What fuel mix for a bush run with the boys ?

[Anthony Drake]

Gday all
Just looking for advice on a good fuel ratio for a TY250a .
I normally run 65/1 for round the house or out the farm and have no dramas .
Im going for a ride on the weekend with blokes on WR's and the like and will be on the gas reving harder for longer .
I wonder how lean I can go without oiling up the exhaust system?
I was looking at going to 20/1 .What do you think?
Thanks Drakey

[yammyty]

Anthony, big mistake changing your oil mixture ratio so much as the more oil added to your fuel, the "thicker" the fuel becomes. thus leaning out your machine and the rest is history.

Best to run 40:1 and tune to suit, also suggest that you look at plug heat range as most Yams run BP6 whatevers, these are for trials use, you may need to run BP7????for trail riding..
Cheers

[David Lahey]

To start with it's a bit cruel to run an air cooled bike with so little oil as you have said. Yes it will run and it may still be OK for now but you will prolong the life of the engine if you use 50:1 or more oil even for just tooling around at home. Water cooled bikes can handle less oil than air cooled because the piston, cylinder and rings don't get anywhere near as hot as air cooled.
I use 33:1 for trials competition and moderate trail riding and never get exhaust oil problems.
Think about the plug too. If you bike is set up for trials, it may have a sparkplug that is too hot. B7ES or B8ES would be the go for your fang ride.

[Anthony Drake]

Thankyou Gentleman
33:1 it is,and B7ES
Drakey

[Stu]

Drakey I just use 50:1 premix in the TY for trials and trail work. And I chase WR's and a CR500 without a problem. Been doing it for years, good fun too! I just put in a new plug last time out, but not too sure what heat range it was. it still starts 1 or 2nd kick every time! Have fun!

[yammyty]

Drakey, Dont forget to adjust your carb settings, if its tuned for 50:1, it will run lean on 33:1