• J3-Cub.com is the largest community of J3-Cub pilots, owners and enthusiasts. With over 1000 active members, we have fostered a vibrant community and extensive knowledge base. J3-Cub.com hosts a library of over 13 years of technical discussions, J3 data, tutorials, plane builds, guides, technical manuals and more. J3-Cub.com also hosts an extensive library of J3-Cub photos.

    Access to the J3-Cub.com community is by subscription only. Membership is only $49.99/year or $6.99/month to gain access to this community and extensive unmatched library of knowledge.

    Click Here to Become a Subscribing Member

    You will also get two J3-Cub decals as well!

Cracked exhaust stack

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.


Apr 24, 2007
Reaction score
Hello everyone. Have a little info that you all might find interesting and hope you'll take a look at these areas on your own aircraft.

Took mine (Serial #0008) for its compliance with Service Bulletin #2 (Solenoid Problem) yesterday. This was accomplished without difficulty. Prior to putting the cowling back on, my mechanic gave the engine compartment a good looking over. I was there during the whole procedure. He called me over and said take a look at this. The exhaust stack on the left (looking from the pilots seat) was cracked just behind the small heat muff. The crack was 3/4 of the way around the circumference of the stack. Quite close to the fuel line just beneath it. At the location of the crack, the stack is secured by a clamp to a bracket, which is solid and attaches to the lower motor mount. The attachment is very rigid and would not allow any movement of the stack as the engine vibrates with starting or whatever. That was the immediate thought as to the cause. My mechanic then said "Let’s look at the right side". There, the stack was not cracked but the rigid support bracket attaching it to the right motor mount was broken. This bilateral finding would suggest that the fixed, rigid support of both stacks which does not allow any motion or dampening effect might well be the cause of this bilateral finding.

Please take a moment and go take a look at these areas on both sides of your respective aircraft. My mechanic spoke with Earl Barnes at CubCrafters and as of today, I don't know the final outcome of their conversation. This may well be a single issue with my aircraft (total of 65 hours with no hard landings or other happenings, at least after it was delivered to me in Tennessee. Had 32 hours when I got it.) but I thought each of you should be aware of this finding.

As soon as I hear from CubCrafters, I'll let all of you know.

The only other issue of significance with my Sport Cub was a long crack along the bottom of my door next to the hinge that went the entire length of the door. Sent them pictures, sent the door back and it was repaired and reinforced with a long metal strip in this area and returned to me, all at CC's cost. Don't know when this happened. My wife noticed it a few days after I took delivery. I was told this had happened to one other Sport Cub.

Hope this information is helpful.

Charlie Czermak

Sport Cub 0008

North East, Tennessee


Latest posts