KDXRIDER.NET

Chuck78 wrote: 04:53 pm Sep 22 2023 How do you have the mityvac hooked up?
Did you perhaps test the gauge itself, with a length of tubing plugged off on the end?

Post a photo of your gauge hookup, as I'm curious for my own testing purposes in the future.

I got a small pressure/vacuum gauge and 1/8 NPT threaded shraeder valve (tire valve) to make a 35mm intake pressure/vacuum testing adapter in conjunction with a rubber plumbing/freezeplug type expanding pipe plug in the exhaust. I could replace a coolant hose with a section of hose with a test tee perhaps, & use the same gauge setup minus the carb intake spigot adapter.

Have you tested your E-Series in this same way? Those bikes are the ones prone to overheating, not the H-series...

What grit of abrasive sheet did you use to true up the head and cylinder deck surfaces???

Best of luck, friend.

JimmyB wrote: 07:41 pm Sep 22 2023 Might be worth trying(I know it is frowned upon) but might help for pressure testing for a head gasket leak and a brief test ride, coat both sides of the head gasket(even a used one) with a thin coat of some crankcase sealant or Permatex PermaShield # 85420, let it set up for 24hrs before trying anything.
I would be tempted to make up a plate( alloy or even plexiglass would work,you might be able to see the leak) in place of the head and pressure test both the cylinder and head separately to see if there might be a casting flaw, but I think I recall you might have tried replacing one or the other(maybe even both) and still have the same results??

There is a product you can use to find if it is combustion gases in the coolant.


Sorry to see you are having so much trouble with this bike.. :(

Chuck78 wrote: 04:53 pm Sep 22 2023 How do you have the mityvac hooked up?
Did you perhaps test the gauge itself, with a length of tubing plugged off on the end?

Post a photo of your gauge hookup, as I'm curious for my own testing purposes in the future.

I got a small pressure/vacuum gauge and 1/8 NPT threaded shraeder valve (tire valve) to make a 35mm intake pressure/vacuum testing adapter in conjunction with a rubber plumbing/freezeplug type expanding pipe plug in the exhaust. I could replace a coolant hose with a section of hose with a test tee perhaps, & use the same gauge setup minus the carb intake spigot adapter.

Have you tested your E-Series in this same way? Those bikes are the ones prone to overheating, not the H-series...

What grit of abrasive sheet did you use to true up the head and cylinder deck surfaces???

Best of luck, friend.

JZ05220r wrote: 09:26 pm Sep 23 2023
Here’s your pictures. They are compression nut fittings.

Chuck78 wrote: 06:12 am Sep 25 2023

JZ05220r wrote: 09:26 pm Sep 23 2023
Here’s your pictures. They are compression nut fittings.

Ahhh.... I see! You've got a special test port radiator cap... I wasn't interested in the mity vac hose fittings, I thought perhaps you spliced in a test tee in place of one of the KDX coolant hoses...

Is that a Mity Vac motorcycle specific radiator cap test fitting? That would be useful to have....

Chuck78 wrote: 12:15 pm Sep 25 2023 Also, I just had another thought. Looking at base gaskets and used KDX cylinders on eBay, you could potentially leave the head attached to the cylinder as is without touching it, remove the cylinder from the engine after disconnecting the power valve linkage pressure test the cylinder / head / head gasket off of the bike with water or coolant to look for any wet spots of coolant / water indicating any leakage. That would tell you exactly where your problem is. You could also just air test it and use dish soap water or some other type of soapy solution in a spray bottle to spray down all areas involved and watch for bubbling like you do when testing natural gas or propane piping, tires and inner tubes, etc.

You could use a barbed tee hose fitting and a length of heater hose from the auto parts store with a couple of clamps and test it completely off of the bike. Then you could see where any water is trickling out or soap bubbles are forming. I definitely would use a liquid with some coloration to it.
Then depending on what you find, I would most likely go through the process of removing the head studs and resurfacing the cylinder head gasket surface as well as checking the head again. Also, checking the head stud threads.

Sorry you're having to suffer through all of this, but this is a learning experience for many of us watching you go at it, as well as our thought processes giving us New perspectives and potential troubleshooting procedures for our own future use or helping others out.
At least you have a good running E-Series! The 220's are my favorite KDX by far though, with the '86-'88 air-cooled power valve engines my second favorite.

JZ05220r wrote: 02:50 pm Sep 25 2023

Chuck78 wrote: 12:15 pm Sep 25 2023 Also, I just had another thought. Looking at base gaskets and used KDX cylinders on eBay, you could potentially leave the head attached to the cylinder as is without touching it, remove the cylinder from the engine after disconnecting the power valve linkage pressure test the cylinder / head / head gasket off of the bike with water or coolant to look for any wet spots of coolant / water indicating any leakage. That would tell you exactly where your problem is. You could also just air test it and use dish soap water or some other type of soapy solution in a spray bottle to spray down all areas involved and watch for bubbling like you do when testing natural gas or propane piping, tires and inner tubes, etc.

You could use a barbed tee hose fitting and a length of heater hose from the auto parts store with a couple of clamps and test it completely off of the bike. Then you could see where any water is trickling out or soap bubbles are forming. I definitely would use a liquid with some coloration to it.
Then depending on what you find, I would most likely go through the process of removing the head studs and resurfacing the cylinder head gasket surface as well as checking the head again. Also, checking the head stud threads.

Sorry you're having to suffer through all of this, but this is a learning experience for many of us watching you go at it, as well as our thought processes giving us New perspectives and potential troubleshooting procedures for our own future use or helping others out.
At least you have a good running E-Series! The 220's are my favorite KDX by far though, with the '86-'88 air-cooled power valve engines my second favorite.

Those are great ideas, I may try that, I have got one more headgasket I’m willing to put on the line. I love the idea of testing the cylinder off the bike. I could test the water pump seal in a similar manner as well. But no coolant in transmission oil anyways. Thanks

Chuck78 wrote: 09:30 am Oct 24 2023

JZ05220r wrote: 02:50 pm Sep 25 2023

Chuck78 wrote: 12:15 pm Sep 25 2023 Also, I just had another thought. Looking at base gaskets and used KDX cylinders on eBay, you could potentially leave the head attached to the cylinder as is without touching it, remove the cylinder from the engine after disconnecting the power valve linkage pressure test the cylinder / head / head gasket off of the bike with water or coolant to look for any wet spots of coolant / water indicating any leakage. That would tell you exactly where your problem is. You could also just air test it and use dish soap water or some other type of soapy solution in a spray bottle to spray down all areas involved and watch for bubbling like you do when testing natural gas or propane piping, tires and inner tubes, etc.

You could use a barbed tee hose fitting and a length of heater hose from the auto parts store with a couple of clamps and test it completely off of the bike. Then you could see where any water is trickling out or soap bubbles are forming. I definitely would use a liquid with some coloration to it.
Then depending on what you find, I would most likely go through the process of removing the head studs and resurfacing the cylinder head gasket surface as well as checking the head again. Also, checking the head stud threads.

Sorry you're having to suffer through all of this, but this is a learning experience for many of us watching you go at it, as well as our thought processes giving us New perspectives and potential troubleshooting procedures for our own future use or helping others out.
At least you have a good running E-Series! The 220's are my favorite KDX by far though, with the '86-'88 air-cooled power valve engines my second favorite.

Those are great ideas, I may try that, I have got one more headgasket I’m willing to put on the line. I love the idea of testing the cylinder off the bike. I could test the water pump seal in a similar manner as well. But no coolant in transmission oil anyways. Thanks

James - which one of the Mity Vac "small bayonet" radiator cap pressure test adapters fit our radiators? There's the MVA351 & the MVA352 (shallow). The 351 I might guess?????

kdxdazz wrote: 07:57 pm Nov 28 2023 did you end up solving this issue?