Camshaft question on a 660

I was looking at the cam on this Rhino I just picked up and on the opposite side of one of the journals is a bump it almost looks like some kind of a pin right next to the lope for the exhaust. 
When I turn the cam this little bump hits the exhaust lifter which would slightly open the exhaust valve prematurely and then the cam lobe will hit. 
Is this normal? Seems like if the exhaust valve is opening too soon it would slap the piston?
Also found that he previously ran a Dynatek CDI with a 9,000 rpm limiter now with a stock motor wouldn't it over rev and cause it to float a valve?
Thanks guys

I meant to say that bump hits the rocker not the lifter lol

That's the decompression pin,it helps with starting, after the motor cranks,the fly weights on the cam sprocket sling out and the pin counter sinks back into the cam,so the only time it protrudes is when the cam is at rest.

Ok thank you, I just did a little reading and found that's what it was, I will get some pics of this one as soon as I get on the computer but from what this one looks like is that it was installed backwards. Is that possible? Because the head of the pin does not go flush it's always sticking out and the hole on the other side is bigger and looks like the pin could go flush on that side.

i ran a stage 1 cam on a stock motor with a 9k rev limiter cdi an never floated a valve an ive held it wide open for long periods of time so I would say it will be fine

Crusty wrote:

Ok thank you, I just did a little reading and found that's what it was, I will get some pics of this one as soon as I get on the computer but from what this one looks like is that it was installed backwards. Is that possible? Because the head of the pin does not go flush it's always sticking out and the hole on the other side is bigger and looks like the pin could go flush on that side.

The pin only goes flush when the motor is running,and the big hole on the cam is where you install the pin and spring,it should be sticking out on the opposite side...this is correct,make sure when u install the cam that that pin is sticking out...or it is wrong.

Ok so with the weights held outward should I be able to push the pin flush? Because on this one I hold the weights out and the pin won't budge in or out

you can turn the piece on the end of the cam that has the 2 pins sticking out and should be able to see the pin go in and out with the cam sprocket off,make sure the pin is sticking out when u install the cam sprocket and you have 3 dots on that sprocket,with the cam lobes pointing up the sprocket installs with the center dot pointing up and the other 2 dots should be right at the top of the head with the piston at top dead center and the timing mark lined up on the crank thru the peep hole with the cam chain tensioner out.

I just removed the sprocket and the decompression lever was 180 off so the pin would never move and was always sticking out causing the exhaust valve to open slightly, even at high rpm's so I'm assuming this is why. This motor has been rebuilt twice. 
Would this cause it to suck a valve when it gets hot and keep running it like that?

Should not cause it to drop a valve,it would not run as good because it would be bleeding off compression,other than that it, would not cause any problems.

Well Dammit lol 
Thank you

glad to help! hope your build goes smoothe...that's a great deal on that rhino!!

Thanks and hopefully it's just the top end. 
I have rebuilt Cat and Cummins engines but this will be my first tiny engine so hopefully it goes smooth, I'll be buying a manual for sure on this one. 
I tell you what you are a damn good bunch of guys with tons of knowledge and I truly appreciate all of your help.

Thanks...that's what its all about,also make sure you put a new timing chain in there and a 700 tensioner,the 660 tensioner is no good...it will back off and allow the timing chain to jump timing,find someone with a chain breaker and you just hook your new chain to the old timing chain and pull it thru then brad the new chain back together.

10-4 on the 700 tensioner but unfortunately the cam was in a box with the cylinder and head.

hey crusty does it need a piston? I just did a big bore kit in my rhino so I have a stock piston with just under 1200 miles on it if u need one

guess it does lol hows the cly. look

the cylinder looks great and no play in the rod bearing so now i just need to find all of those pieces of the piston and valves lol

is it stock bore?

he said it was 20 over

ok the knew that piston was not stock that's y I asked

Thank man, might be a few weeks before I can afford to start buying parts. 
Camshaw has a few also for $320 shipped.

That's a good deal!...I cant afford to spend any money now either.....