Finally started to get the bike stripped, as I now have most parts to repair. The font 'looks' twisted but really touch to know by sight, especially as it doesn't have a front mudguard. So, I have: 1) reset the bars in their pins - they don't look bent or showing signs of stress, although the cloth entirely ripped off at the housing and the brake lever is a little bent 2) undone the bottom clamp and axle bolts (4 that hold it still) and bounced up and down 3) undone top clamp and clips and did the same 4) no signs of stress on the headstock (tabs still there) and bike does go lock to lock 5) I have a fair amount of oil coming from one leg. Maybe be the force has burst the seal, or maybe its a bit bent? Not pouring but weeping a lot and enough to leave a small puddle overnight Any tips? Bike is off the table right now so thinking I'll be sticking a plank on the floor and see if that can help?! If it is, looks like I've spent money buying new stuff to replace the broken plastics etc that may have been a waste
A plank was my first thought but don't underestimate what the lack of oil in one fork leg could do to the appearance of the geometry. Fingers crossed. Andy
Its not that much, and I suspect it had loads in there given its travel left even after braking hard enough to lift the rear.
Stick one of these on the floor, watch how it moves and if your bike behaves the same, you have your answer!
had a polish mate that use to buy up crashed bikes. Seen pics of some of the forks he had straightened and I was amazed. Can't recall where he had em done but have seen a few company's offering this service, I think Brooke suspension ( where I had some work done) were one and certainly worth giving a call as they were very honest with me. not crash related but by comparison with other companies they don't appear to be in the habit of robbing or lying to ya
As the forks are leaking anyway, think I'll just grab them out and take them to Paul at PGP (probably down his way next week) and if they are straight have them serviced and set u for me. Probably do the shock too while I'm there. Its the yoke really, more of a pita or if the frame is slightly twisted at the headstock and I just can't see it with the tank on.
oooh, this thread is relevant to my interests... (I *know* it was bent, the next trick is trying to work out if I've got it straight again...) absent of any better ideas, I'm going to dismantle the forks and roll them on a flat surface, then take out the yokes and see what they look like. bah!
In the meantime I would check how much is a brand new fork stanchion, sometimes they are barely more expensive as compared to a repair. Do not forget once a metal is bent it will never be as hard as before...
IMO the forks and the yokes aren't really the problem - as Bradders says, if it is the headstock that may be twisted, it is a bugger. I have seen loads of bikes on the road that ride with one wheel upright and the other leaning over, yet probably when checked for alignment which is always done at the lower part of the wheels, they appear spot on. The only thing I can suggest to check the headstock (without going to a specialist) is to screw a dead vertical (at 90 degrees) upright on a plank across the rear end of the bike frame (ie top rails) which are known to be unaffected; then put a straight rod through the headstock so it touches the ground at the bottom and so it sticks up high enough above the headstock. Jam it against the side of the bearings or the headstock tube; then sight through the pair of uprights to see if they are parallel.
What bike?? I've bought and repaired 2 damaged Ducats a 848 and 899. They both had bent bottom yokes which sent the wheel and forks well out! New yokes set them both back straight. It's crazy that the forks were true but yokes were bent!
GSXR 750. Ir barrel rolled side over side but tbh there is (relatively speaking) little damage from that other than the destroyed plastics. Rear Sub-frame I think is a tad out too, so hoping once I offer the newseat unit up that will help fix that as I can bend it back...
that's my real worry, if the head-stock is out then at best its a strip the lot to get straightened jobbie. In which case I'll sell what I've bought, break the rest and cit my loses
just to add, on first inspection there seems no stress point anywhere around the font and side of the headstock. Not had tank off yet so cant say about under there
An easy check for yoke damage is to pull the top yoke off and then see if it goes back on easily, ie the stem nut and fork tops are aligned. Bent steerer tube shows up clear enough by not lining up with the top yoke properly.
Dissassemble both yokes check spindle for creasing (shear damage) and straightness make sure the bearings a still a good fit, and havent been brinelled, (notchy)? any damage at all replace steering spindle and bearings Any creases on stanchions , junk them; the leg has been pushed to the yield point, so if only straightened to straight the internal stress is just waiting to pull it back to bent (so slightly over straighten), you have to bend past center; to reduce the internal stress, and end up with the best repair, use a dial guage and vee blocks, (to avoid damaging tubes), (to determine how much you have to bend the leg to get it to yield) and push further past straight, so when the stress supplied to the leg is released the leg returns to straight, any dents creases left on the leg from the bottom clamp need to be replaced as they are stress raisers and have reduced the fatigue, and load carrying, properties of the leg ? fit /new legs to the bottom clamp, tweek the clamp for parallel legs, (look over one leg and under the other untill the visual gap disappears: very accurate if you do it right sighting visually, fit legs in bottom clamp tighten and tweek (bend) the bottom clamp by pushing pulling on the legs, untill the legs are parallel to each other and line up with the top clamp? and tweek the top clamp if required, and assemble, check for straight? and parallel, put knees over front wheel and twist bars the natural position, (needs the neutral position to be the parallel) need the legs to operate without stickion and legs have to be parallel.
yokes are split rings look my post below? normally very easy to straighten (very low force required), easily bent by hand; fix both on the bike 5mins? and still need inspection but rarely need replacing,(in small accidents); use the storchions clamp at top, push one pull one, internal force (resets both sides of the yoke at the same time) to the bottom yoke; do not lever against the steering stops I have done hundreds of these during my life as a motorcycle mechanic
flacking paint? around the tube welds head-stocks can be stretched oval as well best get the frame aligned by specialists with lasers and jiggs
