Beta pro race 50

[jeepchris]

Hello ,My son races the nesc circuit here in the north east. I was wondering  If anyone had any suggestions on why this thing could suck off the line sooo bad here, my info,, The bike is a 2005 beta pro race it is a air cooled with with a pipe ,a19mm carb jetting is 85 main,48 pilot clip on needle is 2nd clip from top. clutch is new and set like this, (()) (()) (()) ( ) / flat is a .10 for a stack of .624 with ss washers, Gearing is 9/42 I am running a ngk B8hs plug any help would be great My son weighs 70 lbs  if that helps any, I think the bike should rip but it doesn't come alive until about 30 feet off the gate and if the gate is full it hurts the poor kid, again any help is greatly appreciated.

[candcracing]

what was the stock gearing and clutch setting
ken

[jeepchris]

Stock gearing was 10/42 and clutching I wish I could find the exact original clutch set up info. I have been folowing specs for the senior adventure . I have messed with the clutch so much...it seems the stack I have works the best currently, but still sucks

[candcracing]

(())(())()()() 640 should be better
ken

[jeepchris]

Thanks for the help ken, I will try it, do you think my jetting is good ? or could  I squeeze any more power off the low end with the needle or pilot ?   I have time to tinker as for our spring series just ended 
 and the fall series doesnt start for a couple weeks ..

[candcracing]

best seting is 1.5 out on the fuel screw  both slide and pilot afect this
if you have a 60 slde and 48 pilot it would be better to with a larger pilot or smaller slide if you are more than 1.5 out on the fuel screw
next do a full wide open throttle run and shut the motor off plug should be a light brown
if it is grey go up on the main to an 86 if black go down or change the needle
ken

[jeepchris]

Thanks for all your help ken, my sons bike is running as it should and seems to rip pretty good I still want to talk a little more about jetting sometime the bike likes two turns out on the air screw so I know I am close but not right on with the pilot, but no rush, I just wanted to say thank you

[candcracing]

your welcome
1.5-2 is just fine
ken