bike sat for few years, now won't start....

[MK]

If your bike spits coolant, it's most likely NOT the water pump. It's the head gasket and the solution is easy : Get one from Yamaha
No aftermarket, they always leak.

If the water pump is faulty, you'd have water in the gearbox oil which would make it milky.

[myrz350jp]

Martin, thank you for your suggestion and insight. You are the only one so far to point out the possible head gasket replacement.
My coolant overflow tank is bone dry, and the engine didn't overheat after restarting her with some coolant coming out from the breather nipple.
Tube on it got lost some time ago so I can see the coolant coming out(now spewing, but steady flow) as it drips to the floor in my garage.
I don't mind buying the Yamaha head gasket on line if that is truly the problem, and it should be a quick, easy fix.
I guess I can take the head cylinder off and take a good look at the head gasket condition and replace it if damaged first, to see
if the leakage from breather nipple stops. I can still rebuild the water pump since I already have the gaskets and parts to rebuild them anyways.
I'll work on my RZ this weekend and keep posting the progress.

[silverstrom]

Martin is correct, it is very likely the head gasket. It is a common problem and most here are aware of it, which is probably why it wasn't mentioned sooner. Most people reading your symptoms would think head gasket right away.

A failed head gasket will push pressure back to the coolant bottle and overboard. If it gets sucked into the cylinders you'll have a much bigger problem to deal with.

Typical water pump failures will see water get into the gearbox oil.

You said it has been years since the engine last ran. Based on that you should expect more problems to surface. I'd be particularly cautious with the crank seals. With the leaks you are seeing now and the length of time the bike has been sitting, you should expect the crank seals to be hard, shrunken and leaking.

All of this gets back to the need to pressure and vacuum test the engine. Leaks and problems will show up if they exist. I wouldn't be starting the engine again until you test it. The potential for damage is there and it could be an expensive mistake. I would suggest not doing anything else until you pressure and vacuum test. A little time and money now and can save you big later.

[myrz350jp]

Dear silverstrom,
Thank you and Martin for your suggestion. Gearbox oil is fine, not milky,
Great to know I won't need to do the water pump rebuild. I'll just keep the parts for now.
I now need to then find ways to run pressure and vacuum test as you suggested.
I'll search YouTube to see if I can find any helpful video that may show me the way visually.
I'll take my time to get it right, with many helpful suggestions from this site.
Appreciate any additional check point suggestions. Hopefully not too expensive. LOL

[(F5)]

It is easy to inspect the condition of the head gasket. . . . Yup. It's used.

It does seem ridiculous that you seemingly cant get a good aftermarket gasket. In the 90s genuine got my 350 watertight after annoying failures. My big block is o-ringed but that's a different kettle of fish.

[myrz350jp]

Dear (F5),
I found a good YouTube and ordered the test kit for pressure and vacuum test.
I'll have to wait for about a week, but will put back on the kick starter(since I was going to rebuild the waterpump...)
and run the test. I had my cylinders bored once, so what psi should I look for? I'm a non-mechanic, and only have done
top end rebuild with my buddie once many years ago, so please go easy for some of my novice questions, thanks.

[(F5)]

Leak down test only needs to be circa 5 psi to check crank seals etc. I never use compression testers. Oil splashed up from crankwebs can give an inconsistent result.

[silverstrom]

Dear (F5),
I found a good YouTube and ordered the test kit for pressure and vacuum test.
I'll have to wait for about a week, but will put back on the kick starter(since I was going to rebuild the waterpump...)
and run the test. I had my cylinders bored once, so what psi should I look for? I'm a non-mechanic, and only have done
top end rebuild with my buddie once many years ago, so please go easy for some of my novice questions, thanks.

You are referring to a compression test, which is useful, but only a pressure/vacuum/leak-down test will show you the location of leaks we are talking about at crank seals, reeds gaskets, base gaskets, etc.

For a compression test anything under 100 is suspicious on an RZ350. Ideally 110 or higher is what you want to see. Install the gauge in a spark plug hole and kick the engine over several times until the gauge stops moving. Throttle opened or closed has never made any difference here. Ideally the engine should be warm, but cold will tell you everything you need to know. Can diagnose ring problems, cylinder wear, head gasket failure and more.

This pic from my shop is what you need to do for the pressure/vacuum test

[myrz350jp]

Dear (F5), sorry for my lack of technical term understanding, but thank you for all the suggestions.
Dear siverstrom, noted about the compression test. Also, thanks for the pic on pressure test.
I bought Bosch FIX 7827 Compression Tester Kit for Engine Compression, 2 1/2" Gauge.
I also bought impact screw driver to loosen up the screw to work on water pump rebuild.
Like I said before, non-mechanic here, trying to figure out many things through my friend and this portal.
I've never had to rebuild a water pump on my RZ since I bought her many many years ago.
Do you think I should go ahead an rebuild it? Or should I keep the parts for rainy days?
Lastly, where I can get the pressure tester like yours? My garage has nothing like air compressors some mechanics may have handy, etc.
I have few tools I have accumulated over the years of RZ ownership, but the biggest rebuild I have done with my
friend's help was the top end rebuild after I blew the piston ring and had to send it out to CA for porting, etc.
Now that I have some garage space and time to work on my RZ, I'd like to get it done and gently begin to ride.
My area is getting nice weather each day, and it will be nice to get some fresh air on weekends riding my RZ.
Again, thanks for your support and guidance.

[Whymee]

IF there are no visible leaks on the outside, leave it alone.
IF your transmission fluid is not contaminated, (milky looking) leave it alone.
IF you start the machine, unscrew the radiator cap and see the fluid moving as it should, leave it alone.

Edit: Now, if you still feel the urge to rebuild the water pump, and I get it, you already have the parts, be sure to replace both bearings, seal, and o-ring & gasket. New seals and new bearings let me sleep at night.

[myrz350jp]

Dear Whymee,
Thanks for your suggestion.
I got the compression tester today so I'll put back on my kick starter this weekend and test the compression.
I'll decide on what to do after the test result. If I just need to change the head gasket without having to do the water pump rebuild,
that would be fine by me. I just wan to ride safely, without worrying about her mechanical breakdown.
She sat for few years, but I had the fluids in. Anyways, I'm ready to get her fixed up so I can safely ride her once again.
I understand that you think t's better to leave it alone if not broken.

[myrz350jp]

Thank you all for going easy on this novice RZ lover.
I finally managed to run compression test and it's right around 100 on both cylinders, but not 110...
I'll go buy coolant this weekend and drain it to open and replace the head gasket alone.
Slow work in progress to get my RZ back up and running in safe condition again.
I'll update again soon.

[Evans Ward]

Don’t cheap out- purchase a new OEM Yamaha head gasket. That is your best option there.