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Discussion in 'Trials' started by Ymirtrials, Mar 21, 2012.
Are the GRP tanks mentioned made to EN, BS, or UL standards, and how long is the guarantee for?
I think that I'm willing to give the caswells a try though it may not be a perfect solution. I unfortunately don't have the cash for a new tank, though perhaps in the future I will be able to spend some money on a restoration. As it is the tank only seeps from the repair when it is full and I already in the habit of draining the tank after use. I will likely from now on only ride the Bul at a few vintage events that I plan to go to.
If you take the advice in my earlier post about sealing a tank, you should increase chances of getting a lasting repair by 100%.
Save yourself a lot of hassles and just put a full plastic replica on it to start with. The original glass leaked from the factory!!! Glass tanks are good for museum pieces that never see gasoline. Note that later Buls like the 199 series have PLASTIC TANKS. They never could keep their glass from de-laminating.
I have not actually found anyone who produces a plastic tank for a m49. Anyone found one?
I don't think one exists for our bikes. I have seen bikes using the Clarke mini z universal tank. Justgastanks.com sells them.
For custom made fuel tanks you can ask:
Romeromoto in Spain, Sant Adrià de Besòs, (I believe he speaks english too):
Then in Germany Heidenreich GFK in Trusetal, specialized in custom GFK construction, but they will need your tank for molds, I hope they can speak english, not sure:
I've got my custom made tank from Orlando Calonder in Buchs in Switzerland, he is a former Bultaco Importer and still in business! He doesn't make them himself, but knows all the suppliers that deliverd Bultaco when the company was still in business. He is a little bit old fashiond but very addicted to Bultaco, gave out some translations of Bultaco books from Spain in English in German. I don't know if he speaks very good english?:
If got a good replica airbox for my model 199b from him too, also made out of fiberglas as the original one is made out of some weird plastic has an unique shape, (only the b model was fitted with this airbox), that is not available anymore.
The fiberglas gas tanks should be made with of gas, oil- and alcohol resistant resin, we use here epoxy resin type C, sadly I only know one good German dealer where you have a good selection Rudolph & Groß Faserverbundwerkstoffe GmbH in Waldenbuch:
technical specs: http://shop.r-g.de/out/media/td_de_Epoxydharz C.pdf
Didnt the bultaco's sell overseas with aluminum tanks? the UK or germany or somewhere, didnt allow plastic fuel tanks or something.
FWIW I had the 79 sherpa t (199) and owned 4 tanks, that bike I kept until about 2001/2002. Including the original, which cracked in 1984, ALL of them split/seperated at the seam, above the petcock, there was no way to repair this, apparently fuel changed the structure of plastic/resin what ever, and tanks would never melt and stick, the plastic would just shrink... Apparently assembled with heat/soldering type system, when MFG'd. I tried a lot of products, most failed due to A> wouldn't stick, B> adhesion was disturbed by flexing even though you just barely touched tank wit your knee while riding, or most cases whatever glue/compounds I tried, gas would eat it off...
Most of it's life from 84, I would seal all 3 I had at the time, 2 spare tanks with silicone sealer on outside best I could, cover with duct tape so you didnt roll off that silicone with your pant legs. I even tried fiberglass once, to cover the silicone... then I ride or practice, took off that tank that was leaking, put one on that I had prepped already and patched, went to trials with the 2 other tanks, put fuel in only when time to ride, would be leaking by time ride was over... round and round with 3 tanks to try to have some use of the bike... Did that for several years too, by the way...
My Last tank, (#4) was one I paid $400+ dollar (1996 US-Dollars) fiberglass tank, produced in the 90's before ehtanol was widespread problem. I sold the bike with that fiberglass tank that had never been used. I bet is felt the same fate as other fiberglass tanks have come to bear since those days...
Anyhow, I was thinking of the flexing problem I had with any type of glue/compund that cured harder than the tanks...
nice thing about fiberglass tanks, they dont seem to flex near as much as the as the plastics, with knee hits, you know?
so I still think you have Fiberglass a tank, clean best you possibly can with acetone, and a nice sharp aggregate, to sand the insides a little, then probably a fiberglass tank could be coated fairly well. sure if you fall directly on that tank, which causes a big flex, maybe MAYBE, break the inner coating, I dont know. sadly that is the corner we're painted into I guess.
Your only other option is to find NON-Ethanol gasoline I guess? (or of course DEEP POCKETs never hurts.)
In UK where plastic tanks not allowed, the Bultaco plastic tanks are approved by German TÜV there should be a TÜV badge engraved on the gas tank underside. Otherwise ANY gas tank that is not the standard one will attract the inspectors eyes here. We need a certification of registration for nearly everything here. As long as the gas tank looks like the original it can be overlooked as they are not so familar with these brand anymore.
For the Bultaco there doesn't exist a real cure I believe beside using the aluminium tank the UK models had, -expensive if you find one-, the PE tanks will discolor and crack, the fiberglas will leak or bubble when painted*1, the painted PE tanks will bubble even worse*2.
*1: If you not empty the gas tank after the ride.
*2: Even if you empty the gas tank after the ride.
The AVGAS or other gas erivaties are a good hint.
If you know how, opening a damaged tank and installing a proper chemical resistance liner using novalac vinyl ester resin system, will in most cases mean the tanks perfectly ok to use with modern fuels. Seems unfortunate that no one seems able to make fuel resistant tanks for off-road bikes, even though industrial fuel storage tanks have been in use since the 1960s!
http://i1258.photobucket.com/albums/ii521/Twin-Shocker/IMG_0320.jpg provides a good idea of what happens when tank "sealers" are used rather than carrying out a proper repair job!
Have you actually done a repair as you have explained, splitting the tank etc? I'd love to see some photos. I think I'd be afraid of trying to split my tank incase I screw it up and then I'd be really hooped because an aftermarket replacement does not exist. I have done fiberglass repairs on my canoe and such so I do have limited experience with resins etc, but if you do open up the tank to seal the inside then how do you seal up the seams after you reassemble the tank? Where would a person find a novalac vinyl ester resin system?
Sorry about the crappy photo, still learning the wife's new camera!
Try Hughes Bultaco in Craryville ,NY. They can fix you up with a plastic re-pro or a fibrglass tank that can withstand our alky/fuel. Perhaps a 199 tank will work on an M49 also.
I've been in contact with Tim at Hughes and there isn't a re-pro for the early style M49, he figured they may have an old used one but it would need to be resealed too.....
Yes we did do a proper repair job on the sealed tank pictured, but its not the sort of job for anyone other than a pro laminator, and the reason it was carried out is the tank is very rare, and we were interested to see if a proper repair job was feasible, as replacements are completely impossible. If your Bult tank has already been attacked by Efuel, then the fuel will probably have permeated the laminate itself, and ideally you will need to heat it in an oven of some sort to get rid of the fuel residues, before making any attempt to seal it. Those selling the sealers never advise end users of the need for this, and failure will occur almost immediately if there is still fuel in the tank lay up.................
Another option would be if you are experienced in woodworking, have some passion and spare time to make a replika in wood and give it to a car body builder for making one out of aluminium, the main costs for a custom made tank is the mold.
Divide the tank in a vertical grids in the same thickness of board thikness that is available where you live, 24mm = about an inch, measure out the outline with a profile rule the cabinetmaker have, and draw these on the board, cut them out, glue and screw then together then align the surface and you have a nice mold. Use limewood for this, it's hard but can be processed very good.
A good car body builder then can shape the tank out of aluminium.
costs for the mold wood, srews, ...: 50$ and around three to five days of work
costs for the aluminium tank: around 500$
As you now have the mold you can make a small production run and sell them through E-Bay.
No more problems with gasoline and ethanol.
If car body builders are able to easily make one off custom alloy tanks for $500, I wonder why more are not doing this, as Yamaha TY alloy tanks are being sold for e495 on a French trials related web site?
There are a few people in the UK who can make low number production runs of alloy tanks to very high standards, but prices would be substantially higher than $500, and shipping to the US would obviously also need to be considered.
Way to go with the M49 tank would be to approach all the small scale producers of GRP bike tanks in the US, and see if any of them would be interested in providing you with a reduced price new tank, if you provided your damaged original for them to make moulds from.
There is a difference in pricing between the US and Europe:
US: hourly rate: 50$ 8h x 50$ = 400$ + 20$ material + 40$ profit + 40$ tax
EU: hourly rate: 75 8h x 75$ = 600$ + 40$ material + 60$ profit + 100$ tax = 800 $ = 500
Don't forget Europe wages are around 30% higher then in the US due to our social system and tax is about 200% higer! As a rule of thump anything you can get here in Europe which cost 100 , you will have to pay in the US 100$. We here in Europe sadly pay around 20 - 30% more for the same goods as you, just look up car prices, motorcycle prices, ...
The only realistic option here is GRP formed from tooling made from the original, which by the look of it would need a fair amount of work before it would be good enough to take a mould from. As I think the M49 tank looks quite close to that used on the Pursang (?), it would be commercially viable for someone to make GRP ones as they may well fit both bikes. So why not try some of the GRP manufacturers in the US making tanks to UL standards?