MicroSquirt.com read only forum (Jan.15,2018)

Got the motor running, actually runs pretty good. The response off idle is very good but....it never seems to settle back to the same idle each time. If I rev it up it drops down to about 2500 and then creeps back to my 1200 rpm idle i want.....sometimes, other times it goes to 1700rpm for a while. This motor is a V-twin 2 cylinder in a rhino type UTV. It has extensive motor work including 11:1 compression, lots of port work, and really wild cams that don't make power till 7000rpm (this is normal for a CVT belt system). The side effect of the real wild cams is crappy vacuum at idle, it idles at about 80-85 kpa. I did make a little plenum to connect the 2 cylinders together and then to my MAP sensor. I have done no tuning yet except to play with the required fuel to see where the idle likes to be. Is this the type of situation where I should be going down the Alpha N path instead of the speed density? or maybe a blend?? Just some initial ideas anyone? I will play some more this weekend and post my msq and some datalog files.

Anyway you slice it...its already better than my crappy carbs I had that everybody on the UTV forums swore were the best.....whatever!!!

Are you using an IAC valve?

Also, if you could post a data log of this and your MSQ, I'll have a look at them.

No IAC just Fidle, will post files late this weekend, thanks.

Use Alpha-N blend and if you are not running forced induction you could even use pure alpha-N, it's not possible to tune a twin with a big cam using speed density, the idle bins, light load, medium load are the same, making the fuel erratic.
My bike has a stock 245 ° cams @ 1mm and is a mess, I do blend it before the turbo spools up.