Can't find OEM part!



9 replies to this topic
  • promills52

Posted June 22, 2016 - 01:07 PM

#1

I have a broken spring on my auto decompressionews cam. I can't find the part on any forms or specs. Not even the owners manual shows it. It's a 2008 yz450f. Any ideas where I can find it? Or do you have to buy entirely new hot.cams just for one spring?

  • William1

Posted June 22, 2016 - 01:41 PM

#2

Did you call Hot Cams?

Quad or Bike???

You just bought it and the part failed? I'd bet dollars to donuts the seller knew there was a problem and jury rigged it 'for a quick sale'. Better watch the valve clearances too.



  • promills52

Posted June 22, 2016 - 01:50 PM

#3

This is on a bike I've owned for awhile. Went to the track and all of a sudden it wouldn't kick. To much compression. Took the head cover off and saw the decompression spring had broken on the cams.

  • grayracer513

Posted June 22, 2016 - 02:19 PM

#4

The spring is not serviced, and you would most likely be unable to replace it if you had one.  The pin that it pivots on has to be pressed out, and then back in to accomplish this, and may not fit tightly enough to stay put the second time in.

 

All the same, You won't get one from Yamaha, so I'd recommend you get on the phone with Hot Cams.  If it makes you feel any better, this is the first one I've heard of breaking.



  • Chocos

Posted June 22, 2016 - 03:04 PM

#5

I have a broken spring on my auto decompressionews cam. I can't find the part on any forms or specs. Not even the owners manual shows it. It's a 2008 yz450f. Any ideas where I can find it? Or do you have to buy entirely new hot.cams just for one spring?

Remove the auto decomp lobes, these mechanisms bring more issues than provide anyway.



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  • promills52

Posted June 22, 2016 - 06:53 PM

#6

It's the spring that's visible right on the front of the sprocket of the cam. That closes the decompression when centrifical force stops forcing it open.

Attached Thumbnails

  • 1466650232098.jpg


  • grayracer513

Posted June 23, 2016 - 06:20 AM

#7

Remove the auto decomp lobes, these mechanisms bring more issues than provide anyway.

 

And how, exactly, do you propose to start the engine with no decompression method available?

 

It's a completely baseless statement, anyway.  The decomp system in YZF's and related engines are as trouble free as a mechanical device gets. 

 

 

It's the spring that's visible right on the front of the sprocket of the cam. That closes the decompression when centrifical force stops forcing it open.

 

Yep, that's it.  My answer remains as I first gave it.  The spring is not available from Yamaha, and would be very difficult, if not impossible, to replace for most people if it was.  Call Hot Cams.  See if they can help, or go buy a new exhaust cam.



  • Chocos

Posted June 23, 2016 - 08:01 AM

#8

And how, exactly, do you propose to start the engine with no decompression method available?

Manual decompressor?

 

 

It's a completely baseless statement, anyway.  The decomp system in YZF's and related engines are as trouble free as a mechanical device gets.

Really? What is this topic about then?



  • grayracer513

Posted June 24, 2016 - 07:52 AM

#9

Manual decompressor?


None available.  Unless, you wanted to take the head to a machinist along with one from a 426 or a '03-'05 450 and have him bore, drill and tap the head for a 426 manual decomp set up.  Probably cost about 4 times what a new cam would.
 

Really? What is this topic about then?


Cite one other example.



  • Chocos

Posted June 24, 2016 - 11:23 PM

#10

None available.  Unless, you wanted to take the head to a machinist along with one from a 426 or a '03-'05 450 and have him bore, drill and tap the head for a 426 manual decomp set up.  Probably cost about 4 times what a new cam would.

I thought it had one, I was wrong then sorry.







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