Rear timing guide play

2 replies to this topic
  • 02WR426Cali

Posted March 25, 2011 - 05:33 PM


Hey guys I'm curious if anyone else felt some play in the rear timing guide. How much side to side play should there be in the rear timing guide? I know it's supposed to move freely front to back but side to side left to right sitting on the bike. With the cylinder installed and the head off mine moves very freely side to side. I took it out to ispect the bottom bracket/ rivet that is mounted on the bottom. It seems ok but it is a little sloppy like the hole in the guide is worn. Is it supposed to be a loose fit on the rivet or tight? I can't remember how it was the last time I had it apart.
The front guide has two extensions to keep it in place with the head on, but the rear does not.

Also I just picked up my cylinder head from ASRacing and there is valve seapage. He said he cut the seats for the new SS valves from a 00 426 and also lapped them. Yet gas seaps right through, I don't have any solvent so I used gas. Gas did not seap through with the old valves I just replaced. To me it looks like he bead blasted the head and barely cleaned it, then assembled the new valves in. It doesn't appear to be cut or lapped. But I just talked to the owner and he assurred me it was along with cleaned.

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  • Padgett

Posted March 25, 2011 - 07:31 PM


The rear cam chain tensioner guild does wear out. Most the time the cam chain from normal wear cuts into the guild so if you see any major grooves then replace it. As for the rivet at the bottom, it should move forward and back, but it should not be as you say sloppy. If your concerned about it then replace it.

If that was my head and the valves would not hold gas, I would be tearing it back down to find out why? It should hold and pass the liquid test.

  • 02WR426Cali

Posted March 25, 2011 - 08:31 PM


I did take out one of the exhaust valves and nothing looked out of the ordinary. The seat was cut after the bead blasting as it was shiny and not dull like the blasting creates. They claimon their website that they lap the valves yet when I called him on it he stumbled and wouldn't give me an answer if he did or not. He said "just run it, they will seat when it runs" "I have never had a head failure or one come back with issues" blah blah blah.

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