Home Forums TaG Rotax Max How's your EVO upgrade experience been? Reply To: How's your EVO upgrade experience been?

Eric Alexander

So I thought I’d add an update on my EVO experience thus far.  I’ve gotten to the track about three times and I’ve yet to really get my engines performing better than the non-Evo engines did.  I’m hitting that 12,000 rpm ceiling (which at GoPro Motorplex is a lap killer).  I’ve been progressively leaning out the jet and today I was down to 118, which is a little scary as its uncharted territory for me.  Still no top end however.

Another thing I came across today was conflicting information regarding the pulse line feeding the RAVE valve solenoid (See this thread: http://ekartingnews.com/forums/topic/evo-pulse-line-to-rave-solenoid-which-one-is-it/). I find it hard to believe Rotax isn’t proofing this stuff, or making some in-depth explanations of what mechanically is going on.  Again, it seems as if the kits are just thrown together from parts initially designed for something else and re-purposed to work on the Rotax engine.

Another example is this little pill added to the pulse line.  It states the pill reduces pressure and makes the RAVE valve open .5 sec later than normal.  Really?  So all this talk and power curve diagrams about the RAVE valve must open at 7600 is BS??  I mean .5 secs later could be as much as 9000-10,000 rpm.  This just reads like really poor engineering IMHO.  It should open at 7600, unless you want it to open at 7900 (remove the ground??). Or, place this pill in the line and it will open half a second later that either of those specs.  The power valve is the Achilles heel of this engine.  The EVO update was supposed to address this.  Now, I’m starting the get the feeling even Rotax doesn’t understand how the thing works.

Okay, okay… I’m venting a little.  I really wanted to be blown away by the EVO updates and I’m a little disappointed that I’m still changing main jets all day and trying to get the engines to run well.

On a positive note, when I hooked the RAVE pulse line up to the metal nipple on the bottom of the solenoid, the low-end power increased significantly.  I’m talking better than any of my Senior Rotax have ever run.  But with the lack of top end, I get the feeling all I did was convert my engine to a well-tuned Junior.  LOL!  But I definitely heard the RAVE valve open and the engine start to growl at close to 8000 rpm.  So I don’t know.  Is that the way it supposed to be hooked up? Which diagram is correct??  If I could get bottom end power like that and get this thing to pull to 13,500 rpm, I think I’d start singing the EVO praises.  I’m just not sure what to try next to accomplish that and that has always been the frustrating part of running a Rotax.