michaelmoore Posted September 9, 2008 Author Report Share Posted September 9, 2008 I've had to work hard to overcome my natural inclinations for bodging things. Taking short cuts often seems to result in false economies where I end up having to fix even more stuff down the road. I want to put this bike together right, and then hopefully not have to do anything other than normal maintenance to it for a long time. Bent frames/swing arms, wheels out of alignment, knackered swing arm pivot bushes don't qualify as "right" for me. They may be fine for other people's bikes but I'd prefer to not have them on mine. If I can improve on the original spec and make things "righter" then that pleases me. cheers, Michael Quote Link to comment Share on other sites More sharing options...
michaelmoore Posted September 10, 2008 Author Report Share Posted September 10, 2008 Here's a mockup of what I did to straighten the swing arm.. Pry/clamp on the free (right) end of the arm. I put the frame on the fixture and aligned the pivot shaft at right angles to the sides of the base. There is .004" variance in height from one end to the other so I'm going to take that as meaning that the frame is plenty straight enough. Triple clamps are next on the list to look at as I have some suspicions about the lower one or the stem being bent. cheers, Michael Quote Link to comment Share on other sites More sharing options...
copemech Posted September 10, 2008 Report Share Posted September 10, 2008 I respect what you are doing Michael, I will tell you that judging from my distorted eyeballs, I am not sure that all thing totally line up on my modern bike! I have two theories, 1- The Spanyards really do not care! 2- The theory that certain neglidgable offsets may actually lead to some added stability could be true. As you never really feel it when riding?????? The brain just adjusts, it seems????? Quote Link to comment Share on other sites More sharing options...
michaelmoore Posted September 10, 2008 Author Report Share Posted September 10, 2008 Bent lower triple clamp. The rear fork leg is weighted so it sits flat on the 1-2-3 block: and the front fork leg doesn't touch but at a corner: Of course, the bend is magnified when it finally gets down to the axle, much less the contact patch, which are 20-30" away. I have another set of clamps (199?) but the stem threads aren't great and my thread file isn't having much luck cleaning it up. I was able to get the stem out of that set, but the one in the 159 clamps has yet to budge. It would be convenient if I could just swap the stems over (presuming the 159 stem isn't bent along with the lower clamp). I'm starting to wonder if a DPO was using this as a MX bike. It sure seems to have seen greater than normal loads. cheers, Michael Quote Link to comment Share on other sites More sharing options...
b40rt Posted September 10, 2008 Report Share Posted September 10, 2008 I respect what you are doing Michael, I will tell you that judging from my distorted eyeballs, I am not sure that all thing totally line up on my modern bike!I have two theories, 1- The Spanyards really do not care! 2- The theory that certain neglidgable offsets may actually lead to some added stability could be true. As you never really feel it when riding?????? The brain just adjusts, it seems????? I have to agree with copemech, based on experience riding other peoples bikes which always feel like the bars are twisted etc when you get on, and yet within a few seconds you really dont notice. Just my opinion. Quote Link to comment Share on other sites More sharing options...
michaelmoore Posted September 11, 2008 Author Report Share Posted September 11, 2008 I was just down in the garage and I did my first prying at a triple clamp. Wow, I never thought a cast aluminum triple clamp would be so easy to bend! I put one side of the lower clamp in the mill vise, oriented the clamp so the two holes for the stanchions were vertical (so I could try and pull only in a horizontal plane so I would put as little extra twist into the clamps as possible) and then put a fork leg in the other hole and clamped it up. With an 18-24" lever arm it is not a question of "brace yourself and pull", but rather a "I wasn't even pulling hard yet and I hope I didn't overbend things." In any event, the front axle is now almost parallel to a line across the fork tubes. It is about .020" high on one end. That's not at all perfect, but the fork tubes are almost dead on in the same plane now (a couple thou off over 3" and I've got to measure to see if the axle is out instead of having it glaringly obvious to a visual inspection. Based on how easy these parts have been to bend my guess is that a very sizeable majority of old dirt bikes that are in use today are probably bent more than just a little bit. Before I go back to fiddling with wheel lacing/truing/alignment I'm going to disassemble the front wheel, clean the remains of the hub paint off and lube up all the spoke nipples so they'll have a chance of resisting corrosion in the future. It will be interesting to see how much difference this all makes to the offset of the rear rim. cheers, Michael Quote Link to comment Share on other sites More sharing options...
copemech Posted September 12, 2008 Report Share Posted September 12, 2008 All funning aside, looks as though you are doing a great job Michael!!!!!! Even though I admit I think you are nuts, you seem to be a nice guy! Spending this much time and effort on an old POS just does not make sense! You are your own enemy! Sincerely, MC ps- Remind me one of these days to take some pics of the POS '76 Cessna 150 that has been sitting around since 2001 in my space! Quote Link to comment Share on other sites More sharing options...
michaelmoore Posted September 12, 2008 Author Report Share Posted September 12, 2008 I've had my share of PITA POS bikes (and tools) and I'm tired of them. So I'm trying to get to where I have bikes (and tools) that don't make me swear at them. I may still swear at myself, but that's different. This bike seemed to be in not too bad of condition but there's a lot of stuff you can't find until you take things apart, and I've learned that you really need to take things apart unless you get a bike from a friend where you know the history of it, or it is very obviously a super low-mileage vehicle. I've got the tools and equipment to check this stuff, so I may as well make use of them. Once I find out that something is wrong I now have trouble turning a blind eye on the issue because I've got enough experience of that being a bad move on my part. Fix it now before it gets too bad, or fix it later and spend twice as much time and effort becuase it is really hammered. I'm trying to go with the former plan. Now that I've found how easily the parts of a trials bike bend I'm definitely going to try and keep in mind to not ride quite as spiritedly out on the loop! cheers, Michael Quote Link to comment Share on other sites More sharing options...
michaelmoore Posted September 12, 2008 Author Report Share Posted September 12, 2008 (edited) I should mention that I'm retired and I've got the time to fiddle with things. I'd prefer that I NOT need to fiddle on the Bultaco, but oh well . . . On the Bultaco I'm not doing anything more than fixing damaged parts. New rings or straightening a swing arm, there's really not a lot of difference when you get down to it. Once it is back together and hopefully pretty much "right" I can leave it alone, and I'll do the fiddling on the KT250 which needs it more than the Sherpa T does. Rider/developers like Peter Gaunt are what I'd like to emulate. Since I lack the native talent to be a top-class rider I'll have to look more to the developer side of things. The KT frame is really crying out for replacement. cheers, Michael Edited September 12, 2008 by MichaelMoore Quote Link to comment Share on other sites More sharing options...
copemech Posted September 12, 2008 Report Share Posted September 12, 2008 And that is why I am where I am, duely noted! As one cannot loose perspective, nor pull the Cessna off the side of the road for a quick repair! I get soo deep into things I cannot see daylight sometimes, point being, some will never fathom it! Again , good work man! Quote Link to comment Share on other sites More sharing options...
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