Timing Chain Problems

[WogBoi]

Hi All
Just wondering if someone can help me out with my timing chain.
I had to replace the piston in my bike and i didnt get to see how the timing cog was lined up.
So i have put it all back together and now i just need to adjust the timing chain.

I got the basics on what to do but i can not line up the lines on the timing cog with the little line on the head.

- What i have done/tryed is i took of the screw thing on the left side of the engine so i can get it to TDC, i done that then took off the cover where the timing cog is, i took the chain off and undone the bolts that hold the cog on. i tryed lineing the lines up but i cant get the camshaft to turn that far.

Anyone ever had this problem before?

Its abit hard for me to explain to ill make a vid tomorrow and hopefully you guys can help me out.

 

[Dabomb]

alrite mate, the reason why you cant rotate the cam is cause either the intake or exhaust valve is trying to open putting more resistance to move on the cam.

to take some pressure off the cam, removing the spark plug.

BUT the cam will move most freely at TDC cause both valves would be closed....

how far can u move it each way (in degrees ruffly) each way till u cant rotate no more?

 

[WogBoi]

well the line on the cog is ment to be at a 12 oclock position ( from what i have read )
and i cant get it to move the little bit more to get it where it needs to be, so if i take the spark plug out will it let me go over the valves?

 

[Dabomb]

u gota line the up the dot on the cam sprocket with the notch on the head which is at 9 OCLOCK!

 

[WogBoi]

i actuly tryed that and i didnt work, the kick starter keeped on getting stuck. i have a line on the head which is at the top...

 

[Dabomb]

hmmm....take photos of ur notch and cam sprocket.

 

[WogBoi]

ok will do, ill post them up tomorrow. to late to do it now...

 

[Dabomb]

daytime is for quiters!

 

[WogBoi]

haha thats a good way to put it

 

[DvDRip]

take off your ignition cover and make sure you're at TDC on the commpression stroke, then try to line up the sprocket

 

[WogBoi]

Hey guys, i took a quick vid today on what i have done about the timing

Here is the link - YouTube - Timing Chain Problem

Sorry about the quality, i had to record it off my crappy phone.

 

[NRG]

Look this is really easy.

Firstly, you should have marks on your flywheel and housing indicating when the piston is TDC.

Secondly, you should have 2 marks on your camshaft gear / housing indicating TDC in 2 positions.

1. TDC on compression stroke (this is the one you want to be on) (easier).
2. TDC on exhaust / inlet overlap

But it really doesnt matter on your engine because it only has 1 cylinder and can be set up on either.

Line up your flywheel on TDC marks
Line your camshaft on TDC marks, either will do.
Connect your timing chain.

Give the engine a turn back & forth by hand and recheck the marks.
Do not turn the engine 1 full revolution until you are sure that it is correct, you may bend the valves if you have it wrong.

 

[WogBoi]

thanks for the info mate
so far i have everything you said.
the only thing is im not sure which way the timing chain cog goes

 

[Dabomb]

you have a vertical motor?
the way i turn my cam with the sprocket in front if it is with a small screw driver...

what i suggest you do is get the CAM to TDC FIRST so that you don't have to fiddle around with the cam not being aligned with the sprocket bolts, don't worry about the crank being out of TDC yet.
also if the crank is at 180 before TDC theres not much chance of the piston hitting a valve..

 

[WogBoi]

how can i tell if the cam is at TDC?
do i just look on the sprocket?

 

[Dabomb]

never worked on a vertical motor so couldnt tell tell you where the TDC mark on the head is....can you rotate the cam and sprocket to line up with the other mark at 12 oclock?

 

[NRG]

how can i tell if the cam is at TDC?
do i just look on the sprocket?

Your Vid showed you had freeplay...yeah?

this is near compression TDC.

do you have marks on your cylinder head and cam sprocket?

Line them up, with the bottom lined up its that easy.

 

[WogBoi]

i understand what you talking about NRG
but the cam shaft old turns a serten ammount and i cant get it in the correct position to where it needs to go.
i cant really explain it.
ill give it another shot tomorrow and get back to use
thanks for all the help guys

 

[Kingers]

not sure if this is what ya talkin about but the cam wont turn to far easily because when ur trying to turn the cam the lobes of the cam will push down the walve which has a spring there so to turn the cam around you will need to overcome the force of the spring holding the valve up, also dont think you'll be able to turn the cam around when the piston is tdc because the valve will hit the head of the piston and not go any futher, hope this helps

 

[NRG]

o.k take the cam gear off the camshaft and out of the timing chain.

Find TDC for the piston the very highest point if you cant find any marks

Put the cam gear back on the camshaft on locate TDC for the camshaft by lining the marks up on the cam gear and the cylinder head.

if you cant find any marks, then find the center of the freeplay, as in your video

This is TDC for the camshaft.

mark it with a texta.

take the cam gear back off the camshaft, and fit it back to your timing chain, mindful of where it should be for TDC. Fit bolts to camshaft gear/camshaft & recheck that your timing marks all line up.

If they dont, then you can move the camgear on the chain back of forth until its right.

If you still have problems, then take a better video showing the marks on camshaft gear