oldaz

So you're saying epoxy resin rather than vinylester? Fiberglass mob have poly, VE and epoxy, but say the VE is best for petrol?

Been on to several fiberglass places and for those who may be interested the recommendation is to use a vinylester laminating resin. It has a maximum service temperature of 60 degree C when in contact with pure petroleum, and 50 degree C with 10% Ethanol. Their words "As long as the overall temperature of the tank does not exceed 50 degree C, it will be fine" are the best response I got. I know it can get 50C in my workshop in the summer, so not much safety margin even without E10.

Pretty much describes what I found inside mine, how did you degrease yours to be sure the resin would stick properly? I'm now sanding/grinding the remains of tank sealer and unfinished glass inside the 2 halves. Plan is to re-glass both halves to strengthen and repair, then glass it back together. Only other avenue I'll check out first is I have access to a small 3 litre metal fuel tank that may fit inside the fairing, just got the dimensions late tonight, so I'll check it out tomorrow.

Great idea Phil, would also pay to expose the tank to bright light/sunshine while you look with the scope, cracks/holes show as a dark color. I've wanted to get a long scope for a long time to explore inside some pipes and also under a rock overhang on farm that may be of indiginous interest. Now might be too late for the tank, but a good time for the farm.

Since looking at the shedworks site, my thoughts are heading in this direction using ethanol resistant resin. I don't think the extra glass and resin will add much weight (smiles) or reduce the fuel capacity much for the extra strength and security. I was interesting to see the amount of cracking inside and how much the fiberglass had deteriorated from uv exposure, the new lining was never going to do a good job. Disappointed that I'll have to repaint the outside again and now have to find another set of stickers, not a cheap exercise.

Not officially retired as I'm still farming, but do have time to do a good job. I've decided to go fiberglass, just haven't made up my mind as to whether the repair will be like the original or whether the base of the original will be the base for a stand alone tank to fit in the original fairing. Non ethanol fuel isn't a problem here in Oz, but I'll look into ethanol resistant resin as used in the shedworks glass tanks.

Thanks for the heads up on shedworks and thanks for the nice comment. I've decided to go fiberglass, but yet to decide which way.

What oil are you using? With modern 2 stroke oils I wouldn't go past about 40:1. That black soot also looks like it might be running really rich, so I would also check the carb setup.

I finished the rebuild on my 247 a few months ago, dropped a bit of fuel in it and rode it around the back yard then put it away in the shop with a view to sell it. I figured one ride at my 74 years was enough for this old body. A friend wanted to have a look at it (the bike, not the old body) and to my dismay the paint on the fuel tank had bubbled in several places. I had sealed and refinished the tank, so expected it would be good. This bike had been worked hard, then sat out in the weather for 30 odd years before I got it and apparently our Australian sunshine didn't do the fiberglass any favors. After inspecting as much as I could I decided the only way to fix it properly would be to take the tank apart and fix from the inside. I used a Dremel type tool to carefully cut the base out of the tank assembly and I'm now glad I made this decision. The inside of the top section is all cracked and crazed and no way would a sealer ever have "fixed" it. I now have the dilemma, do I use the base to make a new fiberglass tank that will fit inside the original cowling, or do I re-fiberglass the inside of the cowl section and glass the bottom back in? The bottom is much thicker and no signs of cracking, so I'll at least use it. Attached picture of the bike when I finished it

Put some fuel in it, primed through plug hole and it started first kick. Had a (very) short ride around back yard and put it away, getting too old for this stuff, lol.

Finished the building stage today, just need fuel and carby tune to end project.

Not yet, been out of action for a while, did the second coat of primer filler and sanded back ready for paint. Got the paint, new Ulf Karlsson stickers arrived, but done nothing since. Now hoping to get some tank sealer and maybe finish it off in the next couple weeks, then sadly it will be on the market along with some other projects.

Glen, the bushes on my Ulf Karlsson 247 are a rubber in steel torque type. The bolt is a firm fit in there and when tightened up the rubber acts as a type of shock-absorber, although it does limit the movement of the swingarm. Heating with a torch will burn the rubber, so unless you want to replace the bushes with a different type, go carefully. I believe Inmotion sells a conversion kit, otherwise you might try drilling the bolt out. If your 247 doesn't have the rubber type, then possibly drill one end of the bolt to get a good starting point and press them out.

Looks good, very neat and tidy slider, reason I left mine wider was to protect the engine side covers, any more damage to them and it would be difficult to repair them. Thanks for sharing the pics.

Glad the oil seems to make the box better, will be interesting to see how it goes long term. That's great about the show, we're starting to see similar things at car shows here, where folks are bringing out their restoration/repair projects from their sheds/shops where they've been hidden away from the general public. I still have to paint the tank on mine to finish it off.