YZ400 RE-Nickaseal?

7 replies to this topic
  • beanmop

Posted April 04, 2007 - 11:11 AM


I just acquired a CA plated (it was plated before 2004 so from what I've read I get to keep the plates:thumbsup:) 98 YZ400 for $1000.00. The catch is that it's completely torn apart with a bad rod bearing and a scratched cylinder. The local motorcycle shop says that the cylinder can be re-nicaksealed and that a stock size piston will fit right back in. I've never been this deep into a bike before (first 2-wheeler, finally realized that quads are dumb) so I was wondering if this is a good idea, or if a new cylinder altogether would be better. The scratch is pretty small, would probably run if I left it alone but if I'm putting the whole bike together piece by piece, might as well do it right. Any input is appreciated!

BTW, When I said the bike is torn apart, I mean every single peace is in multiple boxes. The previous owner was starting to do a rebuild, but bought a WR-450 instead and put the bike in storage. I just finished pressing in new pivot bearings and swingarm bearings, with the wheel bearings next. A build up thread with pics is coming soon for any of those interested. Thanks again for any suggestions!

  • grayracer513

Posted April 04, 2007 - 11:27 AM


If the scratch is small enough, the cylinder can be refinished and replated. A competent machine shop with experience in this is the best judge of the feasibility of the repair.

  • dwnlowx

Posted April 04, 2007 - 12:24 PM


are you thinking of selling the bike because i might be interested i have a complete motor that is in great condition i just have not been able to come buy one that i would want

  • beanmop

Posted April 04, 2007 - 04:32 PM


Sell it? I just bought it! Good luck finding a good rolling chassis though.

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  • dwnlowx

Posted April 04, 2007 - 05:03 PM


well thats cool i hope you show some pics of your build up

  • mkporn

Posted April 04, 2007 - 05:15 PM


If the scratch is small enough, the cylinder can be refinished and replated. A competent machine shop with experience in this is the best judge of the feasibility of the repair.

even if the "scratch" is deep it can be welded and replated. Another option is to sleeve it with a steel sleeve fro LA Sleeve. or get a 420 kit for it.

The nice thing about sleeving is the fact that you can re bore it if you have another problem with the jug down the road.....:bonk:

  • grayracer513

Posted April 04, 2007 - 07:06 PM


The downside of sleeving is reduced heat transfer from the piston and upper cylinder bore through the cylinder and into the coolant. The steel liner conducts heat more slowly than aluminum, and the joint between liner and the dissimilar aluminum cylinder creates a hindrance to heat conduction no matter how well it's done.

  • beanmop

Posted April 05, 2007 - 07:47 AM


I wanna stay away from the sleeving due to the heat transfer issues. I live a few blocks away from Oceano Dunes, so I know I'll be heating up the motor quite well. I'm looking into replating it right now, I've got some time till my next paycheck so I can't rush into a decision anyways. Thanks for the replies!

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