil will work, even cooking oil and used motor oil.  They dont all work well and tend to junk things up but they dont sieze immediately, usually theres a noticible decrease in power and increase in heat.  If it feels like its running out of gas but shouldnt be, pull in the clutch:)

More of any oil, appropriately jetted, does not seem to increase smoke, if anything, less oil seems to smoke more.  Maybe less lube, more friction, more heat, more smoking oil?  Someone probably knows:)

Just my .02, plenty of ppl round here that have experimented at a higher level and with real consequences