GRP CFR tanks

[guest27]

Hi All

I know there used to be a limitation on fitting grp petrol tanks to bikes, I think the law was changed to allow non-metal tanks, but have no idea what it is - anyone have any ideas.

R

[002]

Plastic YES !
GRP No No No !

GRP not up to the job.

Jethro

[guest295]

Depends really on how the tank's made. Certainly polyester resin is a no-no, but I can see no reason one couldn't make one from glass/epoxy that would be stronger than a plastic one. A layer of Kevlar fabric on the outside would add security. The lost foam core technique seems best.

[guest27]

HI that was some of the question - were I to make a kevlar epoxy, carbon kevlar or a glass epoxy tank would it be OK - it may look like a pile of poo but.. Used to be that non-metalic tanks were banned then the law had to be changed because the number of cars and then bikes with polyprop etc tanks.  But I am unsure of the ins and outs of this.

R

[Jez F]

If you have a SVA testing station near you ( I think there is a list on VOSA's website) pop over and ask them, they should be able to give you the definitive answer as far as construction and use regs go. I wouldn't bother with the phone unless you've got half a day to waste though.
 jez

[002]

HI that was some of the question - were I to make a kevlar epoxy, carbon kevlar or a glass epoxy tank would it be OK - it may look like a pile of poo but.. Used to be that non-metalic tanks were banned then the law had to be changed because the number of cars and then bikes with polyprop etc tanks.  But I am unsure of the ins and outs of this.

R

The Ban was brought in because of GRP Tanks falling apart at the slightest impact or vibration.
And they still are banned.

Jethro

[guest295]

So paint it and nobody knows. There are certainly plenty of epoxy/carbon tanks around for the poseurs and nobody minds them. Carbon's actually more dangerous because it fails catastrophically without warning.

[andy230]

The Ban was brought in because of GRP Tanks falling apart at the slightest impact or vibration.
And they still are banned.

Jethro

Ooops!  My 750 Norton has a GRP tank, and has been noted to vibrate a little....!  Hasn't given out yet, and the MOT man always smiles when it comes in...  Cos he knows he's allowed to ensure that it is safe.  By disappearing on it for 5 (country) miles!   

Interestingly, I have however had 2 steel tanks rust thru, pissing petrol ontop a hot motor.  Funny that they're legal!

Anyway, I thought it was due to static charge buld up on the tank, and the resultant spark when you broght the (earthed) petrol pump nozzle near to fill up?? Or is that urban myth?

Cheers for now anyway

a

[Steve H]

So paint it and nobody knows.

Unfortunately an insurance assessor inspecting the bike after an acident would know the difference and could refuse to payout if it was considered to be contributory

[guest27]

I am actually wanting a different tank for the CG and have toyed with making one for the RD etc, so thought I would start out simple, was not sure if epoxy/carbon or epoxy/kevlar was allowed, realised that GRP was only allowed on old bikes.  Did not want to go to the expense of CF etc for a first go as this would probably end up in the bin.  Mind I have to make a vacuum pump etc too.

R

[guest295]

A vacuum cleaner provides enough suck for that job. If you must have more, an old refrigerator compressor will do the job without overheating as a vacuum cleaner will.

[MrFluffy]

Do a bimota, plastic inner tank, and a grp/kevlar etc cover over the top?
Quite a lot of the funny shaped german streetfighter tanks coming out are grp moulded covers over a factory tank...

[guest27]

That is a thought - a grp cover on the std tank - mind I was looking for practice - and on the lookout for an old fridge or freezer compressor.

R