WR400F head damage - advice? To


Been quite awhile!!

I got a wr400 for $300 (AUD) last weekend. Seized crank/rod bearing.

Piston/valves and everything else seem in tact.

So after spending all yesterday trying to remove all the thick carbon build up, I found a lot of pits/craters in the head - looks like these are from previous damage, not this current issue.

Just trying to see any advice on this - leave or, maybe lightly try to sand them down or part the thing out?

I'm happy to replace valves, piston and rod/bearings but not too much else.

I have attached a quick before and after image.

Thanks!!ImageUploadedByThumper Talk1417941426.319773.jpgImageUploadedByThumper Talk1417941443.333420.jpg

Its at least a 12 year old bike with top and bottom end engine damage.  After you get finished investing time and money into it, you will still have a 12 year old dirtbike.


If the rest of the bike  (wheels, suspension, water pump, etc...) are in similar condition, then part this thing out.    I don't know the prices where you live, but a running wr450 in fair shape goes for about the same as it would cost you to get this running right.

I wouldn't hesitate to run in as is.  As Mauricedorris says, though, you're going to put some fair coin into the motor to get it running.  Here in the US, you're taking about maybe $150 for a rod kit and another $150 to replace the rod and true/balance the crank, $75.00 for main bearings, and another $150 for a gasket kit and rings. If you need valves or the seats cut, you're starting to get to the point that it will cost you more than the bike is worth to get it to a rideable or saleable condition...


I'll strip the rest and see how it looks.

I was in the process of rebuilding a wr250 (2002) which was in great condition just worn rings - very/no compression and then I got this 400 offered to me.

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