Geoff:

I am telling you....quit throwing money at the popping!

I tried everything imaginable.

The only thing that worked was two new Raptors!

Rob

 

The fuel screw on you bike comes with a cap on it because of some EPA regulation. Remove it. The stock position is supposed to be 2.5 turns open. Close it carefully monitoring how many turns you go. When you reset it go to 3 turns out or 1/2 a turn further than it was. Also raise the needle a little. This worked for me. My cylinder head then cracked and it did this again and couldn't be tuned out. If you are using any coolant this also could be a problem. Note: I read alot of dirt bike magazines and they seem to focus on the fuel screw as a carb tuning mechanism for the 4 banger 2 wheelers. Thats why I tried this.

 

Bye the bye, I have ordered a CDI box for my Predator and am dying to find out more about it. Anyone who has details post more info. I did email vortex today so hopefully they have time to reply also. Reviews of these guys box for the YZ250F were out of site. Hope it is this good also for the predator. In the predator manual it states the CDI starts retarding the timing at 8500 rpms to then cut out a spark at 9K. The advance is about 30 degrees also. I am guessing going to 10K RPM would be dramatic. almost like adding another gear to each gear.(redundant). It also seems that with higher octane fuel (100+) the advance curve could be higher alot earlier in RPM bring on alot more torque. The timing is retarded for quite a while until RPMs build. I guess this is normal but I am sure with the higher compression specs and knowing most people are running pump gas, they had to keep it conservative. When it comes I guess I will find out but waiting may certainly kill me!

 

G'day guys.
Thanks for the responses.
The vortex unit I tried came of my mates pred, after he won a-grade m/x.
He highly recomends it.
I would / will buy one if we get my hassles sorted out.
Unfortunately jj I wasn't able to explore its limits because of my preds limitations.
Rob good to hear your going well.Is your son faster yet?

Everything is popping well from down under, Geoff.

 

New customised vortex bolted on, with one of the 10 maps set @ 10100 rpm limit.
Will be testing on saturday & hopefully racing with it on sunday. [img]i/expressions/face-icon-small-smile.gif[/img]
Anthing you would like me to try?

Herewegoagain, Geoff.

 

keep us informed, did you ever cure your popping?

 

Be careful at 10,000, I have heard valve float is a problem.