CRF 450R Water Pump leak

[whenfoxforks-ruled]

I like to draw a figure eight motion while being ever so careful not to tip it. 2 times should show you what you have. If it has issues take a few more passes and see how much you are removing. If it is bad, do you know any local machinists? Everybody should have a bridgeport mill. I have been known to spray the glass and back of the sandpaper with contact cement, and laminated the paper to the glass. You can put a coarser paper on the other side.

 

[IndyMX]

Excellent ideas Bob.. I have a friend with a mill.. If need be, I'll have him mill it. He's pretty good, I do trust him quite a bit.

 

[trial_07]

Up to how much can you remove from that head? Just asking.

 

[IndyMX]

Excellent question!!

 

[whenfoxforks-ruled]

How much comes off has a few variables. 800 grit, 2 figure eights, pushing it, you will barely take the dye off. If you had to take .005 thousandths off you would be there a while! If you know a guy with a mill, chuck up a dial indicator and go to town.

 

[IndyMX]

I checked the head and cylinder today.. It looks good. No warpage that I can see.

 

[whenfoxforks-ruled]

I would recommend measuring what little skirt there is, ring end gap and look at the small end of the rod. I have seen wear patterns that have to be from rocking side to side. If the day ever comes that you feel snaky, and want to replace the head, we'll track down AJ and see if an 07 head will bolt up. It is supposed to have a lot better intake port. I really think the only difference from 04 to present on the bottom end was relocating the crank. They moved it back using the same cases. If it was not ran long like that, it may not have tell tale signs. Still thinking about the magnaflux though.

 

[IndyMX]

For now I'm gonna put a set of rings in and put it back together.

The ring gap on the compression ring was .013, spec is .010 to .012 with the limit being .018

Once I can save some cash to get everything done, I'll tear it down again.

 

[whenfoxforks-ruled]

Sounds like the alleged hours match the wear.

 

[bwood]

Here are some part #s to keep handy:
12200-MEN-850 Cylinder Head (06) $211.93
12200-MEN-A00 Cylinder Head (07-08) $233.50
06113-MEB-701 Top End Gasket Set $36.92
19215-MEN-850 Water Pump Impeller (06) $21.37

I think the 07 head not only changed the intake port, but they also changed one of the valve diameters (exhaust I think from 31mm to 30mm like the 450X). So if you do go to the 07-newer head, make sure to get the 07 and newer valves. New cylinder heads from Honda do not come with the valve etc., they only come with the valve guides and seats installed. My buddy with the 04 CRF450R bought a whole head and valves (and everything else) from Service Honda after he had it for a few years. We sent the old head to a shop nearby and had new guides and seats installed (factory) and we put new valves and etc in it as he could afford it. Now when we do the next top end, we will install the rebuilt head and keep going.