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Workshop => Engine and Bottom End => Topic started by: bushwesl on April 28, 2026, 11:39:46 AM

Title: Coolant Leak - ESR E2 363 PV Cylinder
Post by: bushwesl on April 28, 2026, 11:39:46 AM

Anyone have any luck with ESR cylinder repair?

Had what I thought was a leaking head oring. After pressure testing the coolant system, found out that I was getting coolant leaks from the exhaust side of the cylinder. I found this crack when inspecting the cylinder. 

Could this crack cause the coolant leaks? Does anyone have any experience or tips to repair it?

Title: Re: Coolant Leak - ESR E2 363 PV Cylinder
Post by: croat1 on April 28, 2026, 03:32:53 PM

I don?t own any ESR cylinders but I have seen others where they leaked at the exhaust manifold studs as they were drilled too deep.

Joe

Title: Re: Coolant Leak - ESR E2 363 PV Cylinder
Post by: 2ndmoto on April 28, 2026, 04:01:17 PM

The crack in the picture doesn't look like it would be the culprit. Looks like it goes from the exhaust port the the secondary a exhaust ports. You could bolt the head on and plug one of the coolant elbows. Then pressurize through the other coolant elbow and see if you can locate the leak easier.

Best regards
-Jason

Title: Re: Coolant Leak - ESR E2 363 PV Cylinder
Post by: bushwesl on April 29, 2026, 12:41:22 PM

Thank you for all of the feedback. I was able to pressurize the cylinder and find the leak with some Windex. It took awhile, but I finally found it. There's some very minor leaking at the cylinder exhaust ports where it meets the sleeve. It's not an ideal fix, but since the cylinder is on its final bore, I added some epoxy to the leak site in hopes that it fixes it. We'll see. My goal is to get it back together in time for a race on Saturday. Fingers-crossed it works.

Title: Re: Coolant Leak - ESR E2 363 PV Cylinder
Post by: 2ndmoto on April 29, 2026, 04:15:09 PM

Interesting. I don't think the sleeve cuts into the water jacket. Can you see the crack in the water jacket? Not sure if you can clean it and get epoxy in there. Would be best to try and epoxy the crack from both sides. Good luck with the race.

Best regards
-Jason

Title: Re: Coolant Leak - ESR E2 363 PV Cylinder
Post by: bushwesl on May 03, 2026, 08:22:48 AM

It survived! Got the holeshot, 3rd in Vet class, and 11th overall of 78 riders.

After I get everything cleaned up, I?ll be able to better assess the situation. It didn?t get overly hot during the race, so that?s good news. I?ve got until June 13th before the next race to figure out a better solution. Or maybe it?s good enough and I?ll be able to keep running it?

Huge shoutout to Blake at DBC Racing for all the last minute help!!

Title: Re: Coolant Leak - ESR E2 363 PV Cylinder
Post by: bushwesl on May 03, 2026, 08:27:11 AM

Quote from: 2ndmoto on April 29, 2026, 04:15:09 PM

Interesting. I don't think the sleeve cuts into the water jacket. Can you see the crack in the water jacket? Not sure if you can clean it and get epoxy in there. Would be best to try and epoxy the crack from both sides. Good luck with the race.

Best regards
-Jason

Thanks, Jason!

The leaks were at the cylinder and the sleeve seam at the transfer ports and the exhaust port.

Title: Re: Coolant Leak - ESR E2 363 PV Cylinder
Post by: croat1 on May 03, 2026, 09:07:51 AM

Wes, good job racing!!!!  Congratulations

Joe