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Reason for editing: Last Edit: February 11, 2020, 16:18:55 PM by Lucky

First and foremost 
dynaojet sizes are LARGER than everyone else's sizes
https://www.jetsrus.com/FAQs/FAQ_mikuni_vs_dynojet_vs_keihin_sizes.htm

a dj136 is everyone else's 140

secondly, the main is only important past 1/2 OPEN, not necessarily RPM or speed, but the actual lift of the slider. unless you are in high RPMs, which is the normal buttdyno way to test performance, a larger main isn't going to help you .. that is, if you are cruising in 5th and have to romp the throttle to get up a hill, and the engine doesn't REV!!!!, you should just down shift, as a larger main won't do anything for this circumstance

so, here's a test -- and it's backwards from what you are asking, but try it anyway --

find a hill that is fairly close by and offers a challenge.. go hit it 2-3 times, just as normal, helps if you have a stop watch and get a feel for it.. decide what gear and what speed you hit this in, and stick to it.

then remove your airfilter and repeat -- this is actually LEANING the bike by allowing more airflow

is there a noticeable difference, other than the really cool sound of air rushing in? i bet there is zero to "its faster with the aircleaner off"

then, put the AC back on, and down shift before the hill .. i tend to baby my bike, so this was a little strange for me -- but going from 3800 rpm to 4600 isn't going to hurt her (i use a cheapo $9 tach ziptied to my bars) and see if she goes up the hill better.

just for reference, i am (now) 225# 6'4, and yes, she climbs better now that i've lost 50#

changing the main larger  without MAJOR changes to the exhaust and air system isn't going to yield much, except she'll run a little cooler

have you adjusted your A/F mixture screw? what tooth sprockets ?

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Posted by rob f

- December 16, 2019, 17:20:11 PM

I am still struggling with getting a bit more power out of my 800 and am looking at changing the main jet. Right now I am running a DJ136 which was the biggest jet in the dyno jet kit that i installed. The bike seems to be running nice through all the ranges but uphill and against the wind the throttle is wicked right out. I see that in some posts that guys say that they are running a 155 main jet. Now is that a DJ number or a Keihin number? A DJ 155 tranlates over to a Keinin 170. My OEM jet was a 135.
Anybody know what main jet you have in your bike?
Rob

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