installed new head kit and wont start

sniper · Nov 5, 2007

Just wondering if anybody can help me out with my new head kit for my 49cc foxico dirtbike.I have the headkit with the gold thing that goes on the head (look at the picture)and have installed it but i cant seem to start my bike.

I have a dellorto rep carby on it and carbon fiber tripple stage reeds.The only way i can get it going (for about 10 seconds)is if i screw the idle screw in all the way,and open up the throttle as far as it can go.

Should i get a new jet?If so,what size do i need?And do i need a special jet for the dellorto rep carb or can i use a jet for a standard 49cc carb?I have i few different sized jets for the standard carb.
Thanks heaps.

Also,the two copper rings that came with it,i put in the gold thing that connects to the head.Is that where they are suppose to go?

crazzy #1 · Nov 5, 2007

Pocket Bike Racing

eichkay · Nov 5, 2007

Alot of the time when you go big bore , you need a bigger carbi.

sniper · Nov 5, 2007

I thought the dellorto rep was a bigger carby.

pb performance · Nov 5, 2007

OK ill try not to confues you to much !!!

here is a real basic run down on how to put these heads on !!!

1, put the piston on with the arrow thats on top pointing towards the exhaust port

2, place the base gasket on the crank case.. Only use one base gasket !!! if you have the copper one use that if you only have the paper type one then just use that !! but only use one..

3, now place the barrel on

4, now with the head.. if you have a 2 piece one then put the chamber part in side the cover. No gaskets go inbetwen them at all !!!! if it a one piece head then it's all good ...

5, now with the 2 copper ring gaskets you should only need one !! you place this gasket on top of the barrel then place the head on top of that !!!

6, now put your head bolts in and do them bolts up !!!

The two copper ring gaskets are for setting the squish or compression ratio !!
There should be two different thicknesses in these gaskets !! use the thinest one first and once you have the haed torqued down try to turn the motor over by hand slowly and make sure the piston doesn't hit the squish band (the top of the head) if you know how it test the squish then it should be around .5 of a mm or less but .5 is good.. if you dont then like I say just make sure the piston isn't hitting the head or if your worried then just use the thicker copper ring gasket instead of the thinner one !! but the closer you can get the squish the more performance you'll get from your motor !!

Also only use 98RON fuel or higher with these high compression head kits !!

and if your carby is a 14/14 dellorto rep or bigger then it wll be ok !!

let me know if ya need any more info and how ya go !!

sniper · Nov 5, 2007

Thanks for the advice pb performance.But i already done exactly what you just said but its just not starting properly.As i said in the first post,the only way i can get it started is if i screw the dle screw in as far as it will go and have the throttle fully open.It will start for about 10 seconds hen it will bog out and die.So,that is why im thinking i might need to ut a ne jet in.The only jets i can find for a dellorto carby are the ones at ozminimoto.com.au.
But i think they are for genuine dellorto carbs.Can i use these?