Author Topic: HELP! 1990 K75 engine trouble (Read 14388 times)

achtung3 · « **on:** November 16, 2016, 04:10:53 PM »

I just checked my compression (if I done it right) I got 115psi, 30psi and 110psi. from the left-front of the bike to the right-rear of the bike.
I stuck the probe on the spark plug hole and cranked the engine and got these readings, I let the engine crank for a few turns maybe 6-8 and read the gauge, if this is not how you do it please someone tell me.

I am trying to figure out if I have a blown head gasket because I am getting some oil in the radiator.

A friend told me that I should ckeck for compression and see if is ok and if it is must be the water/oil pump shaft that has rust and it may be having oil transfer from there.

Now that I checked the compression it seem that something is not looking good.

I need some advice on what to do now.

Thanks.

F14CRAZY · « **Reply #1 on:** November 16, 2016, 05:21:18 PM »

Sounds like it could be a head gasket but I haven't really heard of K head gaskets going bad.

I don't think it's the oil/water pump. Although the pumps run on the same shaft, the water side and the oil side both have their own seals and are separated by an air gap. You would have oil and/or coolant dripping from the weep hole under the pump if they were leaking.

Was the bike recently running fine?

Chaos · « **Reply #2 on:** November 16, 2016, 05:47:47 PM »

Leak down test would be the next step. Odd, usually 2 cylinders read low when the gasket blows between them.

D.Bachtel · « **Reply #3 on:** November 16, 2016, 05:48:11 PM »

I would check the valve adjustments and then perform a leakdown test.

Don in Nipomo

K1300S · « **Reply #4 on:** November 16, 2016, 06:15:11 PM »

wait...you "STUCK" the probe on the hole? is is supposed to be screwed snugly into the spark plug threads.

have you done a search on the correct procedure to do a compression test? throttle open wide? engine warm or cold? spark plugs grounded when you ran the test?

i would recheck your process and do it again.

Chaos · « **Reply #5 on:** November 16, 2016, 06:22:48 PM »

some compression testers just have a rubber plug you hold in the hole. Burnt valve is a possibility, but the oil in the radiator points to the head gasket.

Laitch · « **Reply #6 on:** November 16, 2016, 06:27:46 PM »

Quote from: achtung3 on November 16, 2016, 04:10:53 PM

I am trying to figure out if I have a blown head gasket because I am getting some oil in the radiator.

You wrote about this same concern back in July. Coolant in the reservoir was "grey." You were wondering then if you had a blown head gasket. You were given a few suggestions to consider back then. You didn't follow up that thread. How many miles have you ridden the bike since July when the oil problem first showed up?

achtung3 · « **Reply #7 on:** November 17, 2016, 04:19:25 PM »

I was getting conflicting information from friends and acquaintances, and finally took to a mechanic and somehow he did not due a compression test and told me that I had a blown gasket by just doing a visual, so I was a bit puzzled because all I hear is water pump/oil pump.

I decided to do a compression test by suggestions, and this were I am now.

Engine was cold when I did the compression test, I bought this compression test kit and yes I could have screwed in the tube but I thought that by holding the metal tube with the rubber fitting at end was easier and this is why I did it.

I have no water in the oil but oil in the radiator, and foam in the reservoir.

kennybobby · « **Reply #8 on:** November 17, 2016, 04:43:58 PM »

Since you had that strange reading for #2, i would suggest to repeat the test with both a cold and warm engine using the screw fittings instead of trying to hold the gauge in place, just to rule out that as a possible error and get a consistent reading.

But oil in the coolant... does the coolant reservoir get pressurized during engine operation and overflow the tank?

BAMBAM1039 · « **Reply #9 on:** November 17, 2016, 04:49:20 PM »

also comp tests are done with the throttle wide open so there is no blockage in the intake side and a correct reading results goodluck

Laitch · « **Reply #10 on:** November 17, 2016, 04:56:25 PM »

Quote from: achtung3 on November 17, 2016, 04:19:25 PM

. . . all I hear is water pump/oil pump. . . .

Were you hearing that from people who own K-bikes? Are you waiting for everyone you talk to—friends, acquaintances, mechanics—to be in agreement before you do anything?

You wrote in your July 21 post your trusted BMW mechanic told you that the pump weep hole was "bone dry" and the only other cause was probably a head gasket problem. Did you quit trusting him because your friends and acquaintances know more than he? If so, why don't you have them fix it for you?

Have you been riding that bike since July?

Did your compression testing kit come with instructions and you followed the instructions? You should redo the test using standard procedures and safeguards to eliminate the possibility that you lost your grip during the test of one of the cylinders.

Here's another thing you can do. Take the bike somewhere that can perform a gas analysis of the coolant in the radiator. It's a quick test.

Martin · « **Reply #11 on:** November 17, 2016, 08:51:56 PM »

Make sure you earth the plug leads whilst doing the compression test otherwise it could blow the ignition module.
Regards Martin.

achtung3 · « **Reply #12 on:** November 18, 2016, 10:53:40 AM »

Thanks for all the support.

Laitch, No I did not ride since July, I only flushed and cleaned the radiator.
I did not stop trusting my mechanic he asked me to take to another mechanic (where I had taken to, and only did a visual) because he has stopped doing motorcycle mechanical works and he has changed his shop to specialize on suspensions only.
Well! regarding the compression test instruction, I had a little problem understanding the instructions and I just went on youtube and followed the basics- stick the tube on the spark plug hole and read the numbers- did it cold.
My next step I will take to somewhere as you recommended to have a gas analysis, I will need to truck it.

Martin- What do you mean by earth the plug lead? I don't know what this means and how to.

Laitch · « **Reply #13 on:** November 18, 2016, 11:10:25 AM »

Quote from: achtung3 on November 18, 2016, 10:53:40 AM

What do you mean by earth the plug lead? I don't know what this means and how to.

It's another word meaning "spark plug wire"—the wire that goes from the coil to the spark plug.

Thanks for the clarification about your trusted mechanic. It's always nice to have enough information to get a clear picture of what's going on.

thecableguy · « **Reply #14 on:** November 18, 2016, 11:39:00 AM »

Just to clarify further, "Earth" the plug lead means to not just disconnect the plug wire, let it dangle, and crank the engine. You need to either use a spark tester or reconnect the spark plug to the wire and ground the plug body to the frame somewhere. The electricity for the spark needs somewhere to go so as not to damage the ignition module.

Jim

Martin · « **Reply #15 on:** November 18, 2016, 01:49:26 PM »

I made up a harness, made of heavy gauge wire. Crimped and soldered a tubular wire connector to one end of the wire with 4mm bolt with the head cut off inserted and soldered into the other end of the connector. Cover the connector with a piece of heat shrink with enough of the bolt thread exposed to take a spark plug nut. If your bike is fitted with spark plug wires that require spark plug nuts, acquire four old nuts from discarded spark plugs. Do this four times then insert the other end of the four wires into a wire clamp and solder. You now should have a harness that does 2, 3 and 4 cylinder engines with or without spark plug nuts. If you make 2 harnesses you can do 5, 6 and 8 cylinder engines.
Regards Martin.

achtung3 · « **Reply #16 on:** November 19, 2016, 01:45:31 AM »

Ok! Did I messed up my ignition?

Martin, thanks for this photo, I can make one up for the bike.

Martin · « **Reply #17 on:** November 19, 2016, 02:05:15 AM »

Place the lead with a spark plug attached against an earth on the frame or engine, crank it over if you have spark you have no damage.
Regards Martin.

TX brick · « **Reply #18 on:** November 20, 2016, 07:28:10 AM »

When I had oil in the coolant the weep hole was dry. When I took the pump apart, I found that pieces of the old oil seal had plugged the weep hole and the cavity was full of oil.

kris · « **Reply #19 on:** November 20, 2016, 08:50:27 AM »

achtung3, you may see "earth" referred to as "ground" in other readings....just so you are not confused by this in the future. I'm not sure what language the instructions for the compression testing tool was in but you'd always want to be sure about these things when working on your beloved Brick!

Laitch · « **Reply #20 on:** November 20, 2016, 08:58:48 AM »

Quote from: TX brick on November 20, 2016, 07:28:10 AM

When I had oil in the coolant the weep hole was dry. When I took the pump apart, I found that pieces of the old oil seal had plugged the weep hole and the cavity was full of oil.

This is a useful observation, TXbrick. Thanks for posting it.

stokester · « **Reply #21 on:** November 20, 2016, 09:24:29 AM »

Quote from: Chaos on November 16, 2016, 05:47:47 PM

Leak down test would be the next step. Odd, usually 2 cylinders read low when the gasket blows between them.

:2thumbup: on the leak-down test

Not only will it indicate a compression leak, it will help identify the cause.

Vespa no more · « **Reply #22 on:** November 21, 2016, 04:17:28 AM »

Laitch: Librarian or Rottweilller

I am frequently amazed at two things:

Your accurate powers of cross-referencing and recall. Were you ever a librarian?

Your (occasional) intolerance of newbies. Where's that paper bag? Mind you, you cut through the shit and the issue gets sorted. Were you ever a Deputy Principal?

We've all been there

Laitch · « **Reply #23 on:** November 21, 2016, 06:57:36 AM »

Treacle. :giggles

I was boss of a jail labor crew in rural Florida for a while. That's where I learned patience. :giggles

achtung3 · « **Reply #24 on:** November 22, 2016, 03:14:57 PM »

Great help.

I am going on the offensive in a week due to work schedule.

Thanks for the info about the weep hole being blocked, because on my bike it is bone dry and I don't think the mechanic removed the cover for the (oil/H2O) pump.

News:

Author Topic: HELP! 1990 K75 engine trouble (Read 14388 times)