Big Red 3 whl rear end has a bounce

[SFC]

The rear end has a bounce every revolution in the same spot, it drops then popsup. Anyone know what could be the problem- bearings or something bent. It has been doing it for a while, rode today after deer hunting seems like it has gotten worse. Isnt making any noise like a bearing going out. It has been overloaded a few times. Dont want to put a bunch of money into it.It is a 1985 shaft driven. Thanks

[Macgyver55]

I'd start by making sure the tires are inflated equally to at least 4 or 5 PSI. Then you can raise and support or hang the rear and run it slowly to turn the rear axle to check for a bent rim or bent axle. We have one at the cabin that we only use for deer hunting that has a bent rim and it does the bounce thing too.

[SFC]

Thanks going to give that a try!

[SFC]

I tryed what u said,rims didnt look to bad. From the side I could see a noticable drop in the tire on both sides maybe a 1/4 to 3/8 on 1 spot but didnt notice it being higher when it was rotated 180'.

[Macgyver55]

I have seen some where the bead didnt pop into place evenly when they were mounted, but would still hold air. Check both tire beads carefully to make sure that they are straight. Many tires have a bead protector ridge or a line near the bead that you can look at to see if it is uniform all the way around. Otherwise it could just be a bad tire.....

[Dave S]

My old Kawi V-Force came with a bad front tire that was very noticable up to 20 MPH. After that the wobble went away. There was actually a spot in the sidewall of the tire that was shorter than the rest of the circumference.

Depending on the age of the tires and the abuse they've taken over the years, there could be a separated ply also.

[SFC]

The bounce does go away when going faster.I put on a new set of rear tires about 6 years ago. These tires werent the same as the original tires.(big mistake on trying to save a buck) These tires are alot harder and not soft and spongy like the original tires were, which impacts the ride & safety of the machine. My dad has the same machine Iam going to swap tires with his and see if the bounce goes away. Thanks!!

[Biggerfish]

Bent axle.....

[SFC]

Yea I think u are probably right about the bent axle. U would think they could make something that would last! So anyone have a guess of what will happen running it like this? I plan to run it till it dies.

[Dave S]

A kink in your back from being jolted to one side constantly and the associated back-cracker bill.

After looking at the microfiche on Babbitts, the axle "was" listed at $161. The kicker......it says (NOT AVAILABLE). I have heard of a place that could straighten axles but I don't recall the name.

[SFC]

[Macgyver55]

When I suggested the axle back in my first post how did you go about checking it? I got the impression you did so, but I was wondering how you did it.

The best way is to remove both tires and support the rear end as securely/solidly as possible. Then start the motor and put it in gear and let it turn slowly. Then slide something stationary close to the axle while its turning so you can see if it has a wobble or not. This will give you a good indication of how bad it is.

I've replaced a couple axles, but I can tell you it takes one heck of a hit to bend one.

Straightening it is pretty tough to do but if its not that bad its not really going to hurt anything to leave it.

[SFC]

I did not remove the tires, I marked a point from the top of the tire and put in gear, both sides had a noticable drop at the same point on both sides. I am going to try switching out the tires to see what that does. Thanks.

[McGurk]

I thought bent axle at first, but now not so much. Both sides dropped the same amount at the same time? If so, try this:

Do the same test as you did, marking the tires and the axle at the lowest point of the revolution. Then, remove and replace the one of the tires, but rotate the tire relative to the axle by 1 lug position. Now do the same thing on the the other side but in a the direction that the tire marks line up again (tires in the same position relative to eachother).

Do your rotation test, and note where the low point is. If the low point matches up with your previous tire marks, it is the probably the tires/rims. Could be from sitting too long in one spot with low psi or just old and cruddy tires. Cheap fix for some aftermarket ones.

If the lowpoint is matches up with the previous axle markings, it probably is the axle. Could be from some mad jump it the past (doubtful from a true Big Red 250), or from a heavy tongue weight load attached for a long period of time, or dropped on it all at once. I doubt either of those situations is the case, either.

You'd be better off locating another shaft drive Honda 3-wheeler with a blown engine than trying to get a new axle. I think the shaft drive ones were the 1984 200ES Big Red, 1985/6 250ES Big Red, and 1985/6/7 250SX. I don't know if they all swap, though, and I wouldn't trash a good 250SX if I didn't have to!

[SFC]

I will probably give that a try this weekend. Thanks!

[SFC]

Well I finally got around to trying what you suggested, it is tires or rims.