[Dunkelbierkoenig]

More an observation than a question: I recently installed the Dynojet Stage 2 Kit on my otherwise (except KN air filter) stock 750 Aero. I'm planning to do the 4 degree timing mod and to install new clutch springs next though.
Here's what I observed: The bike doesn't really take gas while it's warming up, it tends to stall. This might actually be good, that way I'm forced to do a proper warm up before hitting the highway. Apart from that it certainly sounds better (desnorkeled the airbox) and it feels it pulls much better at higher rpms. Now the real interesting thing: on longer tours, my mileage went from previously (completely stock) approx. 6.5 l/100km or 36.2 mpg to consistently 5 l/100 km or 47 mpg. The plugs look good to me...Isn't that weird? My theory is that the kit increased the power across most of the rpm band and that because I most of the time actually only cruise at part throttle it needs less gasoline to perform the same.... Does that make sense?

 

[HomeSlice]

It makes sense because it sounds like your bike is now running leaner than it was with the other jets, etc. This is interesting to me because I have a jet kit I have not installed yet, and my assumption was that changing to the stage 2 set would have let the bike run slightly richer. But that seems not to be the case from your experience.

Also, I think I'd wanted to keep an eagle eye on the plugs right away if doing the 4 degree mod, because your bike is already a little leaner, and advancing the timing like that might cause the engine to run hotter. I'm sure you don't wish to melt anything through all this, so just a word to the wise.

 

[gdb069]

32 mpg sounds low so you may have had a carb problem that got corrected when you installed the Dynojet kit.

 

[Dunkelbierkoenig]

Yes, although the only thing I could think of would be a partially plugged main jet? Bike ran fine though

 

[gdb069]

Did you adjust the A/F when you installed the kit? Dynojet uses a tapered needle and requires A/F (pilot screw) adjustment. Also when warming you should use choke rather than throttle. About 30 seconds of choke and slowly close.

 

[cyclejohn]

(desnorkeled the airbox)

Hey D,

Any chance that you have a 'pre' de-snorkle pic and a 'post' de-snorkle pic???

I always find myself curious about such.

John

 

[Dunkelbierkoenig]

Did you adjust the A/F when you installed the kit? Dynojet uses a tapered needle and requires A/F (pilot screw) adjustment. Also when warming you should use choke rather than throttle. About 30 seconds of choke and slowly close.

Yeah I did, although I found it was not much off. I think the "stock" (no idea if it was stock before, it looked unmolested though) was 2 3/4 turns out, while Dynojet asks for 2.5 turns out. And yes, I do warm it up using the choke, I just found that now it takes a little longer than before. This maybe confirms that it was running too rich before.

 

[Dunkelbierkoenig]

Hey D,

Any chance that you have a 'pre' de-snorkle pic and a 'post' de-snorkle pic???

I always find myself curious about such.

John

I'm sorry, I didn't take pictures. But it's super straightforward, you just remove a screw and pull out the snorkel. This changes the point of air intake. Now I can stick my finger behind the airbox and feel the air filter directly, while before it would suck air through the snorkel from underneath the tank. Of course this also leads to a throatier sound.