490 bing/mikuni conversion

[huskibul]

  Different carbs would have different flow characteristic's maybe the flow of the bing just suits the 490? or velocity,  could be something as simple as that,need a carb wind tunnel for that one (maybe that's why there not such a difference in the reed model 

[JohnnyO]

On a dyno, you pick the best gear and roll it on.  You don't just hold it wide open.  Rolling it on gives you the torque curve.  Peak HP is interesting, but not super important if the motor is ballpark.   If you can get good torque where you want it in the rev range, then you're headed in the right direction.  Pretty valuable on a motocross bike if you ask me.  Running a higher gear in corners, anyone?

Every dyno run i've witnessed the bike was always put into top gear then the throttle wound onto to full.
The TC450 Husky's we had dyno'd for the Husqvarna race team that showed the strongest curve were usually harder to ride and more aggressive on a motocross track and we ended up using an engine closer to standard.
There is nothing like track testing and rider feedback rather than the best graph on a dyno.
I think a dyno is better suited for road racing with good traction on bitumen.

[crabman]

Husky HOONS

The jetting as promised.
Mikuni 38 mm ( NOT A GREAT IDEA)
Pilot 40
Main jet 380/ 400.
Airdcrew 2,5 turns out

Bing 54 (SEA LEVEL) Only way to go- absolutely spot

Mainjet 190  ( thick sand 200)
Piolt Jet 60   (thick sand 65)
Needle top last notch
Neddle 6h2
Needle jet 280

Best plug NGK B8EIX

[JohnnyO]

In my Bing i run
190 main jet
50 pilot jet
278 needle jet
8G2 needle (have tried both 6L2 and 8G2)
needle on the 3rd groove

[huskibul]

    Thanks for  your spec's guy's, with all this info i'll be soon  sayin that  maico HOONS !!!!!!!!

[huskibul]

 Hey guys does anybody know the difference in taper and diameter of those two needles ,or where i can find a table for bing needles ?seems the 8G2 is out of mc 400 and the 6L2 is out of the 490,(is it alphabetical with L being richer/thinner?) if so there's a fair gap between L and G ,  like to start on the side of caution  :)cheers

[JohnnyO]

The 8G2 needle is leaner off the bottom and richer in the mid than the 6L2. It cleaned up the bottom end blubbering and mid range pinging on my 490.
It is also the standard needle in the 1980 440.