Fine tuning and Dyno-jet settings

[ReaperVmax00]

Hello again. The Max has been running pretty stellar if I do say so myself. I just have one question about something that doesn't seem to be lining up in my head. The stage 7 dyno-jet instructions say to run the idle mixture screws at 2 1/2 turns out. I currently have mine at roughly 3/4 of a turn out and its running pretty well. My main reason for fiddling with it in the first place is that at steady load under about 3k rpm there's a popping from the exhaust, worse when hot that cold. If I put the choke on just the slightest bit when its doing this it cleans right up. It has steadily improved the more I turned the idle mixture screws in. Just seems strange to me that the dyno-jet settings would be that far off from how my bike seems to want them set. Spark plugs are all clean and properly colored, carbs were just fully rebuilt and cleaned, all new rubber, balanced afterwards, no exhaust leaks, dyno-jet stage 7 with v-boost fully open, 4-1 UFO exhaust with the 1 1/2" megaphone outlet reducer. I've heard that the lower end of a fully open stage 7 is a little sloppy but I feel like I am missing something since a little bit of choke clears it right up perfectly. Thanks in advance!

 

[Fire-medic]

Popping says lean, & the enrichener lever confirms it .

 

[ReaperVmax00]

Agreed, so unless im thinking of the mixture screws backwards, turning them in is leaning it out, correct?

 

[ReaperVmax00]

I'm mostly curious why my mixture screws are far less than half of what dyno-jet says to run them at.

 

[rhino79]

In is leaning it out, if using the choke helps, you need to back the mixture screws out some.

 

[one2dmax]

A/F counterclockwise (out) is richer.
We don't have a "choke" in the conventional sense as nothing is actually restricted to remove a qty of air past some throttle blades. We have an enrichening circuit that adds additional fuel when being used.

 

[gentsvmax]

Sounds like a need for bigger mains, whats in there now?

 

[gentsvmax]

Sounds like a need for bigger mains, whats in there now?

Ohhh Sh&t! I fell right in! Right down the rabbit hole! I swore I wouldn't!
So maybe not those mains, how about that needle position?
Is it shimmed? What about air correctors? 3K you say, is that PAJ1 or PAJ2?
Pods or modified air box? Over heating my one remaining brain cell LOL!

 

[ReaperVmax00]

AH, enricher circuit! Ok that makes more sense I was thinking in choke plate logic. I'd have to pop them apart again, when I went through the carbs I left those items together and did not look too closely at where they were set or what the main jet sizes were. It has the K&N pod filters, and I don't recall seeing air correctors as described in the dyno-jet instructions. All I know is it ran beautifully before it sat and that made me assume (shame on me,) that everything was the right size and correctly shimmed. I know it's not proper, but for the time being is there any harm in running it with the "choke" just slightly active? Finally nice enough here to ride almost every day. Thanks guys!

 

[Fire-medic]

Try the air screw coming out a quarter-turn at a time, and see what happens, maybe you get to a point where the popping subsides. then re-balance the carburetors. The re-balancing may not be necessary as you're not removing/disassembling them, but if you have the equipment, it only takes a few minutes, and you may clean things up as-far as the popping/lean mixture goes in the rev range you found.

 

[Traumahawk]

I'm mostly curious why my mixture screws are far less than half of what dyno-jet says to run them at.

The dynojet instructions.....as they are written, are pig rich. As with most things, tune for your bike. The Vmax usually likes things a little bit on the leaner side.

 

[ReaperVmax00]

Ill do that! I'll try to match it to how it runs with the choke slightly on, because it runs perfect at all rpm ranges when its on. Thanks guys you've been a big help!