TDC on camshaft dots?


28 replies to this topic
  • CaptainKnobby

Posted February 12, 2016 - 03:28 PM

#21

I used a socket...it worked fine.

------------------
'99 WZ with all YZ mods, de-octopused, FMF PowerBomb header, Stroker SX-1 silencer, SS front brake line, forked over by Pro-Action, OEM YZ tank, IMS YZ seat, carb mods by Jim Dean and Sir "Taffy" from Jolly Old England, AMA, NESC.


I did Before I put the piston in. They were all in spec. However I didnt check the valves after I got everything back together.

I dont see how they could have changed by just putting a piston in and mew cam chain, unless they changed sue ti the new piston, rings, cam chain and removing the cam shafts.
I will check the valve clearence on both Intake and Exhaust tomorrow.

  • grayracer513

Posted February 12, 2016 - 04:20 PM

#22

Here's something a lot of people don't know:  The timing mark you use to time the cams IS NOT TDC.  It's a few degrees off of that because of the 15mm forward cylinder offset.  Always use the flywheel marks a shown in the book. 

 

When you think that you ave the cams in right, roll the crank backwards about 5 degrees, then roll back both cams until the front side of the chain has no slack, then slowly turn the crank back forward to the timing mark. THEN check the marks on the cams. 

 

The marks will never line up exactly.  What my advice always is when there's a question is, ask yourself if it would look better aligned if it was one tooth one way or other.

 

To me, it looks like your exhaust cam is one tooth retarded (needs to move forward one tooth).



  • CaptainKnobby

Posted February 12, 2016 - 05:43 PM

#23

Here's something a lot of people don't know: The timing mark you use to time the cams IS NOT TDC. It's a few degrees off of that because of the 15mm forward cylinder offset. Always use the flywheel marks a shown in the book.

When you think that you ave the cams in right, roll the crank backwards about 5 degrees, then roll back both cams until the front side of the chain has no slack, then slowly turn the crank back forward to the timing mark. THEN check the marks on the cams.

The marks will never line up exactly. What my advice always is when there's a question is, ask yourself if it would look better aligned if it was one tooth one way or other.

To me, it looks like your exhaust cam is one tooth retarded (needs to move forward one tooth).


Ok. I will try and just move the cam a tooth an see if it will start.
If not I will go through tje whole process again.
Let ya know Sunday. At work now keeping america safe nu keeping the convicts in....lol

  • CaptainKnobby

Posted February 12, 2016 - 06:19 PM

#24

So when uou sau move the cam one tooth forward .....you mean toward the handle bars?
I will do that.

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  • Thumbster21

Posted February 12, 2016 - 09:45 PM

#25

How many times did you try to start it after you gave it 3 twist of the throttle? Did you stop trying after it backfired?

On mine I pull the choke, full throttle it three times and it usually starts in one or two kicks. If not I kick it over slowly four or five times to clear it out then I kick it a time or two without any throttle to try to start it. If still not starting I'll give it one twist of the throttle and kick it again a couple times to try to start it. At some point during this process if it backfires I know it's close to starting and it will only take another kick or two.

Long story short (too late I know) if your marks are lined up on the flywheel and if moving your cam a tooth doesn't fix the dots then I think you have a fuel issue....assuming your valves are still in adjustment.

  • CaptainKnobby

Posted February 13, 2016 - 01:57 AM

#26

How many times did you try to start it after you gave it 3 twist of the throttle? Did you stop trying after it backfired?

On mine I pull the choke, full throttle it three times and it usually starts in one or two kicks. If not I kick it over slowly four or five times to clear it out then I kick it a time or two without any throttle to try to start it. If still not starting I'll give it one twist of the throttle and kick it again a couple times to try to start it. At some point during this process if it backfires I know it's close to starting and it will only take another kick or two.

Long story short (too late I know) if your marks are lined up on the flywheel and if moving your cam a tooth doesn't fix the dots then I think you have a fuel issue....assuming your valves are still in adjustment.

I dont think its a fuel issue since it ran before I put the piston,rings and timing chain in.
However it never backfired in the past when ever I started it.

  • grayracer513

Posted February 13, 2016 - 07:24 AM

#27

Twisting the throttle with the engine off does absolutely nothing on a '10 or later model because fuel injection doesn't have or need an accelerator pump.  



  • CaptainKnobby

Posted February 13, 2016 - 12:18 PM

#28

Got it going finally.... started on third kick. Just had to do what Gray said and Fill the cams forward and see were it looked lined up the best.
Was a tooth off on exhaust cam.
Here is how it looks om mine lined up.

Thanks everyone for the help. Got to work tonight, so I will check the valve clearence either sunday or monday.

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  • Thumbster21

Posted February 13, 2016 - 09:39 PM

#29

Twisting the throttle with the engine off does absolutely nothing on a '10 or later model because fuel injection doesn't have or need an accelerator pump.


Forgot about the 450's being FI earlier. I was throwing my 2 cents in with my experience with 250's. They didn't have FI until 2013 ('14 maybe?) My bad.
Glad to hear you got it running.

Edited by Thumbster21, February 13, 2016 - 09:41 PM.






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