Who has done a 558 kit? What issues have you had? What other mods have you done?

I did the 558 and cant get it to run right. Its almost as if the timing is wrong, lousy power (it was way faster prior to the kit), cuts out when you get into the throttle (mid and high RPMS).
Ok, here is the scoup on what I have, 03 predator, Pure Polaris pipe, $100 (Big gun ?? I dont know) CDI, and a K&N. I pulled the plug and it looks exactly the way I would expect plug to look with the proper jet. I pulled 5 discs out of the pipe no change, I removed the end cap from the pipe, neither ran any different. Ok so I have ruled out the fact I am not jetted improperly. If a CDI was crap it shouldnt work at all, right? I cant see needing a bigger carb without headwork and cams. Someone school me on what I am doing wrong, adjustments etc. A local shop did the work and it has been back 3 times and it still doesnt run right, its been sitting for a year now I need to fix it. I am competent mechanically, the only reason they did the work is I had the transmission rebuilt (my garage was in no condition to be going that in depth at the time). HELP! any suggestions.

 

someone correct me if I'm wrong, but don't you have to replace the cam (Hotcam??) when boring out that much

 

I'd say your compression ratio would be off, if not I'd say the timing is off

 

Does it have the HO cam and 40mm carb? If so I would think you need to put a bigger main jet in it, What color is the plug, it should be on the black side, these like to be a little on the rich side to run right.

 

Ok a little update on this issue. Yes it took me this long to work on my bike, $$ has been tight.

I played with jets. It had a 172.5 jet. I put a 190 (smallest they had that was larger than what was in it), no change! I took a 170 and drilled it out larger than the 190, made it hard to start and didnt change the top end.

I was on my wifes bike at the drag strip (Pismo) and there was a guy with a fast Preddy out there. He was running bored and stroked and a 46mm carb (I think). Nice guy. well he was saying even with all the motor work he was only running a 155 jet! Said it didnt run worth a darn if he went up one jet size. REALLY??? Well I bought a 160 (what is with these parts places, thats the closest they could get) and put it on. Bingo! Runs decent. I still have a slight pop mid top now and then but 100% better. I am going to put a 155 in it and call it good. I am officially a happy camper. I never would have guessed my issues were too much fuel, now I know.

 

So how do you like it now that it's running nearly right? I have considered boring out my 07 preddy for more power. Is it worth the money? Did it make much improvement? If so, where (low end, midrange, or top end)? I have a um racing intake with no lid, kn filter, hmf full exhaust, jet kit. It runs perfect and is pretty quick, but you know, always gotta try to make it faster! LOL!