tootall Posted October 4, 2008 Report Posted October 4, 2008 Going to cut open my YZF750 frame to remove the sound deadening rubber stuff. Should I build a jig first to stop it changing shape when cut open or when welded? If so how chunky monkey does it have to be?
beek Posted October 4, 2008 Report Posted October 4, 2008 Going to cut open my YZF750 frame to remove the sound deadening rubber stuff. Should I build a jig first to stop it changing shape when cut open or when welded? If so how chunky monkey does it have to be? depends where you decide to cut. personally i dont have a problem cutting frames to suit my needs but others do. If you removing the whole side or headstock then a jig to reweld would be the answer.
tootall Posted October 4, 2008 Author Report Posted October 4, 2008 depends where you decide to cut. personally i dont have a problem cutting frames to suit my needs but others do. If you removing the whole side or headstock then a jig to reweld would be the answer. would be cutting out fairly large sections from the insides of the frame spars to allow removal of several kilos of shite, would then be re-welded with bracing added around headstock and shock mount. Reckon a jigs gonna be the way to go.
beek Posted October 4, 2008 Report Posted October 4, 2008 would be cutting out fairly large sections from the insides of the frame spars to allow removal of several kilos of shite, would then be re-welded with bracing added around headstock and shock mount. Reckon a jigs gonna be the way to go. just a thought cant the shite be desolved with some form of mild acid. maybe as simple as drilling a hole to put it in and another to let it out. maybe some one could comment if this is possible. as for the bits of frame you are suggesting to remove then some for of jig can only help keep it straight while welding. people also say you should reheat treat the whole frame by placing in oven ( a big one ) heat up to ??? then let it all cool down again naturally, but ive never done this.
lorenzo Posted October 4, 2008 Report Posted October 4, 2008 I was told by several sources to get my aluminium subframe heat-treated after it had been welded, mainly to stop it from being brittle. I sent it as part of a job lot of stuff via Simon Martin, but it wasn't especially expensive, about £40 I think. For the cost and the benefits, especially if you're going to the expense of cutting stuff out and bracing bits, it's well worth it.
2639 Posted October 4, 2008 Report Posted October 4, 2008 The requirement to heat treat or not depends on the material grade. Pretty sure the frame will not require heat treatment provided the original frame material is welded in with a suitable filler rod/wire. The material to be added needs to be compatible with this, I think if you use 'ordinary stuff' for the bracing you could create a problem. I believe self annealing 7000 series aluminium could be the stuff to use, but it can be tricky to get hold of. You'll notice the hedging of bets in the above cos materials is a complex subject, I only know a little bit. If your going to do this, please could you weigh the frame before and after. Measuring would be interesting too. I'm curious to see how true the frame is before you mess with it. Lastly do 5vy R1's have piles of crap inside them?
spacemonkey Posted October 5, 2008 Report Posted October 5, 2008 I would have thought the factories would avoid using aluminium that needs heat treating after welding like the plague! They want to keep the unit cost down and it doesn't matter if it is a bit on the heavy/flexible side as long as it looks stiff and 'cutting edge.' If you are going to add bracing then you will definitely get distortion. I think you got a good suggestion there on leaving the engine in... That may help unless you are going to brace the headstock. Why not take the advice of trying to dissolve it? Another variation would be to drill a couple of holes, heat it up and blow in compressed air or oxygen to burn it out? I works on expansion chambers!
speedzephyr Posted October 7, 2008 Report Posted October 7, 2008 just a thought cant the shite be desolved with some form of mild acid. maybe as simple as drilling a hole to put it in and another to let it out. maybe some one could comment if this is possible. as for the bits of frame you are suggesting to remove then some for of jig can only help keep it straight while welding. people also say you should reheat treat the whole frame by placing in oven ( a big one ) heat up to ??? then let it all cool down again naturally, but ive never done this. I'm not sure what exactly the sound deadening stuff is made of but any kind of acid is going to attack the aluminum before it does much to the rubber. A solvent could do, but if its a rubber compound it will take some bad ass stuff to do it and it will be more of a goo than a liquid which could be hard to remove through a small hole. But you would get real high in the process....
spacemonkey Posted October 7, 2008 Report Posted October 7, 2008 Spannies are made (normally) of steel, with a melting point in excess of 1300C, whereas most allys will form a pool at less than half of that (and will start to sag at considerable less). I would not try to do this at all (unless you want to be recycling your frame into Coca-Cola cans-meep ) Hehe... I should have added: 'I am not to be held responsible for any of the stupid things you might do after I told you to!' I suppose it all depends on how hot the stuff burns and you won't find out until it's too late. How about acetone. That dissolves nearly anything but I've never noticed it attacking aluminium although I've never left it in contact with aluminium for long.
tootall Posted October 7, 2008 Author Report Posted October 7, 2008 Not sure how much weight there is to be saved, just that the superbike and wsb 750s always either came from the factory without the rubber in them or had it cut out. Will have to see if its gonna be feasable. On another point someone out there must know of a thunderace motor for sale, let me know eh.
MonkeyJim Posted October 7, 2008 Report Posted October 7, 2008 Seems like a helluva lot of work to save a few kilos of weight. and not unsprung weight at that. plus you are risking knackering your frame. There's a couple of YZF 750 frames for sale on egay at the mo, maybe get one of those to experiment with?
TriGGer Posted October 7, 2008 Report Posted October 7, 2008 If your determined to go ahead, the safest way to remove from the frame spars is to cut circular holes on the inner spars, preferably away from any pressings/stampings etc. When re-welding or adding material, an 'exact' match isn't too much of a worry, but in the same series 7***/2*** etc is preferable, for the rods also (obviously). It may be worth trying a small area, maybe a 25mm hole somewhere where it has least impact and see how difficult the foam is to remove. When its going to be welded, it going to have to be spotless, and I mean spotless. The two biggest lies ever told ... 1. I wont come in your mouth .. 2. Yes, I've cleaned all around the area I need welding, it's spotless .... HTH
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