What do these pics mean? Multiple issues? Any ideas Gray?


5 replies to this topic
  • coop63

Posted November 19, 2012 - 08:59 PM

#1

These pics are of my 04 yz450f after a 2 hour break in period. The cylinder was honed and a Vertex 13:5 piston was installed. At this time i also had to replace the crankcase due to a puncture from a chain guide bolt being squeezed between the chain and the case. So while it was all apart decided to replace all case bearings. The crankshaft bearings were also replaced and a Hot Cams crank and connecting rod assembly installed with an installer. NO hammer!
The reason i tore it down was the presence of a severe vibration that seemed to involve the entire bike especially the handlebars. My fear is that the crank is not true, or severely imbalanced. I have seen where completely new cranks did not have the proper runout. It appears that the piston is really moving front to back in the thrust regions of the cylinder. Would the vibration have something to do with this? However, all piston and cylinder dimensions are in spec. For now. But it does weigh about 3 oz. less than the OEM.
Another issue is the oil leaking into the combustion chamber. Upon inspection the valves are wearing at the face, especially the intake valves. The exhaust valve faces are pitted and oily. Bottom line is its time for a head job, new valves, seats, ....

But i am very discouraged with the appearance of the cylinder and the vibration. In my opinion i have only one choice, and that is to pull the crank and have it inspected and trued. Hell for more money i may even have it balanced to vibrate out of my usual operating rpm range, as i well know that single piston setups are never perfectly balanced.

I really would appreciate some advice, but i think i know what the writing on the wall will be. Would just like some reassurance that i am doing the right thing. Thanks in advance!!! Here are the pics. I'll try to make them small enough yet still be useful.

For videos and all pics please visit http://s1354.photobu...681/drjclark63/

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Edited by coop63, November 20, 2012 - 06:30 PM.


  • marv02

Posted November 19, 2012 - 09:55 PM

#2

Are you using a steel sleeve or aluminum plated cylinder.

If you using a plated cylinder didn't know you could hone them with out getting them replated after boring or honing aluminum cylinder.

Theys pro's and con of steel cylinder sleeves but beening able to do a quick hone on your own then putting a new set of rings or piston and rings when needed is one of the plus of them.

  • coop63

Posted November 20, 2012 - 06:22 AM

#3

Are you using a steel sleeve or aluminum plated cylinder.

If you using a plated cylinder didn't know you could hone them with out getting them replated after boring or honing aluminum cylinder.

Theys pro's and con of steel cylinder sleeves but beening able to do a quick hone on your own then putting a new set of rings or piston and rings when needed is one of the plus of them.



It is a OEM nikasil plated cylinder. The stuff is almost diamond hard. But very thin. The surfacing aids in setting the rings as far as i am aware. Don't know if there is an aftermarket iron sleeve cylinder for this bike.

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  • moto2000

Posted November 20, 2012 - 11:21 AM

#4

Counter balancer timing?

I'm usually a little leery of a crank that has been shipped from who know's where in a box. How many times has it been dropped?

Edited by moto2000, November 20, 2012 - 11:29 AM.


  • coop63

Posted November 20, 2012 - 06:26 PM

#5

Counter balancer timing?

I'm usually a little leery of a crank that has been shipped from who know's where in a box. How many times has it been dropped?


Not an issue, balancer lined up correctly. Connect the dots. When i received the crank, the packaging was intact and dropping it would have crushed the foam
filler. Probably would have been obvious. Unless they reboxed it. So who knows. All i know is the shit ain't right and it pisses me off. i followed the instructions
in the manual to the "t". It must be poor craftsmanship from the manufacturer. But they don't stand behind their product with any kind of warranty. Should have been a signal from the start. Would cost very near $400 to have it trued and balanced by Falicon, hell i could buy another one cheaper than that. Or, may just take my loss and put the OEM back in. But with a HC piston, i wanted to beef up the bottom end to handle the extra pressure. I am going to rebuild the head and that will cost me substantial cheese as well. I told my wife i wanted a new, not used bike!!!

Edited by coop63, November 20, 2012 - 06:27 PM.


  • marv02

Posted November 20, 2012 - 06:58 PM

#6

I had one old CR Cranks rebuilt by a local Honda dealer I knew the head mechanic so you would think he done me right.

Wrong when I first pick the rebuilt crank up from them it was so out of round it would not fit in the cases the crank half were that far off center.

When I picked it the sencond time from the dealer it fit the cases but the motor vibrated and never ran right after that I end up buying a new complete OEM crank fixed all the issues I was having.

I hate sending or bringing my parts to places that I dont know anyting about the local shop I use to go to closed there doors I was going to have them do my bore job on my 426.

Now I have to ask some buddies who they go to around where I live now.





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