Champion Trike Broke Transmission Case

[mc9395]

I,m writing this for a friend who has a 2006 FLHTCU with a Champion trike kit installed. This is not the independent suspension model and the whole rear end is hooked to the pivot shaft on the transmission. Now the rear of the transmission has broken off again. This seems to me to be a bad design on Champion Sidecars part but Champion has hinted to him they might have had "a little glitch" and also told him that was Harley's weak link. Buying and replacing transmission case's are getting pretty expensive on his part. Has anyone else heard of or had this problem. Any reply or opinions will be greatly appreciated.Thanks

[Papa Zook]

On the later model Harleys every trike manufacturers swingarm attaches to that same pivot point, the swingarm shaft, which attaches to and through the rear of the transmission case. This is also where the stock Harley swing arm attaches and is the only option when installing any trike conversion. Its the design HD uses and I have to agree that if there is a weak link, Harley provided it in that design. In all fairness to Champion, there are many thousands of their Harley conversions on the road and I from what I know this is a very rare occurrence. I have never personally seen one crack but have heard of one other occurrence reported here on the forum.

I talked to Champion about this a couple of months ago when the other post was made and they say that it appears that the different cast aluminum trans case batches may not be 100% consistent in their strength because tiny air bubbles were visible in a cracked case that was sent to them for inspection. I'm not sure what year or model the bike was in that instance, it would be interesting to know.

BTW, the other person who posted about this was from New Jersey. Ive been there a couple of times when I helped a friend move to Alabama. Some areas are pothole hell from what I saw. I ran into a couple of 'em that about tore the front end off my truck, so a harsh environment might be a contributing factor. If the rear of the trike did experience severe jarring from hitting potholes over an extended period of time, it could be stress cracking the case and eventually result in failure. I cant see how anything short of that would cause this problem. You may want to ask your friend if he remembers hitting any major potholes. If he did, repairs should be covered under his insurance.

[tis]

Thats what is great about these sites, there's a wealth of knowledge and to have Zook to be able to come up with a possible answer to the problem, and possibly get it covered under insurance is something that probably would have been overlooked. Nice call....

[Gorilla]

I,m writing this for a friend who has a 2006 FLHTCU with a Champion trike kit installed. This is not the independent suspension model and the whole rear end is hooked to the pivot shaft on the transmission. Now the rear of the transmission has broken off again. This seems to me to be a bad design on Champion Sidecars part but Champion has hinted to him they might have had "a little glitch" and also told him that was Harley's weak link. Buying and replacing transmission case's are getting pretty expensive on his part. Has anyone else heard of or had this problem. Any reply or opinions will be greatly appreciated.Thanks

welcome to the board. I have over K on my Champion HD straight axle conversion with no issues. As Zook states about the only thing that could cause that much twisting motion along the swing arm would be hitting allot of big pot holes on one side. This would cause a lot of force being exerted on the side that hit the pot hole. I wish your friend good luck. I think that after he repairs the cases he will need to watch for and miss the holes in the road.

The other alternative is to move to Florida like I did.

[tfdeputydawg]

Just finished talking to an installer about this issue.
He has seen 2 cases of this on Motor Trike conversions.
Motor Trikes response in both cases was:
The isolation motor mounts on both bikes were worn enough, the motor "settled" in the bikes. Thus placing the system in a bind, so to speak. This became a stress on the transmission case eventually causing the failure.

[1550vt]

Good to know...well...you know what I mean and I regret the problem for those who have had it. It's got to be travel on one side causing the twisting motion and what Zook said makes sense...there could be some weak cases out there. We all know the MOCO will skimp where they can and this 4.5 inch connecting point is the only thing that holds the swing arm in place....except for one issue that I am thinking of. If the swing arm twists...it also puts pressure on the rear motor mounts (those rubber doughnuts). All this has to twist together.

Here is my point. To strengthen and prevent rotation of those rear motor mounts (makes the trike corner better) Champion (I think) includes a pair of nylon/Delrin bushings that fit inside those doughnuts. I had a set in mine that I ordered from Champion, but have since removed them and installed some neoprene ones that come with the Sta-Bo bushing kit. Maybe those "hard" inserts are not letting this connection roll as it was designed to do.

This requires some deep thought to see what torsional forces are trying to do with those inserts inside that rubber doughnut or not. Seems to me that having the hardest thing you could in there would help prevent this by reducing the "roll" in the swing arm to transmission junction, but the entire engine (rubber mounted) wants to roll too.

My head hurts now....time for a beer! I know that I have a spare transmission case that I considered getting rid of that I now plan to keep.

[1550vt]

I failed to mention one more thing for our digestion. I had been shopping for a replacement tranny for my 2000 Ultra and I noticed that the more recent models had a different design in this connection area. The early model tranny's have a solid casting and some of the later models I saw (in pictures) had a "webbing" in this area and were not solidly casted. Matter-of-fact, I remember seeing one broken. Funny thing is I thought they just cut the tranny loose from the connection at the salvage yard, or possibly it was from a wreck, which what most of the used transmissions are from. This is very interesting indeed....maybe Harley has weakened this pivot point to save 6-ounces of aluminum in the later models? This would not show up in a 2-wheeler, but a trike applies a much greater torsional force on that connection.