1983 G1 vibrates terribly at low speeds

[Cyclone]

Hey everyone!!!

I'm new to golf cart ownership and ultimately this forum. I recently purchased a 1983 Yamaha G1. After driving it on weekends for about 3 weeks it began vibrating horribly at low speeds (1-5 mph roughly) and feels like it is coming from under the drivers seat. Once it gets past "low gear" it runs very smooth and is FAST (20-25mph). I'm afraid to drive it right now because I'm afraid to cause more damage.

I've used WD-40 on incline ramps and spring inside the sliding sheave which helped smooth the transition from slow to fast speed, but the vibration still remains. I feel like it could be the drive belt, but the vibration seems far too intense to just be a belt. Does anyone have any experience with this sort of vibration? If so, any information would be much appreciated. Thanks!

[smallblock450sl]

I would think you have wornout/busted motor mounts, but could also be primary or secondary clutch bushings are worn out.

[Cyclone]

Thanks, Smallblock. I've been thinking that it is something to do with the clutch because it rides REALLY smooth once it gets past 5mph or so. It also idles without the vibration. Am I looking a full clutch disassembly to inspect the bushings?

[caddylac camper]

The motor mounts can be inspected by lifting the cart onto stands and prying on the motor base with a bar. You should not see large deep cracks in the rubber mounts, some smaller cracks are probably ok but they are not like that new. The inside sheave of the secondary clutch should slide on the shaft easily but not have any wobble to it. I've never worked on the primary clutch but i believe its the outside sheave that moves and it also should not wobble.

[Cyclone]

OK, so I've noticed two things now that I'm looking deeper into this. I watched the clutch and drive belt through the gas tank door while running at low speed and noticed that as the vibration starts, the drive belt looks like it has a large amount of play in it and is oscillating quite a bit. The drive belt looks to stop oscillating as the vibration stops.

I'm also going to check out the engine mounts because it looks like there may be a bit too much play in the engine when there is vibration or the cart goes over rough terrain.

I'm hoping to just need a new drive belt, but I'll inspect the bushings see what else I find.

[sho305]

If the moving sheaves both have little or no wobble, then inspect them for holes and cracks. (one side of each clutch moves in/out) Old carts that were run in dust/dirt a lot will actually wear through them, unfortunately you have to replace the alum sheaves or the whole unit for each clutch. The belt could be damaged someone could have smoked (burned) a spot into it if the cart was stuck/etc or if really old a chunk can fall right out of them, check the cogged part of the belt inside. Note the belt is inside the engine clutch (primary) and at the outside of the secondary at rest. It starts there that is low gear, as you increase speed it shifts the other way to outside the primary and inside the secondary. That might give a clue to where your issue is. Another thing is it could be the primary is not engaging properly; it grabs the belt when you first take off. If something is broken inside it will not do that properly. It is also when the motor mounts get pulled on the most the engine will move towards the trans if they are bad. Some carts like G9 have a tension cable below the generator pulley to the mount that holds this engine torque. I forget but think the G1 does not.