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Please help cam timing does not seem right

B

big_red1a

Well-known member
Oct 23, 2008
157
50
28
So here it goes. Installing head shim for 2010 nytro impulse turbo. I have the head shim installed and while moving on to the cam timing have become very confused. The nytro service manual states several times use the "I" mark on the magneto rotor to align the motor to "TDC" on cylinder #3 "compression" stroke. This aligns the cam timing dots on every other rotation. This is in section 2-7 and 2-8 of the 08 service manual. also refer to section 5-16 to 5-25. you can see that if the camshaft lobes are turned away from each other and the cam dots are lined up with the arrows that this is actually the start of the intake stroke and not compression. Is this a error in the service manual or to i have some thing assembled wrong? It mentions this several times in chapter 5 as well.


Checking steps:

• Turn the crankshaft clockwise.

• When piston #3 is at TDC on the compression

stroke, align the TDC mark a on the AC magneto

rotor with the mark b on the AC magneto

cover.

NOTE:

TDC on the compression stroke can be found when

the camshaft lobes are turned away from each

other.
If you were to rotate the mag 360 deg the camshaft lobes would point up and at each other (all valves closed) this would be the top dead center of the compression stroke but the cam dots would be upside down and out of sight.
I posted pics of my current set up with the "I" in the center and the dots lined up with the arrows


I have had this apart an extra day just looking at it second guessing myself. Am I missing something? Is it assembled wrong? Maybe i just do understand lol!
I cannot see this being a error in the service manual but some thing is not right.

Please Help Me!!!!!

Chris Luiten 306-630-6991


you can download service maual at ty4stroke.com under sticky fx nytro miscellaneous her is link: http://ty4stroke.com/viewtopic.php?t=58910
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08 Apex LTX GT 40th 136" cobra,198 gd,extros, simmons,scratchers,triplepts,7.1revalve,powder coating,gps,snoweliminators,13mm sway, oil-lights,vent kit,grease zirks,OFT steering
10 Nytro MTX SE 162"
 

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Last edited:
S

SPOOLED

Active member
Dec 4, 2007
186
42
28
northern bc
your going of the wrong cylinder you have you have to line up tdc with the dots and number one is on the pto side. dont go off the cylinder by the cam dots.
 
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big_red1a

Well-known member
Oct 23, 2008
157
50
28
your going of the wrong cylinder you have you have to line up tdc with the dots and number one is on the pto side. dont go off the cylinder by the cam dots.

I was pretty sure the service manual says 3 is mag side. It also says that when aligned #3 is at TDC compression but it seems to be 360 degrees off.
unsure if it even matters on this engine i guess i need to find out if the ignition fires every rotation off the mag even on the intake stroke. Would fuel or anything else be affected if it was 360 off?
 
B

big_red1a

Well-known member
Oct 23, 2008
157
50
28
Did anyone read the service maual? Am i out to lunch here? What am i missing?
 
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