Oil Consumption/Oily Spark-Plug

31 replies to this topic
  • blueberg17

Posted May 09, 2011 - 10:19 AM


What is your opinion on running the Hot-Rods piston rod/crank assy.?


Contact Engine Dynamics about the head. It's fixable.

Would I send them my cams? Or do you think it would be best to get new?

  • grayracer513

Posted May 09, 2011 - 10:50 AM


The best bet is to talk that over with them, but I would be prone to say that the best job would be done by sending the complete head so everything could be looked at.

  • blueberg17

Posted May 18, 2011 - 06:30 AM


Update: My cyl-head is off at EDCo getting necessary repairs. My cylinder was .002~.003 out of round... Called a few companies to re-sleeve, but they are 1-2months out, and for what it costs I'm just going to spend the few extra dollars to get a new one.

Is it just me or is there a lot of problems with '08 yz's?

Good thing I like working on my bike as much as I like riding. :smirk:

  • grayracer513

Posted May 18, 2011 - 08:11 AM


The '08 seems to have had more than the usual amount of trouble with cam chains. Otherwise, I don't think they've been any less durable than any other YZ.

  • yz450fcranker

Posted May 21, 2011 - 06:41 AM


send in a 09 cam chain for 08 i still have my bike on the same cam chain

  • blueberg17

Posted May 24, 2011 - 07:25 AM


I got my cyl-head back from EDCo. They did a nice job of cleaning the cams and cam journals that were scared from the PO. Although when I started to measure for new shims I had to completely remove the shims to get my feeler gauge in between the cam and buckets. Two intakes and one exhaust measured on the tight side of spec, without shims! So basically left me no room for growth.

I should also mention, my cams measure= 0.8645" Yamaha specifies 0.8645"~0.8650"(21.959~21.972mm)

I called EDCo. and they recommend I buy new cams to solve my issue. What do you think gray?

Edited by Levi_M, May 24, 2011 - 08:04 AM.

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  • grayracer513

Posted May 24, 2011 - 01:04 PM


New OEM cams won't help. The base circle of the lobes will be nearly identical. What I would do with an engine that had steel valves is grind the tops of the stems down on a valve grinding machine to a shorter length. If the head has ever had a previous valve job, replacing the seats may help. It's hard for me to believe that they would not have checked that, or that they took so much out of the bore that you couldn't reshim it.

What size shims were there to start?

  • blueberg17

Posted May 24, 2011 - 01:15 PM


They said the valves, seats, guides, seals springs all looked good and everything sealed properly. I had them replace the seals anyways...

Intake: 210, 195, 205

Exhaust: 175, 180

Edited by Levi_M, May 24, 2011 - 01:36 PM.

  • grayracer513

Posted May 24, 2011 - 03:50 PM


They said the valves, seats, guides, seals springs all looked good ...

Maybe so, but what you're saying is that the cams are now so low in the head that the valves are too tall to be shimmed correctly. I'd have another conversation with them about how they would resolve that. Having it sent back and essentially telling you that you need to devise a fix for it yourself is certainly not what I would expect from them.

  • blueberg17

Posted May 24, 2011 - 08:44 PM


OK, I had a good talk with them and found out how much material was taken out which wasn't enough to cause this problem. Honestly, it was my fault. I must have been tired last night when I measured originally.:smirk: and I have plenty of room for adjustment!

The reason they mentioned new cams is because my cam-to-cap clearance has reached its upper limit. (loose)

  • blueberg17

Posted May 25, 2011 - 05:52 AM


I highly recommend Engine Dynamics to anybody who needs head work done, they do excellent work! Mike is who I talked with over the phone, He was very knowledgeable and helpful. They also carry a lot of parts, OEM & after-market.:smirk:

  • blueberg17

Posted June 02, 2011 - 08:25 PM


It's finally all back together. Got my top-end power back and Feels like a brand new bike again! :ride:

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