CRF 450R Water Pump leak

IndyMX · Feb 5, 2008

Since I got this bike I've had issues with the water pump leaking.

Previous owner never had issues with it... :blah:

Anyhow, I first tried just putting a new seal in. That did nothing at all to help.

So, I replaced everything except the seal. Thinking the seal I just put in should be fine. I did note that the shaft was pretty well used up.

New shaft, bearing, oil seal, washer.

Still leaked.

Decided to go ahead and try another seal today. Still leaks.

Anyone have any experience with an issue like this?

I'm baffled. with everything being new, except for the impeller & cover, it should not leak. It's not a constant flow, but it does spit out pretty good.

bwood · Feb 5, 2008

Had the same issue on my buddie's 04 CRF450. I replaced the shaft and the oil seal and the water seal and no problems since (about 2 years). His impeller shaft had a groove in it where the water seal lived. I assume that coolant is running out of the weep hole? Believe it or not the water side seal was in backwards brand new. When you install the new ones make sure the spring side of the seal faces the liquid your trying to keep in.

IndyMX · Feb 5, 2008

Yeah, that's how mine is...

Spring side toward the water.

at idle it's a slow drip.. when I rev the engine, it comes out a bit faster..

cthowards · Feb 5, 2008

I have a 2005 and had a leak. I ended up replacing the bearing, shaft, oil and water seals and the impeller. I replaced the impeller with a 2006 version. My understanding is that prior to 2006, the impeller created a vacuum effect whereby coolant was being pushed against the water seal causing it to leak prematurely. Honda fixed this on the 2006 model where the 2006 impeller has a small hole in hole in it (about 1/8th of an inch) which reduces this vacuum effect.

Other than that, what you've done normally fixes the problem based on my and my friend's experiences.

IndyMX · Feb 5, 2008

Where was that hole?

Has anyone else heard anything about this being a fix?

cthowards · Feb 6, 2008

See attached article and picture from Transworld at

http://www.transworldmotocross.com/mx/how_to/article/0,13190,1079767,00.html

IndyMX · Feb 6, 2008

I saw that.. I'm going to go out in a bit and see if drilling the hole will solve this.

IndyMX · Feb 6, 2008

It actually looks like it got worse...

I drilled mine to look like what you see in that transworld picture..

I'm completely stumped.

2strokerfun · Feb 6, 2008

Indy: are you sure there is no difference in the impellers other than the hole? And what size hole? Might try taking yours up to dealer and comparing it to an 06 impeller (if any in stock) and see what you think.

IndyMX · Feb 6, 2008

According to what I've been able to find online, the only difference between the 02-05 and 06 impellers is a 1/8th inch hole in the 06 version.

I only wonder if I got it in the exact right spot..

Theres a tutorial on another site that details how to DIY it.. I guess I need to go pull the impeller back out and measure and make sure I got it in the right spot.

IndyMX · Feb 6, 2008

http://www.quickinet.net/waterpump/

I'm thinking head gasket.. Would I be right, according to this video?

IndyMX · Feb 6, 2008

Just tested compression.. Book says 78psi, I'm getting 55 psi.

whenfoxforks-ruled · Feb 6, 2008

Oh boy Gary, you are jumping into the thumpers up to your ears! If the head is trashed, pick up an 06 head.

770jimmy · Feb 6, 2008

A Friend Of Mine Has A Crf 450 A 04. He Had A Crack In The Cyclinder And He Was Loosing Water.

2strokerfun · Feb 7, 2008

IndyMX said:
http://www.quickinet.net/waterpump/

I'm thinking head gasket.. Would I be right, according to this video?

Is that your radiator bubbling?? Neat way to post video to show people. Are you blowing any antifreeze out the exhaust?? With regular old auto antifreeze, I can usually tell from the smell of the exhaust.

whenfoxforks-ruled · Feb 7, 2008

If you are pushing air bubbles into the radiator you have some big issues. 2t or 4t, same thing, more expensive. Interesting, it was pushing out the weep hole and not the cap. Head gasket if you are lucky, otherwise you will be introduced to magnaflux, crack detector.

IndyMX · Feb 7, 2008

I ordered a head gasket & set of balancer bearings (their noisy).

Hopefully it's just as simple as changing that stuff out.. nothing more.

mkelly04 · Feb 7, 2008

IndyMX said:
I ordered a head gasket & set of balancer bearings (their noisy).

Hopefully it's just as simple as changing that stuff out.. nothing more.

I dont know how many hours you have on the bike, but if you are taking it down that far you might as well put a fresh piston and rings in it while you have it apart.

IndyMX · Feb 7, 2008

I have it apart.. I don't see any definite signs from the head gasket, but I did notice that the rear head bolts weren't as tight as the fronts.

I'd love to put a new piston, rings, valves and all the works in it right now.. but I really don't have the cash at this point.

If by some miracle I do come across a pile of cash, I'll be doing all of that with no doubts!!

whenfoxforks-ruled · Feb 7, 2008

Does the intake have the stock shims in it?

IndyMX · Feb 7, 2008

I believe so. The dude I got it from said he'd never had to adjust them, just checked them. They'd always been right. I checked them before taking it apart, he wasn't lying about that.. They were well within spec.

Rich Rohrich · Feb 7, 2008

IndyMX said:
I have it apart.. I don't see any definite signs from the head gasket, but I did notice that the rear head bolts weren't as tight as the fronts.

Gary - Make sure you check the head and top of the barrel to ensure they aren't warped. If the engine was run for any length of time with the head bolts loose the head might be tweaked a bit.

You can resurface it using a clean sheet of FINE wet/dry emery cloth placed on a flat piece of glass. Spray some WD40 or some other cutting fluid on the emery cloth and just lightly sand the surface. It's worthwhile to flip the direction 180 degrees every few strokes to make sure you keep the pressure even.

I've used a similar method using a granite surface plate and have cleaned up some really warped heads.

Just take small amounts off and check it often. You can use a black magic marker on the clean head surface as a type of layout fluid to give you an idea where the high spots are as you go along.

IndyMX · Feb 7, 2008

I will.. Sounds like a very good plan. Money is always tight, and anything I can do to ensure this goes back together without costing me a fortune is a good thing.

What would be the best method for checking for warpage?

Rich Rohrich · Feb 7, 2008

IndyMX said:
What would be the best method for checking for warpage?

Clean the head surface completely of any gasket material and sealer, then clean it with acetone (or something similar) till it's spotless. Next, take a sharpie and paint the sealing surface of the head black (machinist's dye will work for this to).

Then follow the procedure above using a dry, full sheet of 400-600 sandpaper. It won't take off any real material but it will make the high spots shine and the low spots will not be touched and stay black.

You can do the same thing to the top of the barrel if you pull it off the bottom end.

You could also check for flatness with a feeler gage and a machinist's straight edge, but the glass plate and sand paper method is more reliable in my opinion.

IndyMX · Feb 7, 2008

Sounds easy enough. I'll have to go out and get some acetone tomorrow..

Hopefully there's nothing wrong with it!!

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