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TOPIC: no compression

no compression 29 Jul 2020 10:02 #831805

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Well, if you have spark then it's either fuel or air.
But strange that you were not able to get the engine to fire with starting fluid.
81-KZ440-D2. Louis Dudzik's GM HEI ignition module converted 2015--no issues, Motogadget m-unit blue.

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no compression 29 Jul 2020 18:27 #831838

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Would that mean that I need to service my valves,cause that's the only thing I can think of that would keep it from starting. And all this happened after I let my buddy ride it to try and clear the (what we thought)was a dirty injector. I even took out the plugs and pug my hand over the cylinder and cranked it as and it was building pressure.

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no compression 29 Jul 2020 21:16 #831848

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I would do a compression test first before you take anything apart. See if you can borrow a compression gauge kit. Autozone has them to rent if you're in the u.s.

Did the bike run ok after your friend rode it?
81-KZ440-D2. Louis Dudzik's GM HEI ignition module converted 2015--no issues, Motogadget m-unit blue.

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Last edit: by F64.

no compression 30 Jul 2020 06:15 #831856

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Also, perform a leak down test. That will identify where the compression is leaking out (valve, rings, etc.) Ed
1977 KZ650-C1 Original Owner - Stock (with additional invisible FIAMM horn)

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Last edit: by 650ed.

no compression 01 Aug 2020 14:48 #832042

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I got a compression test the test on a cold engine cylinder #4 was at 33psi #3was at 10psi #2 was at 20 psi #1was@35 psi when I poured some marvel down and performed the test again it went up to 101.psi , my question is should I just look at a motor swap or rebuild the old one?

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no compression 02 Aug 2020 10:24 #832103

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Machete1Z1000 wrote: I got a compression test the test on a cold engine cylinder #4 was at 33psi #3was at 10psi #2 was at 20 psi #1was@35 psi when I poured some marvel down and performed the test again it went up to 101.psi , my question is should I just look at a motor swap or rebuild the old one?

I’m not an expert but maybe there’s a possibility that you have you head gasket blown between 2/3 and your loosing compression between them two, maybe try next time to plug the opposite of the one you check between those two inner ones and see if it changes, do not add oil so the compression is correct and not sealed by the oil. Because your injected make sure your pump is running as well and the injector is also being powered. Let us know my friend
Ricco

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no compression 02 Aug 2020 19:21 #832129

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Wow! That's low for compression.
Did your friend redline the engine when trying to clean out the injectors?
81-KZ440-D2. Louis Dudzik's GM HEI ignition module converted 2015--no issues, Motogadget m-unit blue.

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no compression 03 Aug 2020 16:01 #832172

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I dont know what he did , I know it was late and I had to be at work in the morning so I let him take it out ,I walked out side, right as he was cutting the engine off ,with him telling me that ,that didn't fix anything so I just rolled to the porch and when I tried to start it the next day was when it wouldn't even cough, even with a spray of carb cleaner. I am for sure going to ask him tho.

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no compression 03 Aug 2020 16:12 #832174

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Ok so before I seen your posting checked the cylinders again this time leaving the other plugs in and got about 77 psi in all four. The head gasket sounds like a possible winner because before when it was running I was trying to inquire on another forum about the normal running temp for this bike and nobody either knew or just didn't care to answer me cause it got up to about 214 degrees and then I'm sure when my buddy tried to clean out the injectors he ran pretty hot. Wouldn't there be water in the oil then ,? Cause I just recently put new oil in it and the old stuff looked fine.

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no compression 03 Aug 2020 16:57 #832177

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How is your coolant level in your radiator?

There wouldn't necessarily be antifreeze in the oil. It depends on where the break would be in the head gasket.
You should do a leak down test or hook up an air supply to a compression tester hose.
Set your air compressor regulator to 80 psi
The cylinder you are testing must be at TDC as both valves need to be closed.
Use a ratchet to turn the crankshaft. Just in case you forget to take the wrench off of the crankshaft and the engine spins because of the air pressure--you won't get wacked by the wrench.
Screw the compression hose into the cylinder you are testing.
Hook up the compression testing hose to the air hose(hopefully they have the same air fitting.
Listen to where the air is escaping. Muffler, intake,airbox, oil fill cap, radiator, other cylinder spark plug hole.
You can use a small rubber hose put up to your ear to hear in difficult to reach areas. Just use caution as you don't want a blast of air hitting your eardrum.
If you have a leak down tester that would be good, but it's not necessary to find where the leak may be.

It's not the temp that kills your head gasket at 214 degrees. It's the air bubbles and steam pockets. If your radiator cap is not holding pressure in the cooling system, then your system will boil at a lower temp. Anywhere from 212 degrees to 223(with 50/50 mix antifreeze water). If bubbles form because of boiling, the area where the bubble is will not cool. Coolant needs to be in contact with the metal to cool properly. This is why your cooling system is pressurized ..to raise the boiling point of your coolant(yours is pressurized to 18psi raising your boiling temp to 250 for straight water). . C&R racing's nascar cooling systems run water's boiling point up to 290 degrees. It's all about pressure.

You also have to purge the air out of your cooling system if you drain then refill your coolant.

So 214 is ok. Unless you have air in your cooling system.
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Last edit: by F64.

no compression 03 Aug 2020 23:39 #832190

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You are the man my friend! Thank you very much ,for sharing that little bif of experience and knowledge with me it just saved me from having to take my bike to a shop and having them charge me. Im pretty close to just dropping it off at a shop and spending th ed money to have someone else do it, instead of me sweating my ass off out in the nice AZ Weather right now. 114 today and was 118 the day before.

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no compression 04 Aug 2020 00:39 #832191

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I wish you luck.
Hopefully, it's something minor.
81-KZ440-D2. Louis Dudzik's GM HEI ignition module converted 2015--no issues, Motogadget m-unit blue.

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