Personally I would not run the engine without a prop. Additionally you need to do the crank test to make sure that the crank was not bent. If the engine was not running the easy thing to do is check the runout on the prop flange. Refer to the mantelpiece manual. All that you will need is a dial indicator which is available from Harbor Freight. My guess is that you will find that it is ok but if not the engine will destroy its self. Also I would pull the gearbox and do the runout on the end of the crank just to be safe.
My cabine did have the cross member, I suggest adding a king post at the center of the crossmember going to the low point of the cabine to help strengthen the cabine. Maybe attaching the cabine to the truss would help, but I just don't know. I do know that part of the failure mode is the cross member is deflected downward as the sides of a he fuselage are pulled inward maybe the problem is that the fuselage just isn't stout enough for this style of gear. my new gear has Roberts Rage struts, the cabine also has X bracing in addition to the cross member. The front mount was built heavier with additional holes to mount the cabine. The downside is that it is not a simple bolt on application and requires new mount fabrication. I also built the gear legs wider to attach to the rear gear mount at the strut attach point. I see that Kitfox has also went to a wide stance on their gear legs. The center attach point for the standard gear is a weak point. One thing that I would change is the angle of the gear legs are to steep as are the gear legs on the so called Bush Gear design. If you think of that gear as a Sunday flier gear not as a Backcountry airstrip gear it is probably very serviceable for the average pilot. I do know that I was not descending at anywhere near500 feet per minute when the gear/fuselage failure happened Jim i also reinforced the seat truss on the first rebuild and that has worked good. Here is a link to photo of what my gear looks like now.
The math looks pretty good and I am sure that the engineering on the Tacoma Narrows Bridge looked good also. After two failures I can attest that there are flaws in the design of this style of gear but if you grease it on every time they will last you a life time. If mine were the only failures my experience could be discounted but ther have been others. The wider stance does make the plane handle much better. I sure can agree the doing business with Highwing LLC was right on the money and I would do business with them again but not to purchase that gear.
A split bushing can easily be made and installed using the method Doug showed with his one piece bushing. This need not be a deal breaker just some of a build's little challenges along the way. Take a deep breath, you only need to solve one issue at a time. It is worrying to find these kinds of issues and you will probably do well to have another builder help you go thru the plane to see what other problems are lurking. where are you located? Maybe some one is close by and could have a look at it with you.
One caution about pulling the plane facing forward that I am sure Bandit addressed, be sure to plug the end of the spars and the wing without tanks to avoid pressuring up the under cambered wing and pulling the fabric loose especially if the wing is not rib stitched...
As mentioned in my post in another thread I used one small hard rivet thru the aluminum forward of the break area. I also clad all of the tails when I fixed the broken one. Not sure if the rivet was necessary but I have not had anymore problems and would use the rivet again if I built another plane.
I do believe that the springs bottomed out. I don't know if it is weaker than the stock bungee gear but I would choose the wide bungee gear over the Bush type spring gear knowing what I know. The mod I am referencing uses a spring from a snowmobile and an extended slot. Connecting the cabane to the seat truss may help but don't know for sure. One thought would be to use the gear legs and build Cub style struts to replace the the spring struts. Those use the hoop style bungees. The gear I built uses the Roberts Rage gear uses one hoop bungee and one air shock on each strut. The downside is the cost is high. I picked mine up at half price but they were still pricey. The Cub style should be reasonable to build but I don't know what the cost of the bungee hoops would be. i know there are some out there that are using this gear and are happy with them but the design is not suitable to my style of flying. There have been many fuselages damaged with this gear so I know I am not the only one that has had problems and I will not be the last. There are several ldeas for improvement on this site.
Yes, bent the fuselage twice with it before I gave up and moved on to my current gear. The wheel position was not an issue but the cabane will not fit, the Avid mounts set a little wider than the Kitfox. The first time I had Lowell leave the top bar of the cabane split in the center and spread the cabane which kind of worked but the second go around I built the cabane to fit the MK IV fuselage. So the bottom line for me is I would not use that gear again. The gear will be just fine if you baby the plane and don't fly as close to the edge as I do. Maybe with the mod suggested by Leni it would be ok but I am over that style of gear just not forgiving enough for my flying style. I can say the workmanship is excellent. I will be happy to answer any other questions you may have.
I have been thinking about going to ADS-B out for that very reason. I have Adsb in which is helping to see a lot of the planes and it will be even better in a couple of years. Most of the planes that you are worrying about have ADS-B already. The downside is about $3000 to upgrade.
this is from the EAA https://www.eaa.org/en/eaa/aviation-communities-and-interests/pilot-resources/amateur-built-aircraft-and-light-sport-aircraft-inspection/find-an-faa-e-ab-designated-airworthiness-representative
well I am on my third tire for the wide 8" dual fork tail wheel. Same problem with both, a split in the side wall cheap Chinese Carlisle tires with no other options available about $36.50 USD from Matco. The good news is that they are available thru Walmart.com for about $13.50 delivered to your local store in a couple of days with no freight charges. Anyone else having problems with the outside wall splitting on these tires? I ordered two and put one on the shelf for next year.