jetting advice for modded big bore @ oregon coast

[USMC1STSGT]

I just installed an "Ice cube" 498 kit, 13.5:1 wiseco, I also had them port the head for dunes. my mods are as follows....
hrc cam and needle(3rd clip), dyna fs adjustable set to position 1, Dr D. full exhaust, K&N with no lid. sea level running 100 octane.

prior to the 498 and porting I ran a 185 main and it ran perfectly from top to bottom. Now I have all kinds of issues. The company that makes the kit recommended a 185 main. It didnt work well, so I also tried 190 and 180 with similar results, heres what its doing.

The bike seems to have a rev-limiter of 7-8000 rpms, because it sputters at that point. it also runs kinda bad just off idle at about 2K rpms, you cant "lug" it at all or it wont run. It also dies frequently at idle.

I have to "short shift" the bike to get it to go.

any questions/suggestions would be greatly appreciated, I only have 2 days here at the coast, then Im back to duty in 29 Palms, CA...thanks,

Gary

[mattonln]

sounds like you would be rich, but you say you tried the smaller 170 and it made no difference? check the plug just to make sure its not fouled then try the air fuel screw and smaller jets. does it pop or anything after you rev it? how does it ride, you can usually tell if its lean or rich.

[USMC1STSGT]

I did not go any smaller than 180. Is it possible that I woul need to go down in main jet size after installing a big bore?

Also, one other note, the water temperature is right at 200 degrees at its hottest point. So, I dont think its getting too hot.

The engine feels great in the midrange, but dies out at 7-8000 rpms.

thanks,
Gary

[400exrider707]

Originally posted by USMC1STSGT
I did not go any smaller than 180. Is it possible that I woul need to go down in main jet size after installing a big bore?

Also, one other note, the water temperature is right at 200 degrees at its hottest point. So, I dont think its getting too hot.

The engine feels great in the midrange, but dies out at 7-8000 rpms.

thanks,
Gary


It is very possible you need smaller jets. Each motor has its own "pulse" it sends to the carb to suck a certain amount of fuel in. Installing the bore kit might have given it a stronger pulse. I've seen Nmotion 520 kits running 150 mains. You are definitely rich, that is the bogging in the top end. Lean out every circuit one step and try that. You're just going to have to test it a lot.

[USMC1STSGT]

I put in a 172 main and now it runs perfect on top end, water temp stays around 195 degrees.

I still have a problem on the bottom endso I will try a new pilot jet one size smaller.

[400exrider707]

Originally posted by USMC1STSGT
I put in a 172 main and now it runs perfect on top end, water temp stays around 195 degrees.

I still have a problem on the bottom endso I will try a new pilot jet one size smaller.

Sounds like you got it figured out.:cool: