T: Fuel Tank Tank bolts & Rubbers

[oexing]

Funny to watch people inventing devices just to not use some mild Loctite for securing assemblies . . . . .

Vic

 

[Bill Thomas]

One of our Lads has a Comet that has a lot of Vibration, Not been built long,
I did tell him about the front rubbers, Just in case ?, But He knew.
Anybody else think Comets Vibrate ?,
My Comet / Flash spec' has had a hard life, But I think they are better than Twins ?,
But my Twins are race spec also .
Cheers Bill.

I think when the front bolts come loose, It's because the threads are a bit worn ?.

 

[Nigel Spaxman]

I’ve always fitted them with the large shouldered area between the ufm and the fuel tank..

I always put mine in with the shoulder out, just like shown in the parts book! It is way easier to do it this way and it still holds the tank central.

 

[medat727]

My front tank bolts on the race bike are plastic, always looking for ways to save weight, they are however only supporting a fiberglass cover over a fuel cell.

 

[Chris Launders]

Looking for ways to save weight, machine your Allen bolt heads like this, I've done quite a few on a bike, but mine were for aesthetic reasons.

 

[Peter Holmes]

One of our Lads has a Comet that has a lot of Vibration, Not been built long,
I did tell him about the front rubbers, Just in case ?, But He knew.
Anybody else think Comets Vibrate ?,
My Comet / Flash spec' has had a hard life, But I think they are better than Twins ?,
But my Twins are race spec also .
Cheers Bill.

I think when the front bolts come loose, It's because the threads are a bit worn ?.

I think the shoulders on the bolts are to small, but I realise they have to be so to pass through the rubber bushes, but they are so close to the thread diameter that they can crush the first few threads inwards if you are heavy handed with a spanner, then the bolt cannot be nipped you on the shoulder, then they can vibrate loose. In any event I prefer to use Maughan bolts with extended threads, I should add that for some reason mine have never come loose, perhaps I am lucky.

 

[Bazlerker]

So many replies…so few of them answering my original question.

 

[bmetcalf]

I am about to fit the tank after a 2yr hiatus.. My question is - how tight should the rear tank bolts be? Just enough to deform the rubber?

Just a little tighter than that.

 

[timetraveller]

Dear Baz, the answer is to just nip them down enough to start and deform the rubber and then fit a lock wire, other locking device or use Loctite. Personally I just nip them down and keep an eye on them.

 

[Nigel Spaxman]

Just tighten them enough to slighly squeeze the rubber. If you don't lock them in some way, either loctite or lockwire they will probably come undone. Mine are to loose today for some reason so at higher RPM the tank vibrates if I don't squeeze it with my knees. I should tighten them.