Any technicians on tonight? Loose swingarm bolt...

[Trevor555]

Got a BMW scooter and I've got a nasty vibration when cornering at 70mph.

I've spotted what I think is a loose bolt, but the BMW dealer is saying no fault found.

You can see the grease coming out, service adviser says normal.

Please see the pics, I've told them to road test it and come back to me.







Can anyone tell me if I'm wrong, or is that bolt loose?

[V8RX7]

I'm unaware of the model but your pic appears to show the top "bolt" where the grease appears to be coming from, is a sleeve IE it allows in and out / rotational movement

For vibrations particularly at a certain speed. I'd normally start looking at wheels and tyres first

EDIT - have you got a larger pic is that the wheel bearing ?

Edited by V8RX7 on Wednesday 15th July 20:54

[croyde]

When I first got my s/h Vespa 300 it handled terribly at motorway speeds as well as braking into corners and roundabouts.

Having the correct pressures helped a lot, then new tyres helped loads as the old ones had squared off.

[Trevor555]

V8RX7 said:

I'm unaware of the model but your pic appears to show the top "bolt" where the grease appears to be coming from, is a sleeve IE it allows in and out / rotational movement

For vibrations particularly at a certain speed. I'd normally start looking at wheels and tyres first

Ok, thankyou for having a look.

Doesn't do it at 60mph, but I haven't tried cornering hard yet, it's a new bike.

At 70mph if you steer side to side it vibrates badly both ways.

Perfectly smooth in a straight line.

Sat on it's wheels, with me holding the rear grabrail I can feel play, and a knock, when pulling the bike side to side.

I've also felt a slight knock going over bumps.

I'll see what they say after they've had another look tomorrow.

But I'm a bit miffed they've said no fault found without even road testing it.

[Trevor555]

V8RX7 said:

I'm unaware of the model but your pic appears to show the top "bolt" where the grease appears to be coming from, is a sleeve IE it allows in and out / rotational movement

For vibrations particularly at a certain speed. I'd normally start looking at wheels and tyres first

EDIT - have you got a larger pic is that the wheel bearing ?

Edited by V8RX7 on Wednesday 15th July 20:54

I haven't another pic at the moment.

I think it's the front end of the swingarm where it attaches to the main frame.

In front of the rear wheel, just behind the engine.

Bike is a BMW C400 GT

[V8RX7]

Sorry I clearly wasn't concentrating - I thought you were talking about the bolt head you'd pictured.

Looking again at the pic knowing it's the swingarm bolt going through, I agree that it looks loose, which is confirmed by you saying there's movement - obviously the best way to check is to put it on a stand with the wheel off the ground - there shouldn't be any side to side play

Edited by V8RX7 on Wednesday 15th July 21:27

[Trevor555]

V8RX7 said:

Sorry I clearly wasn't concentrating - I thought you were talking about the bolt head you'd pictured.

Looking again at the pic knowing it's the swingarm bolt going through, I agree that it looks loose I wouldn't expect to see it's thread which is confirmed by you saying there's movement - obviously the best way to check is to put it on a stand with the wheel off the ground - there shouldn't be any side to side play

Ok, thanks for taking the time to look.

It has side to side play for sure.

I sent the dealer the pics and he said the grease coming out is normal, but I'm not convinced it is.

I'll update when I've heard back from them.

The technician will get a little scare when he road tests it. I did tell them not to road test it before they'd found out what's causing the problem so they were following my advice, but they'll have to now I guess as they're saying nothing wrong.

[Rubin215]

Difficult to say for certain from a photo, but where the grease has come from is a pivot point and is designed to move.

There will be a bearing inside there that needs grease to run smoothly, there may even be a grease nipple to allow more grease to be added without stripping it.

Ultimately, it's a scooter and you're cornering at 70 mph; what did you expect...

[Trevor555]

Thought I'd update the thread, I've compared mine to another bike.

It looks like the bolt isn't loose, but it does look like a seal is missing.

The bottom photo of a new, unused bike.





The dealer is going to strip it all down to see what's wrong as there's definitely play in the swing arm, they now agree.

Edited by Trevor555 on Saturday 18th July 10:39

[V8RX7]

Trevor555 said:

The dealer is going to strip it all down to see what's wrong as there's definitely play in the swing arm, they now agree.

If it isn't the bolt it's the bearings - there's nothing else there.

Unless there's a manufacturing fault, doesn't sound like there was much of a PDI

[Trevor555]

V8RX7 said:

Trevor555 said:

The dealer is going to strip it all down to see what's wrong as there's definitely play in the swing arm, they now agree.

If it isn't the bolt it's the bearings - there's nothing else there.

Unless there's a manufacturing fault, doesn't sound like there was much of a PDI

Yes, I'm thinking somethings happened to the bearings inside.

Maybe the seal split when the swingarm shifted?

Maybe whoever built the bike has missed something out?

Anyhow, I'm happy that it's going to be sorted.

BMW assistance were good, collected the bike within 2 hours.