Possible 450 Cam Prob...Suggestions??


11 replies to this topic
  • Chills

Posted July 17, 2005 - 08:53 PM

#1

Hey Guys,

Installed the 450 cam in January without problems, and have adjusted my valves for clearance a couple, so I know I have the procedures on how to install the 450 cam down. Last night I tore the top end apart and replaced the entire top end including the timing chain. Got it all back together and timed with the exhaust cam as close as possible. Went to fire it, and nothing. Kick and kick and kick, and 2 foot flame out the pipe, and still kicking without even a hickup like it wanted to fire. Tore apart the cam cover, rechecked, and took the cams out and started over from scratch, got it all back together, and still, 3 kicks into it, 2ft flame out the pipe, and once again, not even a hickup like it wanted to fire. Checked for spark, and spark is there. When I put the new timing chain it, I did notice that when trying to time the exhaust cam, it wasnt as symetrical as it was with the older timing chain. But 1 notch either way and it would have been off a ton rather than where it was. I plan on tearing it down again and checking to make sure the magneto got on drift key the right way. Has anyone else had probs with a new timing chain. The only other thing I can think of is that the chain itself isnt as stretched as the old one throwing the timing off just enough not to get it to fire....

Any thoughts would be helpful...
Thanks in advance

  • mkporn

Posted July 17, 2005 - 09:32 PM

#2

I would make sure you don't have a valve hanging open or not sealing completely.... Or you are getting the exhaust cam out of time and it is opening early.... You said it seems to be off a tooth one way or the other? I would put the cam in with the alignment a tooth in the other direction....So if you are installing it with the tooth being off one way go the other way with it..

I think you already knew that, not trying to insult your mechanical ability

  • grayracer513

Posted July 17, 2005 - 09:37 PM

#3

Check the intake cam timing. It has marks that work for the engine. Time the exhaust by counting pins between cams.

Clean or replace the plug and check your spark.

  • mkporn

Posted July 17, 2005 - 09:39 PM

#4

Check the intake cam timing. It has marks that work for the engine. Time the exhaust by counting pins between cams.

Clean or replace the plug and check your spark.



What exactly do you mean by pins?

  • Chills

Posted July 18, 2005 - 12:24 AM

#5

Check the intake cam timing. It has marks that work for the engine. Time the exhaust by counting pins between cams.

Clean or replace the plug and check your spark.


Hey Gray,

I also would like to know what you are refering to when you say counting pins? IS that in reference to the pins on the Cam Chain?

Also, No problems on the insults, no harm taken. I was soo tired from working in my counsins garage here in AZ, and the temp was around 116 degrees, I actually lost 9lbs that day. Went to the track in the morning, rode for 4 hours, and my buddies finally said it was time to do the top end. Called the shop, and by 230pm we were rebuilding. At 630 we had it all back together and started kicking it over, from 630-830, we racked our head until we finally called it quits and decided to re-group the following day. Problem was I was soo wiped out from being int he heat, I couldnt even muster the engergy to go outside today in the 116 degree heat to work on it. Maybe tomorrow I will be rested enough to work on it some more and take some pics of what the cam looks like while I have it timed. That new chain is such a pain in the butt since its soo tight, but I will definately rotate it so that is opens later than sooner. With the Ex. Cam with the closest possible tooth, it seems to be rotated slightly clockwise from the gear side of the cam, thus engaging the automatic decompression device sooner than later....

Will post some more thoughts tomorrow and maybe some pics if I am still having probs...

  • Chills

Posted July 18, 2005 - 05:59 PM

#6

Well, I took some pics before I tore it apart and started over. Here are the pics. From what I can tell according to the 450 Mod PDF install, the intake cam isnt retarded like it says and thge exhaust needs to be one more tooth forward, but who knows... Have a look!!

Posted Image

Posted Image

Posted Image

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  • MNellis

Posted July 18, 2005 - 07:19 PM

#7

Based on the pictures your exhaust cam need to be rotated one tooth. You should be showing 14 pins between the marks on the cam and yours is only showing 13. On the last photo it looks to me like the exhaust cam is pointed to high. Use a small machinest rule and measure from the top of the head to the bottom of the hole in the cam and I think you'll see the exhaust is a fair bit higher and they should be pretty close to the same.

Good luck.

  • grayracer513

Posted July 18, 2005 - 08:45 PM

#8

Based on the pictures your exhaust cam need to be rotated one tooth. You should be showing 14 pins between the marks on the cam and yours is only showing 13.

That is correct. Set up as it is, you may have too little cranking compression for the engine to start, because you have delayed the reseating of the exhaust valve by 22.5 degrees. The 450 cam has marks on it for a different head that sets the cams apart at different distances.

The easiest approach is to sort of guess where the exhaust cam belongs, just so the chain can be run over it. Now, you can set up the timing on the intake cam based on the timing marks, by the book. The exhaust cam needs to be there so that the chain be pulled tight on the front side, as it is when in operation. Without being able to do that you can't accurately guess how much slack should be in the back side run.

Finally, with the intake cam timed right, count 14 pins of cam chain (pins, not link) between the two 12:00 marks, and you'll be done.

  • Satch0922

Posted July 18, 2005 - 08:50 PM

#9

Based on the pictures your exhaust cam need to be rotated one tooth. You should be showing 14 pins between the marks on the cam and yours is only showing 13. On the last photo it looks to me like the exhaust cam is pointed to high. Use a small machinest rule and measure from the top of the head to the bottom of the hole in the cam and I think you'll see the exhaust is a fair bit higher and they should be pretty close to the same.

Good luck.




:applause: :eek:

Correct timing... 14 pins

Posted Image

  • mkporn

Posted July 18, 2005 - 09:25 PM

#10

Never even crossed my mind to count the pins..... Good call. :applause:

  • Chills

Posted July 19, 2005 - 09:54 AM

#11

Ok Guys...Its running....

I went ahead and just started from scratch. Pulled the Exhaust and Instake both out, and just started over. Read over the PDF doc one more time, and started the install. With my old timing chain, I had no problems what so ever getting it timed the first go around. But with this new chain, what threw me off was the fact that the instake is slightly retarded, which is confirmed by the PDF 450 Mod install. I didnt know about pin count thing, that helped a bunch.

Thanks again guys for the input and help...

  • mkporn

Posted July 19, 2005 - 11:01 AM

#12

Sweet! :applause:





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