Kawi2strokes.com Forum

There was a post over at the Canadian board stating excessive jetting richness caused by fitting Uni filters (as opposed to dyno setup with open carbs). One of the examples sited is a 150hp Gast 750 engine in a 500 frame.

Has anyone determined what sort of flow/hp these filters cost? Anyone know the performance differences between clean and dry unis VS treated with Uni oil or fuel soaked caused by normal spit back?

J

Tony N. told me run the Uni's dry !!!!!!!! No oil !!!!

The post went both ways, Walm's ran worse, Zambia ran better, with and without filters. Jetting changes need to be made with or without filter, so there is an effect. But dirt grinding rings and bearings without filters will cause more engine wear. The hp difference really only should matter to drag/road racers running for money or a championship. And if you don't think it is dusty where you live, fun fact 1,000 TONS of space dust falls to earth every year.........

And I never did dyno runs without filters, and only spray a very light mist of light oil on my filters to make the outside a bit sticky. And my motors are modernized, so spit-back is not a factor........

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Twist the throttle, tilt the horizon, and have a great time. What triples are all about...........

Over 510,065,600 km²

Any HP gains from no filtration will surely be outweighed after a couple of thousands miles by worn cylinders/rings?.
When i dynoed my tuned 400 i resisted the temptation to do a run with no filters...What i have never had i will never miss!
Happy with 62 rwhp though.

I run filters on everything I own. I would not be in the least surprised if there were tens of thousands of tons of dust and dirt suspended in the air at any time. However if you wanted to run velocity stacks for maximum power, that's up to you.
ANY modification to increase output will reduce service life, where you draw the line is individual choice.

It would be interesting to try velocity stacks with big Uni filters at the input bell. Kinda like Battleax's setup without as much bend, and with a bell. Heck, try Battleax's setup while you're dynoing all the others.

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If it surges, that's normal, upshift.

Yeah.

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Using a poorly conceived idea along with bad mechanical practice is not an upgrade but rather a recipe for disaster.

I use a larger filter than would fit on the mouth of the carb. I used two 90s on the H2 and a 45, but on the H1 I used three 90s, I thought about going to one or more 45s, but the thing works so well, I am unwilling to mess with it. I know the bends make a difference in the air flow, but it might not be a bad difference.

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Using a poorly conceived idea along with bad mechanical practice is not an upgrade but rather a recipe for disaster.

Joe, any other things we need to get Looney Cylinders to try while he's renting dyno time?

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If it surges, that's normal, upshift.