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Jeff Fredette told me he lapped the cases and obviously he replaced the crank bearings and seals so I just can’t fathom this being a crank seal/transmission fluid consumption issue though it just sounds like it to me. I’m coming to a stop on the trails and the smoke cloud will just surround me. Not an insane amount of smoke but I can assure you all that it is excessive.

JZ05220r wrote: 10:25 pm Sep 07 2023 Jeff Fredette told me he lapped the cases and obviously he replaced the crank bearings and seals so I just can’t fathom this being a crank seal/transmission fluid consumption issue though it just sounds like it to me. I’m coming to a stop on the trails and the smoke cloud will just surround me. Not an insane amount of smoke but I can assure you all that it is excessive.

that was the same with me when i ran the cek needle, i would ride through the city and people would cover their mouth when i stopped at traffic lights, it was so embarrassing

kdxdazz wrote: 04:38 am Sep 08 2023

JZ05220r wrote: 10:25 pm Sep 07 2023 ...coming to a stop on the trails and the smoke cloud will just surround me. Not an insane amount of smoke but I can assure you all that it is excessive.

that was the same with me when i ran the cek needle, i would ride through the city and people would cover their mouth when i stopped at traffic lights, it was so embarrassing

Oh my... We just ordered a DEL needle for my buddy's 200. I was trying to keep it a bit more mellow of ahit. Stock slide. Hoping to get it nicely jetted for 40:1.

James, did you change the type of premix oil or gasoline that you run any whatsoever? Did you mix up fresh gas? Or is the same gas that's been sitting in the tank for a while? Or just old gas that you just premixed?
Just trying to cover all bases here.

Chuck78 wrote: 05:13 pm Sep 08 2023

kdxdazz wrote: 04:38 am Sep 08 2023

JZ05220r wrote: 10:25 pm Sep 07 2023 ...coming to a stop on the trails and the smoke cloud will just surround me. Not an insane amount of smoke but I can assure you all that it is excessive.

that was the same with me when i ran the cek needle, i would ride through the city and people would cover their mouth when i stopped at traffic lights, it was so embarrassing

Oh my... We just ordered a DEL needle for my buddy's 200. I was trying to keep it a bit more mellow of ahit. Stock slide. Hoping to get it nicely jetted for 40:1.

James, did you change the type of premix oil or gasoline that you run any whatsoever? Did you mix up fresh gas? Or is the same gas that's been sitting in the tank for a while? Or just old gas that you just premixed?
Just trying to cover all bases here.

Yes I mixed fresh gas, however I just found that I have a head gasket leak again, with the new cylinder and the rb head. If you can recall I had a head gasket leak with the old cylinder and stock cylinder head that I could never really get rid of. Now I’m at a loss as the new cylinder was resurfaced and the cylinder head was from Ron wasn’t ridden with more than 20 hours. I’m running engine ice, not sure what color that would smoke compared to conventional coolant. Hopefully the coolant getting in didn’t do any harm to the cylinder or rings.

As soon as I started it up the bubbles and coolant level came to the top of the filler and when I turned the bike off it dropped right away.

Called engine builder Ken O’Connor this morning. He told me to try the following: 1. Use 220 grit on a perfectly flat piece of material. I used a surfacing stone I purchased a few weeks ago and kept going. There was a low spot toward the exhaust side of the cylinder head crossing over the two weirdly shaped water ports. I kept sanding till the spot disappeared. I included a picture of where the low spot was using my stock head as an example. Ignore the point on the arrow. All above the contour of the curved was where the low spot was.

2. Make sure the retaining pins were shortened to compensate for the RB head. I already shortened them but went a bit more.

3. Permatex Copper spray a gasket on an oem headgasket. I sprayed both sides of the new oem head gasket and let sit for a half hour then installed. I prepped the surfaces with carb cleaner and then used rubbing alcohol and blew dry. I used my 1/4 torque wrench and worked up in increments of 2 foot pounds all the way up to 16 ft pounds. I then finished off with my electronic torque wrench set 18. I ended up torquing them to 20 ft pounds due to the nature of the electronic wrench.

Noticed my cylinder already has markings on it that I could not feel with my finger. My old cylinder ended up with the same markings. I’m thinking it’s the coating on the wossner piston.

I hope it works.

It didn’t work

your cylinder has some serious pitting around the top edge of the cylinder bore, is that cylinder the original nikasil coating or has it been redone at some point?
you may have to take the cylinder off and try the same sanding technique but its unlikely you will remove all that pitting in which case a sleeve is your option. one of the reasons i went with a sleeve is they mill the top surface so you know its dead flat, i struggled for 6 months trying to solve head gasket issues so i'm well versed in this, did you get the pin shortening idea from my youtube channel?
as you remove the cylinder head each time take photos of the cylinder and cylinder head surface, you should see oil leaking past the head gasket
i also tried permatex but think its a useless messy product, threebond 1211 is better
the OEM gaskets come from the factory with a sealant thats why you can't touch the surface before you put it on, you can use mineral spirits and scotch bright to remove all the old sealant so you can reuse the OEM head gasket

forgot to say if you can't get the pits out then a custom made copper head gasket might be an option, i got mine laser cut from 0.8mm copper, granted i am in thailand where costs are cheaper, cost me 18 US dollars

Wow James... I can't believe the issues with compression leaks into the coolant system that you're having perpetually, and with multiple cylinders and heads, correct?

That seems quite odd...

When I get my bike back together, I'll have to give it some revs with the radiator cap off to see how much the water pump will cause the radiator level to rise... Have you considered that some of this could be normal and perhaps not a compression leak????

kdxdazz wrote: 04:13 am Sep 10 2023 your cylinder has some serious pitting around the top edge of the cylinder bore, is that cylinder the original nikasil coating or has it been redone at some point?
you may have to take the cylinder off and try the same sanding technique but its unlikely you will remove all that pitting in which case a sleeve is your option. one of the reasons i went with a sleeve is they mill the top surface so you know its dead flat, i struggled for 6 months trying to solve head gasket issues so i'm well versed in this, did you get the pin shortening idea from my youtube channel?
as you remove the cylinder head each time take photos of the cylinder and cylinder head surface, you should see oil leaking past the head gasket
i also tried permatex but think its a useless messy product, threebond 1211 is better
the OEM gaskets come from the factory with a sealant thats why you can't touch the surface before you put it on, you can use mineral spirits and scotch bright to remove all the old sealant so you can reuse the OEM head gasket

So I initially got the pin shortening idea from Ron at RB designs. Then was reminded of it by Ken as a possible reason for the headgasket leak. The sleeve seems like a good fail safe way to get the head gasket to seal. Unfortunately I wasn’t able to find a cylinder in better shape then the one with all of the pitting. I have watched many of your YouTube videos in the past and they are very informative.

Chuck78 wrote: 10:40 am Sep 10 2023 Wow James... I can't believe the issues with compression leaks into the coolant system that you're having perpetually, and with multiple cylinders and heads, correct?

That seems quite odd...

When I get my bike back together, I'll have to give it some revs with the radiator cap off to see how much the water pump will cause the radiator level to rise... Have you considered that some of this could be normal and perhaps not a compression leak????

Me too. I did consider that as a possibility, yet the bubbles were minimized after going through the motions with the resurfacing and copper coated headgasket so that tells me it is still leaking. Video of leak. https://youtube.com/shorts/F_wm-t9-nkM? ... Ka8OFSDlzu

Chuck78 wrote: 10:40 am Sep 10 2023 Wow James... I can't believe the issues with compression leaks into the coolant system that you're having perpetually, and with multiple cylinders and heads, correct?

That seems quite odd...

When I get my bike back together, I'll have to give it some revs with the radiator cap off to see how much the water pump will cause the radiator level to rise... Have you considered that some of this could be normal and perhaps not a compression leak????

there shouldn't be bubbles in the cooling system once all the air is bled out, i was confused about what was normal, my perfectly sealed kdx has zero bubbles and the kdx which had chronic overheating had bubbles , here is a video of it

kdxdazz wrote: 03:01 pm Sep 10 2023

Chuck78 wrote: 10:40 am Sep 10 2023 Wow James... I can't believe the issues with compression leaks into the coolant system that you're having perpetually, and with multiple cylinders and heads, correct?

That seems quite odd...

When I get my bike back together, I'll have to give it some revs with the radiator cap off to see how much the water pump will cause the radiator level to rise... Have you considered that some of this could be normal and perhaps not a compression leak????

there shouldn't be bubbles in the cooling system once all the air is bled out, i was confused about what was normal, my perfectly sealed kdx has zero bubbles and the kdx which had chronic overheating had bubbles , here is a video of it

I have got the same funnel after watching this video awhile ago and it helped confirm that the bubbles were in fact coming from outside of the cooling system.

Lots of copper flakes in my cooling system makes me concerned that I may have got some in the cylinder as well. I drained the coolant out just after I realized it was still leaking. Let it cool, turned the choke on and revved it to expel/burn any of the coolant out of the cylinder. What an epic fail.

JZ05220r wrote: 09:35 pm Sep 10 2023 Lots of copper flakes in my cooling system makes me concerned that I may have got some in the cylinder as well. I drained the coolant out just after I realized it was still leaking. Let it cool, turned the choke on and revved it to expel/burn any of the coolant out of the cylinder. What an epic fail.

What on Earth are the copper flakes from? Head gasket? How did you get flakes of it into the cooling system?

Buddy I'm sorry you're having so much trouble with this thing, and with multiple cylinders and heads even. I don't think I've ever seen someone have so much difficulty with head gasket leaks as this.
Have you checked the deck for flatness with the cylinder torqued down to the crankcase? Perhaps it can check out completely flat prior to installation but upon install and torquing to crankcase, it distorts the cylinder deck surface?

So you have a second KDX with no issues, and you've checked it similarly and gotten zero bubbles?

I just wonder if there is still perhaps air trapped in the cooling system that has not been fully bled out? Are you using all of the bleed ports in the system, I believe there are at least one or two, one on the opposite side radiator and I believe one on the top of the head, correct?
Getting a large surge of bubbles and pressure when giving it a little bit of throttle with the radiator cap off might definitely indicate this, but I would wonder if that would also just be normal with the water pump pressurizing things?

I'm really sorry to hear that you're still having problems. You mentioned being close to Ken O Connor. I like to do my own work but after everything you've been through I'd consider dropping off the whole bike to him and saying call me when it's done.

Chuck78 wrote: 09:33 am Sep 11 2023 So you have a second KDX with no issues, and you've checked it similarly and gotten zero bubbles?

I just wonder if there is still perhaps air trapped in the cooling system that has not been fully bled out? Are you using all of the bleed ports in the system, I believe there are at least one or two, one on the opposite side radiator and I believe one on the top of the head, correct?
Getting a large surge of bubbles and pressure when giving it a little bit of throttle with the radiator cap off might definitely indicate this, but I would wonder if that would also just be normal with the water pump pressurizing things?

I am using the bleed port on top of the cylinder head. I noticed the level in the expansion tank dropping after riding. And like you mentioned, when I initially saw the bubbles I started the bike and watched the level instantly over flow and drop back down the moment I killed the engine.

John_S wrote: 12:38 pm Sep 11 2023 I'm really sorry to hear that you're still having problems. You mentioned being close to Ken O Connor. I like to do my own work but after everything you've been through I'd consider dropping off the whole bike to him and saying call me when it's done.

I’m not too sure he would take the bike but it’s worth asking I suppose.