My Second $500 K75 Project

[Smudgemo]

So I need another bike like another hole in the head, but when is enough ever enough?

I just happened to see the CL post one day, and it just happened to be a couple of miles away, so I went to look.

Seller stated: K75 Was running nicely until about a year ago. Turns over but won't start. Best theory of an non professional is this: Began to overheat determined that a seal on the water pump was bad (coolant in the oil), the seal was replaced and it ran again but poorly. More coolant in the oil and then it wouldn't run again. Best guess was the head-casket went bad during the orginal overheating.

Don't have the time or skills to attempt a fix. Lots of nice parts. Oher than the major engine issue it is in good shape. The seat and cases are probably worth the price of admission.

So the seat is a Corbin and appears to be in okay shape for the amount of time it probably sat outside uncovered, and the plastics (not all shown) at first glance are okay, but I don't think the cases are original because design and different key (school me if I'm wrong.)

Anyhow, first order of business is to remove the plastic, drain the tank and start poking around the oil/coolant pump to see what clues I can find.  Seller's son apparently bought it from a friend less than two years ago, and rode it all of about 40 miles before it crapped out.  Probably lucky for him.  The tires are nearly 25 years old and I noticed a large sidewall crack on the front when looking for the date code.

The plan so far is get it running properly, and then decide.  Either I go through things fully and make it really nice, or I just do enough to make it a safe and reliable beater.  Knowing me, I'll probably take it too far.  I usually do.

Oh, and props to Uhaul and their $30 moto trailer rentals.  Complete enablers in this hobby we have.

[Edward]

Try a new seal between the water and oil. The last attempt might have damaged it. Keep in mind that a little weeping from the drain hole is common after replacement until seating occurs with running and the subsequent heat. Be sure to flush the system well. Oil tends to cling to the sidewalls of the coolant pipes. If you get carried away, Samco makes a nice set.

[Laitch]

Anyhow, first order of business is to remove the plastic, drain the tank and start poking around the oil/coolant pump to see what clues I can find.

Do a compression test. Probe into the pump weep hole to verify it isn't clogged.

[Smudgemo]

I'm also going to dig out my handmade leak-down gauge and check the thermostat to see if it's stuck closed. 

Just sitting on it, I like not having my knees hitting the RT's fairing, that's for sure.

[Edward]

EME coolant caps are now in stock. Yeah, the thermostats tend to go bad over time. If you end up getting a coolant cap, you might as well get new rubber supports for the radiator; they are inexpensive. Test your fan as well—most likely, it's fine.

[TriSpark]

Nice score ! I would do exactly the same even though I don't need another bike to go with the 5 I already own.....but, No Brick Left Behind is our motto, right?

I'm sure you can get it running again and enjoy some riding time on it. It looks good, maybe just a bit neglected. How many miles on the clock?

Also a thumbs up from me for U Haul and their cheap to rent bike trailers, I've used them many times to pick up my next money pit around here.

[Smudgemo]

Mileage is 32k, the battery is supposed to be newish (PO maybe bought it?  who knows..), but the tank dent is a bummer.  I might try a paintless outfit just to at least make it nicer looking.  The old tires suggest it wasn't used much before the PO got it.

I pulled the fuel filler cap and I can see rust down low, so I'm going to clean it out and look for damage.  Maybe the filter is clogged and the coolant wasn't the problem.  That would be funny.

Then I figure I'll drain some oil as it's at the top of the site glass to see if there is coolant present.  That will make me feel better about turning it over to look for spark and checking compression.

After that I'll dig into the water pump and see what sort of mechanic the PO was.

[Edward]

look in the coolant reserve bottle for oil. If none most likely it's fine. Do tend to the weep hole. Use a wire to remove crude. Easey to do before opening if need be.

[TriSpark]

Nice one, 32K is barely run in, as you know. Rust in the tank is either the fuel pump/filter collapsing or the base of the fuel level sender, not the aluminum tank itself, so given the age of it maybe the fuel pump is the culprit of the non-starting. Wouldn't be the first time.......

Looking forward to hearing what happens next.

[Smudgemo]

The pump and filter looked quite good, but I don't recall how the sender looked.  Maybe someone replaced the parts w/o a proper clean-out.  Some people are lazy.

Yesterday I ran a bit of brazing rod up in the weep hole and a couple-three drops came out.  Dumped the overflow tank into a jar and the coolant is very blue and has lots of particles slowly settling (bottom of the tank has white-ish gunk to be cleaned out which is what the particles are, I think.) 

There doesn't appear to be any oil as I'd expect it to be floating on top.  I did get a gallon jug of parts store anti-freeze that isn't very old in the sale, and it is down just about the amount I have in the jar.  There are also some used parts that suggest a pump seal kit was installed.

Makes me wonder if the overflow bottle was empty and it was the only thing that got refilled.  The whole system takes less than a gallon, so I would expect most of the bottle to be used up unless the old stuff was dumped back in after the pump was worked on.  Not sure why anyone would do that, though.

Puzzles are fun, aren't they?  I'm dying to dig into this project, but there's too much work to do the next few days.  And I have to get over to DMV for the title process - worst part IMO..

[Edward]

The rust color might be, and probably is, old ethanol resin from sitting. There should be a bit of gel near the pump screen. Good news about the coolant so far. Oil would float. Run distilled water before or after your coolant additions. The white blobs are probably oxidized aluminum bits. The weep hole is clear, so that's good. A little fluid is expected if the seal hasn't been broken in yet, as suspected.

[Smudgemo]

I noticed there has been a little bit more dripped from the weep hole since yesterday. 

I gave the coolant hose that runs through the crankcase cover some squeezes and I didn't hear anything that would suggest there was coolant in there, which would explain why the jug of coolant was still 2/3 or more full.  So I pulled the hose at the pump and got 10-12oz of pale coolant with some crud, a stale smell and a bit of oil.  For comparison, I got about 16oz from the overflow tank so I don't think the PO bothered to refill the system, or just thought he did.  Does the pump burn up when lacking coolant?  Might be good that it didn't run for him. 

I just did the actual math - the title says 32,068 and the odo shows 32,086, so the PO got all of 18 miles of riding before things shut down.  What a bummer.  For him.

[Edward]

I'm not sure if the pump would be affected since it's at the bottom of the system. Have you taken the tank off to uncap the system? When squeezing the larger coolant hose, if it is filled even somewhat, the fluid would rise to the edge of the coolant spout. Even when full, it's hard to tell if there is fluid in there by squeezing hoses, so seeing it helps. In the end, you'll see what is what when you undo the coolant drain plug. Keep in mind that the oil you may see might be residual oil from the prior leak of the seal. Oil is a real bugger to flush since it coats surfaces and likes to stay there. For me, I said "F that" and ordered Samco hoses. Given that it's an '87, new hoses were due anyway.That drip will continue if it's a seal that's not bedded in. Don't worry about that for the time being. By the way, the coolant reservoir's black container is an expansion chamber. The level should be just above the minimum marking. When riding, if the system is problematic, you'll know when hot coolant soaks the back of your thigh—ouch. Usually, that happens when the valve malfunctions and also the cap. If it's an original cap, just get a new one and be done with it.

[Smudgemo]

I drained about 8oz of oil and it does look like there is a bit of coolant or something in the bottom of the jar.  The bike is on a very slight incline so having drained oil from the top of the site glass circle to a little below center, hopefully that's most of anything unwanted.  I'm getting spark on all three cylinders and even tried the old plugs from my other brick, but it just turns over.  At least it turns over nicely. 

Compression and the fuel delivery next.  Maybe compression first because it's fast and I'd like to know why the seller mentioned a head gasket in the ad.  Hopefully clueless instead of coy?

On the plus side, I was led to believe the bags were on a different key.  Turns out I got two folding keys and one regular and they fit all the locks (though two bag locks are missing), so yay!  I also got in and out of the DMV fast (!) for only $59 for non-op when the online calculator primed me for a $390 hit, so shout-out to the PO for not letting the reg expire. 

The only hiccup was the DMV guy spelled my name on the title with an n instead of m.  Upon noticing at home (of course) the DMV chat person said I could get it fixed only in the office and once the title arrives by mail, so I typed "thank you" but was actually thinking "No thank you."  Close enough. 

[Laitch]