Checking a Crank for Endplay/rod clearance

31 replies to this topic
  • grayracer513

Posted December 06, 2010 - 10:57 AM


Interesting. I do remember a bit of that. You'd think he would know better. :thumbsup:

  • tech24

Posted December 06, 2010 - 11:02 AM


Interesting. I do remember a bit of that. You'd think he would know better. :thumbsup:

I would have thought so. From what I understand though is he is not doing much of the work himself anymore and may have sub-par employees just a rumor). So its possible the story I got from what an o-crap cover up but I'll never know.

  • Brawg

Posted December 07, 2010 - 10:16 AM


I have had the bike back together now for 1 race and 1 ride. I changed the oil after a mild break in (pre race) and once after going back with Motul 300v after the race. I am curious why you guys say you cant face the valves. It clearly states in the Yamaha manual to do so. I did it, they dont leak and are running fine. What coating are you talking about? I got confirmation from a yamaha "pro" dealer that facing the valves was perfectly ok to do.

  • Brawg

Posted December 07, 2010 - 10:18 AM


Oh, the reason it would not start (as previously posted) was due to the ignition coil or "spark plug cap being faulty. It would fire outside the bike, but put it in the head and it was grounding to the head rather than firing the plug. I put a new/undamaged coil in the bike and it fired on the first kick.

  • tech24

Posted December 07, 2010 - 10:23 AM


My '04 manual says the same thing but I believe yamaha has a tendency to not update all the information to current from year to year. I believe the 2001 was the last year before switing to ti coating. Its common knowledge grinding the coating off will decrease the life of the valves. This must be a topic of debate and theory and I'd like to hear how yours are doing after some good hours of riding. It will ease my mind if they last and if I ever get my '04 back to one piece.

  • Brawg

Posted December 07, 2010 - 12:12 PM


No sweat...I'll update after a few races. Grinding anything "decreases" the life thereof...but when you're talking about $500 for valves it makes a little sense to try.

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  • grayracer513

Posted December 07, 2010 - 12:15 PM


Titanium has a lot of great attributes. Unfortunately, hardness isn't one of them, and it can't be effectively hardened without becoming brittle. In order to make them hard enough to serve as a engine valve, they are coated with an extremely hard compound of titanium nitride. The problem is that this coating is also very thin, usually less than .001" thick, so there is NO margin for removing any of it, and they absolutely can't be refaced once worn unless one has access to a facility that could recoat them.

The risk you run in lapping them is not that they might leak, it's that the coating may become damaged by the abrasives, and fail early. If you did either of these things to yours, I can only say, "Good Luck".


  • Brawg

Posted December 07, 2010 - 12:36 PM


What kind of life deterioration are we talking about here?

  • Brawg

Posted December 07, 2010 - 12:37 PM


My experience is that 450 Yamaha valves last forever unless bent or otherwise damaged. If the wear is accelerated by removing the coating how fast will they wear?

  • Erik Marquez

Posted December 07, 2010 - 01:19 PM


My experience is that 450 Yamaha valves last forever unless bent or otherwise damaged. [COLOR="Red"]If the wear is accelerated by removing the coating how fast will they wear?[/COLOR]

From what I have read,, Your about to find out.. Keep track of your hours run, oil and air filter changes and keep us posted.


  • grayracer513

Posted December 07, 2010 - 01:24 PM


It's very difficult to answer that in definitive terms. Ti nitride is very, very hard. In fact it's somewhat off the Rockwell C scale at over 85 somewhere, but the abrasives use in lapping paste are hard, too. As thin as the coating is, it would be very difficult to measure the wear caused by lapping even if you wore almost through the coating, so in practical terms, you just can't tell. If I had to guess (bear in mind, I didn't watch you lap them), I'd probably venture that you didn't hurt them significantly, because the coating Yamaha uses is as tough as it it is, but of course, I have no way to know.

Valve clearance checks will show you when and if the coating wears out, though, just like usual, so you may as well run it and see how it does. I probably would.

  • Brawg

Posted December 09, 2010 - 11:56 AM


Gray...the valves were faced by a machine shop. The coating is surely gone. I will report the degression of the clearances....I dont ride motocross or ride with the engine screaming. I ride it in the woods in the middle of the engine occasionally/semi-often calling on WOT. Hopefully this will prolong their life.

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