ATC 70 cam sprocket help

[Hornetpowerspor]

I bought an aftermarket head for my ATC 70 it has a roller bearing camshaft. My problem is that not only is the center boss larger, the bolt pattern is larger also. Has anyone else ran into this problem? I need a different timing sprocket. Unfortunately I have had this for a couple yrs, so im not sure where i bought it from or i would call them. Here is a makeshift picture of the dimentions i am looking for. Any help would be much appreciated.

[oscarmayer]

looks liek you have a chinese knock-off. i do a lot fo quad motors for my son's racing motocross using chinese motors and parts.
www.tboltusa.com is an excellent place to start with what you have and see if it will fit. when doing performance and csutom, noting is EVER bolt on.
you ended up with a lifan bolt pattern head. that does have a larger stud pattern. i run both types of motors. what size valves are you running? i may be able to do some swapping with what I have ins tock, or if nothing else, offer up some $ for it and help you find the right head. you probebly need toe e22 type head n ot the honda larger bold patern head. that head was for the 125cc engines. i probelby do have a performance chinese head with upgraded cam, valves, valve springs and retains i could trade ya if your interested. let me know.

mike

[Hornetpowerspor]

the heads bolted on everything's fine there, i just need a cam gear that fits

[oscarmayer]

did you measure the inside head chanper compaired to the bore of your engine? if the head is larger you will loose a ton of compression and it will run worse than before.

how many teeth are on the gear you have now? how many are on the stocker gear?
www.tboltusa.com sells several different gears for these heads and motors including one that woudl fit the cam and the chain. you jsut need it to be the sale size as the old one (teeth count) because a larger count will force the chain to stretch or will not fit at all. i suspect your running a 32T gear with the new head and your stocker was probelby a 28.
here, so you cannot use the excsue of being lazy. ;)

http://tboltusa.com/store/pit-bike-engine-parts-cams-c-51_52.html

you can order anything you need size wise. again you need the tooth count of the stock gear and match it as close as possible.

i forgot to mention, you can even get a new chain that is longer and replace the stock one so you cna sue the cam gear that came with the new head if you wanted too. so differnet options.

[Hornetpowerspor]

Ok, thank you. I will check out that website. My head had the same size chamber as the stocker. The new head did not come with a cam gear or i would just get a longer chain. The stock gear is a 28 tooth. Thanks again!!

[oscarmayer]

n/p! post up your results, and hood luck sir!

[Hornetpowerspor]

Oscarmayer Thank You very much for the info. T bolt had the camshaft sprocket that I needed! Its bolted on and should be running within the hour. Thanks again!!