Noisy 426


9 replies to this topic
  • zacreeves

Posted May 03, 2008 - 07:06 AM

#1

I just put in a new top end and clutches and now the top end seems to be knocking harder than normal. This was apart for over 2 years so it's not like I completely remember how it sounded but it has seemed to get worse since I got it together. I have checked the valve clearance and its is in spec. I rechecked the timing and it is correct. So what else could it be or what should I check?

  • GONE1445

Posted May 03, 2008 - 12:53 PM

#2

I know my 426 is pretty noisy when its running but maybe its the water pump howling?? dunno what else it could be

  • zacreeves

Posted May 04, 2008 - 07:28 AM

#3

Mine is more of a knocking that sounds like its in the top end.

  • Kasjok

Posted May 04, 2008 - 07:40 AM

#4

You probably just imagine it as now that you did your top end you are paying too much attention to motor noises.

  • zacreeves

Posted May 04, 2008 - 01:54 PM

#5

Maybe but it doesnt seem like it. Is there anything else it could be?

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  • zuch95701

Posted May 04, 2008 - 01:57 PM

#6

did you rebuild the top end new piston wrist pin clips and stuff. it could be your rod is warn out and your piston pin is loose. you might have to replace your rod. Also depending on some things if you did manage to get the wrong head gasket some times they well make a sound alot like a knock.

  • 642MX

Posted May 04, 2008 - 04:50 PM

#7

I just put in a new top end and clutches and now the top end seems to be knocking harder than normal. This was apart for over 2 years so it's not like I completely remember how it sounded but it has seemed to get worse since I got it together. I have checked the valve clearance and its is in spec. I rechecked the timing and it is correct. So what else could it be or what should I check?


Did you use a Wiseco piston? Maybe a higher compression than stock?

  • bustersat

Posted May 04, 2008 - 06:03 PM

#8

If your piston clearance is on the high side you could get some knocking. It depends on your exact bore and what piston you used for the rebuild. Cylinders and pistons need to be matched to get the tightest tolerances. You can make up for some of the difference with rings, but you may end up with a noisy engine that also may not last as long! I just replaced a top end on my 02 426 with a big bore from Luke's racing, and all my engine noise went away. I was paranoid at first going with a bigger bore and high compression, then I kicked it over for the first time and holy s##t, I love it! :eek:

  • zacreeves

Posted May 06, 2008 - 08:29 PM

#9

I used a wiseco piston and it was just stock bore and compression. And I did replace the pin and clips. Everything felt tight so I'm not real sure.

  • 642MX

Posted May 07, 2008 - 04:52 AM

#10

I used a wiseco piston and it was just stock bore and compression. And I did replace the pin and clips. Everything felt tight so I'm not real sure.


Wiseco's are louder than stock. They have a piston slap noise thats very easy to hear. There is nothing wrong with the Wiseco, its just how it is.

Chances are you've built it right, go ride it. :eek:





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