Need help with camshaft timing

[SlOoT]

I have timed my exhaust camshaft.

Reading A = 120
Reading B = 353
120+353+180 = 653
653/2 = 326,5
326,5-120 = 206,5

That is 100 degrees to much...

What is wrong here ? Are readings A and B totaly wrong or is the formula I use wrong ?

[SlOoT]

Checked teeth count on idler and noticed it was a teeth of. So I corrected that. The gears are the same now as shown in the manual. I also used a dial meter to check if piston was a TDC.

Intake:

A=353
B=452

352+452+180/2= 492,5

492,5 - 353= 139,5

Exhaust:

A= 143,5
B= 364

143,5+364+180/2= 343,75

343,75 - 143,5 = 200,25

[SlOoT]

I have taken it all apart and reasembled it with all the dots lining up like in the manual.

The first problem I encounter is that when I install the chain-tensioner that the idle-gear teeth marked with 0 in the manual is not pointing up anymore but is half a teeth to the left.

The chain-tensioner went out 4 clicks.

Could this be my problem ?

[Easy E]

First off, where are you getting your A/B numbers from? The highest number on the degree wheel is 90, so you shouldn't have anything larger than that for A or B. An exhaust cam in a motor I degreed recently looked like this:

A: 58
B: 24

58+24 = 82
82+180 = 262

262 / 2 = 131

131 - 24 [B] = 107

[SlOoT]

lol, my degree wheel goes to 360

I have also fixed the other problem I have. I have swapped the sprocket on the crankshaft with a spare one and everything lines up perfectly now.

Thanks

[SlOoT]

Ok, did a new reading on the exhaust camshaft:

A=45 (45 after the first 90)
B=5 (5 after TDC)

45+5= 50
50+180= 230
230/2= 115

115-5= 110. Correct ?

EDIT: Also did the intake:

A= 75,5
B=44

75,5+44+180/2= 149,75

149,75-44= 105,75. Correct ?

[Easy E]

QUOTE (SlOoT @ Dec 15 2007, 02:52 PM) <{POST_SNAPBACK}>

lol, my degree wheel goes to 360

I have also fixed the other problem I have. I have swapped the sprocket on the crankshaft with a spare one and everything lines up perfectly now.

Thanks

Ahh, using a "non" Cannondale degree wheel - makes sense where the numbers come from! Looks like you got it now.

[cannondale27]

Yes math is correct. That is real common timing from factory so I bet everything else is correct. Now try to get the exhaust down to about 108 or ideally 106 and then get intake up to 108 or equal. 110 like you have on exhaust is going to make motor flat on top but bottom will be strong and smooth. If you don't mess with the intake which is close at least adjust the exhaust to 108 which will give you 105.75 I/108 E. That's a good combo for all around riding. I like it for TT for nice control in corners. If you want max power at topend for a drag quad or something let us know. Good job. Cam timing can be the most time consuming project of a entire rebuild. Once you do it a few times with confidence comes speed.

[SlOoT]

My exhaust :

A=45
B=5

Easy E exhaust:

A=58
B=24

That is a big difference I think. And after aplying the formula there is only a 3 degree difference. Is that also suposed to be like that ?

Also check this out:

A=45
B=5
45+5+180/2 -5= 110 Degrees

A=50
B=10
50+10+180/2 -10= 110 Degrees

A=55
B=15
55+15+180/2 -15= 110 Degrees

That means that if the timing is 110 and you will make the valves open and close 10 degrees later, the timing will stil be 110?

[cannondale27]

Yes. What its doing is finding the center of the lobes. Some guys do the measurements at .050 lift that would account for difference or different cam profile. There are all kinds of ways to do this but the formula is agreed to get you what you need universally. After doing many of these I know it works. I wish I had a better answer for you.